No spark - where does the mechanic begin?

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  #1  
Old 10-15-10, 06:52 AM
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No spark - where does the mechanic begin?

1995 Buick Riviera. Neighbor of a friends car. He got stranded. Car would not start. Suspected fuel pump. Further tests show ohms in motor plus 12 volts at pump + whir sound for 2 seconds when turned to ON. A friend said fuel pumped at filter but not at rail. But that is 3rd hand information.

I tested and got no spark at any of the 3 coil packs. Tested in plug wire with spare brand new spark plug, up against all kinds of metal places under the hood. Not one tiny spark, nowhere.

That said - you hear how common it is for crankshaft position sensors to go out. Exactly what/where do you test to find out there is no juice? Natrurally this is one of these cars where you can't hardly see where anything is. Mechanics, naturally being in the business, must have knowledge of exactly where to look and tap into the wire(s)/connectors to test. Where? Do they usually have to get the car up on a hoist, or not?

The guy is still in bed and I also want to ask him about a possible security system if he has one of those. I understand that if somehting is amiss, that that can cause a no spark situation also. What is the most common thing to go wrong when that is the issue. Where would you look first, say if had a security system? Or do cars only with key chips have a security system. Another friend seems to think he has just a regular key. I'l find out later when he gets up.

The battery and 2 big fuse boxes are under the back seat. I tested the fuses that say "ignition"(several are 50 and 60 amps) and they test good (13.5 volts)to ground, on each side of the fuse.
 
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Old 10-15-10, 01:07 PM
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Ecman51,

With all due respect.
Do your friend a favor.


If you have to log onto this forum to ask us where your friends mechanic should begin looking for the cause of the no spark issue, tell your friend, to find a qualified mechanic.
 
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Old 10-15-10, 05:50 PM
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Well. That don't help much.

Anyone else?

Surely there must be something pretty common with these crankshaft position cars where a person first goes to, with your meter. I'm sure, being how I am, that I'd have the answer IF I ever owned a car with a crankshaft position sensor or camshaft sensor. But I never have - yet.

I was in the guys trunk last evening, testing on his fuel pump terminals and wiring jack - ohms and volts. That was easy enough. So with the CPS, I'd like to know like where it is, and where the best place after it is to test the wire(s) so I can know if the CPS is dead. The guy doesn't have much money.

The reason we all post here is to get help to be able to DIY.
 
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Old 10-15-10, 06:22 PM
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I'm sure, being how I am, that I'd have the answer IF I ever owned a car with a crankshaft position sensor or camshaft sensor. But I never have - yet.
Sure you have....you just didnt know it..... CKP, and CMP, take the place of the pickup in your distributor.......

It may be cheating a bit.. but its been about 95% foolproof for me. You have a 2 second prime...does the fuel pump run when you crank the car? The 2 second pulse comes from PCM, the run signal for the pump activates after PCM sees RPM. If you have a 2 second pulse....but no pump activation when cranking....you can assume PCM doesn't see RPM. If the pump does run...PCM sees RPM and you can look elsewhere from CKP and CMP.

Ignition modules were also a known sore spot.
 
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Old 10-15-10, 06:39 PM
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well, my 84 buick century actually did have a 2ry fuel pump in the carb. and it won't start until THAT ONE will finish priming carb with fuel.
but that's times long past gone.

so, you have no distributor and you have coil packs, prolly more than 3 though, i do not see buick making a 3 cylindered engine.

here's suggestion #1. you are blessed with a pre OBD2 vehicle. but! cuz GM was the 1st one to come with on board diagnostic system, they started doing OBD2s on some 95 vehicles. you might be lucky. check and if so - any parts store will rent you a scanner.
2. if not lucky, you can - and should still read error codes of the engine computer. just google how to read codes off OBD1 GM vehicles. this should give you more or less solid base to jump off.
3. do not allow your self to get fixated on a single idea. oh, it's this. read codes 1st. you might have your suspicions confirmed, or guided towards something else. like, say, low coolant level, causing transmission overheating, causing ECM to put powertrain into a limp mode, resulting in non-start situation. could not believe my ears when i heard this, but that's what they did - added coolant and fixed leaking something, and that was it.
4. chasing a no -code situation is tedious work, and that's nicely said. here's helpful page:
Handling No Trouble Code Problems
but for this, you will need to be nicely equipped, esp with a repair manual - which you should have anyway.

now, do the spark plugs smell of gas? you prolly have gas. how old are spark plugs, btw? fuled with gas, they will never start.
ignition packs should have power at connector terminals.
my guess, unfortunately, for 95 vehicle, is ECM - engine control module.
i have no doubt it's timing chain, not belt, engine, those last forever. chains.
CPS will give you backfiring, misfiring, but doubtfully no spark.

btw, coolant temp sensors are known to cause no start on GM cars.

as a base line, engine, to start, must have gas, spark, and a good one, oxygene, and proper timing.
you can fairly easily check if timing is correct.
you can easily check for gas.
if there is no spark, you need to work it from the spark tip all the way back to ECM. did you check ECM fuse, btw?
air filter?

but, firstly, read the codes.

of course, if i misunderstood you, and it does have distributor, then cap/rotor/ignitor, or whatever is that brown thing that is deeper inside the distributo(we used to call it chocolate bar, looks like it)r, and a little condenser on the side of distributor will be culprits # 1 to look at.
 
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Old 10-15-10, 06:46 PM
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not to clutter my previous post:

1) early 95's are usually a 12 pin configuration located under the steering wheel inside the car, if so you can stick a paperclip in holes A and B which when looking straight(from drivers position) at the 12 hole pin is the top right one and the next to top right.

2) 16 pin configuration is a paperclip in the 4 and 5th hole to get the flash codes

3) 16pin requiring the same code II as a 1996 car or later would require, this would be a late model 95 and the code II along with the computor brain should be under the hood. (you are lucky! this is your OBD2 port, grab a scanner)

all 3 of these scenarios are only possible on the 95's and once you figure out which one is yours the codes are easy to read, you will receive series of flashes from your check engine light the first series is the first number the second series of flashes is the second number.....ie 6 flashes then 4 flashes, would be error code 64

Buick Trouble Codes or Buick Service Engine Soon Codes at TriShield.com The Buick Enthusiast Network
 
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Old 10-15-10, 07:34 PM
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Originally Posted by Unclediezel View Post
Sure you have....you just didnt know it..... CKP, and CMP, take the place of the pickup in your distributor.......

It may be cheating a bit.. but its been about 95% foolproof for me. You have a 2 second prime...does the fuel pump run when you crank the car? The 2 second pulse comes from PCM, the run signal for the pump activates after PCM sees RPM. If you have a 2 second pulse....but no pump activation when cranking....you can assume PCM doesn't see RPM. If the pump does run...PCM sees RPM and you can look elsewhere from CKP and CMP.

Ignition modules were also a known sore spot.
The fuel pump makes prime sound for 2 seconds. That is all I know about the fuel pump situation. Plus no spark from the 3 coil packs.

What is CKP and CMP? (crank and cam?)
 
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Old 10-15-10, 07:37 PM
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Ukrbyk,

Tomorrow. You said a lot I need to injest. Calling it quits tonight. Going out for some fast food now. Beer 4U2
 
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Old 10-15-10, 08:20 PM
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What is CKP and CMP? (crank and cam?)
Exactly....

ukrbyk....

Reading codes, while it might give you a clue, really doesnt mean anything for an early control system on a car that doesnt run....The later stuff, yes...but the early OBD cars are kinda primitive. PCM doesnt recognize a missing crank signal as a problem, because if he doesnt see a crank signal, he doesnt know the motor is turning, and simply thinks you arent cranking it...Same thing with Cam sensor. Cam sensor interrupts crank signal for timing purposes.....But it cant interrupt a signal that does not exist.....so you go back to square one.....PCM has no idea you are trying to crank the motor over.
Just to clarify...yes there are only 3 coils, because DOMESTIC vehicles use a waste spark system, 6 cylinder, 3 coils, 2 towers per coil, feeding opposing cylinders...1/4, 2/5,3/6.
 
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Old 10-16-10, 07:53 AM
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What is a "waste spark system"?

So where does the mechanic tap into the wires so he knows say the crank or cam sensor is not working? What other components are they generally between, so that if you locate the one, then the other, that you know where to tap into with yor test meter?

Is there a common answer here? Or are most cars different so that you need say a Haynes (or equivalent) manual for every vehicle? I mentioned to him to buy one, but I think he has a hard time affording one. Or are there sites online here where you can look up schematics for individual cars by make and year? THAT would REALLY be nice.
 
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Old 10-16-10, 08:20 AM
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thanks, uncle. though you prolly correct, but in his situation, a clue is better than clueless wondering through the wiring, taking chances on burning something else along. and i have done that before myself.


also, does not look like meaningless codes to me, esp one that is relevant to ignition, sensors, and the computer itself. and if computer is so dumm, why in the world does it know that it's sick itself?

CODE 41 - Cam sensor (CAM)
CODE 42 - Electronic Spark Timing Circuit (EST)
CODE 43 - Electronic Spark Timing Circuit (EST)

CODE 51 - Electronic Control Module (ECM) - PROM Error
CODE 52 - Electronic Control Module (ECM) - Calpak Error
CODE 55 - Electronic Control Module (ECM) - Error

also, if he has 16 pin or late 95 vehicle, he's almost positive to have OBD2 onboard. let's not discourage him.

this should help with sensors:
Crankshaft & Camshaft Position Sensors

but as it says in the article, 2 things are needed:
1. PRESENCE OF ERROR CODE, otherwise it's guesswork
2. trouble shooting flow chart, otherwise it's guess work for no spark situation.

ahm, just like i said...
any chances of finding a buddy with a flow chart or Aldata?

ok, how about this:

Diagnose and Repair why Car doesn't Start or Stalls - Troubleshooting Flowchart from Starter through Spark Failure and Fuel Pump

not a specific flowchart, but prolly very good step by step guide. personally, will save the page for my own reference. i am dumm electrically.
 

Last edited by ukrbyk; 10-16-10 at 08:40 AM.
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Old 10-16-10, 08:40 AM
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Originally Posted by ukrbyk View Post
well, my 84 buick century actually did have a 2ry fuel pump in the carb.
2ry? ?????

so, you have no distributor and you have coil packs, prolly more than 3 though, i do not see buick making a 3 cylindered engine.
As unc said - 2 towers on each coil pack, per cylinder.


- any parts store will rent you a scanner.
I have a feeling - actually I know - that if the guy doesn't think I can hone in on it for free, he wil take it to mechanic. But - sometimes even feeding the ear of the mechanic can cut down on labor time, if say you might be right on an assessment.

3. do not allow your self to get fixated on a single idea. oh, it's this. read codes 1st. you might have your suspicions confirmed, or guided towards something else. like, say, low coolant level, causing transmission overheating, causing ECM to put powertrain into a limp mode, resulting in non-start situation.
Good suggestion for sure. I already asked the guy if he was low on oil, for reasons you just mentioned, as that can cause a no start in some better vehicles.

now, do the spark plugs smell of gas? you prolly have gas. how old are spark plugs, btw? fuled with gas, they will never start.
I did not pull a plug. He just changed them 3 days ago. In fact, he thought by reaching behind the V-6 to get his arm in there, he made something slowly come loose that finally fell off/disconnected. So I looked with bright pen light and saw nothing that he possibly could have disconnected. The only thing are 2 wires sticking up out of the oxygen sensor back there, and they are on. I told him there is probably no association, and it is a coincidence. My middle name is "coincidence". That is why I bring that up a lot in my posts, to rule them out.

ignition packs should have power at connector terminals.
Well. I'm sure with no spark at any coil pack, that they do not have power at those terminals. If only one coil pack went out, I'd test to be sure. Now we have to find out where the wires go that feed those terminals. Directly to the crank or position sensor? The computer or ICM first? ???

my guess, unfortunately, for 95 vehicle, is ECM - engine control module.



i have no doubt it's timing chain, not belt, engine, those last forever. chains.
Huh. They never seemed to on my older 60's-70's cars. They titanium now?

btw, coolant temp sensors are known to cause no start on GM cars.
Seriously? Why would they have that happen? Unless perhaps they fail in a too hot mode?, or the computer interprets some open circuit condition or closed condition as a too hot mode, and does not let it start, to protect the engine? If this is for real, then one surely needs to be able to test the coolant sensor. I wonder what the ohms? test is for that? Or how you can tell if current either flows through it or doesn't flow through it(coolant sensor), as it should.

as a base line, engine, to start, must have gas, spark, and a good one, oxygene, and proper timing.
But since no spark, some of this, in his case, is a moot point.

you can fairly easily check if timing is correct.
If the timing was off enough, that could assuredly cause a no spark with those crank/cam sensors? How do you test, on his car? Obviously no rotor to see where it points. (I HATE these new rocket science cars!!!!)

you can easily check for gas.
But does this car have a system where if there is no gas, there is also no spark? We gave up on the gas situation after we heard the whir(fuel pump) and got no spark.

if there is no spark, you need to work it from the spark tip all the way back to ECM. did you check ECM fuse, btw?
What would that fuse be called on the fuse box cover ID, I wonder, in the fuse boxes under his back seat. 2 big rectangular fuse holders, with many assorted fuses, that have even many high amp IGN fuses, and they all checked good. Wouldn't the ECM be a high amp fuse, like 50A or 60A or?A?

air filter?
Huh? Air filter? Why air filter?

(See why I didn't respond last night? Do you know how long this took me? )
 
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Old 10-16-10, 08:47 AM
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Originally Posted by ukrbyk View Post
CODE 41 - Cam sensor (CAM)
CODE 42 - Electronic Spark Timing Circuit (EST)
CODE 43 - Electronic Spark Timing Circuit (EST)

CODE 51 - Electronic Control Module (ECM) - PROM Error
CODE 52 - Electronic Control Module (ECM) - Calpak Error
CODE 55 - Electronic Control Module (ECM) - Error

also, if he has 16 pin or late 95 vehicle, he's almost positive to have OBD2 onboard. let's not discourage him.
Great! Now where is the OBD2, and what might it look like?
 
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Old 10-16-10, 03:31 PM
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Like I said. Your friend must find a competent professional who can confirm the following.

Not a cam sensor issue. Possibility crank sensor. Basics must be ruled out before blame is put on crank sensor.

Post any error codes. (For DLC location, and more info click on link below)

Confirm all ignition/spark related circuits and wire connections.

Make sure all connections are on tight and free of all dirt, corrosion, and there aren't any pushed back pins at the connectors.

Rule out corrosion under the coil pack and between the computer plates.

Remove the ignition module and have it professionally checked at a qualified auto parts store. Donít have it checked at Auto Zone, Advance Auto Parts, or OíReilly Auto Parts.


Ignition Coil Test

Remove the ignition coil(s).

Using an ohmmeter, check the resistance between the primary terminals on the underside of the coil. The resistance should be 0.50-0.90 ohms.

Check the resistance between the secondary terminals. It should be 5,000-8,000 ohms.

If the coil failed either test, replace the coil.



Address tsb 04-06-04-047H


Click below

http://www.actron.com/media/usermanu...ge_MNL_Eng.pdf
 
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Old 10-16-10, 03:54 PM
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well, believe it or not, my 84 century had 2 pumps. one in the tank, and a small solenoid operated one in the carb base. every time i'll turn the ignition key to on position, i will hear a tsa-tsa noise coming from that thing. some guy told me it's a 2ry fuel pump, building pressure in whatever it was building pressure in in the carb. all i knew - after several attempts to start engine right away - that if i do not wait for about 10 seconds, until that tsa-tsa-tsa noise stops, car won't start. let it do its job - boom, no problem.

if you do not have any meaningful air volume coming in, there is no oxygen to burn fuel with. it's one the BIG FOUR. gas, spark, oxygen, timing. one is missing, no start. of course, not applicable in your case.

hey, found 2 things for you. 95 buick riviera, no start, no spark, cause - corroded contacts in the ignition lock.
95 skylark - yes, i know - had corroded base plates on ignition modules, resulting in no spark situation.
if i were you, i'd have them ignition modules removed and checked out at a parts store.
and my apologies. parts stores do not charge for scanners, just ask for your driver license as bond.
link i sent you clearly says - on-board diagnostic system connector is under the driver side dashboard. it's a rectangle, sometimes covered with a plastic cover, about 2 x 1 inch. count pins!!

bad coolant sensor, once again, is known to cause no start problems on GM cars.

though i appreciate thorough dissection of my post, maybe it was a better idea to, actually, print out that flow chart and dedicate that time to following it?
 
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Old 10-16-10, 04:13 PM
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ukrbyk,

But that flow chart ends at the mechanics 101 stage. I am beyond that. It is where that flow chart ends, that I need another flow chart. Seriously.
 
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Old 10-17-10, 06:40 AM
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Are we kidding????

I'm almost waiting for someone to suggest a bottle of seafoam into the intake thru a drinking straw....

Now.....

Back to basics.....Every Caveman knows that yoou need wind (AIR), Fuel (Something that will burn), And something to ignite your fuel , whether it be two sticks, two rocks, or an electromagnetic "Breakdown", a SPARK.

There are quite a few approaches to this, but one thing must be kept constant.....LOGIC....

A guy walks into my shop and says "My car doesnt start, Whats Wrong".....
My answer is always the same....."You just told me what is wrong" "It doesnt start".. You are here because you want me to tell you.................

.....................................WHY?.................................................................

Whether it be a car, a washing machine, or your kids Suzy bedwetter doll, You cant fix anything unless you know what it is supposed to do.....2 times out of 100 you will get a lucky guess, but those other 98 will end up costing you thousands of dollars in parts that you know own......

I hope he doesnt take offense, But ASE is a professional....With years of experience, But his advice is based on knowledge and experience of having a vehicle in front of you, with no-where to turn, and no one else to ask.Its a purely logical approach, where the most valuable tool in your box is your brain, followed a close second by the INFORMATION available to you. There is no MYSTIQUE, or VOODOO or MAGIC involved in this...It was designed by a thinking mind, to do a task , in the environment it is subjected to. A Doctor cant tell you that your arm is broken without an X-ray...He can guess, when your forearm is folded at a 90 degree angle before your elbow, But until that X ray comes back...he doesnt K N O W...
Until you have performed the equivalent tests to that xray...YOU DONT KNOW..
Professionals in any business , act professional, and do things professionally, simply because somewhere along the line, the "Unprofessional " behavior BIT US IN THE ARSE, hard enough to make us think twice about Guessing.

 
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Old 10-17-10, 10:54 AM
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Unc,

I don't hardly know what to say, regarding your last post. A little dumbfounded, actually.

If someone asks me here what is cause of their furnace symptom of no fire, I tell them what to look for, precisely and consisely, and give them all the possible scenarios, and how to specifically test. Same with fridges, dishwashers, plumbing issues, household electric outages ...a host of things.

You mean to tell me, that if I tell a mechanic no power is getting to a group of power packs, and ask where the power comes from, and how to test that, that no mechanic that has been in the business 20 or 60 years can't tell me to look such and such place, and hook up a test meter HERE? ??? Seriously?

Contrary to in your post, I did not ask generally what is wrong. I said exactly where there is a problem - no spark coming from any of the coil packs.

I guess, I had better start getting into the mechanic business, as some people in real life have actually told me I should have become, if nobody else can tell me where on the car to look when no spark coming form coil packs. I can't hardly believe this.

I, a shade tree mechanic my whole life since high school, was actually able to run down a power outage in a fuse, at the block, caused by, of all things, a faulty steering column multi-switch, and change it out, no instructions, in less than an hour. Or change out my ignition switch in the steering column, with no instructions, in less than an hour. Or trace down a blown fusible link for someone and fix it so they could be on their way, and other more advanced complex stuff.

And no mechanic can tell me where the power comes from that feed the power packs, and where then best place is I can tap in, and how to test? No wonder why car repairs at shops cost so much. I hope they arent' in the dark and have to ponder where to begin looking if I tell them the coil packs are out.
 
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Old 10-17-10, 11:00 AM
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Originally Posted by Unclediezel View Post
Whether it be a car, a washing machine, or your kids Suzy bedwetter doll, You cant fix anything unless you know what it is supposed to do.....
It is supposed to spark. So I know what it is supposd to do. It isn't sparking. I know it is not sparking.

.....advice is based on knowledge and experience of having a vehicle in front of you, with no-where to turn, and no one else to ask.
No one to ask? The customer asks why no spark from coil packs? Not that the car simply generically "doesn't work".
 
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Old 10-17-10, 01:24 PM
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(Question) No one to ask? No one to ask?

What do you call me and diezel? We told you what to do and what to check. We canít advance you to the next level till we get the results to our tests, and the answers to our questions. So far no results and no answers.

(Question) The customer asks why no spark from coil packs?


You canít ask your way out of a no spark issue. You have to:

Test.
Confirm.
Rule out, and post results.


[I]Tell your customer that he may have to spend some money on tests and possibly a new ignition module, crank sensor [/I](or both).

Hereís a good piece of advice.

Donít play the same game with your friendís car that youíre playing with your Dodge. Your friend wonít continue to be your friend, if 7 months from now his no spark issue still exists.

Basics, Basics, Basics, Basics.

I can't stress them enough.

Rule out the basics and post the results.
 
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Old 10-17-10, 01:38 PM
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ASE,

With my Dodge, the trouble is...... rather than that car's problem getting worse and worse, while I do nothing about it really......it is getting better and better.

I have not had major bucking in weeks, and only a stutter here and there, say like if the car is in cruise control and coasts down the hill and tries to repick up speed again at the bottom. There might be a delay. But THAT does not even do it every time. It is pretty hard to try to test and catch something like this in the act, with any kind of meter. Nor is the urgency there now, compared to someone's car that does not even start, and he has no money, and is stranded in his apt.

Back to friend of a friend's car issue: Test, confirm, rule out basics, you say. Answer: test = no spark. Confirm = no spark. Rule out basics? Well, I ruled out spark. What next do I rule out, and how do I do the test that rules it out?
 

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Old 10-17-10, 05:49 PM
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(Question) What next do I rule out, and how do I do the test that rules it out?

You start by using common sense and logic

1. Since spark is voltage (that comes from the battery) you must confirm a battery that can take and deliver a change.

2. Since voltage moves through wires and circuits you confirm that there arenít any blown fuses, circuit breakers, or fusible links.

3. You confirm all ignition/spark related circuits and wire connections with a close visual check.

4. You make sure all ignition/spark related connections are on tight and free of all dirt, corrosion, and there aren't any pushed back pins inside the connectors.

5. You scan the cars computer for stored error codes. If codes are present you post them.

6. You remove the ignition module and have it professionally checked at a qualified auto parts store.

You donít have the module checked at Auto Zone, Advance Auto Parts, or OíReilly Auto Parts.

7. You do the coil test below and post the results.

Remove the ignition coil(s).

Using an ohmmeter, check the resistance between the primary terminals on the underside of the coil. The resistance should be 0.50-0.90 ohms.

Check the resistance between the secondary terminals. It should be 5,000-8,000 ohms.

If the coil failed either test, replace the coil.


[I]8. You apply tsb [/I]# 04-06-04-047H.
 
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Old 10-17-10, 06:12 PM
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Numbers 1 and 7 would not apply (because 1. it cranks good, and 7. it has 3 coils, none of which work). But the suggestion 2-6 are those which are generally helpful. But probably do need it scanned, AND a manual.
 

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Old 10-17-10, 06:44 PM
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You would remove the coils from the module to test them. depending on configuration, there are 3 individual packs with blade terminals on the base, or a 1 piece pack, which will have wires at the base which plug into module blades.ANY coil with low resistance, can disable the other two, as well as burn a new Module...So , yes #7 does apply. #1 also applies because a loose ground strap to the engine can wreak havoc with engine control, while not affecting the starting system. Also, the battery has a "Piggy backed" positive cable, which can "OPenCKT" between the two cables, once again, leaving starter unaffected, but engine control not supplied.

Before you spend the cash to rent a scanner.. Humor me...try what I told you by testing at the fuel pump connector while cranking. Since the fuel pump "RUN" is initiated by Engine rpm signal, you can rule out CKP and Primary ignition Ckts. It will take all of 30 seconds, and its free.
 
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Old 10-18-10, 04:07 AM
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I didn't go back to read all your answers, so I'm just going to ask you now. Is there no spark at all the plugs or just one plug? No spark at only one plug, most likely means there is a crankshaft position sensor issue. No spark at only one or two plugs that share the same coil, means mostly likely that the coil has failed. Are the injectors firing? No spark and no injector activity most likely means a crankshaft position sensor issue.

Try this test and post the results.


This test will show if a DIS module and its crankshaft sensor circuit are working. Connect a halogen headlight to the spade terminals that connect the DIS module to the coils. Itís better to use a headlight because it puts more of a load on the module than a test light. If the headlight flashes when the engine is cranked, then the DIS module and crankshaft position sensor circuit are operational. Therefore, the problem is in the coils.
 
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Old 10-18-10, 05:06 AM
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ecman51,

Remember this,

DIS GM coils have one side of the primary coil attached to battery (Ignition voltage). The ground side of the primary coil is grounded by the ignition module. If the engine isn't running, the ignition module won't receive a signal from the triggering device (crank sensor) and it won't ground the primary coil. Spark is not created when the primary coil is grounded. Spark is created when the primary coil is opened, and the electromagnetic field quickly collapses, and the secondary voltage is induced in the secondary windings. This is what creates the voltage for spark.
 
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Old 10-18-10, 04:01 PM
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Problem solved!

The car owner DID disturb some harness back there when he changed the plugs!

Another maintenance man gets the glory. He found it. I wonder how I did not see it! I had a bright flashlight and looked, plus never felt anything back there either. Ya win some and you lose some, I guess.

The car is now up and running.

Well, now we know there is some wire connection back behind that V-6 that supplies power to those 3 coil packs. (This is 3rd hand information)The owner is happy, and even thanked me for steering everyone in the right direction about the coil packs/no spark, rather than the fuel pump.

Thanks to everyone who stuck with me on this thread.
 
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Old 10-18-10, 04:23 PM
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Originally Posted by Unclediezel View Post
Before you spend the cash to rent a scanner.. Humor me...try what I told you by testing at the fuel pump connector while cranking. Since the fuel pump "RUN" is initiated by Engine rpm signal, you can rule out CKP and Primary ignition Ckts. It will take all of 30 seconds, and its free.
Just so we all know this, who read this thread, I presume for most if not all cars, this is a good test? If so, then the fact a person knows the fuel pump works for the first 2 seconds, when turned to ON, is not a good enough tes?, and one should really continue the test for say 30 seconds? Even if the car is not actually "running", but is just cranking, will determine what you say?

If you could block out engine cranking noise, does that also mean that the fuel pump would be whirring the whole time? I thought the engine actually had to be running for the fuel pump to work after those first 2 seconds?

(Anyone else have words enter on their screen slowly, or in groups of words, after you type? I am wasting 6 times of my life posting here! I could have helped 6 times the people yesterday, in the same time period, from the loading up problem I am experiencing! It is even happening on two unrelated computers at separate addresses.)
 
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Old 10-18-10, 04:27 PM
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Originally Posted by ASE MASTER View Post
ecman51,

Remember this,...........Spark is not created when the primary coil is grounded. Spark is created when the primary coil is opened, and the electromagnetic field quickly collapses, and the secondary voltage is induced in the secondary windings. This is what creates the voltage for spark. [/I]
I actually know that. From the days of cars with points. They did that too.
 
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Old 10-18-10, 05:14 PM
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While it is nowhere near The RPM of a running engine, cranking an engine will produce an RPM signal. and the pump should continue to run for a second or two after cranking.

On the Mopars I see at work, I go to the ASD relay output, Which is basically the same as fuel pump feed on a GM. anything the PCM

Listening to a pump while the starter is singing away is rough, so we just stick a Test lamp in there. we really arent concerned with actually pressure from the pump at this point, since it isnt a fuel related issue.

It simply verifies that CKP works,and PCM can read it. On your particular vehicle here, After the engine starts, fuel pump is dependant on Oil pressure to complete the ckt.
 
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Old 10-18-10, 05:24 PM
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What about sticking a plastic funnel into the tank's fill tube and listen like a megaphone? Cars like mine sit low to the ground and have no trunk access to the pump/wires like that Buick Riviera has.
 
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Old 10-19-10, 03:54 AM
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Ecman,

Glad to hear the car is up and running, and that the problem was something basic. Remember to rule out the basics first for the future. Note, that youíre not out of the woods yet. Diezel and I will be sending you separate bills. Watch for them in the mail. If you donít pay up both of us are coming to Wisconsin to slap you around a little. After the slapping we wonít stop you from buying us dinner.

Sam
 
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Old 10-19-10, 05:05 PM
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Cars like mine sit low to the ground and have no trunk access to the pump/wires like that Buick Riviera has.
Yes , you could use a funnell, BUT.....

Hey Sam...would you hear a fuel pump buzzing, over the Little drummer boy in your headers while you cranked that really pretty HEMI car you posted a few weeks back?????????

Problem is, if you could get the funnel in deep enough to pass the check valve in the filler neck, you would still spend the afternoon getting the neighborhood kids to shut up long enough to listen to it.

Your DODGE......Get creative..... Yours is even easier, ASD output......

Coil, Injector hot lead, And a bit new but possibly the heater wire for the O2 sensor.....
 
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