Knocks on an incline

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  #1  
Old 03-25-06, 04:39 PM
vhfireman
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Knocks on an incline

I recently purchased a 1994 Pontiac Grand Am with a 2.3L L4 Quad with 172,195 mi. When the car is on a flat surface it purrs like a kitten, but when on even a slight incline it develops a very noticable knock. The knock seems to be at a very slow rate 15-20 per minute at idle. I am just beggining to try and figure this out, and suggestions on what to check would be appreciated. Oil is at normal level.

Thank you,
Mike
 
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  #2  
Old 03-25-06, 05:29 PM
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it does sound like a mechanical problem with internal engine parts, maybe oil pump malfunctioning among other things does the car smoke ? check for noise coming from pulleys,check engine mounts too.
How's tranny fluid ?
 

Last edited by mattison; 03-26-06 at 04:18 AM.
  #3  
Old 03-25-06, 08:03 PM
vhfireman
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The car does not smoke. I did notice an oil leak, not sure if its oil or tranny fluid. The tranny fluid is full, and actually is still red, must have been changed at some point. I actually bought the car at an auction earlier today and was going to go through all that tomorrow. I did notice that the knock goes away when the car is in gear. I also noticed is "slams" into gear, not rediculusly hard, but enough for concern. I think there will be a few projects on this car over the next couple weeks, hopefully all minor, is the preference that I start a new thread for every project, or keep the same car on the same thread?
 

Last edited by vhfireman; 03-25-06 at 08:35 PM.
  #4  
Old 03-25-06, 08:06 PM
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Originally Posted by vhfireman
I haven't checked the tranny fluid yet. I actually bought the car at an auction earlier today and was going to go through all that tomorrow. I did notice that the knock goes away when the car is in gear. I also noticed is "slams" into gear, not rediculusly hard, but enough for concern. I think there will be a few projects on this car over the next couple weeks, hopefully all minor, is the preference that I start a new thread for every project, or keep the same car on the same thread?

keep everything on this thread, you'll see a lot of good advice here , post any codes you may have,as much info and feedback as possible too.
 
  #5  
Old 03-25-06, 09:13 PM
vhfireman
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Well, I started to edit my last reply, while in progress I decided to check the tranny fluid as I noted. While doing so lou replied again. Anyway, when outside the car this noise is loud, it sounds like someone hitting the block with a 3lb maul, and it shakes the whole car, but as soon as it is in gear, no knock. Im frustrated and have owned the car for 12 hours.....
 
  #6  
Old 03-26-06, 07:52 PM
vhfireman
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During the day today I noticed that the thunking also occurs in neutral, and on flat pavement. When I rev the motor in both neutral and park it goes away. Even without revving the problem is slightly intermittent, it is there most of the time, but occasionally it sounds fine. And It still seems fine in Drive and Reverse.

Well I have been poking around the engine area and checked the motor mounts. The mounting bracket that attatches to the engine from the strut mount had loose bolts on the front side of the engine. I tightened them and checked the engine, still thunks in park, not as loudly, and quite loud in neutral. According to my hayes manual there is the strut mount and the engine mount, both on the passenger side of the vehicle, and both appear fine. I find it hard to believe there are no mounts on the other side of the engine, does anyone know any different? Im starting to think it is a bearing inside the transmission. When I first start the vehicle or shift to N or P the noise starts quietly, and slowly picks up intensity and speed, but if I increase engine RPMs even slightly it goes away. I looked around on the net and found used transmissions as low as $80 bucks, and as high as $600, with a bunch in the middle. The trans in this car has no OD. Since I would have to pull the trans in order to replace any bearing that may have gone, I am inclined to get a lower mileage replacement and swap them out entirely. I found one with 10,000mi for $110. I would like to explore other options and pick a few more brains before I jump to that conclusion. If anyoMne has any Ideas for me to check before I take it to a tranny shop for their opinion I would greatly appreciate it.

Mike
 
  #7  
Old 03-26-06, 09:38 PM
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Do not think it is a bad tranny but is in engine.Sounds like spark knock. Dose car have a distribitor.If so Try to turn distribitor to advace or retard timing to see if knock goes away any but remamber distribitor spot you start from so you can put it back if it dosent work. Good luck. (This is just my opinion.)
 
  #8  
Old 03-27-06, 07:20 AM
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I can't say I have a warm fuzzy feeling that I know what is wrong with this car, but, I will throw something at you to think about. You might want to check the torque converter to flywheel bolts to be sure they are tight.
 
  #9  
Old 03-27-06, 01:58 PM
vhfireman
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The car has electronic ignition, no distributor. If it was the timing would the knock go away when in gear and at higher RPMs?

I assume I would have to pull the tranny out to get at the torque converter to flywheel bolts? If so I am going to have that as my last resort. My next step is going to autozone to get codes read, Ill post them within the hour hopefully.
 
  #10  
Old 03-27-06, 02:13 PM
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Originally Posted by vhfireman
The car has electronic ignition, no distributor. If it was the timing would the knock go away when in gear and at higher RPMs?

I assume I would have to pull the tranny out to get at the torque converter to flywheel bolts? If so I am going to have that as my last resort. My next step is going to autozone to get codes read, Ill post them within the hour hopefully.
There is usually a metal or plastic cover that is easily removeable that would allow access to those fasteners. Once the cover is off you can turn the flywheel to get to the boltsor nuts, usually 3 of them. This shouldn't be a difficult task.
 
  #11  
Old 03-27-06, 02:27 PM
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Originally Posted by SLJ2137694
I can't say I have a warm fuzzy feeling that I know what is wrong with this car, but, I will throw something at you to think about. You might want to check the torque converter to flywheel bolts to be sure they are tight.
+1

Check the torque convertor bolts.
 
  #12  
Old 03-27-06, 03:16 PM
vhfireman
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Well, freshly back from autozone with no codes in hand but some useful info. My ODB1 port is missing some wires.... great. The guy said he was pretty sure the code is from the idle control valve. It does Idle quite high and this would explain the slamming into gear. On my way to autozone I did notice that when I coast I get a "surge" effect slowing me down. He also listened to the "thunking noise" and also said he thought it might be a loose bolt or clip in the transmission. So my plan is to check the Idle Control Valve and try and find the bolts on the flywheel and check their tightness.

Hopefully I can get one of the tasks done tonight, I have fire drill in an hour and a half.

Thanks for the help guys, I didn't even know where to start.
 
  #13  
Old 03-27-06, 04:28 PM
vhfireman
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Ok, I removed the IAC, cleaned all the soot off it with a rag and reinstalled it. It seems better, but I think Im going to replace it if it isnt too expensive, there is a lot of soot on the spring and up in the piston part of it I couldn't get. Now tomorrow I can look for the loose bolt on the flywheel. If it isnt one on the flywheel is the torque converter bolts easy to get at as well?
 
  #14  
Old 03-27-06, 08:27 PM
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Originally Posted by vhfireman
Ok, I removed the IAC, cleaned all the soot off it with a rag and reinstalled it. It seems better, but I think Im going to replace it if it isnt too expensive, there is a lot of soot on the spring and up in the piston part of it I couldn't get. Now tomorrow I can look for the loose bolt on the flywheel. If it isnt one on the flywheel is the torque converter bolts easy to get at as well?
I am not going to deny that I haven't seen first hand what damage a loose fly wheel bolt can do. But they are easily accessed through a panel between the motor and tranny on every car if you needed that info. Typically 2 or 4 bolts and the small shield comes down.

Sounds like IAC is not the problem because this problem happens when you are using the gas pedal. I doubt its a flywheel bolt unless they were touched recently. This is a hard issue with out hearing it first hand and driving the vehicle.
 
  #15  
Old 03-28-06, 06:57 AM
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Originally Posted by vhfireman
Ok, I removed the IAC, cleaned all the soot off it with a rag and reinstalled it. It seems better, but I think Im going to replace it if it isnt too expensive, there is a lot of soot on the spring and up in the piston part of it I couldn't get. Now tomorrow I can look for the loose bolt on the flywheel. If it isnt one on the flywheel is the torque converter bolts easy to get at as well?
The bolts I was speaking of are the torque converter to flywheel bolts which are generally easily accessable. The flywheel to crankshaft bolts could be loose and while you might be able to see this loosness with the cover removed, you most likely would have to remove the transmission or engine to tighten the bolts. While you are checking bolts, see if you can see any cracks in the flywheel also.
 
  #16  
Old 03-28-06, 07:03 AM
vhfireman
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The Idle problem only occurs while my foot is not on the accelerator. Only while at a standstill, or coasting to a stop. The bolts Im looking for are torque converter to flywheel.

I think I understand the Idea, Im going out right now to start digging.
 
  #17  
Old 03-28-06, 07:43 AM
vhfireman
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Made it to the flywheel to torque converter bolts and they were torqued to spec. I think I am going to bring it to a tranny shop and see if they will listen to the problem and tell me what they think it is and give me an estimate. Im reasonably sure the problem is in the transmission since the problem changes when I shift.
 
  #18  
Old 03-28-06, 04:10 PM
vhfireman
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So much for what I think. The tranny shop said it is definately not in the transmission, unless its the flywheel to torque converter bolts, and I checked'em.

I've been driving the car quite a bit today and the problem is starting to dissapear, which makes me nervous. I sat in park for about 10 minutes, and the only time it happened was when I revved the engine and let off the gas, I heard one thunk and that was it. I tried it a second time and it did the same thing. I am still getting the surge when I am coasting to a stop. I think now I am going to open up the timing chain and take a peek in there. Any tips or hints would be great.

I also went to the junk yard there to get some trim and body pieces, While I was there I got a MAPS sensor and an Idle Air Control Valve and threw those on. The idle is much more in check.

I also looked at the OBD hookups on the cars at the JY and they were all the same as mine, but flipped upside down.... must have ran into a real bright one at Autozone. I will bring it there another day to try and get codes.

Back to the garage.
 
  #19  
Old 03-28-06, 07:38 PM
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Is this car OHC if so check timming chain, A pal of mine had one and timming chain was slack and knocking against timming guides.Had to replace chain and guides. (This is just my opinion.)
 
  #20  
Old 03-29-06, 04:18 PM
vhfireman
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I haven't made it to the timing chain yet, but I really want to read these codes. I went back to a different autozone to have the codes read and he couldn't do it either. He even tried using a jumper and couldn't get that to work either. Is there any other way to read the codes or do I need to try and fix the OBD port?
 
  #21  
Old 03-29-06, 04:47 PM
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GM OBD-1 code read is by jumpering the two pins that sit side by side at one end of the plug. You're missing one or both of these terminals?
 
  #22  
Old 04-01-06, 11:00 AM
vhfireman
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Both the pins are there, and he tried jumping those two and the light just stayed on, no flashing. First I will try jumping the pins myself, then Im going to try and track the wires a little and make sure they are intact.

I also took the car to the mechanic down the road to have him take a look at it. He said I have a bad motor mount. He had me stand on the brake, put the car in drive, rev it a little, then at idle shift to reverse. The motor torqued about 30 degrees. He did it for me to have a look too. My question is, Are there more motor mounts than just the two on the passenger side, motor mount on top of the wheel well and strut mount under the wheel well? I can't seem to find one on the driver side.
 
  #23  
Old 04-01-06, 12:53 PM
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Be sure key is off until you connect the jumper, then turn key to "on" (not "start").
 
  #24  
Old 04-01-06, 01:21 PM
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Motor mounts......Converter to flywheel bolts........Check EGR function........EGR failure will make a car ping/knock under load
Vehicle has a KNOCK SENSOR. You'll need a scan tool to tell if it's working...........94?????.........Is this vehicle OBD1 or OBD2??? You're in the changeover year.......
 
  #25  
Old 04-01-06, 01:39 PM
vhfireman
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motor mounts are now new. Engine still knocks with NO load. I went to a nice flat parking lot, came to a complete stop, put the car in neutral, and again it started knocking. This time because my foot was of the brake and I was on a flat surface I noticed the knock moved me forward. Not enough to actually make me roll, but enough that the whole car rocked forward, and i rocked slightly with every thud.

Now that I noticed this there is no way it isn't in the tranny. Since I already checked the flywheel to torque converter bolts I guess I need to drop the tranny out and probably do a rebuild. How big of a pain in the arse am I looking at here? Can I remove the transmission without pulling the motor? I may be best served just to get a used tranny, saw one with 10000 mi for 110 at a local JY. I'm really not looking forward to this.

 
  #26  
Old 04-01-06, 06:02 PM
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Not gonna be fun. You're gonna need a crane/like device to support the engine while you remove the trans and probably half the lower frame under it
 
  #27  
Old 04-11-06, 08:57 AM
vhfireman
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There are two types of AT's in this type of car. One is the three speed, which I thought I had, and the other is 4 speed overdrive. I am following the removal procedures in my repair manual and some things follow the procedure for the 3 speed and some for the 4. How do I tell which one I have for sure.

Also, does ATF have to be disposed of differently than other drain oil?
 
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Old 04-11-06, 09:31 AM
vhfireman
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well it says right on the oil pan 4T60E..... guess I answered my own question.
 
  #29  
Old 04-11-06, 11:30 AM
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The tranny fluid can be disposed of with other lubricants. And that would be a 4 speed, transverse mounted [4T] transmission.
 
  #30  
Old 04-13-06, 05:39 AM
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Make a final ellimination on it being the motor. While its knocking remove the plug wires one at a time with proper tool to see if the knock stops. If you have a bad rod bearing or wrist pin the knocking will stop when the fire is removed from that cylinder. Does not sound like the problem but its easy to check.
 
  #31  
Old 04-13-06, 10:14 AM
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Wouldn't hurt to have a professional ear take a listen, too. Some, although not all, engine noises are very distinctive and easily identified. Good idea from chevydrivin. Major embarassment to swap the tranny and then find out it WAS a motor problem.
 
  #32  
Old 04-15-06, 06:53 AM
vhfireman
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I have had three sets of professional ears listen to it. The first was at a tranny shop and he said it was definately not in the transmission because nothing is spinning in the tranny in park or neutral.

Well nothing is supposed to be spinning in the tranny in park or neutral. Both of the other people said the clutches in the transmission were catching for some reason. They both also said there was a bad motor mount. Since I replaced both motor mounts one guy threw it up on his lift. We poked around and found the transmission mount was shot. My crappy repair manual doesnt say a darn thing about a transmission mount. So now I replaced that, and the problem is still there.

The reason he says its a clutch catching is because in both park and in neutral if you put your hand on a drive tire you can feel it jerk forward every time you hear a thunk. It also slams into gear when shifting from park or neutral to drive or reverse. If it were an engine problem would the problem change as I shift from one drive mode to the other? When in drive the problem is gone, the tranny shifts from gear to gear quite smoothly actually.

If you still think it could be an engine problem I will try the spark plug thing, but im pretty convinced it is in the transmission.

Any of you shop owners, what would you charge for an R & I for the tranny in a '94 grand am, 2.3 quad 4 ohc, 4T60 - E transmission? Just so I have a ballpark figure to go on.
 
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