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94 mustang starting problem


jwater7's Avatar
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10-01-04, 01:07 AM   #1  
jwater7
94 mustang starting problem

I've got a 1994 Ford Mustang GT Manual 5.0L with cobra groud effects and aftermarket exhaust and intake.

The problem is that, on intermittant warm starts, the engine won't start.
It turns over, it's just as if it's not getting fuel or the battery doesn't quite have enough juice to get it started.
It doesn't happen every time, but when it does, I have to wait a bit and after a while it will start.

I had the battery checked at sears and it turned out okay. I cleaned the terminals and checked for loose terminal connections. The lights don't dim when I turn them on, so I don't think it's a battery problem.

The fuel pump is working (as far as I can tell from the noise).

After it starts, it drives fine, unless I stop and idle at a low idle,then it has been known to quit again.

I would greatly appreciate any suggestions or ideas. Does this sound like a common symtom of a known problem with the 94 mustang gt?

Thanks,
jwater7

 
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10-01-04, 08:58 AM   #2  
Best guess is the alternator, or the starter itself.

 
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10-01-04, 09:25 AM   #3  
jwater7
if it were the alternator, the battery wouln't be charging back up right?

It could possibly be the starter, but it seems like it's doing it's thing properly.

One thing I forgot to mension was that I wanted to try to replace the fuel filter. Maybe this will help.

Could it be a sensor issue?

Once thing that also wouldn't make sense to me is that at low idle (around 1000rpm) it would shut off.

Thanks for the comments though.


Last edited by jwater7; 10-01-04 at 09:41 AM.
 
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10-01-04, 02:00 PM   #4  
Posted By: jwater7 It turns over, it's just as if it's not getting fuel or the battery doesn't quite have enough juice to get it started.
jwater7
You need to further clarify the problem. Is the engine turning over normally when it doesn't start? If so, there is no need to check the battery. Or are there times when the engine is turning over slowly?

1000 RPM idle speed seems to be on the high side, not low.

 
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10-01-04, 02:20 PM   #5  
jwater7
Yes, it sounds to me like the engine is turning over normally with little or no speed change (at least I can't detect by hearing it).
I had the battery checked because the terminals were corroded and I wasn't sure of the "ummf" of the battery.

I'm going to replace fuel and oil filter today, and I'll update.

One thing I did notice, but not extreemly bad, was the negative terminal on the battery was warm.

Thanks again,
jwater7

 
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10-01-04, 03:21 PM   #6  
Your going to have to test some things at the time it won't start. Check for spark at the plug, fuel pressure and injector pulse with a noid light. That's the only way to narrow it down. You could have a crank sensor or ign. module overheating. Find out what your losing first.

 
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10-06-04, 12:01 AM   #7  
jwater7
I finally got this narrowed down a bit I think...

(I did replace the fuel and oil filter as mentioned above)

I bought a code reader and got a "continous code":
542- Fuel Pump circuit open connection - Electronic Control Assembly (ECA) to motor ground.
Another site describes this message as:
Fuel pump circuit open, EEC processor to motor ground.
and other says:
Fuel Pump circuit open; PCM to motor

I'm not quite sure where the ECA is and where I can check the connection.

Can someone give me a little more detail than in the manual?

Thanks,
jwater7

 
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10-06-04, 03:28 AM   #8  
The ECA is the computer. The code is telling you that the computer did not see a clear path to groung throuigh the fuel pump windings. This can be a problem anywhere between the computer and the pump or pump ground. including the relay, the pump and all related wiring.

 
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10-07-04, 12:25 AM   #9  
jwater7
I guess I jumped the gun a bit. All that probably means then, is that I disconnected the "inertia" switch to release fuel pressure to change my fuel filter.
Although, I'm still having the same problems. After the engine has warmed up, and I turn it off, it has trouble starting...If I run it for a while, it will actually stop.
When I run it and it stops, it feels like it runs out of gas (but the tanks full). The gauges all drop (except speedometer), and the service engine light turns on. But when I check the codes with my code reader, nothing new shows up (and by then,the engine lighthas turned off).
I'm sure that spark plugs are working, and timing is correct. Injectors seem to be working. I don't know yet what the fuel pressure is, and it almost seems like the pump isn't working hard enough.
I may have talked myself into more tests I can do.

Thanks,
jwater7

 
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10-07-04, 02:01 PM   #10  
[
I'm sure that spark plugs are working, and timing is correct. Injectors seem to be working. I don't know yet what the fuel pressure is, and it almost seems like the pump isn't working hard enough.
I may have talked myself into more tests I can do.

Thanks,
jwater7[/QUOTE]Sounds like you are guessing that the injectors are working.I suggest you follow Desi's advice and find out what's missing during the failure.

 
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10-08-04, 02:15 PM   #11  
jwater7
ok, sorry, I've got it a bit more narrowed down now. I checked the gas pressure, and injectors were "ticking". I was, however, NOT getting spark. Appearantly, at the time I checked it before, it was working, but I know for sure now, that there is no spark.

So, back to Desi's post, I've checked everything suggested, and there is no spark. So, I had the ignition module checked and it checked out alright.
Any ideas?

Thanks again,
jwater7

 
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10-09-04, 11:00 PM   #12  
jwater7
Okay, so I did a little more testing...
I don't get any error codes with my handy dandy code reader (even when and after it isn't starting).
The distributor is turning (when it's just cranking and not starting).
There is a 12V wire(s) going to the coil, and they are both at 12V when it starts when it doesn't.
There is also a 12V wire that goes to the coil, when turning over, goes to around 9 (but my guess is that's the average from it cycling.)
When I put a timing light in between the coil and the distributor, nothing happens when it's not starting, and it blinks when it is working.

So, I'm guessing it's the coil's problem, so I'm going to get it replaced fairly soon.

Any comments on this would be greatly appreciated.

Thanks,
jwater7

 
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10-10-04, 04:53 AM   #13  
Take a testlight from battery positive to coil negative and crank the engine(during the no start)if the light flashes you need a coil if not you need a module or stator(pick up coil).This is only if you are correct about not getting spark.If it were my Ford I would change the stator and module at the same time as a faulty stator can wipe out a new module in a split second.

 
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10-10-04, 07:01 AM   #14  
I think this is an Ohm's Law problem.

"One thing I did notice, but not extremely bad, was the negative terminal on the battery was warm."

The neg. - cable will be warm if excessive cranking was done or if it has a poor ground. If you have resistance ( corrosion or poor contact) it will not only cause poor or no starting, it will cause havoc in other electrical components.

Is their a redundant ground (another smaller cable off the neg. - cable)?
Try relocating the opposite end of the cable to another (clean) grounding location.

A poor location would be a bolt that attaches to the water pump or intake manifold. These areas were known to corrode (thread of bolts) making a poor contact in time.

 
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10-10-04, 02:37 PM   #15  
Posted By: jwater7 So, I'm guessing it's the coil's problem, so I'm going to get it replaced fairly soon.
No, don't guess. The next thing you have to test is for injector pulse with a noid light. You can pick one up at any discount parts house. If your losing BOTH ignition and injecter pulse, you need to look at the crank sensor. If your losing ONLY spark, then look at the ignition module or the coil, depending if you got a pulse signal on the negative side as Davo recommended. Remember, wiring or plugs to either of these components can be the problem also.

 
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