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Discussion Starter #1
I am having a problem with keeping the car running. I can start it and it will run very poorly for about 5 seconds and then die. The exhaust also smells like gasoline. This was a spontaneous problem. The car was driven 2 days prior without issue. I came back out to go somewhere and I experienced this issue. I thought it was spark, and I have replaced the ignition coil. But if it runs at all it obviously is getting spark. I have no oil in the coolant or coolant in the oil (not head gasket). I have unplugged the MAF, swapped the IAC with another spare, swapped the cap/rotor, and checked the timing (pulled #1 and spun until it was at the top and rotor pointed correctly). I read that it could be an EGR vacuum regulator sticking or a loose wire. I haven't had a lot of time to tinker with it. I was going to swap the plug wires in case they may be arcing. Any other ideas?
 

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Discussion Starter #2 (Edited)
Any ideas guys? I have swapped the IAC, plugs, wires, cap, rotor, the whole distributor, coil, EVR, and ignition control module. The plugs were black and wet with gas. I can get it to start but it runs really bad. I can get it to spin up by pressing the gas, and then it will idle down below 500 and die. Sometimes it will restart, sometimes not. Exhaust smells like raw gas. Could it be the EEC, or the ignition switch (in the column)? I'm at a point where I have no more ideas. (Seems like it's getting plenty of gas, just not enough spark). I really need to get it running.

Thanks for any help or insight.
 

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I would take a closer look at the MAF sensor..Remove it, and clean it..

This is what I use to clean MAF sensors with..Along with a Q-tip..



If you don't feel comfortable using a Q-tip on the MAF sensors delicate wires..Just use the cleaner I suggested..

Normally I wouldn't tell anyone to go to Autozone to have their car scanned...
Just because they will try and sell you every sensor known to man if something comes up in the scan..

Under your circumstance..I would suggest taking it "somewhere" to get it scanned for codes though..
Rather than replacing all your sensors and crossing your fingers.. :rolleyes:


I suspect it's a MAF or Oxygen Sensor issue..






Rayo..
 

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I would take a closer look at the MAF sensor..Remove it, and clean it..

This is what I use to clean MAF sensors with..Along with a Q-tip..



If you don't feel comfortable using a Q-tip on the MAF sensors delicate wires..Just use the cleaner I suggested..

Normally I wouldn't tell anyone to go to Autozone to have their car scanned...
Just because they will try and sell you every sensor known to man if something comes up in the scan..


Under your circumstance..I would suggest taking it "somewhere" to get it scanned for codes though..
Rather than replacing all your sensors and crossing your fingers.. :rolleyes:


I suspect it's a MAF or Oxygen Sensor issue..






Rayo..
And thats why I have my own code scanner
 

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Discussion Starter #5
The MAF is a re-man from a parts store (not Motorcraft), and is almost a year old now. I clean it about every 2 months. I have that exact can of spray ^^. I have tried unplugging it and it made no difference at all.

As for the oxygen sensors, would they have that much of an effect on the car when it is cold? I'm not sure so pardon my ignorance. I have no cats, and ever since I put the SCT chip in I don't get any CELs.

FWIW, I will go and buy some used O2's and a MAF and swap those also. (Rather than buying new, non-returnable parts...) My car being a 1994 model, has the OBD 1 system and it being a V6 I am pretty sure the port on the passenger side under the dash doesn't even work. I haven't found a place that can scan it, and getting it to that place would be a problem. It runs so bad that I don't trust it to go anywhere. Like I said before, this was a spontaneous problem. It drove fine one day, then 2 days later it was like this.
 

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Discussion Starter #6
I am at a complete loss on this. I'm going to push it out of the way and fix my S10.
 

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Dude, you can read code flashes with a jumper wire between the self test terminal and the grey/red wire in your eec test plug under the hood. Screw that s10, everybody knows the bird is better ;) OBD1 codes suck though, they can be very vague and attributed to many more causes. OBD2 is nice because you know what to expect on almost every car.

Since you are smelling raw gas, I would hook up a fuel gauge and see how quickly you are losing fuel pressure KOEO. If it degrades quickly, you might have an injector sticking open. This will make it run rough and have foggy exhaust that burns your eyes and has a fuel smell. You wont know what you are up against until you do some testing. You may also just have WAYYY too much fuel pressure. My dads old 87 F-150 with a 5.0 would run really bad at idle, but OK on the highway. Turns out his FPR was making him run at 90PSI instead of 40.
 

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The OBD1 computer is basically just a comprehensive test - if the solenoids / sensors have continuity they are OK, it will only display a code if something has a shorted circuit or an open / disconnected sensor for example. There are no diagnostics / monitors that are ran to determine operating conditions the same way an OBD2 would work.

You may need to do like ROb said and go back to the basics, check fuel pressure, make sure you have a vacuum line at the FPR .. if the EGR is stuck open, that could cause the engine to run very rough / die .. it might set a code for excessive flow, but if not the only way to tell is if the EGR tube is very hot - it doesnt get as hot when closed and there are no exhaust gasses actually flowing through it.

Youve checked spark outside of the vehicle with a spark plug tester, or just a plug grounded out ?? Should have a nice blue spark, if its dull orange it could be weak from something in the ignition system but if spark is good, and fuel pressure is normal, it could have something to do with o2 sensors, MAF, etc .. getting an incorrect reading and throwing off the air/fuel. Stuck open injector, you might need to ohm check them all, use a noid light/digital multimeter to verify duty cycle or pull the fuel rail with the injectors attached, and turn the key to run to see if the fuel line pressurizes and any fuel leaks out of the injectors ..
 

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Discussion Starter #9
Dude, you can read code flashes with a jumper wire between the self test terminal and the grey/red wire in your eec test plug under the hood. Screw that s10, everybody knows the bird is better ;) OBD1 codes suck though, they can be very vague and attributed to many more causes. OBD2 is nice because you know what to expect on almost every car.

Since you are smelling raw gas, I would hook up a fuel gauge and see how quickly you are losing fuel pressure KOEO. If it degrades quickly, you might have an injector sticking open. This will make it run rough and have foggy exhaust that burns your eyes and has a fuel smell. You wont know what you are up against until you do some testing. You may also just have WAYYY too much fuel pressure. My dads old 87 F-150 with a 5.0 would run really bad at idle, but OK on the highway. Turns out his FPR was making him run at 90PSI instead of 40.
I plan to get the clutch in my S10 this weekend so I can get out of this gas-hog company truck they are letting me drive. Then I will get under the hood of the bird. I'll go rent a fuel pressure gauge ($120) and test it for too much/too little pressure. I am fairly certain it's not an injector sticking, unless all 6 are. All of the plugs were wet when I pulled them. Where is the FPR located on this engine?


The OBD1 computer is basically just a comprehensive test - if the solenoids / sensors have continuity they are OK, it will only display a code if something has a shorted circuit or an open / disconnected sensor for example. There are no diagnostics / monitors that are ran to determine operating conditions the same way an OBD2 would work.

You may need to do like ROb said and go back to the basics, check fuel pressure, make sure you have a vacuum line at the FPR .. if the EGR is stuck open, that could cause the engine to run very rough / die .. it might set a code for excessive flow, but if not the only way to tell is if the EGR tube is very hot - it doesnt get as hot when closed and there are no exhaust gasses actually flowing through it.

Youve checked spark outside of the vehicle with a spark plug tester, or just a plug grounded out ?? Should have a nice blue spark, if its dull orange it could be weak from something in the ignition system but if spark is good, and fuel pressure is normal, it could have something to do with o2 sensors, MAF, etc .. getting an incorrect reading and throwing off the air/fuel. Stuck open injector, you might need to ohm check them all, use a noid light/digital multimeter to verify duty cycle or pull the fuel rail with the injectors attached, and turn the key to run to see if the fuel line pressurizes and any fuel leaks out of the injectors ..
I can't get the engine to run long enough for the EGR tube to even get warm. I might go ahead and swap the EGR if that isn't too much work. I'll have to see what it takes to get to it.

For the spark, I have changed everything to do with it. The coil, wires, ignition control module, cap, rotor, distributor, and plugs without any change in performance. I have not actually 'tested' for spark. How would I go about testing with a spark plug grounded out? I've never done that.

The MAF is relatively new, and clean. I also swapped it for a different one without any difference. The o2's are probably about 5-6 years old so they may need to be replaced. When I removed the cats from the exhaust I got a CEL. When I put the SCT chip in (about a week after) it eliminated the CEL and I have never gotten one with the chip in. I was assuming the chip was over-riding the o2 input to the ECU. Also, with it being a cold start would the o2's have much effect?

The only sensor that I can think of that I haven't changed is the TPS. This engine doesn't have a crank sensor (that I am aware of). The CCRM that is in there now came from my wrecked 94 (due to the previous one not running the e-fan). The CCRM harness does have some cracked wiring, but I have done my best to tape them up (I know :rolleyes:) for now. I did that prior to installing the engine. I do have another pigtail I can swap in if that might be my issue.

FWIW, I have had this car intermittently have a very similar problem with running like this. Every-so-often when I would start it, it would run like crap - sometimes die. I would shut it down, wait a second, and then it would run fine. I never put much thought into it because it would run fine for long periods in between those episodes.

Sorry for the novel guys. I want to cover all bases and be as thorough as I can be. I've given you everything I have done, and can think of up to this point. Thanks for your help. I am willing to follow any suggestions.
 

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Discussion Starter #10
Finally took a day to get this fixed. It turned out to be a corroded wire on the IAC plug. I fixed it, and she fired right off. Now I have a new problem. It has a speed sensitive squeak coming from what I believe to be the right rear. I'm going to search and maybe post in the suspension forum. I'm thinking wheel bearing.
 
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