Car Problems...

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Dr_Deathweed

Dr_Deathweed

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I need help form all of you pro/home mechanics out there...

My 1993 Oldsmobile Cutlass Supreme T up and died on me on Sunday. It started vibrating badly and stalled after only running for ~5 minutes. I checked to see if the exhaust was clogged but it seemed to put out plenty of gas when running, but a lot of black soot as well. I pulled the spark plugs, and they were fouled as well. I will clean them when I get a chance, but I am wondering why I am running rich in the first place.

The plugs and air filter are only 6mos old, and the air filter is clean. The air intake is also clear, and the spark plug wires are brand new a couple of months ago. There is no check engine light, so I believe the O2 sensors are fine, but will check them with a volt meter when I get time.

I am starting to lean toward either a distributor problem, or excess fuel pressure. My last oil change about 3 months ago ended up cutting the wires to the fuel pump (whatever idiot at GM decided to run those wires right under the oil filter.... grrrrr.... one wrench gets away and YANK!) There is a small possibility I swapped the wires on it, because the color coding was funky, It looks like this had happened a couple times because those wires had been spliced a couple of times.

If anyone has ideas, PLEASE let me know, I had rather do this myself than take it in for a repair that may cost more than my vehicle is worth...
 
Coil pack is a good thing to check. Just out of curiosity, which engine is it? I've worked on a lot of cars, mostly foreign though, so I don't know the engine off the top of my head.
 
Sounds like, A) the Fuel filter is plugged B) The Fuel Pump is bad C) The Coil Pack could be bad
Click to expand...

Coils either work or they dont.

Plugged filter wouldnt give the impression its running rich. Id check to the if the Idle Air sensor is bad or crank/cam angle sensor
 
Nope Nope and Nope.... Since you ripped the wires to the fuel pump, if they were wired up wrong after you fixed them, the pump would not work. So thats check one. Fuel pump rarely "start to go bad". They are one thing that is either working on not working. Check 2. Clogged fuel filter. This would limit the amount of fuel going in, so you would more then likely be running lean. Check 3.

Hmmm... Try pulling the distirbuter cap and look for any white burn marks. If they are present replace the cap and rotor. if not, close and move on.

I would try gonig to the store and buying a can of Sea Foam, ask for it by name. Put it into your gas tank right before you fill up, fill up then run the tank to damn near empty. This will clean out your fuel injectors as well as the lines. I would also replace the filter just for good measure.

This is a start, and this is also 5 years of experiance behind this.
 
MikeFlynn74 said:
Coils either work or they dont.

Plugged filter wouldnt give the impression its running rich. Id check to the if the Idle Air sensor is bad or crank/cam angle sensor
Click to expand...

I have had plugged filters cause both Shaking and stalling and Bogging way down, it is definatley a possibility.
 
Klainmeister said:
Coil pack is a good thing to check. Just out of curiosity, which engine is it? I've worked on a lot of cars, mostly foreign though, so I don't know the engine off the top of my head.
Click to expand...


No Coil Pack, its got a cap and rotor
 
To start answering questions:
- It is a 3.1 L 6 cylinder engine, and unless I am GROSSLY mistaken, it is fuel injection
- fuel filter was replaced 6mos ago when I did all the other work on the vehicle
- I run injector cleaner every 3 months.. Or I have been for the last year or so. I cant vouch for any maintnence before that.
- Don't think its the idle sensor, wouldnt I get a code for that? It also idles fine, It is when I get moving, or start slowing down after driving that it starts shaking bad and stalling

I will deff check the distributor tonight. I orriginaly thought it was a clogged cattalytic converter, but the amount of exhaust coming out kinda dismissed that one. The distributor is rapdly becoming the prime suspect.

Please keep the ideas flowing, so when I get home I cam make a more efficent use of my time:D
 
deathweed said:
To start answering questions:
- It is a 3.1 L 6 cylinder engine, and unless I am GROSSLY mistaken, it is fuel injection
- fuel filter was replaced 6mos ago when I did all the other work on the vehicle
- I run injector cleaner every 3 months.. Or I have been for the last year or so. I cant vouch for any maintnence before that.
- Don't think its the idle sensor, wouldnt I get a code for that? It also idles fine, It is when I get moving, or start slowing down after driving that it starts shaking bad and stalling

I will deff check the distributor tonight. I orriginaly thought it was a clogged cattalytic converter, but the amount of exhaust coming out kinda dismissed that one. The distributor is rapdly becoming the prime suspect.

Please keep the ideas flowing, so when I get home I cam make a more efficent use of my time:D
Click to expand...

Since it is not a throttle body, My next vote goes to the distributor as well.
 
RICLARK said:
Since it is not a throttle body, My next vote goes to the distributor as well.
Click to expand...



Actually now that I think about it, it may have a throttle body.... If someone could double check to see which is standard on this model that would be awesome...

I am nowhere near the car, and trying to study for a radiology final, so I will try to answer questions throughout the day, and I will give some updates when I get back home this evening.

Thank you everyone for your help already!
 
If you're running that Rich you are either not getting enough air or too much fuel. Bad spark is a possibility. I would pull the injectors and have them checked. They are 15 years old and that is a alot of life to get out of them. I wouldnt be surprised if you have one or a couple leaking a fair amount. Could be an ECU issue but I would run down the injectors first.

EDIT- Oh! Seafoam is the shiznit! Run half a can into your break booster line while the engine is running and let it sit for a half hour and restart. You will clean all kinds of carbon deposits out! The thing willblow all kinds of nasty smoke for a while but it got rid of my spark knock and cleaned the valve stems up super nice. Marked improvement in air flow.

You're not loosing oil are you?
 
Don't think its the idle sensor, wouldnt I get a code for that
Click to expand...

not always- If its running within normal parameters it wont set a code.

It may be stuck- also you might have a Mass Air Flow sensor as well.

Ever replace your 02 sensor?
 
RICLARK said:
Since it is not a throttle body, My next vote goes to the distributor as well.
Click to expand...

I think you mean Carborated. All cars have a "throttle body" in one way shape or form.

Pull the Dist. cap off tonight and see what it looks like. If you think it's the Cat. then put a thermomitor up to it. Get the car up to operating temp. Check the front of the Cat then the back. There will be a differance in temp, if I remember correctly the back will be hotter. If there is a gross differance in temp., I'm talking 100 degrees, then the cat would be bad. You really need a no-touch laser thermo. to do this. If you just put your hand behind the tail pipe and you feel good flow, then this is proboly not your problem
 
Many years of auto experience tells me this is an ignition problem. The "rich" appearance is the result of a cylinder not firing for several cycles, then finally firing with lots of extra fuel in it, and then the extra fuel in the exhaust burns, albeit innefficiently, and makes a bunch of black smoke. I'm gonna go with distributor cap and button. BTW did these symptoms come on slowly, or just start happening all at once? Lastly, are you 100% sure that you didn't get diesel fuel in the tank? Crazy, I know, but I've heard of that happening around construction sites and stuff when someone thinks they can get free gas out of a fuel barrel.
 
dirtymike1 said:
It doesn't sound like a timing issue to me. It's is possible, but this sounds like an air/fuel ratio problem
Click to expand...
I only mention it because the symptoms are exactly what happened when I mistimed a car I worked on in college (only off by a single tooth, IIRC).
 
The throttle position sensor will also cause those symptoms

This is what I was trying to think of. I bet 50$ its this.

Many years of auto experience tells me this is an ignition problem. The "rich" appearance is the result of a cylinder not firing for several cycles, then finally firing with lots of extra fuel in it, and then the extra fuel in the exhaust burns, albeit innefficiently, and makes a bunch of black smoke. I'm gonna go with distributor cap and button. BTW did these symptoms come on slowly, or just start happening all at once
Click to expand...

Its not like that on EFI cars- It just doesnt work like that. The O2 sensor would account for it and greatly reduce the fuel to the injectors.
 
GM lineup (2.0/2.2L, 3100, 3300 and 3800 V6; 5.0, 5.7L and 7.4L V8, etc.) are all pushrod engines that use a traditional timing chain and gear set to turn the cam
 
shafer- I may of had some stumbling in the past,but the violent vibrations and stalling came on suddenly.

Yuri - I am pretty sure that my car has a timing chain, and if thats the problem, I may think aboug just shelling out for another new-to-me car:D

dirtymike - I do have good flow out of the tailpipe, but if I can get the car to run long enough w/o stalling or risking further damage I will check the catalytic converter
 
As of now, I will check the distributor when I get home.


MikeFlynn - Got a good way to check the throttle position sensor?
 
unplug it see how it runs-

Throttle Position Sensor - Testing

Set DMM to read DC Volts.

Connect black COM lead probe tip to the TPS ground wire.

Connect red Volts lead probe tip to the TPS Reference Voltage wire.

Turn ignition ON. Do NOT start engine.

Look for a 5 volt reading - (some manufacturers may differ - verify correct reference voltage for the specific vehicle being tested).

If reference voltage is too high or too low, look for a problem with the wiring harness or PCM.

After establishing reference voltage is O.K., connect the red Volts lead probe tip to the TPS to PCM signal return wire.

Look for low voltage at idle position that will smoothly increase as throttle is applied. Any fluctuation of the DMM Bar Graph or erratic voltage readout indicates a bad sensor. Verify factory specs for low voltage (idle) setting, even one tenth off can make a difference in vehicle performance. The high (full throttle) voltage should reach at least 80% of the reference voltage.

Turn ignition OFF when test is complete
 
Oh yeah MikeFlynn, in response to a post a while ago, I have not replaced the O2 sensors, but I am not getting a check engine light either. I will replace them eventually since I do have about 140K on the car, but if you think it is a good idea to do it wether they are the problem or not, I may go ahead while I have the tools out.

Of course I am putting off changing these after having to replace the exhaust manifold on my sisters car after pulling out her O2 sensor.....
 
02 sensor work by over heating. If you could get it out of its rusty embrace with the exhaust- usually takes an impact to break it loose.

It was just a thought.
 
If you're blowing black smoke and fouling your plugs AND you're not getting a code from your O2 sensor, then it's bad. Even if your O2 sensor isn't causing the rich condition it should still report it. The fact that it isn't reporting it makes me think that it's the problem.
 
Fingers said:
If you're blowing black smoke and fouling your plugs AND you're not getting a code from your O2 sensor, then it's bad. Even if your O2 sensor isn't causing the rich condition it should still report it. The fact that it isn't reporting it makes me think that it's the problem.
Click to expand...
Normally the ECU will throw a fault when an O2 sensor becomes un responsive. Narrow band o2s are all over the place all the time, its not like they can sit towards one end or the other.
 
Normally the ECU will throw a fault when an O2 sensor becomes un responsive. Narrow band o2s are all over the place all the time, its not like they can sit towards one end or the other.
Click to expand...

Not in o2 sensors case. Easy way to check an 02 sensor. While the car is running after its hot- Test the hot wire. If it flucuates(sp) quite often up and down then its working. If it only changes every 10-seconds or so or doenst at all then its broke. Reporting nothing causes a code- Incorrect reporting does not. It could still be bad
 
MikeFlynn74 said:
If it only changes every 10-seconds or so or doenst at all then its broke. Reporting nothing causes a code- Incorrect reporting does not. It could still be bad
Click to expand...

True, my point was normally an ECU will pick that up as an error. All my experience is with Fords so their ECU may be different.
 
MikeFlynn74 said:
All my experience ended when I joined the AF. Never again do I want to work on someones 50$ junker.
Click to expand...

HAHAHAHAHA I stopped working on cars about a year ago, and now everyone and their mother wants me to fix there car. I had to give it up after I screwed up my shoulder and back... I'm 22 and feel like I'm 72.... But I loved every minute of it. But I can't even work on my car or my girls, can't sit, stand, lay down without some kinda pain.
 
I know that feeling. I spent about 2 hours under the hood of my girls BMW last weekend, and then perceded to miss a wedding because I couldn't get off the couch.
 
MikeFlynn74 said:
The throttle position sensor will also cause those symptoms

This is what I was trying to think of. I bet 50$ its this.



Its not like that on EFI cars- It just doesnt work like that. The O2 sensor would account for it and greatly reduce the fuel to the injectors.
Click to expand...

The O2 sensor's ability to trim fuel is just that... a trim adjustment. Big plumes of black smoke indicate lots of fuel burning innefficiently, ie, without the proper amount of oxygen and/or not at the proper pressure. The O2 sensor, especially a narrow band, cannot cause this severe of a fuel/air imbalance. Even at full rich trim, a car will still run. It'll be a little boggy at low throttle positions and it'll have really low fuel economy, but it won't be blowing a ton of smoke. Some at startup and when pulling away from a stop, but not a cloud. However, liquid fuel in the cylinder and exhaust as a result of non-ignition events can. I do agree with those that suggest a throttle position sensor problem. If the computer thinks the throttle is open wide, it'll provide a ton of fuel and too much ignition advance which would result in the symptoms described. It's just that my experience points to the distributor. Especially since there's no trouble codes. Plus, it's just so darn easy and cheap to put on a new cap and rotor. Please leave the O2 sensor alone until you've tried some other possibilities. They're very difficult to change without damaging the exhaust, and I've NEVER seen a bad one that didn't throw a code.... Actually I've only once seen a bad O2 sensor that didn't throw a plethora of codes, and that one time, it did throw several O2 sensor codes.
 

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