Car Problems...

[MikeFlynn74]

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.

 

[Fingers]

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.

 

[CodeRage]

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.

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.

 

[MikeFlynn74]

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.

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

 

[CodeRage]

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

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]

All my experience is with Fords so their ECU may be different

All my experience ended when I joined the AF. Never again do I want to work on someones 50$ junker.

 

[dirtymike1]

All my experience ended when I joined the AF. Never again do I want to work on someones 50$ junker.

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.

 

[MikeFlynn74]

yea it took me 6 months to get the black oil off my hands

 

[dirtymike1]

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.

 

[shafferpilot]

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.

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.

 

[Dr_Deathweed]

Ok, update:

It was never a huge billowing cloud of smoke coming out, sorry if I misled there. When I checked the flow coming out of the tail pipe, within 30 sec or so my hand was covered with thick black soot.

Got home and fooled around for a while, turns out that it is a coil pack on my car not a distributor (must of been thinking of the wifes car for some reason... I feel like an idget...) I started it up and drove around the block a few times, and noticed it seemed to miss/vibrate more when I would cruise than when I accelerated.

I tried looking for my voltmeter, but realized I lent it to my BIL. Instead, being the patient soul that I am, I disconnected the TPS and started it up, and it seemed to idle very high. I killed the engine, reconnected the sensor, and now the engine will not stay running without pressing on the gas. It would make sense to me that this would mean the TPS is the problem, so unless someone tells me otherwise in the next hour or so I will run to the parts store and try and find a new TPS. I am getting an engine light now, so I will try to borrow a scanner and get the OBD code.

I feel like an incredible doof with this whole situation, perhaps I should just stick with working on living things..... So for the complete car noob here, "Did I ruin my ride?"

 

[CodeRage]

Nah, you're okay. Since it is a 93 though you may have a hard time finding the appropriate scanner. The standard ODBII protocol wasnt enforced until 96 and before that every manufacturer had their own system. Odd are you will have to find a special scanner. I know autozone does free scans and they may have the one you need. good luck!

 

[mr_goodwrench]

I would say that your culprit is very likely to be either the TPS or the ignition module. The SES light that is on now is no doubt due to the fact that you ran the engine with the TPS unplugged. If it wasn't on before this, the DTC that is stored wouldn't be any help in diagnosing your problem. If it was on before, then the DTC is the best way to get to the bottom of things. As far as parts store code readers, I don't really have any experience with them since all I have ever used is GM's scan tool.

 

[MikeFlynn74]

shafferpilot

You do know that 02 sensors measure exhaust gas temps. Too high its too lean, too low its too rich. It consistnantly bounces between reading as each puff of exhaust passes it. OBD3 may be able to tell if the 02 is reporting incorrectly but I didnt think obd1 or 2 could. Ive seen them stuck reading with no change in voltage and it did not set a code because for all the cpu knew is it was within tolerances.

 

[shafferpilot]

You do know that 02 sensors measure exhaust gas temps. Too high its too lean, too low its too rich. It consistnantly bounces between reading as each puff of exhaust passes it. OBD3 may be able to tell if the 02 is reporting incorrectly but I didnt think obd1 or 2 could. Ive seen them stuck reading with no change in voltage and it did not set a code because for all the cpu knew is it was within tolerances.

Interesting..... and completely wrong! O2 sensor is NOT an exhaust gas temperature sensor. That I can promise you! An oxygen sensor DOES actually monitor the oxygen content of a gas. In an automotive application, it only reads properly when at the appropriate temperature, but it doesn't READ temperature at all.

My point is that even at full rich trim, the engine WILL stay running. Here's an example of why I know this to be true:

When the computer discovers a major fault, it will go into what is often called, "limp home mode". When in limp home mode, the computer ignores the O2 sensor and runs at "full rich fuel trim" to ensure that the engine doesn't get damage from running too lean. If the OP's engine is stumbling and stalling, the O2 sensor can not be the culprit because the O2 sensor is not capable of enrichening the mixture to that extent. Here's some info on how an O2 sensor works for those who are interested:

http://en.wikipedia.org/wiki/Oxygen_sensor

There IS an ignition issue with this car. It could be in the ignition module or coilpack OR it could be one of the sensors in the ignition loop (throttle position, knock sensor, manifold absolute pressure, crank/cam position, or RPM).

 

[MikeFlynn74]

Interesting..... and completely wrong! O2 sensor is NOT an exhaust gas temperature sensor

Well not completely wrong- EGTs are directly tied to the fuel/air ratio but I never knew it actually measured the 02 content of the exhaust.

I still stand by the TPS being the issue- 15$ part that goes bad often.

 

[iamcroweman]

Check the coolant temp sensor. If the ecm (engine control module ) thinks the engine is to cold (like -40F ) then it will flood the engine

 

[Dr_Deathweed]

Well, life happened last night and I was not able to swing by and pick up a TPS. I will be without a car today because i will be getting picked up/dropped off at the house. So rather than losing a day, I figured do as much work as I can without having to run to the parts store. I was also advised to rule out the following before I go and start blaming sensors:

fouled spark plugs - I know I have this problem from the rich mix, I will pull and clean them today, and continue looking for the major problem
bad plug wires -just replaced them, don't think this is it
a weak ignition coil - possible, waiting on getting voltmeter back and I can check
a leaky EGR valve, vacuum leaks - will look into this
low compression - don't know how to check, I will look it up unless someone gives me some ideas
dirty injectors - been trying to run cleaner through regally. I don't think the problem would get worse the more cleaner i run through.....
fuel pressure, low charging voltage - again don't know how to check off hand

Thank you so much everybody for your advice, I know you have already mentioned many of the things above and I had already taken them into account. I will try and pick up a TPS tonight when my wife gets back with her car, but any ideas of what I can clean up/get going before hand is very appreciated.

 

[CodeRage]

fouled spark plugs - I know I have this problem from the rich mix, I will pull and clean them today, and continue looking for the major problem
bad plug wires -just replaced them, don't think this is it
a weak ignition coil - possible, waiting on getting voltmeter back and I can check
a leaky EGR valve, vacuum leaks - will look into this
low compression - don't know how to check, I will look it up unless someone gives me some ideas
dirty injectors - been trying to run cleaner through regally. I don't think the problem would get worse the more cleaner i run through.....
fuel pressure, low charging voltage - again don't know how to check off hand

A Leaky EGR will make you run lean. Stuck EGR Wil make you rich when it should open. Vacuum leak will make you Lean too.

To check the compression you need a cylinder leak down tester like this
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190
I dont think low compression is going to hurt peformance and smoke real bad if there is alot of blow by.

Just my take on your list. Oh and just saw you know, you got company.

 

[mrk305]

Lot s of people posting here that don't know squat about cars. A TPS usually fails at idle position. they have a graphite resistor that usually wheres out at the most commonly used position, idle. Looking at the plugs might tell you something. If a one or two plugs is fouled, suspect an ignition problem like a coil. Does 93 have 3 coils each firing two cylinders? I could be more helpful is I was at work. If all 6 plugs are carbon fouled, I would suspect a bad fuel pressure regulator or the O2 sensor. Don't try to clean carbon fouled plugs. If the plugs are wet or sooty looking, just replace them. The O2 sensor being in the exhaust gas for 140,000 miles is getting old and since '93 did not have OBDII diagnostics it might not throw a code.

 

[Dr_Deathweed]

Lot s of people posting here that don't know squat about cars. A TPS usually fails at idle position. they have a graphite resistor that usually wheres out at the most commonly used position, idle. Looking at the plugs might tell you something. If a one or two plugs is fouled, suspect an ignition problem like a coil. Does 93 have 3 coils each firing two cylinders? I could be more helpful is I was at work. If all 6 plugs are carbon fouled, I would suspect a bad fuel pressure regulator or the O2 sensor. Don't try to clean carbon fouled plugs. If the plugs are wet or sooty looking, just replace them. The O2 sensor being in the exhaust gas for 140,000 miles is getting old and since '93 did not have OBDII diagnostics it might not throw a code.

I will be the first to admit I know just enough about this for me to get into trouble....;D

Just pulled the plugs today and looked at them, Only two seemed overly fouled. Yes, the 93 has 3 packs firing 2 cylinders each. I wish I had kept track of which cylinders were the ones that looked fouled, for some reason I am thinking it was 3&4....

Like I said before, my voltmeter is MIA and I don't know when/if I will see it again. Do you have a quick and dirty way to make sure it is a coil before I go and try to pick up parts tomorrow or Saturday?

And yeah, I know I should replace the O2 sensor, I have just been putting it off for two years. I was hoping I could get a new car before I had to mess with it....

 

[CodeRage]

Lot s of people posting here that don't know squat about cars.

Okay, you post a car problem question on a brewing forum, dont expect to get many 'experts'. Now I wouldnt say I am an expert but I have a pretty sound understanding, more than your average person. But then again I dont peddle parts all day either. If you want to help, then help. Dont make a blanket statement like that to give your input more merit.

Edit-
Oh and I dont think there is one thing that you mentioned that other people havent already covered other than the inner workings of a TPS.

 

[Mutine Bullfrog]

Sounds like your miss firing. in one or more cylinder. this would explain the roughness, stalling, fouled plugs, black smoke and excess fuel. This is usually caused by some ignition problem. cap, roter, wires, plugs, etc. you can also check to see if a sensor plug got knocked out

 

[RodfatherX]

Go to auto zone and tell them what is wrong.........don't ask some kid ask and older gent. Most of them have lots of experience with cars. I know you said yours is Fuel injected, but I had an old truck that had to have the carb rebuit and it was missing real bad, fouling plugs, and spitting carbon enough to make a mark on the drive when I started it. I think it also clogged up the cat converter.


could be the map sensor or mass air flow sensor depending on which one it has



actually
I would go the auto zone route heck go ask a guy at autozone oreillys and napa and see if they all agree on something.

 

[Oakwoodforge]

I've run into this a few times before, I used to be the Shop Foreman for a used car dealer for over 5 years. That Chev 3.1 L Has a few Issues , especially the mid to late 90's models. 2 major things my shop ran into all the time with those, # 1 Intake manifold gasket leak, #2 Camshaft Positioning sensor failure. Your Problem with the chugging and plug fouling sounds like # 2 ( the 3.1 l is basically a 350 Block with 2 cylinders cut off - the Cam shaft Positioning sensor is located were the distributor would be on a 350. You will have to remove the air plenum and filter housing to reach it. IIRC should be 2 5/16 or 7 mm screws holding it in , roughly Diamond shaped with a 3 wire plug - Should cost less Than $50 for a new one.

Its one of the few sensors that when it goes bad ,It wont throw an OBD2 fault Code though if you have the Genesis Scan tool you can access Gm datastream and see that the CMP sensor is not sending a signal. Any way one more thing to check ...


Prost !

Jens

 

[MikeFlynn74]

the 3.1 l is basically a 350 Block with 2 cylinders cut off

Um no- that would be the 4.3l v6

 

[MikeFlynn74]

Lot s of people posting here that don't know squat about cars.

speak for yourself buddy-

TPS fail all the time and not just at idle- the whole thing moves every time you move the gas pedal.

 

[shafferpilot]

Lot s of people posting here that don't know squat about cars.

Dude, who pissed on your wheaties this morning?

Anyways, you're wrong. TPS most commonly fails at the cruise throttle setting. The throttle is moving slightly back and forth at that spot because no one can hold their foot perfectly still. THAT is WHERE most of the WEAR occures

Back on topic: If you only have two cylinders misfiring, and the engine uses the three coil system.... Well, I think it's self-explanitory at that point, isn't it? One of the coils is out, or the wiring to the coils is screwed up, or a gremlin snuck under the hood and switched some of the plug wires around.

The quick and dirty way to check a coil without an ohm-meter is to pull the plug wire on one of the offending cyliders. Plug in a spare spark plug and use a battery jumper cable to connect the metal portion of the plug to a metal bracket on the engine (ie grounding it). Have someone turn the key. While the engine is trying to start, you should see occasional bright blue/white sparks. If the sparks are really small, thin, and hard to see; the coil is bad. Whatever you do, DO NOT TOUCH THE PLUG OR JUMPER CABLE WHILE THE KEY IS TURNED ON. Trust me, you don't want to know what that feels like.

 

[MikeFlynn74]

DO NOT TOUCH THE PLUG OR JUMPER CABLE WHILE THE KEY IS TURNED ON. Trust me, you don't want to know what that feels like

Do this on a car with a big coil and an MSD box. not fun

 

[PeteOz77]

Do this on a car with a big coil and an MSD box. not fun

BAH! What's 100,000 volts?

My Auto Mechanics Instructor (many many moons ago) used to pull off plug wires and test them with his hand.....until the HEI came along.... He would still do it once in a while when he was pretty sure it was dead..just to make sure.