Codes

Yes the motor runs very ruff when trans. Is put into any gear. I found a short description of the code p0640 from the scan tool that I used from a tool seller I know. It was somthing about the quad 4 system. The hookup for this car has a 16pin connector that a obd2 scanner will plug into but will not read. That's when I looked under the hood and found that it's obd1 certified. It seems that the ruff running only happens when the rpm, s are low. I am a deseil mecanic and have been for ten years. I rebuild engines and know engine management systems. But in the hanyes manual there is know mention of these codes or the quad 4 in the scumatics for the pcm.

Where might these quad drivers be located and what purpose do they serve? The pcm is the GM factory unit.

O.K I got the pcm out it's right here in front of me but i'm not sure which # is the part #. Also do you know of any good aftermarket companys to get one of these. Alright here are the #'s

serv. No. 16183247

86bmyum643127udd

16211694

bmyu

That's how it looks on the label?
Thanks for all your help it means alot
If you know which is the part # let me know.
Oh and by the way I bought a preaty nice scan tool that does live data and the engine has missfiring cylinders 2, 4, 6 on and off not all the time.

Brian

Thank you for all the help you have been!

Brian

I found the problem with the quad 4 system. The place you told me to look for those fuses, I found the 15amp fuse was blown. Ialso found what caused it. The a/c compressers clutch was locked up an the coil that makes the clutch engage melted togther do to the heat from the bearings and created a dead short. If your wondering the a/c compressor has been bypassed with belt designed for engine without a/c. Also the motor still is running ruff. I spryed starting fluid around intake manifold and vacum lines plus throttlebody found nothing. Then when it was dark I started spraying water around sparkplug wires and the ones that where missfiring on and off, you could see the wires arcing togther all over. I, m going to change plugs and wires tomorrow. I hope this is the only problem. It also serges when throttle is held in one spot do you think those spark plug wires could cause this?

Well changed the wires and plugs still doing the same thing. Cylinders 2 4 6 all rear head cylinders. Now I have two more codes since I let the motor warm up. One is p0300 multipule missfire and p0406 liner egr pintle position error. Plus when I look at live data on my scan tool it shows no change in position of egr at all even when I rev motor all other sensors inticate change when rpm's change. Is it posible that the egr valve could be causing these problems. The engine serging when throttle is held in one positon and these mutiple missfires?

I have a 95 Buick LeSabre and I recently had a new harmonic balancer( whatever that is) put in but now it is making up the same noise it was making before I put it in there! What should I do?

Krystal

I pulled the egr valve off and cleaned bottom and pindle very well with brake clean. The pindle was moving very well with my finger before I cleaned. But I got all the gunk off. Do you think that egr vale could cause Those missfires and serging? I have seen egr vales cause the fuel pump to shut down in a caviler. Well I should of worded that properly the pcm wouldn't tern on the fuel pump because of the egr valve. I have also seen egr valve make an engine overheat. Well here is something I thought you might like to know cat and detroit are starting to use egr vales and egr coolers. These big deseil engines are starting to get tested and have to pass smog tests and can't even build the engine unless it is going to pass an emissions type of test. I never thought I would see egr valves on a big deseil engine but the ozone is getting messed up and trucks is one of the top causes. Well let me know what your opinon is on this egr vave and these symtoms. Ohh by the way I herd that it's posible to get coolant in your oil because of an upper intake. Does coolant run though the upper intake manfold, the only place I know of is coolant going though the throtle body? Well let me know I typing your eyes off!

Thanks for all your help!

Brian p.

I cleaned the egr vale and the code went away. I am sorry you miss understood what I was saying in my last post. I am not not the one havimg the problem with the uper intake manifold. I was just asking you if you thought it was possible to get coolant in oil from cracked upper intake. Well anyway back to the buick it only has the one code now multiple missfire. But I found out some new info on this car. When that belt broke because of the a/c clutch the motor overheated. So I am wondering because all the cylinders that are missfiring are in the back head. But when I had my scan tool hooked up I was reving the engine looking at the live data and I noticed that the injector pulsewith would drop way down sometimes to zero when the motor starts to serge from being reved. I was also thinking about the prom chip in the pcm might be bad. Please let me know what you think about this new info.

The missfiring is very bad once the car is put into drive. Even at low rpm it is horrible! When your in gear and try to accelerate it pretty much falls on it's face and takes awile to get up to speed. It's like it loses all three of those cylinders all together. Then once the car gets up to speed it's not to bad. It's like when you put a heavy demand on the engine it dies so to speak. The car does not have tags on it yet so yesterday was the first day I realy took it for a small road test. I will do compression test and let you know. What I was saying about the injector pulsewith was that it was dropping down to zero when the motor serged when the fuel pedel was held in a steady position about half throttle. The motors rpm goes up and down very fast and it's very bad! But idels pretty good.

I know I give horrible descriptions but am having a hard time putting into words.

Brian