Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
This is a lot of info. to cover so bear with me .
The code 22 sets when the throttle position sensor voltage goes too low. This can be due to a bad sensor or wiring.
The code 32 sets when the computer commands the egr valve open but does not sense that egr flow has taken place. This will need to be fixed, but does not affect the way the engine idles.
The code 33 sets when MAP sensor voltage is high, this can occur when the idle is rough or unstable, this code is more than likely set as a symptom of the problem, not the cause.
The code 35 sets when the computer is unable to properly control the idle speed.
My suggestion is to start diagnosis with the throttle position sensor. Use a voltmeter to check voltage at the throttle position sensor connector. You should have ground on the black wire, the gray wire should show 5 volts with the key on. If both of these are correct, test the blue wire (with key on and tps plugged in) voltage with throttle closed should be 0.5 volt. and with throttle wide open should be approximately 4.5 volts. Let me know what you find and we'll take it from there.
Good info Dave. I understand it is alot of info. No rush. I appreciate your help. I will check and get back to you. I'm going to accept now. Follow up questions OK?
5 volts from blk to gray. .575 volts throttle closed. 4.505 wide open.
OK. Here is what has happened. Checked voltages as per your direction. Plugged tps back in and started car. Check engine light is now out and it stays running. The engine is still missing a little and throttle response is not crisp, sort of has a couple of dead spots when you push on the accelerator. Could be the idle air motor a little lazy, (I put a used on in awhile back) or do I still have issues to resolve?
The strange thing is, is that I had already disconnected all of the plugs to idle air, tps, map and egr suspecting a bad connection. This time when I plugged tps in it is running. I haven't taken it on a road test, but at least it is letting me open the throttle.
Dave, I pulled, wiggled and tugged and of course cannot duplicate the problem. The car was compeletly undrivable before.
I took it around the block and up the hill. Throttle response is not the best and it is still missing and died once while pulling the hill but restarted. Power seems down, but no check engine light now.
Alzheimers time. I had a small engine fire due to ruptured fuel regulator about a year and half ago that singed some of the wiring around the trottle body. Mostly damaged the corrugated insulation but I see that the tps plug is somewhat melted. Sorry forgot about all that till I pulled the plug off.
Seems to be working but I think I'll go to the junk yard and get a plug and splice/replace.
Do you think I just need to do a tune up or is there more that needs to be done with the egr?
Ok, I unhooked the battery to reset ecm. I reconnected and started the car, revved it a few times and all seems ok, other than running a little rough. Shut off and rechecked codes. All clear.
Last question! I've had the egr valve off previously. Am I cleaning the passages in the valve or the manifold?
Cool! I know exactly what you mean. I appreciate your time and knowledge.
Positive feedback has been posted and bonus on the way.
Hi Dave, I finally got around to installing the tps pigtail on my Cutlass. I also replaced the idle air motor.
Unfortunately still runs like crap. It will start and run pretty good for a couple of minutes until the engine gets a little heat in it and then it starts missing badly and develops huge 'dead spots' in the throttle. Ultimately you can barely get it off idle after that without the engine dying.
I replaced the plugs as they were old, no difference. I did pull the egr and it wasn't plugged but I cleaned it up a little anyway. Also went back through the test procedure we discussed before and the tps voltages are right on.
I checked them with the engine running and got it to a point where it would die and the voltage held steady where it should have been. The voltage increases and decreases smoothly as I work the throttle.
I double checked the computer and there are no codes showing up and no check engine light.
I'm really puzzled. Seems almost as though the ignition is being turned off intermittantly after it runs for a couple of minutes.
If you have any further suggestions, please let me know. I will gladly pay for your time.
Thank you! Tom
Also, fuel pressure regulator was changed out about a year ago, fuel pump about 2 yrs ago. Fuel pressure holds steady at about 40 psi at all times.
I've swapped out the mas and map sensors from another car with same result. I also hooked a new spark plug to the front 3 cylinder wires and good spark is maintained even with it running rough.
About the only things I can think of is a problem with the oxygen sensor or possibly an injector issue?
Originally talked to you 2/16/'10
Is there much more I can check on my own?
need help on a 1999 Chevy K3500 pickup with a 7.4 L