I posted this query in general discussion. It was probably the wrong section for my dilema, so I'll try it here. My li'l white 85 has developed a very confounding, and frustrating problem. I had the water pump replaced, and a 190 degree installed, up from a 180 last week, and after I left the shop my check engine light kept coming on at highway speeds. I'd shut it off, and the light would stay off until once again, on the freeway the light would come back on. I went back to the shop, had the codes read, and they came back as an EGR code, and another code that my mechanic didn't specify other than to say that it could only be cleared by disconnect/reconnect the battery. Having done that, the car started belching black smoke, acting like it was in full choke, and barely running. :confused: Ater it cooled off it started fine, but after it reached operating temp the belching started all over again. I have since replaced the MAF, Idle/Air sensor, TPS, O2 sensor, Cold Start Timer Switch, Spark Control Module, and knock sensor. I have cleaned the Throttle body, and installed a new ECM and new EPROM. All wires are intact, but to no avail :rant: I HAVE to be missing something here :sleep: I need help! I am DESPERATE!! Thanks, Larry

 

You got an EGR code previously, and you replaced everything BUT the EGR valve or system parts?? That should have been the 1st thing to replace.
I think you went a 'bit' too deep in your repairs..
Hope your mechanic isn't the one replacing your parts at a nice cost, as he is happily cashing in on you ... watch out..



[Modified by MrNuke, 10:34 PM 3/3/2003]

 

Well, your EGR code is probably just the sensor. It is mounted on the base of the EGR valve. It has one wire going to it. The sensor has a stainless steel appearance to it. I think it is a 3/8 or 7/16 wrench. It has nothing to do with what your shop did. I'll bet if you put that 180 degree thermostat back in your problem with the EGR will go away. It all has to do with your engines temp. Don't get me wrong when I said your problem would go away, in reality it's just your light that will go away(you'll quit tripping the code 32)

NOW! you have a bucket of other crap you need to figure out.

I don't know your mechanical abilities but you really should have come here first, before you spent your time and money on all those parts you didn't need.

You need to look for your engine coolant temp sensor and remove it from the engine or find a way to take a resistance reading off it while it's still on the engine. Having said that there are "2" sensors. One for the gauge on your dash, and one for the computer. You want the one for the computer. More than likely it went south on you and is telling the car it's cold when it's really hot. This will cause your black smoke when the car is warmed up. It's cheaper than the other parts you already bought too.

I tend to ramble on too much.

In short, check the one wire sensor on the egr valve for a broken wire, it's a common problem.

Since you like to change parts, change out the ECM's coolant temp sensor. Then let us know what you found so others can learn from you problems.

Good luck,

ps, I'm a full time tech, if you need something else (troubleshooting charts, wiring diagrams or any other maintenance manual stuff just e-mail me) If you decide to measure the resistance of the coolant temp sensor then note the temp of the engine and what your reading was then e-mail it to me. It's always best to take the reading after the car has sat all day, then you can just use the outside temp.

 

Forgot to mention....the EGR valve has been pulled and cleaned :rolleyes:

 

Hmm. were all these things replaced on your vette the same time? or 1 after the other after not fixing the problem(s)?
Not sure what else to try, check timing, make sure your plugs are still all firing, ignition is good, make sure injectors aint sticking fully open.
Dunno what else.. :confused:

 

did you replace the electrical wire that connectecs to the egr? If not, you proabbly need to replace it as it usually breaks. I replaced my egr back in like '96 and it still threw an egr code until I replaced the egr wire on the '85.

The '85 egr system is specific to that year.

you are checkin for codes right?

 

Well, some partial good news anyway... :cheers: the EGR problem has been corrected. There is going to be a new Coolant temp sensor installed this morning hopefully correcting the other problem(s) If that doesn't fix it, I guess I'll be taking the car to Chevy, and let them deal with it. Thanks for all the feedback from everyone! :thumbs: I'm keeping my fingers crossed.

 

I know LT1 guys have that issue when crusing at a constant speed on the highway. I had it several times. I replaced the egr vale 3 times so far and the sensor was faulty once. :cheers:

 

What fixed the egr valve problem?

Don't take it to a dealer, give us one more chance, hey were 1 for 2 so far and we've only been playing for one day.

 

I want to thank everyone for their input. I don't know where all this is going to lead, but the car will be fixed eventually. Whatever the problem is, I'm quite sure that it is something very simple that is being overlooked. I think the biggest problem is the shop that's working on the car. We'll soon find out.