90 350ci runs bad when warm

[bbernhardt]

Well cool Rick, glad to see that you are still trying to beat it and not let it beat you. You know I've seen a few people over the internet that are having the same problems, but nobody seems to come up with the answer yet or doesn't post it lol.

Hopefully, I get the egr blockoff plate tomorrow in the mail, I'm probably looking at monday for the new computer I'm not even sure if it's the right one, my mom had it packaged up so she couldn't read me off any numbers. It's running a lot better with the egr blocked off, but there is still air pumping out from the side, so I'm hoping that once I get the plate it will block off all of it and make it run that much better. We'll see, I guess?

I just noticed that you had a "hypertech" chip too, there is another forum I visit called "fullsizechevy.com" and the hypertech is like a 4 letter word there lol. Well, good luck with the new parts, try one at a time and see how it goes, maybe knock it out and get your money back for the 2nd part? My brother wishes that he could have had it a little longer so that he could have hooked up his scanner and watched it as it went to crap to see if it would pinpoint something. He said that while it was on the scanner, nothing came up as unusual, everything was in working order, not sure if it had entered "closed loop" yet though.

Oh well, good luck buddy and I hope you beat it this weekend!

Bobby

[afd8]

not to keen on newer models but could it be all that emissions crap??? may b try takin all that off?? acidently owned a ford once andhad simaler probs

[bbernhardt]

Originally Posted by rpreston

Hope the new ECM takes care of your problem, Bobby. Last weekend I borrowed my buddy's 90 truck again and swapped in his ECM and the ESC module and neither made any difference. Before that I checked the wiring from the knock sensor to the ESC and from the ESC to the ECM. I also monitored the voltage signal from the ESC to the ECM. There was no change in voltage at any time so the knock sensor circuit is working fine. I even monitored the the output signal from the ECM to the distributor. It was a nice even signal increase as the timing advanced on exceleration. I also hooked up the timing light to his without pulling the wire and his timing did the same exact thing as mine, so that must be normal. I'll try the coolant sensor and maybe even IAC valve for the low idle... I'm running out of things to try. Could the CAT be clogged and causing this? The old 305 was burning a lot of oil...

So far I've changed ECM, chip, ESC, Knock, O2, TPS, MAP, Injectors, rebuilt the distributor, New plugs and wires. Also ohmed out coil. No codes or SES light...

Sorry Rick, just noticed the statement about your cat. You may try rapping on it to see what kind of sound it makes. It may be clogged and probably is if it's the original. I cut mine out since we don't have to be smogged in Washington and it was full of crap! I was blowing chunks of carbon out of the pipes for a while afterwards, probably screwed something up having it in there? If you have to have one where you're at, you might try gutting it, not sure if that would work anymore? Or buying a new one, high flow maybe? Just thought I would throw that in there, just in case that was your problem?

Again, good luck!
Bobby

[rpreston]

Thanks to all who read or responded to this post. The final piece of the puzzle was a bad coolant temperture sensor! Running good now. Again thanks!

Rick

[rayb]

hello fellas,having the same problems.Where is the coolant temp. sensor located on the 350 ci.Mine is also a 90 model.

[bbernhardt]

Originally Posted by rpreston

Thanks to all who read or responded to this post. The final piece of the puzzle was a bad coolant temperture sensor! Running good now. Again thanks!

Rick

hmmm, they're cheap and might be something to try myself? Mine is running a lot better since pulling the egr and installing the block-off plate, but still doesn't seem to be up to par. I think I will go buy one tomorrow after work. Glad you got her running good Rick!

Bobby

[bbernhardt]

Originally Posted by rayb

hello fellas,having the same problems.Where is the coolant temp. sensor located on the 350 ci.Mine is also a 90 model.

I don't have a stock '90 intake, but your's should be off of the intake manifold, pretty close to your thermostat housing, maybe right next to it. It will probably be brass, threaded into the intake with a couple of wires coming out of the end.

It looks like this: http://www.partsamerica.com/PartDeta...pe=290&PTSet=A

It has a waterproof connection that snaps onto the black plastic part of it.

Hope this helps,
Bobby