i'm jsut wondering how the EGR would be accounted for by the ECM..

here's my predicament.. I am getting EGR codes constantly. I have a new EGR on the car, when i replaced the original one I noticed a TON of buildup in the EGR passages but didn't ahve the time to pull off the intake and get it tanked..

i'm wondering if the ECM will throw the EGR code if the EGR is functioning correctly but isn't able to route the gases because of blockages in the intake..

i do notice a fair bit of ping with the EST connected, even set at 0 BTDC. Could this be my problem? I'm going to buy another '86 intake and have it tanked regardless..

as well, the car tends to surge on the freeway.. i know EGR can cause this.. the idle is rough, to the point the car is missing.. could this be the EGR, too?

What i'm 'really' trying to find out here is this:

With the EST disconnected the car purrs, with it connected the car runs horrible. I'm assuming that with the EST disconnected the ECM would not be pulsing the EGR, only running off the PROM?

thanks for the input guys...

Colin

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Webmaster: www.IROC-Z.org

 

Collin, I think to only way to verify that would be to monitor the EGR through the ECM and see if the EGR duty cycle changes for different throttle angle/loads...even if the EGR is not acting correctly, the ECM will still try to adjust the dutycycle (if unplugging the EST has no effect).

There's no actual monitoring of EGR gases, just solenoid operation vs. duty cycle.

 

hmm..

that's weird then, I'm getting EGR codes but there's a brand new AC Delco EGR on the car..

ya know, I've seriously about had it with this car.. dad and I looked at a nice '81 Corvette yesterday, I might just trade this car in

how much is a half decent scanner worth? just out of curiousity

 

Acorrding to what i read the computer looks for a temperature change to see if the egr is working or not. Your egr valve is obviously good. So you could have a bad egr switch or vacuum line or clogged passages. I wouldn't worry much about a code 32 as they seem to be very common and don't really affect performance. Sounds like you have more of a problem with your ignition system.

 

Don't you all just love that god damn EGR system?

I'm sure everyone on this board has heard about my $400 futile attempt to fix that stupid thing!!

I have a new GM brand EGR in my car, along with a brand new computer, and I STILL get the damn "SES" light on everytime I go on the highway... pisses me off!!!

The car runs fine, but that orange "SES" light makes me grit my teeth everytime it comes on, on my way to a from work....

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Year: 1990
Make: Chevorlet
Model: Z-28 / IROC-Z
Color: Artic White w/ Gold decals
Engine: 5.0L V8 TPI
Trans: 700R4 Auto w/ Overdrive
Wheels: 16" 1992 Z-28 rims (w/ white trim)
Tires: Z-rated Fulda Extremos 245/50/16s (new)
Extra: T-Tops, Tinted Windows, Koni shocks, K&N Air, Edelbrock catback exhaust (soon)

 

Ya, there is a temp sensor for the EGR valve, I always thought it was to enable EGR operation, but gio may be correct.

Didn't GMTech write a Tech Article on the EGR valve and how it operates in our cars? Might be worth a look at tech central?

 

well..

it can't be ignition, I have new cap, rotor, GM 8mm plug wires, plugs gapped correctly, pickup coil, ignition module, and coil..

it's not ignition because the car runs perfectly when the EST is disconnected..

so does the ECM disregard the EGR when the EST is disconnected? I'm trying to narrow things down, I'm thinking the passages are blocked..

 

im just curious,do you diconect the est then start the car or while the car is running and running funny you disconect the EST cause my car is also acting funny and i have a new cap,rotor,coil,plug wires,plugs(correctly gapped),new EGR valve,new Diagnostic temperature switch that screws into the EGR Valve,new IAC and IAC adjusted properly,and TPS voltage right on the money.Im pretty stummped myself,and id like to give that a try with diconecting the est.

 

i start the car with the EST connected and see how it runs, turn off the car and disconnect the EST and turn it on..

i've never (dis)connected the EST with the car running..

i'm going to take my intake, runners, and plenum down to the place to be tanked on Tuesday..

if you'd like me to stay in touch so we can work this out drop me an email: admin@IROC-Z.org

ttyl man

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Webmaster: www.IROC-Z.org & www.GMPerformance.org