jbenge

iTrader: (2)

I just picked up a 91 Z28 5.7L TPI car. I've had other thirdgens but no TPI cars so I've been reading about all the things a code 32 could be.

The car seems to run well but the service engine soon light comes on after driving the car 5-10 minutes(about the time it gets up to temp). It doesn't hesitate or miss at all. Does this year of TPI have a EGR temp sensor? Since it runs well I'm thinking that it could be the sensor not sensing that the EGR valve is opening?

Tuned Performance

iTrader: (92)

on a 90-92 7730 ecm it does not use the temp sensor like the 85-89 maf setup uses. I would be looking at the egr solenoid.

jbenge

iTrader: (2)

Will this one work?

http://www.rickscamaros.com/camaro-s...1985-1992.html

I can't see the one on the car very well but from what I can tell it looks like the one pictured. That is the only place I've found online that has the egr solenoid valves.

Tuned Performance

iTrader: (92)

the original one is sandwiched under the coil bracket. should work fine although the bracket is not correct for you application.

jbenge

iTrader: (2)

I changed out the egr solenoid. None are made exacty like the original so i adapted the autozone EVS30 to work. Had to put a different electrical connector on it and modify the rubber pieces that slide on to the vacuum ports. Still had the same issue code 32.

The distributer was making noise and was severly corroded so I put a new one in and set the timing. Also replaced the plug wires and plugs.

I took the old EGR off this morning. I seemed to hold vacuum ok but when I pressed it in with my finger it would stick and not come back without being pulled. I put a new egr valve on it and still have the same problem. I did find that the gasket between the throttle body and plenum was missing, and some of the plenum bolts were loose. The EGR passages in the intake weren't plugged. I replaced the missing gasket and put new gaskets on the plenum. I get a code 32 after driving around 55mph or higher for a few minutes. If i drive in town staying below that speed or stop and go I get no check engine light. The car seems to run well, even better after the new distributer and plug wires. If the tach is correct it only idles about 525rpm when warmed up though but drives perfect. Any more ideas?

jbenge

iTrader: (2)

I've also bypassed the thottle body coolant lines. I normally don't drive the car in cold weather but I drove it today when it was about 32 degrees could the lower intake air temp have any affect on how it senses if the egr is functioning?

Tuned Performance

iTrader: (92)

you might want to read this article, is it a free flowing exhaust ?

http://www.gearhead-efi.com/Fuel-Inj...BI-EGR-code-32

jbenge

iTrader: (2)

Thanks for the link. The car has the original dual cats and a 3in dynomax catback exhaust system. I wouldn't think it would cause that but you never know. A carb or ls swap is sounding better all the time...I've never been a tpi fan.

jbenge

iTrader: (2)

I just went out and double checked the vacuum lines again and they did hold vacuum, no holes in them. Then I added a T into the vacuum line that feeds the egr solenoid(comes from the throttle body on the bottom side). I'm getting 0 at idle ant goes to 15 or so if I rev then engine.

Maxdtran

Dear all,

I also have a 91 Z28 5.7 with the code 32 "Service Engine Soon" light on. I've owned it for about 3 months now.

At first the car had a slight hesitation from start and go where the EGR valve was stuck opened and the hoses all had leaks. So i decided to tightened all the leaks. Once vacuum was established the the car idled real bad. But no service engine soon light ever came on.

So far I've changed the EGR solenoid (from a vette), EGR valve, MAT, MAP, CTS, TPS, Ign coil (MSD), wires, plugs, dist cap, rotor, vapor cannister, vapor valve, and cutted the airbox! The car runs just fine. But the code 32 seems to love this car. So far I cannot get rid of it. After changing out all of these I'm still seeing this code 32 after i drive on the highway for about 15 minutes. Does anyone have a clue as to fixing this code 32.

jbenge

iTrader: (2)

I did another experiment this morning I hooked my vacuum gauge to output of the egr solenoid valve and ran a long vacuum line all the way inside the car. I drove the car and watched the vacuum gauge. When cruising at a steady speed around 50 or higher I could see the vacuum gauge move to about 5 and pulse off and on. Anyone know if that is what I should see? I'm guessing it is by everything I have read.

So I think this proves that the EGR solenoid works. The EGR valve is brand new and I made sure it did hold vacuum. I think the EGR system is operating as it should but for some reason it doesn't think it is. Could it possibly be a bad MAP sensor not sensing the EGR opening and closing? I thought if the MAP sensor was bad it would throw other codes or not run well though.

jbenge

iTrader: (2)

Sounds like you have a similar issue as me. Only thing I could think of is to do what I have done and put a T in your vacuum lines before and after the solenoid and attach a vacuum gauge to see what is going on. Prove you are getting vacuum to the solenoid, then prove that its opening and providing vacuum to the egr. Maybe we should just remove the Service Engine Soon light bulb and be done with it? This tpi engine is already driving me nuts.

herbyj

Tuned Performance

iTrader: (92)

the egr temp switch does not apply to the 730 ecm.

Maxdtran

Jbenge,

Don't get discouraged. I'm reading up on this code 32 and discovered that this is a recall issue, but has stopped being serviced by GM 12 years ago. I've did a few things to research and manouver around this PIA problem. I foud a used solenoid on ebay (stated that it works) so ordered it. Let see if this will fix the problem? At the same time I will be contacting 1 800 smog help to rebuild my original one. If they can't rebuild it then you can have an smog free vehicle due to lack of emission products available.

But here are the other options.
One: is you can get the prom reprogrammed to disable the EGR. You can either do it yourself and find a link in here in this third gen forum that'll guide you through it.

Two: There's a guy on ebay http://www.ebay.com/itm/190645297857...S:1123&vxp=mtr
He will send you a programmed prom for $89 free shipping. I just sent him a message if I install the chip will I have to extract all of the EGR items or can they stay? 82-89 camaros run better without the EGR, but 90-92 will need the EGR system to accelerate on the highway at higher speed at a precise moment. Note the horsepower difference on the 90-92 Stock(245) compared to the 85-89 (220-235)

Third: Local Dyno shops that work on muscle cars will also be able to assist, since they run into this infamous codes night and day. Shop around if you like.

Fourth: I will be contacting jet $129-$300, superchip $49, autochipsdirect $59, to see if their chips are a prom direct replacement. And if so was it set with the EGR repair after the recall? I'm thinking it could also complete the EGR setting to be corrected and should give us better MPG.

We'll see I'll be emailing them by tonight since they don't work on sundays anyways. Who knows maybe the performance chips are an enhancements and plus who knows.

If anyone out there knows of the 4th option with the performance chips assisting on the code 32 recall to be repaired, please fill free to let us know before we keep doing all these nasty trial and errors.

herbyj

Oh snap, that's the pre-`91 chart

Here's the info/diagnostics for code 32 that applys to 91-92 Z28 305/350





CIRCUIT DESCRIPTION:

The Exhaust Gas Recirculation (EGR) valve vacuum is controlled by an Electronic Control Module (ECM) controlled solenoid. The ECM will turn the EGR "ON" and "OFF" (Duty Cycle) by grounding CKT 435. The duty cycle is calculated by the ECM based on information from the coolant temperature, air flow and engine rpm. There should be (NO EGR) when in park or neutral, Throttle Position Sensor (TPS) input below a specified value, or TPS indicating Wide Open Throttle (WOT), or the MAT sensor below 15~C (59~F). With the ignition "ON," engine stopped, the EGR solenoid is de-energized and by grounding the diagnostic terminal, the solenoid is energized.

The ECM will check EGR operation when:

• Vehicle speed is above 30 mph
• MAP is as listed in table below
• TPS is between 5% and 30%
• No more than 0.4% change in TPS

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. By grounding the diagnostic test terminal, the EGR solenoid should close and hold vacuum. The vacuum may bleed off slowly, but this is not considered a fault.
2. This test will determine if the electrical control part of the system is at fault, or if the connector or solenoid are at fault.
3. By plugging the EGR valve side and ungrounding the diagnostic terminal, the solenoid valve should open and allow vacuum to bleed off through the vent
4. With the engine not running and vacuum applied to the valve, the valve should move to the fully open position.
5. Due to this engine using a negative back pressure valve, the valve should close when the engine is cranked over.

jbenge

iTrader: (2)

Thanks for the info, let me know what you find out. I'm only planning on running this engine for a couple of years but I would like to get rid of the code 32 if possible. A custom chip may be the way to go.

Maxdtran

Okay j benge,

I just installed a used EGR solenoid, haven't driven long enough to see if it works or not, but sooner or later its gonna go bad. So I'll be back to square one anyhows since they don't make the exact one for the car any longer.

But on the chips. These performace chips will all have the EGR code on them. By law you cannot take them off for emission purposes. Yeh Like we give a **** right! The guy on ebay is the fastest and safest bet. If you decide to burn your own prom. The steps of programming, soldering on a new one, and all the equipment will cost you around 80-200 dollars. Depending on how you shop. But the nightmare is the soldering on a new prom or create a ZIF bracket for future use. Still that's buying the items, programming a new prom, de solder the prom off the memcal, solder back on a programed prom to the memcal, and then installing it back on the ecm.
This is a PIA if you ask me.

http://www.ebay.com/itm/190645297857...S:1123&vxp=mtr guarantees his product for 15 days. If not happy he'll refund you and it's just detach the memcal and install for $89. No soldering required. That's it!

I use this car as a daily driver. I'm not going to go crazy on all this programming until I decide to turn this into a Twin Turbo Race Car. But even if I decide to or not, I'm just going to do this simple fix for now. Because I can't stand seeing that Service Engine Soon light any longer.

Hope this helps.

jbenge

iTrader: (2)

Maxdtran,
Thanks for the info, keep me posted. When you get one of these chips do you just plug it in on the ECM or do you have to solder it? I'm from the world of carbed race engines and LS engines I don't know much about tpi.