MDC9966

Well, same symtoms as a lot of others, SES and code 32 after about 20 miles at 70-80mph. So far I"ve checked the gas cap (clicked a bunch), sealed loose cat pipe, replaced air pump, air diverter valve, egr, egr solenoid, egr temp switch, replaced all vacum lines under plenum, checked all connections with vac pump, checked passages for clogs. I checked the voltage at the ECM and it reads 12V. Grounded it at the switch and it works too. I can manually open the valve with a hook and the heat tube heats up. When the tube heats up the voltage at the ECM drops like it is suppose too.
SO!, the EGR is not opening when it's suppose to. It is getting 7-15 vacuum while driving. I also tested it by hooking up a direct vaccum to the EGR and with the motor running it wouldn't open the EGR either. It is not getting the negative backpressure to allow at least 7 vacuum to open the valve. I don't know why. I"m sure it is not opening though. I bench tested it on and off the car with the motor not running and it works.
Any ideas anybody. I'm looking into a chip and I also consider welding a fitting and locationg the temp switch on the exhaust pipe coming from the exhaust header. That should give the ECM the signal to drop voltage and pervent code 32.
By the way the car is an 86 L98 stock exhaust with cats, auto.

vettenuts

It is a pressure balanced system. Any intake mods? I didn't have the problem with mine until I ported the intake, cat back and ported plenum had not set if off prior to porting the intake. Guess that just took the balance too far out.

INTIMIDATOR ZO6

I'm interested on the fix because I have a 1990 L98, and just today replaced EGR Valve and EGR Soliniod Switch and still have a "Service Engine Soon" light come on when I crank it up to take for a spin :mad So my plans for tomorrow is to cut out my pre-cats (already took out the catalytic converter/running true duals) :D Also the vette has 115K miles :cool: It's running like it's bogging down at all MPH :confused:


[Modified by Intimidator454, 10:00 PM 11/26/2001]

Juliet

Curtis - Thanks for the update. I've been busy with exams (ignoring my code 32). Now you've really got me wondering about mine too!

Intimidator - Are you definately getting code 32? Or do you by chance also have 34? When mine was bogging and running like I had bad gas it turned out to be one of the MAF solenoid - behind the battery closer to the car centerline (there are 2 side by side there with cute little circuit diagrams printed on top of the cases). :D Mine was intermittent - car ran like crap. Finally it totally fail - car wouldn't hold an idle AT ALL. At the same time I had the code 32 issue. You can jump A&B on the diagnostic connector under the dash and turn the key to ignition (car not on) and count flashes to get the codes. ~Juliet

MDC9966

Well today I had an extra heat riser welded to the exhaust between the manifold outlet and the precat. I'll thread it in tonight and test drive. If the temp get's out enough it should lower the volts and stop the SES light. I'll post my results.
Also, if this works I'd like to remove that pipe going to the exhaust from the manifold. I know how I can plug the pipe coming from the intake but does anyone know if that pipe is a through pipe going into the exhaust. I think it's a blind bottom like a heat riser. Will I have to plug that end too.
Anybody know?

WINNER

Curtis, i sent you an e-mail.

INTIMIDATOR ZO6

Juliet, I haven't re-checked the code from the last time :confused: So it could very well have a code 34 :mad I'll try to find the soleniod and see what happens as soon as I can weld in a straight pipe to re-place the gap in my exhaust where the pre-cats used to live :D Many Thanks :seeya


[Modified by Intimidator454, 10:08 PM 11/28/2001]