IRC

I noticed that there are some differences in my 85 from other L98 years. Can someone tell me where is my EGR tube is? is it an internal passage within the head? All the pictures I have seen of the MAF relays has them behind the battery. I have one below the brake booster, only one behind the battery and one by the wiper motor. Can anyone tell me which of these are the burn off and power relays for the MAF? Or provide the part numbers for each. I am trying to sort out a MAF code and have checked wiring already. The previous owner put an after market MAF on trying to stop the code but I'm not sure if he replaced the relays. Thanks for your help.

Jim



[Modified by IRC, 7:43 PM 5/9/2004]

jmrl98

The one behind the battery is the power relay, your burnoff is up under the dash, passenger side by the ECM. If you have a 4+3, one of those mentioned is the OD relay, the other is the fuel pump relay.

SBNova

:iagree:

Your burnoff is behind the "breadbox" in the dash. Its a silver metallic box thats expensive- hope you dont need one. I think your egr is in the head. I would have to look at mine but I dont think theres an external tube.

Bluevette85

85's don't use maf relays. As stated above, there is a burnoff module behing the breadbox. I have a working one and a remanufactured ecm for $100 + shipping. What codes are you getting?

Egr is internal to the manifold and heads.

IRC

I have 3 codes

32 EGR
33 MAF
43 Knock Sensor

I have followed the Haynes EGR trouble-shooting process for EGR but it is intermittent and hard to nail down. The previous owner replaced all the hard parts in the EGR system and when there is no code 32 it passes are the steps the manual says to test for. But I am more concerned about the MAF and KC/ESC codes.

When I clear codes everything is fine then under medium acceleration the car will miss/stumble the SYS shows, it then backfires through the TB under everything but WOT. Turn the car off and everything is normal until it happens again. It happens much more when it’s cold and seldom when it’s hot.

I have checked MAF wiring it has a new NAPA MAF part number 2-18850 and the car will not run with the MAF unplugged. The MAF does not seem to have a wire in it but what looks like a circuit board.

I have not started to trouble shoot the code 43 yet. Bluevett85, do you have any insight. Any help would be very much appreciated.

Jim

vader86

Fix the MAF code before you fix anything.

Always fix the code coming from the front of the engine first, usually you can eliminate at least one other code, possibly both since MAF readouts influence everything.

Bluevette85

What I have noticed with the Maf's with the circuit board inside is that they report a higher maf voltage than stock which can set an error code. Try swapping a maf from another 85 vette or f-body, clear the codes, and see how it runs. The 86-89 stock mafs may not work in an 85.

You ecm could also be failing. I can send you the shop manual diagnostic pages for your codes.

JAKE

A couple of years ago when I was trying to verify a MAF problem I borrowed my buddy's MAF of his 85 and it worked fine on my 86.

Let me know that my MAF was bad.

Jake

IRC

Thanks for the replies, I will continue the battle tonight after work.

Jim

JAKE

I believe the metal tube that runs from the #7 exhaust to the intake manifold is called the EGR tube. I dumped mine so long ago I've forgotten, for sure, if that's what it's called.

Jake