I have an 88 IROC 350 TPI L98, all power options and A/C, 700R4, no major mods.

A few hours after doing a tranny swap, my car just about stalled out and got a horrible idle (almost like I had a nasty cam!). Then the SES light came on with a 33 (33. High voltage (low vacuum) at mass air flow sensor (or MAP sensor)), then smoothed right out and continued on.

After some quick diagnostics, it looked like it was a relay, so I replaced that. There are 2 identical relays on my car on the driver’s side firewall that seem to be closely related to the MAF. If I pull out the closest to the fender, the car runs fine and the SES doesn't even light up. But the MAF sensor never lights up like a toaster either. So at that point we figured it wasn't the relay.

If I leave both relays plugged in, the MAF sensor runs constantly and eventually kills the battery, plus will give it the horrible idle again and set the code 33 again.

I was able to acquire a brand new stock bosch MAF sensor for testing, so I plugged it in with everything else connected, and sure enough it lit up, which means it's not the MAF sensor.

Next logical step was on to the computer to see why it was getting constant voltage. I happen to have a spare computer and chip lying around, so I swapped chips first to see if there's any difference, which there wasn't. I was about to swap the computer it self, but then figured I'd test it with no computer at all plugged in. There was still voltage and the MAF sensor lit right up.

I can't seem to find any wiring diagrams on the L98 from the material I have, so I can only do so much.

Does anyone have any wiring diagrams for the L98?

Is there anything else I should check?

What else would give the voltage to the MAF sensor? The constant voltage is on before the relay, but not sure where it's coming from.

Are there any other sensors involved here? Or am I just looking at bad wiring or a bad ground?

Any ideas would be appreciated, as this is driving me nuts!!!!

 

MAF cars have two relays: power and burnoff. Replace both and your problems should go away.

 

does as mentioned above, replace both relays. the failing burn-off relay maybe sticking in the "ON" positon. hence the wire stays red all the time and the battery eventually drained.

 

Hrmm... Ok... I'll give that a shot now... Thanks for the fast replies!!!
:hail:

 

Ended up checking out the wiring, and found that the entire wire loom is pinched between the bell housing and the block!!!! hopefully all will be well tomorrow morning when we loosen up the tranny and pull it out, as I don't want to deal with the wiring disaster!!!!