i am getting a MAF code and i want to know if my car has a MAF burn off relay? if so i want to be sure i replace that with my new MAF, whats a burn off relay usually cost?

also my timing is a bit off (i thinbk its maf related) and i know there is a possibility of it being a stretched chain, i want to know if i can use a noisy gear drive in an 85 TPI car??

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1989 pontiac firebird
bright red exterior(just repainted)
grey interior
5 spd
305 TBI (stock)
WS.6 formula wheels
3.73 posi rear end
http://members.aol.com/j007golden/Mikey89.html
http://www.geocities.com/firebird/myfirebird.html
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1985 trans am
factory bright yellow
4 wheel disks
16 inch wheels
305 TPI
power antenna and mirrors
t tops

 

My condolences...

The 85 doesnt have a burnoff relay, it has a separate module though... and its quite expensive. I'd check for air leaks past the MAF sensor to make sure the engine isnt getting air from somewhere else that it shouldnt be, and maybe try a new sensor. If thats not it, you may want to look into a swap rather than replacing the maf module.

 

Max is right, that burnoff module is over $950 at the dealer and there is no aftermarket for it, so the dealer is your only source. On Camaros it is piggybacked to the ECM, on the Trans Am it is mounted with it's own bracket just above and forward of the ECM.

One of the easiest ways I found to see if it was working was to listen very closely to the passenger side of the dash when turning the car off. A few seconds after turning the key off I would be able to hear a slight click from the solenoid in the burnoff module as the burnoff cycle was complete. Sometimes it would work, sometimes it wouldn't. I got tired of it being so unreliable and with Mike Davis' help we switched it to the '86-'89 setup which eliminated the module and instead uses 2 $9 relays. Also, the "165" ECM is 51 times faster than the "870" ECM that was used in '85.

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Kevin Irving
85 Trans Am WS-6, 305 TPI, custom burned '86 PROM with '87 "165"ECM, Accel Supercoil & 8.8 Wires, Rapidfire #2 @ .055", MSD 6AL, 1.6:1 Roller tipped rockers, Homemade AFPR, K&N cone, no airbox, Aluminum Driveshaft, Wonderbar, TB Coolant Bypass, Ported Plenum, Descreened MAF, Syclone Fuel Pump, JET Airfoil, Mobil 1 synth in all but transmission.

http://www.geocities.com/transam85tpi/

 

O.k. - it's expensive. Brutally so. Has anyone tried fixing a MAF burnoff module? My guess is that something in the power circuit goes on them. Maybe a board-mounted relay? A transistor? Thankfully, mine still works. Before shelling out more $$$ than for a miniram, I'd take a look at repairing the thing if (when)it does go.

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-Greg

'85 Trans Am - WS6,TPI:
Original owner, original paint/engine/interior, plus the usual bolt-ons

 

Never tried, but if it doesnt work you cant hurt it, right? Hell for a grand you may as well give it a shot.

 

When mine went out, I brought it to just about every electronics/electrical repair shop in the Hampton Roads area and no one wanted to touch it. Why?? GM won't let loose of the schematics and has branded the burnoff module an "unrepairable item".

 

Usually, a bad electronic part reveals itself thru discoloration or smell. Often, a piece of equipment can be repaired w/o the schematic. If I ever get the chance, I'd like to crack one of these things open. I'm sure its full of pretty basic technology.

I'm really curious now - what the heck can be worth this much money and do so (relatively speaking) little???

 

The problem with mine, was that it would stop working intermittently, and when I opened it up there was no evidence of anything frying or burning up. I even cycled the ignition key a few times and watched the solenoid do it's job, and it always worked when I had it opened up, but I wasn't about to drive around every day with a burnoff module hanging out of my dash, so it was swapped out. There's really not much to it, about 20 resistors, a few caps, a heat sink and a few other doodads, and that's it. The dealer told me that the reason it's so expensive is purely because there weren't many made since it was used only for one year. It now has a home holding down papers in the top of my toolbox..... the most expensive paperweight I've ever had.

[This message has been edited by Kevin Irving (edited June 13, 2001).]

 

ok so what are the chances of my problem being he burn off module? i always get the MAF code from my check engine light. If i buy a new MAF and later find out my burn off is bad wouldnt i fry my maf??

BTW other than idle problems would a bad maf or burn off make my performance worse? id imagins so but i am unsure.....

 

A bad burnoff module won't necessarily fry your MAF. I would check the usual, air leaks in all the ducting, TPS voltage, etc. Take the five pin connector off at the MAF and clean all the pins on the MAF and all the sockets in the connector with a jeweler's file and/or a q-tip with alcohol. If the weatherpak on the connector is bad at all it can get corroded in there in a hurry.

Pretty much all the burnoff module does is supply power to the MAF (hence a code 33 when it isn't working right) and perform a timed burnoff cycle when the car is shut down, heating the wire to well past red-hot for a few seconds to "burn off" any dust or particles that might have gathered on the wire. I have the troubleshooting tree from the GM service manual somewhere here (I just moved)and will scan it for you and post it when I find it. Good luck

 

thanx for the info, ill clean the connection off today. I think my MAF sets my timing off a bit, do i need to reset it or will it adjust its self acording to what the car wants? If i need to adjust it would it be worth it to reset my timing before my new MAF or would it just retard its self again? also how do u set TPS? sorry for all the questions.

 

TTT

BTW i do hear a click after i turn the car off right by the passanger side dash pad. I havent been paying that much attention to it but it seems consistant becouse its a very familar sound.

 

Hey MadMax, I was just wondering...you stated that the '85 firebirds did not have a burnoff relay, instead having a burnoff module. However, in my '85 service manual, the wiring is seen going to the burnoff relay. Was this a misprint? I am trying to find out because I posted a question on the connector on what the manual is telling me belongs to a relay. Is it the module? Can you tell me what the plug looks like? This '85 setup I just bought (unfortunately) appears to almost be done. I would like to finish it and swap it in my Chevelle. Thanks!

 

My 85 Firebird Service Manual also refers to the burnoff relay, but there is no such animal in the 85 setup. I figure that the book is referring to a part in the module when it talks about a relay, but there is no relay in there either, all I saw in there was a solenoid, a bunch of resistors, caps, a heat sink and some other junk, but no relay per se.

 

Kevin, I'm sure that "solenoid" is the relay. A solenoid is just an electromagnetic device with an armature and a coil field. Some board mounted relays (as well as open types) look different because they're not in a case (check out a "washing machine" relay sometime). According to the Helms schematic, there's something in that module that has coils and contacts. That must be it - and its probably the thing that fails most.

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-Greg

'85 Trans Am - WS6,TPI:
Original owner, original paint/engine/interior, plus the usual bolt-ons