Ok I know this has been a talked about subject but I have not seen a definite answer. There is the maf sensor power relay and the maf sensor burn off relay. The power relay is easily available at any parts store. I have yet to find the maf burnoff relay anywhere? The only one I found is for a 86 corvette. Nothing for a 87 Iroc Z 305 tpi? Are they the same relay or no? In the picture On the left is the maf power relay, center fuel pump relay and on the right is the burn off. Same relay or what? If not why can I not find the burn off relay anywhere?

 

 

 

great! Have not seen the schematic before. Thank you. Now I hope I can find one. All those part numbers are old. Like I sais all that comes up for the burnoff is for a 86 vette

 

 

Thanks, I will give it a try. I have a new maf sensor coming tomorrow. The Bosch crapped out. Bought a new Spectra and that didnt work at all. But it threw a code 36. Im hoping the new Delphi maf sensor takes care of it but wanna be ready if I have to buy a relay

 

 

ha! Yeah Im happy Oreillys refunded my money after it had been in the car

 

I put in the Delphi today and the car ran great. Drove about 25 miles. Just about home felt the car bog a bit and up came the dreaded code 36 again? At least the stalling is about gone. Guess I will try those relays.

 

I replaced the maf burnoff relay and nothing changed. Still code 36 so then I was lightly moving the connector wires to the maf power relay and the car died and wont start. I found 3 of the 5 wires were bare! I have had this car 20 years and I sure didnt do that. What is that connector called? Anyone know a part #? I guess I will bring it into the auto store. Im going to replace both connectors. Pretty dirty and gunked up. Im ready to drive this ****in car into a lake! Yeah probaly not. See photos. Thanks

 

Also does anyone know if there is a inline fuse somewhere for the maf power relay? I thought there was a 20 amp near the battery? Didnt see one.

 

The insulation shrinks with age. I had to replace a couple of mine for that also.

https://www.ebay.com/p/86-87-TPI-Camaro-Corvette-Firebird-MAF-Power-Relay-Wiring-Harness-Connector/1117847808?iid=362303249128&chn=ps

Unfortunately, the power and burn off relays are different internally. They have different resistors inside and this makes them incompatible and the ECM will throw a code. They can be opened up rather easily and the correct resistors added, or even a resistor added to a generic bosch style relay and the pigtail changed to accommodate.

MAKE SURE you don't accidentally get the connectors for the relays swapped. This WILL lead to a code 36 as the relays are not the same. I chased this problem for MONTHS because I swapped to an 89 bin and that only throws the code after 6 failures of the burn off function are recorded in a row.

Rather than troubleshooting by Visa, why don't you do the proper tests to find out where the failure actually lies? Like as not with that level of harness corrosion, insulation damage, and age, the problem may in fact be in the wiring harness or connectors. A little voltage drop and the ECM will throw a code as the MAF voltage has to be within a fairly strict range during burn-off or it considers it a failure.

GD

 

I had the wiring tested at a gm dealer. They said it was good. I only started getting code 36 when I replaced the maf sensor. The original Bosch died. The relays are both the original parts. But like I said the car died when I was slightly jiggling the maf sensor power relay wires. It will not restart. Im pretty sure that connection is bad and when I moved the wires it must have blown a fuse.

 

Thank you for the link GD! I had it in for warranty transmission work and had them run a diadnostic and the only thing they found wrong was the maf. Before that another shop found the transmission problem and also the maf.

 

Well the aftermarket MAF's often don't include the burn-off function. Indeed they are not even hot-wire sensors and so don't require the burn-off function. That function was actually found to be pretty much a waste of time anyway later into the 80's and 90's and was removed from later hot-wire implementations. Relying on a good air filter and occasional cleaning with a gentle evaporating degreaser should the element collect too many contaminants. The thin-film style MAF's either have no burn-off function or attempt to emulate it with a simple resistive circuit. Sometimes unsuccessfully.

The best thing to do if it otherwise runs fine with the new MAF is to have a tuner burn you a prom chip with code 36 deleted. Either that or do the speed density conversion and get rid of it altogether. Rbob's EBL system can help with a speed density conversion making it relatively painless.

GD

 

I did get a Delphi that I believe has the hot wire. But yeah I would just as soon get rid of it. Nothing I seem to do gets rid of the code 36. At least theres options. I just wanna get it running again. I will look for that fuse tomorrow. Thanks again!

 

I was chasing a code 36 as well. 86 Iroc Z, based on pictures, looks like the same setup as yours. I replaced all three relays in that location. Napa sells the appropriate relays. I'm not sure the information that the MAF power/burnoff relays are different, is correct. I am using the same relays there, with no more code 36.

AR255, "fast idle relay" (for both MAF power, and MAF burnoff) is what they call it, although it's not, for our application. Ordered two of them.
https://www.napaonline.com/en/p/ECHAR255?interchange=1

AR257, "throttle control relay" is the one for the fuel pump. I replaced it for good measure.

Both types are still made by Echlin.

 

My maf relays are different. Easy to find the maf power relay. Not so much for the burnoff. I did find that Autozone has them. In fact it is the exact same part thats in there. I bought the 2 connectors at Hawks. Mine were really badly corroded. So I will put that stuff in this weekend. Anyine know if theres inline fuses somewhere for those relays? I see nothing in my Haynes manual.

 

The only inline fuse I know of is the one near the battery. It is involved in the fuel injection, so it may be related but I'm fairly certain the engine won't even start without it. So chances are that's not your problem here.

GD

 

I will get a better look this weekend when I get those parts. As soon as I wiggled those bad wires at the maf power relay with the car running it died and I cant get it to start. I was thinking it popped a fuse somewhere?

 

I found the correct burn-off relay in my 1988, 5.7L listed for a 1989 car.
Hope this helps!


I still have Code 36...

 

For my 87 thats the one I use for maf power.

 

I had quite a few problems. The corroded bare wires on the maf power relay blew the fuse to the fuel pump relay. I replaced the connector and also found the 5v power wire at the ecm was bad. I replaced the maf burn off relay and everything is working properly. However I still get the code 36? I had bought a remanufactured 700r4 transmission from GM 3 years ago with the 100,000 mile warranty. It has less than 15,000 on it. I had it in less than a month ago and it already needed a temp senor a 4th gear switch the valve body rebuilt and a solenoid. Now theres a problem with the torque converter lock up not releasing at slow downs causing tooo much load on the engine stalling it. So its going back for that and I will have thhem reflash the ecm. It never ends!

 

 

Yes, Im going to have the GM guys do it after they get my transmission right. I try to do whatever I can myself but transmissions are way over my head. And its under warranty. Cant imagine the ecm will be much of a expense.

 

It is doubtful, at least to me, that the dealer can/will do any reprogramming to eliminate the code 36. This may be outside of their area of expertise. You actually need a chip burner, and someone that has the ability to either lookup your PROM broadcast code, modify it, and put it on a custom PROM adapter board, or that can read the existing PROM, modify it, and put it back on with a UV eraser, etc.

GD

 

Just a re flash is what will be done. I do have a old hyper chip I may toss back in there too.

 

Reflashing isn't a thing. The dealer has to physically change the chip. And if you are putting in a hyper chip (poor idea honestly - they do little and a custom chip can do much more for you), that renders any chip swapping the dealer might do irrelevant. The chip IS the flash. They are the same thing.

GD

 

Oh really. This I did not know? The guy I talked to claimed the eprom could be re flashed? I do have a updated ecm in it but dont know which one? And yes the hyper chip is crappy I just wondered what it would do?

 

Essentially it just dumps in a lot more fuel, and changes some of the power enrichment.... probably sets it up for a lower coolant fan temp, and some other bits. But it certainly will not delete the code 36.

The EPROM can be reflashed - but requires it be removed and put in a special UV eraser...... it's not as simple as whoever you talked to thinks it is - hyperchip is a replacement EPROM...... you see where this is going?

Get a proper chip from a respected tuner like TunedPerformance here on the forum. It's usually less than $100 and you can have them delete the code 36 for you. Don't have the GM dealer do anything with the EPROM or ECU or code 36. They haven't got the brain trust for these cars anymore (for the most part).

GD

 

 

Just run $6e on it. I have $6e on my 86 LB9. Then you can delete the cold start injector as well. Runs great for me.

Either that or someone can probably define 36 for the $32 or at least give the address for it.

GD

 

All great info! Thanks again guys!

 

I just ordered this relay at Rockauto.com

https://www.rockauto.com/en/moreinfo...k=937184&jsn=3

 

Well my car is now running great. I came across this service bulletin. I got this part through a GM dealer they didn't charge me for it. Anyhow it did not fix the trouble light from coming on but the burnoff works and all is well. Its almost time to store the car for the winter. I guess next spring I will look into finding a programmer to just remove code 36. Anyone have any suggestions? Thanks!

 

Which part did you get? The burn off relay or the PROM chip?

GD

 

I got the burn off relay and they updated the prom chip which was part of the service bulletin. Still didnt fix the trouble code. Even with everything working. The relay works the maf works but that code 36 cant be cleared.

 

There are specifications for what voltage the ECM wants to see from the MAF sensor element. Outside that range and it causes the code 36. It is possible to test these conditions.

GD

 

Tested all good.

 

Hhhmm - tried another ECM? They are pretty cheap actually.

 

Yeah I have been looking at them. May just have to wait till next spring. Going into storage next week.Ive had this car 23 years and this is the first time Ive ever had the check engine light come on.

 

That relay is in your first picture on the left, the number stamped on it....

 

Seems like about every GM from that era that I touch (including mine) already has a reman or replacement ECM in it. Mine was original when I got it but was bad. Cracked circuit board I think. If you tapped on the case it would sometimes idle ok. Other times it wouldn't start. Never could establish any communication with it. Just dead. Did sit for 11 years prior though.

GD

 

Yeah mine went out about 6 months after I bought the car.