Hey guys, first I would like to introduce my self. Im new to the tpi world. I'm more aquatinted to the ls stuff and just picked up a 1986 iroc with a LB9. I've been having trouble with a code 36 which I understand to be maf burnoff relay? I recently replaced the maf and the two relays. I verified that the maf is going thru it's burnoff cycle. So the maf works and the relay works. So can any one tell me why I'm getting this code? What else do I need to look at. Thanks

 

Anyone? How could I be getting a code for missing burnoff voltage yet I can hear the relay click and see the maf wire glow? This code is killing me!

 

Did you reset the ECM after putting in the new parts?

 

Yes I did!

 

Does the car run okay?

Reason I ask is I *think* when the burn off occurs, the info is sent from the MAF sensor back to the ECM...if there was a poor connection on the plug or the ECM not allowing the proper voltage to be sensed on the burn off, I'd think incorrect MAF info would be sent as well.

 

Yeah it runs great. Is it possible that the burnoff cycle is happening and the ecm just doesn't see it happening? Would this mean a bad ecm? Because the burnoff cycle is defiantly happening. The relay clicks the maf wire glows I checked and cleaned all the connections. Reset the ecm and after I shut it down and fire it back up the code is set. Also I changed the battery thinking maybe not enough voltage but that did not work either

 

I sure hate saying "change the ECM"...have you reseated the connectors at the ECM?

 

I haven't touched the connectors at the ecm. I will give it a try I may change the ecm to. I don't know what else to do. Are the ecm's on these a common fail point? Is it something that will go bad eventually?

 

I wouldn't same common failure, and certainly not a part to replace "just in case".

I did look and code 36 in my manual, the only feedback the ECM sees is from the MAF sensor signal...which would lead me to think if the ECM is bad and not getting the BO signal, then it would also be getting improper MAF signal while running.

A scan tool can read the MAF signal, but unsure if they read the BO signal, I've never tried it.

 

Thanks for your help man. I took a look at the ecm and it looks ok. I did notice though that it's a remanufactured ecm. I'm not sure what brand. I'm wondering if I should just change it out for a acdelco reman or a good used one.

 

these cars do not tolerate in expensive MAFs. such as what you get at auto zone ,advance ect. don't waste your time and money fooling with a re-man MAF and its somewhat tricky to get the correct relays. the parts counter may SAY its the one you need BUT.allow me to share the part numbers. burn off relay GM#10094701.... MAF power GM#10067925.... and the MAF itself, GM#14094712.... and don't forget that the fuel pump relay plays a part in all this. I get my parts from oreilleys BWD relays and a NEW MAF sensor made by a company called "rich porter" it was $450, but hey ,its the cost of playing with TPI. I hope I have helped you a lil

 

Thanks for the help. I actually found this out the hard way with the maf. I bought one from advance auto and returned it and bought an acdelco reman which works well. I also replaced all three relays with acdelco units. I'm gonna try changing out the maf connector and relay connectors. Hopefully it's just bad connections

 

Well I'm stumped! I replaced the connector for the maf and all three relay connectors (maf,burnoff,and fuel pump) reset the computer and still code 36. I don't know what else to do. If anyone has any suggestions please chime in!

 

Your distributor being weak can throw some of these things out of wack

 

Really? Like the electronic spark control or the actual distributed itself?

 

at this point I would go to oreilleys and get a re-man computer.#7165. and if that don't do it. these cars were released with a wonky PROM. (ask me how I know!) there is a guru on here named "tuned performance" he can provide you with a updated PROM that may well be the end of your problems. he helped me and countless others on this board. and he can help you as well. shoot him a PM. also a factory service manual is absolutely impossible to do without. I got mine from "helm inc". un plug your ECM and use a dvom meter to check your grounds. bad grounds are one of the biggest pains in the a$$ on these cars. but in the end ,man what a satisfying driver they are. good luck ,and let us know what is happening

 

of course things like your coil and ICM and pick up coil need to be up to spec. but none of these things has anything to do with a code 36

 

Thanks for the advice. I may just have to try a new computer. I don't know what else is left

 

I have been chasing this issue for 2.5 years.
About that new ECM, I have/had the same issue you had in my 87, I would not get a new ECM. The problem for me is the ECM is seeing ~2.2-2.4v and it requires ~2.52.7v signal to indicate that the cycle happened. I have two ECMs myself and both produce this issue. My problem lies between the MAF and the ECM.

The signal wire actually runs directly from the MAF to the ECM via a green wire. Where the burn off voltage goes from the relay to the MAFvia a blue wire, and travels through the green wire to the ECM to indicate the cycle is happening.

I know for a fact that my burn off occurs, as I can both trigger it manually and feel it occurring by holding onto the relay. You will know if that cycle does not complete.

In the end I never could solve the problem but I had a custom chip burned that raised the tolerance for the code to be thrown.

Start and check your voltages at the ECM and MAF. Google austin thirdgen wiring diagrams to get which pins to test.

I believe you should check connector 1 pin B12 on your ECM. Probe with a multimeter into its harness and groud the other end somewhere. Have someone or you turn off the car after it has been running a while and see if once the voltage drops to zero briefly it goes back up. I like to ground my multimeter to the door jam switch.

 

Thanks for you suggestions! It makes me feel a little better knowing I'm not alone and other people have had the same problem with there cars. I was actually considering a chip that would raise the tolerance signal since I know the burnoff is properly working.

 

My experience was quite different.. I had a code 36 and decided to take the intake apart and see what was up just in case. What I found was astonishing.. In my air filters there was a set of plyers sitting on them (the garage that changed the hood latch years ago left it there no doubt..), the air filters were SUPER dirty (I cleaned them), the intake tract was dirty (cleaned it too), the MAF sensor screens and element inside were both dirty (I cleaned the screens as best I could and shot pressurized air inside the MAF sensor and perhaps this broke off crusty stuff from the element?), I sprayed throttle body cleaner inside the throttle body and wiped it all down so it's clean, cleaned MAF connector, re-installed everything, unplugged battery for a few mins.. Re-connected.. Code never came back and I've been driving it for weeks now and it runs perfect. Maybe try cleaning the MAF that is there with pressurized air and clean the grease of the screens, it might all help!

 

NP, I hope my suggestions help you out, http://austinthirdgen.org/mkportal/m...ine_wiring.gif , is a link to the wiring for your car I believe. I was ready to pull my hair out over this since I knew the burn off is functioning but the ECM still set the code because it is not "sensing" the correct voltage values.

I just recently ran a new signal wire to the ECM as I was getting some VD on there, I am not sure if that is a viable solution for you though, or if it would even solve the problem, but test it first..

If you do want to get a chip burned contact Tuned Performance, while I believe his account is turned off he has other methods of contact.

See this thread for him: https://www.thirdgen.org/forums/dfi-...ml#post5774306

He really is a great guy, took care of me beyond what I expected.

 

This sounds a lot like what I went through. My check engine light kept coming on no matter what I did. Finally I took it to an older GM Dealership in town and they traced my issue to the ECM and the harness that hooks to it loose solder on some of the wires shorted out the ecm and the maf and the burn off sensor. Once the ecm and burn off sensor were replaced I then went on line and bought a New MAF, a Granatelli for 309 at Summit Racing. It fits both 305 and 350 TPI and is part number 350100. I hope this helps as well. All I know is now my car runs great. but then it only has 19k original miles on it to. it seems like this is a common issue the ecm causing all kinds of code failures. If I had it to do over again I would have started there in the first place. Mine is a remanufactured one, but there may be new ones still out there somewhere, I'm not sure.