OK experts - need your help.

Have an 86 giving me a 36 code (MAF) issue. I have had this code for awhile. Replaced the MAF relay and burnoff. Didn't correct it. Took off the MAF and cleaned it (didn't touch inside). I removed the screen long ago so that's not related. Made sure the connector connects well even if the wire harness looks a little beat. Still didn't correct it. Is it the ECM or is there something else I need to check?

Possible related problem? I get crappy gas mileage and there is (more significant than normal) a fine black powder coating the inside of the tail pipes. Am I running rich? Is it related to the Code 36? Or is this just another project separate project for the list?

Last interesting item. Just replaced the plugs and wires. Old wires looked awful and were all bound together. Put on the new ones and seperated them all - looked great. Took the car out and it ran rough. An old Vette friend suggested I bind the wires together again. I figured what the heck and did it. Car runs better!

Coincidence or sound electrical theory behind that?

 

If the code 36 still exist after replacing the burnoff and power relay and cleaning the MAF then there might be a problem with wiring. Recheck the connections at the MAF and ECM. The MAF could also be faulty even after cleaning. This would cause a richer than normal condidtion but mostly just in open loop. First I would disconnect the battery for atleast 30 sec or take out the ECM fuse engine off. This will reset any codes and if it still exist then could be the above.

 

Disconnected the battery for awhile as I was working on a few things with the doors open yesterday. Started up the car and within a few seconds that Check Engine Light popped on. Checked it and it's a Code 36 again. Checked the wires and they look fine till they run into the wire harness that runs along the head. Can't see them after that unless I pull the harness apart. I'm afraid to do that because there are OLD wires in there and I don't know how much damage I'll do.

Other than a wire problem, is there anything easier and less potentially damaging I should check first?

 

Well just because you cleaned the MAF doesn't mean it is still good. It would be nice if you had a spare laying around to try out because they are not cheap. Do you have a FSM or and troubleshooting chart for the code 36? If not I will try to lead you in the right direction (I have a 86 also). You can also check the connection at the ECM but it is buried under the pass side dash and you would have to remove the carpeted panel to get to it. Let me know.

 

Well, if you have a FSM, I know you have a code 36, but read the second paragraph of code 34. There are 3 relays that affect the MAF, you've replaced 2, now read the section I just mentioned...then try a new Fuel pump relay.You should also make sure all connections are snug and corrosion free.Also when you're looking at the FP Relay...check the wire insulation on the wires going into the relay...you might be shocked!

 

 

http://forums.corvetteforum.com/show...post1555282320

Here is a flow chart that should work from the FSM. You can by pass the parts of the harness by running seperate wires from one end to the other. Just check one at a time, but it sounds like with an ohm meter and test light you should be able to find your problem.

 

http://members.shaw.ca/corvette86/Code%2036.pdf

 

Thanks Guys. All the code 36 info is great. I had gathered it all and was ready to read it to get ready for some real work analyzing all of it this weekend. So sure enough (like feeling sick and going to the doctor), when I got to the car it isn't sick anymore. No check engine light! I'm thinking it must be a connection somewhere right?

 

It could be a short in a circuit. Did you reset the code. The ECM only throws the code if it has seen numbers out side of its limits.

 

Reset the code? Do you mean disconnect the battery for a couple minutes? I disconnected the battery and it went away. Started the car again today and no Check Engine light. Is there something else I need to do to reset the circuit?

 

No, nothing else to clear codes, but you may have and intermitent problem..in others words, it may come back, in which case you may have a bad connection etc.

 

don't be disapponted if it appears again. An intermitent code shows up sometimes and other times not. I hope not.

 

So far so good! Code has not returned. Probably because I haven't driven it much. Reason is I have a larger problem but that's another thread (Easy Question). Thanks for your help!!

 

before you replace everything there are some things you can check first

first of all 36 is the mass air flow burn off circuit not the mass air flow
so it means the little wire is not heating up for the 2 seconds to burn off any dirt.

i have the same problem right now and tested it with a scanner
i reset the codes and they set right away again
changed the mass air flow nothing
changed the relay nothing

so i disconnected the terminal at the mass air flow and put a meter on the circuit that should get power
then i shorted the ground on the relay
that relay fired and set the second relay to fire and it sent power to the mass air flow terminal
so now i know it isn't the relays
it could be the rebuilt mass air flow but more likely the ECM or a bad wire coming from it.

i plan to check to see if the ground circuit to the relay works for the 2 if the ECM isn't sending the signal to the relay then that is the problem.

the car goes into limp home mode and runs like crap when the light is set

you may ant to try this
disconnect the battery then take the chip out and replace it with a spare. i did that and the light went off. Only when i restarted the car did the light go on and there after. each time i switch the chip it goes out on the first start up. This leads me to believe it is a quirk in the ECM

 

i too have been chasing code 36..i replaced ecm, maff burn of relay,maff power relay, fuelpump relay, and checked every wire connection, and then replace the maff sensor itself..all the relays work , i can hear them set, check for power at the maff sensor, read 5 volts to the maff, and the mircro-voltage from ecm Sensing circuit . al read normal. reset for code.. the minute the car starts the F*&%$NIN "check engine litecomes on....although the car runs and idles great the code still read 36.. whT THE f*&%ck..lIKE I SAID BEFORE I AM TRIED OF FIXING THESE CARS!!! retired the 87 and bought C5 . i gonna do the same with the 89 soon!

 

I hope I don't have that problem fixing mine
Are you sure the ECM works that you got?
Did you reuse the same chip?

I hooked up a snap on diags on mine and the code 36 sets on start up.
The ECM senses the little wire in the mass air flow didn't heat up to burn off any dirt or some other problem with it. The power to the MAF should only be powered for a few seconds or it could set for being on to long.

When i took the stock chip out and put my hypertech chip back in it didn't set the code. But once i shut it down and it set the code and every time after that

Then i took it out and put the stock one back in. It didn't set again until i restarted it the second time.

Try that if you have a different chip around to see if it does it for you to. This leads me to believe it is a combo problem a lot of people may be having.

my stock chip also does not put the rad fan and overheats.
When i put the Hypertech in the fan goes on all the time.

My car also runs fine except it runs rich because it is in limp home mode
It also sucks gas like that

I will be trying different ECM's
what controller do you have?

1987 Corvette
Controller (ECM)
Ident: 1227165
Ident: 16198445
Ident: 88999201 Located RH kick panel.

Interchange

ASTRO 87-90 Elec Cont Module (ECM); (behind right kick panel), 4-151 (2.5L)
BLAZER S10/JIMMY S15 87-88 E1ec Cont Module (ECM); 4-151 (2.5L)
BLAZER SI0/JIMMY S15 91 Elec Cont Module (ECM); (6-262, 4.3L), ID 1227165
BRAVADA 91 Elec Cont Module (ECM); ID 1227165
CAMARO 86-87 E1ec Cont Module (ECM); 8-305 (5.0L), EFI
CAMARO 87-89 Elec Cont Module (ECM); 8-350 (5.7L)
CAMARO 88-89 Elec Cont Module (ECM); 8-305 (5.0L), MFI
CAVALIER 86 Elec Cont Module (ECM); 4-121 (2.0L), MT
CIMARRON 86 Elec Cont Module (ECM); 4-121 (2.0L), MT
CORVETTE 86-89 Elec Cont Module (ECM)
FIREBIRD 86-87 Elec Cont Module (ECM); 8-305 (5.0L), EFI
FIREBIRD 87-89 Elec Cont Module (ECM); 8-350 (5.7L)
FIREBIRD 88-89 Elec Cont Module (ECM); 8-305 (5.0L), MFI
FIRENZA 86 Elec Cont Module (ECM); 4-121 (2.0L), MT
SI0/SI5/S0NOMA 87-91 Elec Cont Module (ECM); 4-151 (2.5L)
S10/S15/S0NOMA 91 Elec Cont Module (ECM); 6-262 (4.3L), ID 1227165
SAFARI (GMC) 87-90 Elec Cont Module (ECM); (behind right kick panel), 4-151
SKYHAWK 86 Elec Cont Module (ECM); 4-121 (2.0L), MT
SUNBIRD 86 Elec Cont Module (ECM); 4-121 (2.0L), MT