Samurai_Of_Dawn

Info on car for reference
1987 IROC
305 swapped to 350 (bought it from previous owner that way)
-Runs a lil bit on the rich side, but runs alot better this day compared to the day when I first got her.

I've had a code 36 on the car for about a good year or so. I diagnosed the car and it came out as this:
Mass Air Flow (MAF)
Sensor Burnoff
Circuit Problem


Now I have a few questions, in which again, I did follow up on this site, but came to a dead end. (alot helping, but some a lil bit misleading and confusing).

If anyone encountered this, I'm curious as to know what you did to solve/fix the problem.

1. I come to an understanding that there's 2 relays.
- MAF Power Relay
- MAF Burnoff Relay
Where are they located exactly? I read it's near the brake booster on the firewall on the driver's side. HOWEVER, I read that it's different from other 3rd gen camaros. Example 86 is different from an 89 etc..
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2. I also read that the 2 relays are different from eachother, in which they have different part numbers. HOWEVER, when I read on here, people were coming up short on a different relay part number, and were/was ultimately using a relay that was the same (ex. 2 burn off relays OR 2 power relays) due to the computer not listing any part # for the other relay. Good example is Autozone only having 1 part # for one relay.
Anyone have the correct part numbers for the two relays?

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3. Where is the 02 Sensor located? I figure I change that as well. I just don't know the location of it, or part #.

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4. Last but not least, I also read the MAF differs. 305 MAF is different from a 350 MAF. My question re. this is, how can I tell which MAF I currently have on the vehicle? Anyone have any part #'s I could use for reference to see what I may have?


All help is greatly appreciated! I want to get questions 1-3 done since they are the least expensive compared to #4 (If and I do mean IF it comes down to replacing that hellishly expensive piece of GM product). That is assuming I have the wrong one on (hoping I don't)

camaronewbie

I'm no TPI expert.

Having said that, 1st thing that comes to my mind is something you didn't consider - knock sensor. Code 36 can also refer to " Missing pulses in electronic spark timing signal".

Since you mentioned PO swapped in the 350 - maybe they didn't swap in the knock sensor for the 350 (it is different between 305 and 350 on a TBI car - not sure on a TPI car).

Anyway - it was a thought - not sure if it's a good one or not - but at least my bad idea bumped up the thread

Samurai_Of_Dawn

Thanks for the input. Some help is better than no help, right? I'll look into that and see if he may have done that swap or not (have a list of things he changed/replaced).

Today I unmounted the boxes (the connectors that connect to the MAF power harness relay and MAF burn off relay harness), and both harnesses were pretty gunked up pretty bad (chunky n black on the inside). I cleaned both out with a bristle brush and napkin, and now it looks much better. I also did a battery reset as well.

Out of curiousity, would that be enough to trigger a code?


Also, does anyone have a pic on where the O2 sensor may be? I have chilton book, but that thing is so "useful" it's not even funny.

camaronewbie

O2 should be driver side exhaust pipe, after manifold, before the cat converter.

Samurai_Of_Dawn

Wow, that far? I was thinkin it was near the engine bay, a little more on the top. Thanks for the tip.

When/if I go about changing it, what kind of signs should I look for on it to see if it's going bad, or poor working order? Are they obvious?

Also, what kind of torque do I put on it when putting in a new one?

hdis2002

iTrader: (1)

I've got an 87 IROC, too. Mine has headers and I'll tell ya, that o2 sensor is a PITA to get out. I dont know if it fuses to the pipe or what, just be prepared to use some major muscle to get it out. Oh, yeah, if you have headers you'll probably have to remove it from underneath the car. Relatively inexpensive part. Go ahead and change it.

To address your other issue, I replaced both MAF relays on mine. Cheap part, easy fix. Got'em from Advance. I also replaced one of the wiring assemblies. I know what you're talking about the black gunk all over the wires. I don't think it really made a difference but it looks better.

Samurai_Of_Dawn

I'm ready for a fight with the 02 sensor when it comes down to it lol. Don't have headers, so I'm in the clear of that.

Did you have a code 36? If ya did, did changing the relays make a big difference? Also, you have any part #'s for the relays? That would greatly help!

hdis2002

iTrader: (1)

Yes, I was getting code 36. I changed the relays and it cleared but would come back intermittently. I ended up replacing the MAF and it fixed the problem. My MAF was a piece of crap installed by one of the previous owners so it was doomed to fail eventually anyway. I hate to tell you that's what fixed mine because it is kinda pricey. Look around though. You can get one for a decent price. Of course, it's only decent if you have the money to pay it. As far as the relays are concerned, my replacements don't have part numbers but the same one will work for both. Don't know if they are supposed to but mine work fine. Just go to advance/autozone and tell'em what you need. I'm kinda lucky here. Both have pretty good folks working there and one guy at Advance has done a couple of camaro restores over the years. Problem is, he's retired and only works two days a week.

Samurai_Of_Dawn

Ah that's interesting to hear.

I'm not certain on the MAF I currently have on the car. You got a part # on that, so I may be able to distinguish between the one I have with the one you have?

I don't want to take a shot in the dark and get one if I don't need it (they go for 500+, and I haven't seen any cheaper for a 350)

Also, something that I was wonderin (thinking of asking on the board as well) is, are the MAF from the LT1 camaros or from the 5.7 pontiac GTO (newer ones) compatible with my car? Figure it's worth a shot in asking.

I assume the ones from the older vettes work with my car. That's assuming though lol.

hdis2002

iTrader: (1)

Replace the relays. It can't hurt. Get a can of MAF cleaner while you're at it and clean your MAF really good. It may just be dirty. Also, don't remove the screens if they are still on it. They have function beyond protecting the sensor.

unprdictable1

iTrader: (2)

I have an 85 Z28 TPI 305 to 350 conversion. I had the same #36 code when I got my car. Needless to say fixing my problem is different than yours because you do not have a "Burn module" (piggy backed on the ECM). But, what I found through out my research was that the MAF Sensor part number was the same from 1985 to 1987 for a 350 engine. I know this from going to my local Napa and having them look up each MAF sensor with the corisponding years. The part numbers were all the same, as well as the specs on them. I looked them up under a Camaro, and a Corvette for a 350 engine. Hope this helps........

Vader

Unless you want a new MAF because your old one is the wrong color, or you need an empty box exactly that size, don't waste your money or time. Perform some diagnosis instead.

Here are some things to check:

1. The MAF Burnoff relay should have a constant 12VDC supply (battery voltage) on both the 'E' terminal and 'C' terminal (via the orange wire).
2. The 'B' terminal should switch to ground through the ECM output transistor within 20 seconds of the engine shutting off and the oil pressure switch opening. The ECM awaits the loss of power on its 'B2' terminal (Fuel Pump Voltage) before it can initiate the burn off cycle.
3. When the ECM commands a burn off cycle, the relay should close, and 12VDC is switched to both the 'D' terminal on the MAF Sensor itself, and the 'D' terminal on the MAF Power relay.
4. Power is routed through the N.C. contacts of the MAF Power relay to the MAF Sensor to enable the MAF Sensor electronics package. This is critical, since the MAF Sensor must report a signal back to the ECM to prove a good burn off cycle. This is also why a failing MAF Power relay can cause a MAF Burnoff error.
5. Upon receiving all these signals, the MAF Sensor hot wire is heated to full incandescence, and the MAF Sensor reads the hot wire current at full. This causes the MAF Sensor to report a full, 5VDC saturated (non-duty-cycling) signal to the ECM.
6. Upon receipt of this signal, the ECM registers a complete MAF burn off cycle, ungrounds the 'B' terminal of the MAF Burnoff relay, and is satisfied.

NOTE: Any interruption of the cycle will cause an error, and subsequent error code. This includes marginal relay contacts, poor connections and grounds at any point, and intermittent operation of the auxiliary oil pressure switch, since any voltage from the oil pressure switch will indicate to the ECM that the engine is not shut down, effectively terminating the cycle.



Other things to check:

1. The MAF Power relay should have a constant 12VDC supply (battery voltage) on the 'A' terminal (via the orange wire).
2. There should be a 12VDC supply whenever the ignition is ON at the 'B' terminal (via the blk/pnk wire).
3. The 'E' terminal should have a good ground at all times through the blk/wht wire.
4. Both the normally closed and normally open contacts of the relay (from terminals 'E' to 'A' for N.O., and 'D' to 'A' for N.C.) must be operational and reliable (see above).

Samurai_Of_Dawn

unprdictable1: That is interesting. I DO have an appropriate prom chip for the ECM, as without it, it would run like crud. Everything on the prom chip is set to 350 spec. so I'm good in that area. Thanks for the tip. That does help



Vader: Good God that's ALOT of info to soak up! From the looks of your post, something tells me that you've came across this problem before in the past.

I'm no car guru expert, but I'm doing my best to deceipher this as I read it, so bare with me.

Now buying a new MAF is a waste of money you say eh? Just a guess, but what would happen if I have a MAF from the 305? I was thinking that a 350 MAF along with some new harness/relays would eliminate the problem of the Code36. The difference I see between the two is calibration since the 305 and 350 are essentially the same engine with size (with the obvious between the two).

Now from my basic understanding of this puzzle you posted for me, if the 12V battery isn't constant, it'll actually trip the code36 since it's not receiving the proper amt. of voltage it needs to do the proper burnoff that is required from the MAF. That, and any interruptions will cause the code36 to spring back up. Am I correct in this area?

From my understanding is that the MAF needs a constant voltage ammount. That's what I'm guessing at by reading this.

Something I would like to bring up, even if it's small is the battery voltage. It MAY play a part on this, but I'm not 100% certain.

When I drive the car, the battery meter should always read 12V consistantly. Something I noticed is when I drive the car for a fair ammount of time, the battery meter will drop below the 12V area around the 9/10V area. The battery is in good shape, but was thinking it was the altinator. Could that play a small part in what's going on, or would it be a parasitic leak somewhere perhaps?

Awhile back I had the alt tested, and it came out good from the results. Even did a charge on the battery, and nothing is wrong with it.

What's your take on this? I greatly appreciate yours and everyone else's help thus far. Much oblige

fastgascar

Did the 36 code ever get resolved? IF so, what was the resolution?