Ok guys, We managed to get rid of code 36. How....Change MAF burn off relay/MAF Power Relay/Change PCV Valve. No code(except 12) Car runs great, Idles great, but.......When I reach that speed of 70-80 and hammer it, it bogs down and sputters. I can hammer it from 0 mph and roach-em in the first two gears.(automatic) Any ideas?

88 iroc 305(lb9) automatic. The auto shift plate only has P R D 1 2, but I can shif P R (overdrive I think) D 1 2. In over drive I can hammer it with less of this problem. Could this be transmision problems(maybe change fluid).

I still have that mysterious object under the hood. If looking at the engine.....all the way to the back to the right of the distributor but lober and to the left of the MAF Relays/Fuel Pump relay. It is a medal pipe with a nickel sized opening and it blows air, but it is not hooked to anything. What is this? All the help I can get would be so appreciated!!:hail:

 

If I'm understanding you correctly bro, that metal pipe (with the nickel sized opening), is part of the A.I.R. tubing that gets plugged to you're exhaust manifold. It's blowing air, because she's not hooked up.

Just plug it up, or re-connect (if the exhaust manifold isn't already plugged) to the drivers side exhaust manifold....

As for her bogging down at higher speeds, go under the car.... and lemme know what kind of tranny you have (did someone change it)? Give us the design of the tranny fluid pan itself.

 

Will just plugging it cause bad performance or should I try to some how to re-connect it? What is this supposed to do?

I will get you the tranny specs later today, I am in class until 2:00.

Thanks for your help "street lethal"

 

Actually.... removing the smog pump, and plugging up the A.I.R fittings on the exhaust manifold, will not only increase performance, but will un-clutter you're engine compartment.

It was put there by the factory to help aid in burning 'un-burned' gas as it exits the combustion chamber. To be honest, awhile back.... I had them run a smog check with both before and after results.

Even without the smog pump, I got the same reading.... but when I removed the catalytic converter, well, let's just say that's another story.

 

Ok the tranny fluid pan looks just like the one in the chilton/haynes books.(Automatic) The pan is not a perfect square, but looks like 12" by 10" or close to that.

I put Fuel cleaner in it today and the car runs great. I took it out and barried the speedo and no hesitation at all. I still have a code 36 though. What kind of gas would you reccommend(I use unleaded right now) Should I switch?

If my car is automatic, in Drive going around 60, do you know what rpms I should be at. Maybe we could tell this way.

Last question for the night. I here a light rapid clicking noise coming from the engine. I don't think it is belt related. Could it be a bad lifter or......

You have been a great help street lethal!!!!!
I thank you

 

Try using premium (93 octane) then, see if that helps.

 

Not sure about the 305 but my 350 in OD (3.27 gears) at 60 (or 100 kph) the tach will read approximately 2000 rpms (give or take as I don't tust the stock tach but everything I have read says that is about right

Try the calculator here...

https://www.thirdgen.org/newdesign/t...ulations.shtml


As for the ticking, assuming you have the TPI, it is most likely the injectors firing... my TPI has a noticeable tick and it is the injectors batch firing but it could be an exhaust leak or a sticky valve as well...

 

You're more than welcome my friend!

Ticking noises can be a pain to locate. Yes... it could be a bad lifter, but it's probably a rocker arm that got a little loose due to hard acceleration.

Or like was mentioned by the above response... that it might be an exhaust leak (that A.I.R. fitting, especially if the exhaust manifold port is exposed.... this would explain a lot if so).

Code 36 can make your'e ECM act very strange at times.... and although she runs strong, with no hesitation, Code 36 can make the tranny shift horribly.

If you're still having a problem with hard acceleration (at higher speeds) with the car bogging down, it might just be you're torque converter lock-up switch.

 

The car is running a lot better. My code 36 came back after replacing the MAF burn off relay and Maf power relay and pcv valve. Any other ideas for me. What can I do with the torque converter? I will say that I erased the codes after doing the above and it took a day for code 36 to come back. , not sure if this will narrow it down.

In a couple days I will have a pic for you on the strange pipe under the hood. Maybe then we can narrow it down for good.

Have a good one

Punisher

Listen=Learn=Plan=Command=Conquer

 

That strange pipe has me scratching my head, as the only piping behind the engine (on the side), can only be two things;

One.... on the passenger side, it's the tubing leading from the Catalytic Converter,

.... and two, on the drivers side, it's part of the tubing that is bolted to the back of the head, coming from the smog pump on the passenger side.

Remember.... if the ECM doesn't sense the right amount of air (cooling) coming from the engine after it is shut down (through the PCV valve to the MAF), it's going to tell you there is a problem.

If there is an opening in you're exhaust somewhere, especially by the A.I.R. tubing, then the PCV (pollution crankcase ventilation) valve isn't receiving/delivering the correct amount of exhaust to cool down the MAF (which means that even though you initially got rid of the code 36, once you shut the engine down after you're driving around, the ECM will then tell you that something is wrong)....

Also, believe me, the stock connectors that house the wire terminal's leading to each relay, they weren't designed that well. With you're two fingers (you're thumb, and you're index), gently/firmly push each wire from the bottom of the connector going into the Burn Off Relay 'upward', as the clamped terminals (inside the connector) on the wiring have a tendency to come off the relay (even though it 'looks' connected, it might not be).

The connectors have a 'flap' door on them, and what I used to do when I ran a TPI, was with the flap door open, I would hold each wire 'forward' in place, close the flap door, then.... connect it to the relay.

 

So basically, you've been fighting a MAF burn off failure problem for the last five days. The reason the code "disappears" is that you clear it by disconnecting power to the ECM. If it reappears, the condition that set it in the first place is still occurring. That means that the MAF sensing hot wire is not being burned clean, and the MAF is probably under-reporting intake air flow to the ECM. Eventually, you'll get a code 34 from that.

You mentioned in another post that you had found frayed wiring. Was that in the MAF circuit?

You should also follow Street's advice and visually monitor the MAF after engine shut down to see if the wire burns off (glows). If that isn't happening, you are probably already getting low intake flow information, a resultant lean mixture, poor performance, possibly overheating and detonation, and will eventually get another error code as a result.

For the "mystery pipe" problem, you should read this thread, too:
https://www.thirdgen.org/techbb2/sho...hreadid=198384

As for the other advice, I fail to see how 1,600°F exhaust gas can possibly cool down a MAF sensing element that is rarely over 240°F temperature. Beyond that, the PCV hose couldn't handle the temperature, and the valve doesn't connect to the exhaust system anyway.

For reference, the MAF sensor doesn't care what the air temperature might be. The only critical measurement is the difference in temperature upstream and downstream of the hot wire. Air mass is determined by the level of current required to sustain a 75°C differential. Once the engine is shut down, the ECM diverts 12V to the burn off circuitry, and expects a current signal from the unit - not a temperature indication. After a few unsuccesful burn off attempts (engine run cycles), the ECM will set the error code.

 

'Crankcase pressure' buildup happens all the time, and both the breather plugs and the crankcase itself builds pressure while the engine is running. Once the engine is shut off, then air bleeds off through the PCV valve, back out through the throttle body....

The ECM is waiting for a feedback signal from the MAF sensor to tell if the wire got hot enough. This signal voltage is proportional to the temperature of the wire. When the crankcase is bleeding off during the burnoff cycle, the air blowing past the MAF will cool the wire just enough to keep feedback voltage low... enough to tell the ECM it didn't get hot enough.

Result: Code 36.

 

Of course, you realize that the MAF burnoff cycle is initiated by a sequence of ECM events, the least of which is not the loss of voltage to the fuel pump (monitored on terminal B2). The MAF burn off won't initiate until the fuel pump voltage is 0, which usually happes 2-5 seconds after the engine has stopped spinning so that oil pressure can bleed off and open the auxilliary fuel pump power switch. Conventional wisdom would dictate that most of the significant crankcase pressure that hadn't leaked out through exhaust valves, rings, or intake valves in that amount of time wouldn't affect air flow through the intake tract enough to cool the MAF hot wire more than a degree or two. Since the MAF TPI programming allows about 12 seconds to successfully perform a hot wire burn off, I would suspect that the air flow after only a few seconds would be inconsequential.

However, I have seen cases where the auxilliary fuel pump power switch (oil pressure) had become intermittent, and interrupted the MAF burn off cycle in "mid-burn", causing a '36' with no apparent MAF hardware nor wiring problems.

 

Ok guys....I watched the filament inside the MAF as a friend started the car, let it run for a while (1 minute or so) and then shut it off. NO GLOWING! The glow should be very noticable right? I am just taking off the air intake and looking right inside the MAF, is this correct? The sensor looks very clean, but I am going to try street lethals advice with the conectors. I will be posting some pics sometime this week on the strange object under the hood. If I understand correctly, I may have bad wiring or a bad sensor. I will check the wiring again since that is the cheapest.
Thanks Guys!!

 

After the engine shuts down, and the oil pressure switch opens, the MAF burn off relay should energize and initiate a burn off cycle. During this cycle, you should be able to see the MAF hot wire glowing if you are in dark surroundings. You might not see it in daylight.

In any event, it would be easier to check the voltage at the MAF burn off terminal ('D') after shut down.

 

Alright Men,

Located below is a picture of what have changed. From left to right with red arrows pointing to each of the two items. First MAF Burn off Relay, Second pointing arrow MAF Power relay. I can't help but notice that the MaF Power relay and the relay in the middle of the two i have pointed out(Witch I think is a fuel pump relay) are identical relays. Is this correct? The one furthest to the right is newer of course, but they have the same prongs, same shape annd some number on top. Is this supposed to be correct or did the auto store sell me the wrong thing. I was comparing it to Vadar's Pic he posted awhile back and mine looks diffirent. Are there some numbers I can look for on new and old relays? Also is there anyway elso to check the MAF sensor itself to see if its working, besides the glowing, which it is not. I want to make sure everything else is working before I purchase a new MAF sensor.

Last thought, A guy told me to check my TPS. What did he mean?

WOW Guys a lot of info here, If you lived closer I would have to take you all out for beers.

JT

 

MAF PIC

 

Many of the relays on the vehicle are the same. They use the same type connector as a result. The key will be the wire colors. Refer to the schematic to see it what you replaced is appropriate.

If you have 12VDC at the 'D' terminal of the MAF after the engine is shut down, you should get a MAF burnoff cycle. You should be able to verify that by monitoring the 'C' terminal during burn off to read a 2.0VDC signal or higher.

 

I don't think you're Throttle Position Sensor (TPS) is the culprit here, and to be honest.... I don't think it's the MAF sensor itself either. But to be sure, we'll have to eliminate other areas that might be the cause for the Code 36.....

First, let's do the very basic. Pull out the ECM, and double check that the connectors are connected firmly (nothing loose).

Second (which is a longshot), reset you're transmission kickdown.... because if memory serves me well, shift points which are way off will trigger a Code 36.

Before we continue, just confirm that the above is okay.... then we'll check MAF voltage.

As for the relays, they normally do share the same part number. However the Fuel Pump Relay has five wires, and both the Power and Burn Off relays have four each.

Fuel Pump Relay;

Green/White (12 volt Key on)
Black/White (switch ground)
Tan/White (Fuel Tank Unit)
Red (Fuel Pump Prime)
Orange (Power Constant)

 

Will you please give me a quick run down on how to reset the transmission kickdown.

I am going to do this Wednesday.

thanks,
Again!!

 

Sure....

The Kickdown cable is right next to the throttle cable on you're Carburetor's lever. The kickdown has a 'snap on', that snaps to a small round cylinder on the arm.

Follow this cable back towards the bracket that's bolted to the intake manifold (this bracket keeps the kickdown, throttle.... and cruise control, in position).

On the side of the bracket facing the firewall, find the kickdown housing, and depress and hold the metal re-adjust tab. Move the slider back through the fitting in the direction away from the cable actuating lever (which is the Carb's armature), until the slider stops against the fitting.... then release the metal adjust tab.

Now.... open up the Carb (Wide Open Throttle). The slider must move forward (you'll hear it, it'll sound like a ratchet) when the armature on the Carb is at wide open throttle. Then release the lever.

You're all set.....

Whoa, wait a second.... I keep forgetting it's TPI. The principle is exactly the same, only the bracket is on the plenum, and the lever is on the throttle body.

It takes roughly 30 seconds.....

 

Street,

I thought I knew most of the problems and causes associated with the MAF burn off cycle, including the obscure ones like a sticky oil pressure switch or alternator diode feedback, but how does the TV adjustment affect the MAF burn off cycle? Not trying to challenge you or anything (since I don't know), but I haven't heard of that one, so walk me through the logic if you would.

 

What I was told back in the early 90's, from some friends who worked for GM.... there are various areas to inspect which are heavily associated with the error code 36;

Obviously, the Burn Off Relay and/or it's connections (especially by the ECM) are the first assumption. It's doubtful (although possible) that the MAF is bad.... if it were, there would normally be other codes that accompany the 36.

Another possibility is the ignition system itself... which would explain the 'bogging' down at higher speeds if it is worn down, or on it's way out (especially considering a missed ESC pulse)...

They mentioned improper shifting (only with automatic's of course), but I will get back to you on this..... as this is why I mentioned in a prior thread that it was a longshot....

But the bottom line is that the ECM relies heavily on the signal wire for feedback to tell whether to set any error codes. A code 36 doesn't necessarily have to be in the burnoff circuit itself (although it is a common area).

Judging by what Punisher is saying though (considering the fact that he inspected the wiring, and bought new relay's).... it's either that the burnoff circuit is going open in the Mass Air Flow sensor, or a faulty ECM trigger....