So I bought an 88 firebird last year and haven't been able to get it to run right. It has a 305, upgraded exhaust, and the air pump system has been removed. It is throwing a 22, 34, 36, and 42 code. It runs but idles bad and the exhaust smells rich. Ive replaced the tps for the 22 and calibrated it, still have the code. Ive replaced the maf for the 34 and 36, still have the code. Any ideas? I have no clue what to do for the 42. It has a new distributor.

 

Welcome Aboard!

Spend a little time and effort searching the board archives for threads related to your problems.

For instance, a MAF code 34 and 36 frequently involves the MAF power and burnoff relays and their wiring, and not necessarily the sensor itself. Your MAF may have been serviceable in the first place.

As for the 22, so long as you were able to set the voltage on installation, the sensor may be O.K., and the 5VDC power wiring to the TPS or signal wire from the TPS to the ECM may be suspect - Including connectors.

The 42 is related to the EST output signal not changing as expected when the ECM attempts to retard/bypass the EST signal at the HEI module. The problem could be in the distributor at the HEI module or the wiring, or could be outside the distributor at the connections (again). Since a 1988 model has the ESC/knock retard circuits (which also interface with the ECM for ignition timing control) located in a separate module attached to the firewall, The connections there are also worth investigating.

Don't automatically presume the problem(s) is with a hardware device connected to the suspect circuits. A little diagnosis will go a long way toward finding and resolving the fault(s) faster.

Since all your reported codes might involve the engine harness, it may be a good idea to verify a good, solid ground connection at the rear of the right head/intake bolt area.

 

I would add to Vader's advice:

A code doesn't automatically mean "the so-and-so is bad, replace it". What it REALLY means is, the computer saw a signal coming from that sensor that is recognizably impossible for a working one to produce. For example, if the engine has been running for 10 minutes but the coolant temp still reads -40°C, the ECM knows this CANNOT be true. But the sensor itself might be fine: might just be unplugged. Similarly, if it sees a combination of low RPM, low manifold pressure (high vacuum), and high throttle position (throttle wide open), it can recognize this as an impossible combo as well, and it simply guesses that the throttle pos sensor is the one giving the incompatible reading, especially if it sees the vacuum rise and fall over time but the TPS stays at WOT. But it might guess instead that it's the MAP sensor, regardless of which one is actually "bad". (if any)

Sometimes you gotta do a little digging.

As he says, multiple codes at the same time rarely mean that all of the parts they refer to, are actually bad. It makes no sense whatsoever for half of the car's electronics to all fail at the same time. Just blindly swapping parts in such a situation is almost guaranteed to fail at everything except lightening your wallet.

Check all the wiring; clear the codes by disconnecting the battery for a couple of minutes; drive the car again; see if they return. If they do, start troubleshooting at the FIRST code that re-appears (they often won't appear all at the same instant. I.e. the instant the light comes on, STOP, pull the codes, and start there.

 

https://www.thirdgen.org/forums/tech...formation.html



http://www.chevythunder.com/maf_code_34.htm
http://www.chevythunder.com/maf_code_36.htm

http://www.chevythunder.com/tps_code_22.htm

http://www.chevythunder.com/est_code_42.htm

 

Just a thought from a novice...did you disconnect the battery or pull the ECM fuse to reset the computer after you replaced those parts?

 

Thanks for all the help. I have been busy with work and have yet to try out some of those ideas and really trace the wiring back. I did take a quick look under there for loose wires and vacuum hoses. I found one plug, a single wire plug(see attached image), that was just hanging out. I couldn't find another mate to it and maybe this has something to do with my problems. Also, I found what looks like a vacuum hose that is buried in a harness that goes to the firewall that has been snipped off(see other image). I'm going to assume this is why my air only blows out of my defrost(or so all the threads lead me to believe). I looked for the spot that it might go to but couldn't find it. Any ideas? There is another vacuum hose coming out of the same bundle that is attached to some round device connected to the by hose to the intake near the opposite side of the throttle.