All,

I am hoping someone will be able to help me with this problem I am having.

I am trying to fix my 85 iroc 305 tpi and get it ready for the road. The car
has been bogging like crazy after it reaches 220 degrees on the guage which
happens after 2 minutes of driving. It seems that the computer goes into
closed loop at this point.

I bought Auto-Xray and extracted the following codes from the computer
34 MAF TOO HIGH
33 MAF TOO LOW
44 02 LEAN
43 ELECTRONIC SPARK CONTROL FAILURE

I have already replaced the MAF Three Times with no change.
I have replaced the 02 Sensor once.

I am out of ideas. Do you guys have any suggestions for me on how I can
troubleshoot and fix this?

I have not changed the MAF Relay cause as many of you know 85 is an odd-ball
year and does not have these relays on the firewall. It is actually attached
to the ecm and is a slight fortune to replace from my understanding.

=Scott=
85 Iroc
99 Tahoe

 

34 MAF TOO HIGH
33 MAF TOO LOW
44 02 LEAN
43 ELECTRONIC SPARK CONTROL FAILURE



Code 34 -Vacuum sensor probable cause- this code will set when the signal voltage from the MAP sensor it too low. The ECM will instead substitute a fixed MAP value. On newer cars it will use the TPS to control fuel delivery.
Code 33-also the sensor, check all the vacum hoses to/from the sensor and check electrical connections at the ECM
Code 44-Lean Exhaust
probable cause-check the ECM wiring connections, particularly terminals 15 and B. You can also check for vacuum leakage at the TBI base gasket, vacuum hoses or the intake manifold gasket.
Code 43-Electronic Spark Control unit
probable cause-the ESC retard signal has been on too long or the system has failed a functional check. Id replace the spark control module located beneath the rotor/cap on the distributor, small piece that fits in the palm of your hand and has metal prongs coming off it.

Hope you nip it.

 

You can ignore most of this, the only things that pertain to your car are the code 44 being lean exhaust and code 43 being the esc circuit. The 33 and 34 as you know are MAF related. Generally, MAF codes mean something else besides the MAF is wrong.

What I would do with all of those codes coming up (generally, 33 and 34 at the same time means its not sensor related) is check to make sure all the grounds are hooked up and not corroded. Start at the battery, check the connection of that cable to the engine, check the ground strap at the passenger side rear of the engine on the head, and also all the grounds that are the at the back of the heads. Also check the wires running to the distributor, there was a TSB for your car pertaining to the wiring, the wires would rub on the engine hoist bracket mounted next to the distributor and cause problems. Make sure the ground strap is in the distributor as well(its a metal thing that fits inside the cap and under the coil, sometimes people leave it out by accident or they just dont know). I hope its a ground problem, because if thats not it, it could get real expensive.

 

right on madmax
On my 85 I was pulling a code 34 every once in a while and it turned out to be a bunk alt cable/bad battery connection. I'd start here and move on as madmax suggested.