So I have 1986 iroc z 305 tpi with the service engine light illuminated, it reads code 34 which indicates MAF sensor, now I do not have any issues with the motor it starts, idles and runs without incident I have reset the code several times and it continues to come on immediately after starting the vehicle, I am concerned there is a problem and I am either not noticing it or its developing and will result in a noticeable more serious issue I would like to prevent this does anyone have any experience with a similar problem or have any advice on how to fix this?

 

Typical causes for this code include:

1) Faulty air ducting to or from MAF sensor
2) Faulty ECM-to-MAF connections
3) Poor routing of MAF harness (i.e. near coil packs)
4) Maladjusted TPS sensor
5) Defective MAF sensor
6) Defective ECM

 

1. If you have a cold air induction installed...check your connections.
2. Check/clean all your wiring and connectors
3. If wiring is close to plug wires, consider re routine them.
4. Replace your MAF sensor.

Troubleshoot in that order!

If you ECM reports a Code 12, avoid tinkering with your ECM...it's most likely fine.

 

any suggestion on what order to start inspecting considering the motor does not seem to be having any issues

 

E cm reports 12 I have replaced the maf sensor I still can't figure out why it is throwing this code

 

The maf sensor is the reman Bosch from any part store would it be worth time and money trying to find an actual new maf sensor

 

Oh and no cold air she is 100 percent stock

 

If your MAF is truely acting wonky, your driving in limp mode...or should be. If your ECM doesn't know the air inflow it will default. Try this...unplug your MAF sensor and start it up....it should run like crap...or not start at all. Let that be your first step. If...unplugged...it runs fine...then start looking for vacume leaks. Leaks are almost 100 percent of the culprit of issues on an otherwise healthy TPI setup.

 

Another thought....does your IROC have the snorkel intake system? The twin tubes that intake air from the front? Or the type that pulls air from the passenger side?

 

The snorkel that pulls from front

 

Standard Camaro. My 89 TA puls a single air feed from the passenger side. Either way, the MAF is installed in the air flow path...they perform the same function.

Have you done the TPS reset procedure? For some reason your ECM is confused about the air flow ratio relative to your throttle position. Search this forum...I think the tps reset steps may be pinned at the top of this forum. It's kinda lengthy but it works.

 

I've learned these OBD1 systems are very easy to dial in if ya take simple logical steps. They aren't as complicated as some might think

 

The conditions for setting this code are:

no Code 21 or 22 (TPS Error) present, and
the air flow reported is < 4 grams per second, and
TPS indicates 10% or more throttle position, and
the engine speed is 1800 RPM or higher, and
the above conditions exist for over 5 seconds.

 

Check your tps...you might find your problem there

 

Future thought....think about this after you have ruled out your tps. Have you had any temp issues? Running hot this summer? Coolant temp code 14 perhaps?

 

No code but radiator cracked and she got super hot replaced radiator all hoses thermostat and water pump since I had it torn apart and she hasn't had a problem since

 

I searched Tps reset but to no avail anyway you could post link to that here?

 

K. A code 14 will set at like 275 degrees plus....that will def cause drive ability and fuel/air related code issues.

Just FYI...most t-stats these days have a mechanical stop built in that will lock them full open at an extreme hi temp. It's a mechanical tab that prevents it from ever closing again once it gets too hot. Ya hafta replace it....of course, after the real cooling issue has been fixed...usually a leak somewhere.

 

Ya the one I pulled out did not have it but the one I put in did here is some background on this car found it with 30k miles and had been put away for last 20 plus years everything I have done I am pulling off factory parts I doubt it even saw any major service

 

It's in the TPI group

https://www.thirdgen.org/tpimod2/

Ignore the part about the IAC reset....or you can reset it too...it's easy. But do attempt the tps steps

 

Even the original maf was not a reman when I started with this problem but it was not running right when I first had issues with maf sensor

 

Are you the long time owner or did you get the car with these issues?

 

I can't explain how much I appreciate your help on this I am going to research that link and give it a shot

 

When I got the car had no issues but I have had it for about 2 years now I had to completely replace fuel and brake systems because it sat so long calipers were leaking and all shirt in tank was chewing through fuel pumps

 

**** not shirt lol

 

No problem bro.

I've been on this board...under various names...for over 17 years.

Various names because I was military and moved a lot. Moving meant forgetting my username and password...lol

I'm driving an '89 TA, 305 TPI, original motor, freshened up once...has over 400k miles on it. To this day it's still my daily driver. Ppl ,make fun of it because it looks rough but I'm still enjoying it.

 

That truly is kick *** man this is my third 3rd Gen first 2 were both 91 rs with 305 Tbi those damn throttle bodies gave me headaches but both cars were well worn passed down from one teen who drove the **** out of it to the next this is my first iroc and tpi setup and I must say I absolutely love it the car has had minimal owners maybe 2 hard to really find out but not missing a single screw so I want to get it running in tip top that is what brought me here to join this site after much research this seems to be THE place for any smart 3rd Gen owner to seek more knowledge.

 

Keep us posted on your troubleshooting. These cars get butchered over time but are fairly easy to get back on track.

 

Okay so completed Tps procedure and dialed it in to .54 now I notice a big difference in response and performance however the maf code is still coming up