MotorCity_87_C4

Been chasing an intermittent code 34 on my 87 coupe. I have a K&N air filter. I replaced the MAF about 3 weeks ago and continued to have the intermittent code 34. Went back to the FSM and followed the troubleshooting procedure and it said the MAF was bad. I got an exchange on the MAF and got another rebuilt MAF. Could the K&N air filter cause a code 34 to return after less then 50 miles?

floridamale

Did you over oil it ? also when you change the MAF you should do the relays also

MotorCity_87_C4

Nope didnt over oil it and no didn't change out the MAF power relay.

1stvet87

I recently opened up my filter inlet on my 87 and got 33 & 34 codes repeatedly. Disconnecting the negative battery cable will clear the codes, but expect them to return for a period of time. The ECM has to relearn the new peramiters and adjust accordingly. It took a couple of tanks of gas before mine quit setting codes. I would probably go ahead and disconnect the battery and replace the MAF sensor relays, and then just drive and expect the check engine light for a while.

MotorCity_87_C4

Still throwing the intermittent code 34. Changing the car's name from Nickel -n- Dime to Money Pit.

WW7

Here is what the book says could be wrong, theres more then the MAF that could be causing the code 34...WW

Code 34 (1985-1990) Clean the throttle body. Check MAF connections. Replace MAF relay. Replace MAF Sensor. Possible ECM failure.

MotorCity_87_C4

ok, I have not cleaned the TB since last summer and have not replaced the MAF relay....yet.

JrRifleCoach

I too have experienced the same problem.
IMHO;
Clear the codes and clean the MAF.
Ditch the K&N and replace with a paper unit.

It has been long recorded here that the early MAF and K&N's are not the best match.

turbodiesel

its still ok to run the cut open lid with the factory paper filter? just a fram or wix?

MotorCity_87_C4

Would just driving under 50 miles cause the new MAF to get gummed up and throw a code?

vader86

I ran the open lid with K&N before I got a SLP CAI, still runs a K&N. If the MAF is continually failing even with a new one, I would not suspect the filter to be the problem.

When I do clean and oil mine, I take it out and let it sit for a day on a towel so any excess will drip out. Sometimes I put it in front of an old fan. You only oil it til its just pink.

If the relays have not been changed, they should be. Its a good rule of thumb to always change the relays if you go to the expense of changing the MAF itself.

Assuming all that is good, I bet on wiring. ECM failure is rare.

JrRifleCoach

Need to go thru the engine compartment and inspect all the wiring harness connectors for exposed copper. Chances are you will find some.

MotorCity_87_C4

Changed the MAF power relay today. Looks like someone was messing with them an owner or two ago as they were not on their firewall brackets but laying down next to battery and on top of the main power connection terminal. The plastic that slides over the bracket was broken and the L bracket was bent and mangled. I need to get a new MAF burn-off relay now so I can attach it to it's bracket.

MotorCity_87_C4

Update, 3 days no return of the SES code 34, looks like the MAF relay did the trick.

Pingman326

Thanks for posting the results !