K&N Air filter + MAF problems question
Thread Starter
Pro
Joined: Aug 2007
Posts: 509
Likes: 8
From: Livonia Michigan
K&N Air filter + MAF problems question
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?
Advanced
Joined: May 2010
Posts: 89
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From: Morgans Point Resort Texas
code 34
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.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 413
From: WV
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.
Code 34 (1985-1990) Clean the throttle body. Check MAF connections. Replace MAF relay. Replace MAF Sensor. Possible ECM failure.
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
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.
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.
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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.
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.
Team Owner
Joined: Sep 2003
Posts: 20,179
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Need to go thru the engine compartment and inspect all the wiring harness connectors for exposed copper. Chances are you will find some.
Thread Starter
Pro
Joined: Aug 2007
Posts: 509
Likes: 8
From: Livonia Michigan
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.
