K&N + Aftermarket MAF problems?

[OrLackThereof]

Ive heard about this happening before but wanted to get opinions.

Starting about a week ago, my car started running strange. Before now, it had just occasionally backfired or missed maybe once in 3 or 4 days....not often at all. Now all of a sudden it has started to lose power....it's getting slower by the day. The powerband feels 'chunky'....like it'll be going, and suddenly drop out of power...or it'll stumble during acceleration. It usually happens at lower rpms under moderate load. Between 1500 and 2000 rpms is about the normal range for my problems.

Ive been tracing back what I could have done to make it start doing this and the only thing that makes sense is my K&N filter. My MAF is an aftermarket Granatelli unit and it's SUPER-SENSITIVE to ANYTHING I do to the car.

My question is, could the oil from the K&N filter (Mine was VERY oily out of the bag and box) be getting onto the MAF sensor parts and causing incorrect readings? The last time I had MAF problems, it acted like this too. Sudden powerband problems and power loss...except it was MUCH MUCH worse.

Thanks for any help...I've got some electric parts cleaner I can try to clean it off with in the next few days.

 

[HISSIN50]

sounds like you are right on. air filter oil is not good on the MAF.
if worst comes to worst, stick a paper filter in for a week or two (in case the new filter still has too much oil on it and this repeats after cleaning). hang the filter on the roof and drive for a week with it up there to wick the extra oil away. J/K.
good luck.

 

[OrLackThereof]

You're 12 hours too late, but thanks..... I sprayed the sensor down repeatedly with electrical parts cleaner today and once I got the car running again and left work...well, I'd bet good money that it picked up at least 10 horsepower. Running like a champ again and pulling like a beast. Now I just need to get the fuel pressure right...running 5 psi over stock and it's pretty rich. Misses and backfires a little, but it gained a LOT of power back.

 

[HISSIN50]

glad to hear you're back up and runnin decently. dial in the FP and you will be good to go. good luck.

 

[autoXr1]

Do you have the air filter and MAF covered with a box or some sort of shield? If you do not, then I would suggest that you do that and see if there is a difference. Large, aftermarket MAF units can be sensitive to "fan wash" and interference from resonance. Sometimes simply reducing the amount of engine and fan vibration will smooth out the idle and improve drivability. I didn't think much of it untill I went to the Pro-M site and some of the forums and found that it may help. Sure enough, it worked for me. I made a shield out of some sheet aluminum. I've seen others made out of plexiglass.

 

[OrLackThereof]

Well I've got basically zero fan wash because I'm running a modified version of the stock airbox. When I ran a conical, the MAF completely FREAKED out. Car did nothing but misfire and stumble, and at WOT, it would throw a check engine code that translated into something like "MAF reading out of range". So I put the stock airbox back on and dremeled the back out of it. That opened up airflow substantially but eliminated the MAF freak-out.

I dropped fuel pressure 2 1/2 psi, to about 42.5 psi at idle. It runs much smoother now and picked up a LITTLE bit of mid/top-end power, although the bottom-end suffered.

All in all, it's hauling balls right now. Running great. Thanks for the help.