MAP Sensor troubleshooting.

deyjason · #1 06-24-2008, 07:48 AM

I have had a problem with losing power on accelration, (rpms dropping) and fluctuating. I have checked fuel pressure, changed air filter, change fuel filter, changed plugs, wires, rotor, cap, coolant temperture sensor, o2 sensor. It seemed to improve after the O2 sensor and Coolant temperature sensor, I was getting a code for bank1 sensor 1 O2 sensor. Now it seems to run better unless I run the A/C then the RPMS fluctuate. CEL is off, I unplugged the MAP and there was no change it the way the car ran, still fine with A/C off but flutuating with A/C on the only difference was that the CEL came on. Is this an indicator that my MAP is bad since it didn't affect the way the car ran? I don't have a multimeter.

deyjason · #2 06-24-2008, 08:14 AM

Failed to mention '97 civic ex,, also replace PCV

RonJ · #3 06-24-2008, 08:50 AM

You might want to clean the IACV (see forum DIY) and check whether the ignition timing is slightly out of spec.

Another possibility is that the alternator is on the way out. Is the battery light ON or does the intensity of the lights fluctuate occasionally at night?

mk378 · #4 06-24-2008, 10:39 AM

I doubth this is the MAP. They rarely go bad, and when they do, it will generally run like crap and set the CEL on.

Engine slows down with the A/C on because not enough air can get into the engine to maintain the proper idle speed. Definitely clean the IACV and see if that helps. If not try opening up the air screw which I think is on the top of the throttle body. (Do NOT adjust the screw that stops the throttle plate).

The official procedure is with the wire to the IACV disconnected and all accessories off, the engine should still barely idle at about 420 rpm. Adjust the air screw until it does.

RonJ · #5 06-24-2008, 11:37 AM

Quote:

ORIGINAL: mk378

The official procedure is with the wire to the IACV disconnected and all accessories off, the engine should still barely idle at about 420 rpm. Adjust the air screw until it does.

Depending on the specific model of sixth generation Civic, you either do or do not disconnect the IACV or IAT connector when adjusting the idle.