MAF disconnect

[tommy583]

Well I left work a little early. My findings were: On the positive side dead solid idle. It fluctuated a little before. Pulls strong to 6,500 RPM full throttle.

On the negative side, I got a CEL with in the first mile after i started it.

So at this point i will hook it back up, read the code and then clear the code. I already had the MAF out of the car a few weeks ago. It looked brand new, but i cleaned it with CRC MAF cleaner anyway.

So what do you guys and gals think?

[Johnny Danger]

The CEL is likely the result of pulling the sensor. The code that will probably appear is P0102 . Many have reported having a failing maf sensor without it necessarily causing a CEL.

[Topless]

Tommy,
When you disconnect the MAF your DME will light a CEL and revert to default fuel trims. If the car runs better you know you have a failing MAF that was sending faulty info to the DME. If the car runs no better or worse, your test was inconclusive.

This is a simple test anyone can do that will not harm your car as long as you don't have something else seriously wrong. The process of elimination works.

[tommy583]

The codes I had were P0102 and P0112. I cleared the codes and hooked the MAF back up. No codes on my way to work. I cleaned the MAF a few weeks ago, it didn't show any improvement. But it seemed to run quite a bit stronger with it disconnected. So i guess my next purchase will be a new MAF.

[Johnny Danger]

Originally Posted by tommy583

The codes I had were P0102 and P0112. I cleared the codes and hooked the MAF back up. No codes on my way to work. I cleaned the MAF a few weeks ago, it didn't show any improvement. But it seemed to run quite a bit stronger with it disconnected. So i guess my next purchase will be a new MAF.

I thought so .

[pothole]

Check for air leaks, too. Unplugging the MAF will also effectively zap bad running due to leaks.

I ran my old BMW 328i with the MAF unplugged for four months including a track day with no ill effects, so I wouldn't worry too much - the ECO will just default to stored values that aren't too far off reality.

It will run a bit better with a good MAF plugged in, however.

[thstone]

Originally Posted by pothole

Check for air leaks, too. Unplugging the MAF will also effectively zap bad running due to leaks.

Can you explain? Even when running on the default maps with the MAF disconnected, wouldn't an air leak cause the engine to get more air than the default map expects resulting in poor running? I would expect an air leak to result in poor running either with or without the MAF. Yes?

[Topless]

Originally Posted by pothole

Check for air leaks, too. Unplugging the MAF will also effectively zap bad running due to leaks.

I disagree with this. Unplugging the MAF removes it from the equation but does not affect intake air leaks. A significant air leak will be revealed in O2 sensor codes like 1128.