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Driving without MAF sensor?

31K views 22 replies 8 participants last post by  sipes216 
#1 ·
I've had P1127 & P1138 error codes for a while. A few days ago, my car drove like total crap with misfires in all 4 cylinders. I scanned again and the P300, P301, P302 & P303.

I ran a course of Techron to clean the injectors and that didn't help. Driving home last night was CRAZY. It would misfire at any slight acceleration.

Well, I disconnected the MAF sensor this morning, and boy, did she drive smooth - not even a misfire or jerk. I ordered a new MAF sensor, but won't have it over till a couple of days.

How safe is it to drive with the MAF sensor disconnected?
 
#3 ·
You can be fine indefintely, but you'll have to get used to a CEL and you won't know if there's a second code for the CEL either. May just run a tad richer in some driving conditions and overall mpg may drop a few. Fuel trims should level it out for the most part.
 
#4 ·
How safe is it to drive with the MAF sensor disconnected?
Well, in your particular case, it's probably better for your engine if you do drive with the MAF disconnected. Your ECM "guessing" how much fuel to provide is more accurate than your ECM calculating off the bad data provided by your faulty MAF (that's why it's running better this way).

When you get the new MAF installed, it should run even better.
 
#6 ·
Well, got a remanufactured MAF from AutoZone for $55. Car runs smooth, it's unbelievable. This would be the 4th I've replaced in the last 2.5 years.

By the way, I changed my air filter last week, and today when I go to change the MAF, it looks like it's being soaked with some mixture of oil from somewhere. Any ideas?



 
#9 ·
That stain does not look normal. I run a 4" COAM from my lower grill up to a 3" reducer that enters the bottom corner of my airbox and I've driven in heavy rain and not had my filter liquid-stained like that. Is your intake path stock?

I wonder if that's why you're going through MAF's at the rate you are. Could it be that the MAF sensor is becoming dirty/contaminated with the oil and dieing? Have you ever tried cleaning the MAF sensor with MAF sensor spray cleaner?

I'd pull things apart and start examining really closely to see where that oil is coming from. It's bound to be leaving oil traces along it's path of travel.
 
#11 ·
:thumbup: It's full.

Carefully disconnect it and dump it.
 
#13 ·
The puck valve is downstream from the filter. I fail to see how it could overcome gravity and send oily residue UP and thru the maf, then onto the filter.

Are you sure there are no problems with your SAIP? The stain looks to be on that side of the box. would also stand to make sure the coimbi valve is working too.
 
#14 ·
Had SAIP issues in the past. Indy said it was not working at all, but I got home and found out it was disconnected, and the fuse was out. I connected it and replaced the fuse, and it seems to be working fine - at least I hear it come on when I turn the car on for a cold start.

I doubt it is the puck valve, as I did a complete PCV replacement not too long ago (well, sort of long ago; ~1 yr)

Maybe the SAIP is really out, then.
 
#15 ·
If the SAIP isn't connected, that should throw a code and light the CEL. The filter stain looks like it may be coming from where the SAIP air intake connects to the filter box. I wonder if this is why the PO disconnected it. Perhaps he decided it was better to live with a SAIP CEL then to keep buying MAF's?

If the SAIP system is working properly, it draws air in from that port on the air box and pumps it to the combi valve. It shouldn't be backflowing anything up into the filter box. Problem with the combi valve?

If you get under the front of the car you can disconnect the two hoses from the SAIP. (1. from air box to SAIP, 2. from SAIP to combi valve)They clip on and if you push on the tabs just right, they will clip off. See if they are filled with liquid. They should be relatively clean and dry inside.
 
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