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KyAllroad
KyAllroad SuperDork
9/11/15 7:33 a.m.
Flight Service wrote: I was gonna say clean the MAF sensor. If not it is probably on it's way out.

This is getting old. Died on the way to work yesterday. Sat for a minute, restarted and finished the drive no problem. No CEL.

Drove home fine, except from a small stutter/hiccup when I tried to accelerate hard.

This morning fired her up, fine. Ran perfectly for maybe five minutes and lost power and died. Sat a moment, restarted and ran fine for maybe two more minutes. Getting so frustrated at this point...... So after a couple more of these "events" I pull off and unplug MAF. Fire up the truck and it runs perfectly again the rest of the way to work.

Mechanic in Florida replaced the MAF 4 times! Are they really that E36 M3ty a part that they can't make ones that work?

Brakes, shocks, alternators: I'm pretty good at. Diagnosing weird electric/vacuum/sensor gremlins: makes me see red.

CGLockRacer
CGLockRacer GRM+ Memberand SuperDork
9/11/15 7:39 a.m.

Could the fuel filter be blocked from the gunk loosened up in the tank from the fuel system cleaner? Either the external filter or the sock on the pump. Sounds like it might be sucking up crud, stalling, then it falls off when the pump shuts off, and it is fine again until it gets sucked up again.

KyAllroad
KyAllroad SuperDork
9/11/15 6:44 p.m.
Knurled wrote: It does sound like the MAF took a dump. It stopped running until the computer failed the MAF out of the equation, at which point it started running again. When you replaced the MAF did you get a good new one or a cheap new one/reman one? (Half of those are junk out of the box) Did you replace the connector as well? Seems like most of the time, MAF connectors have broken/loose pins. Mostly GMs but have seen it on Fords too. If you're not awesome at wiring, a few drops of Stabilant on each female pin works wonders for loose pins and won't introduce new problems from an imperfect repair, but it's probably more expensive than a new connector.

Winner winner chicken dinner! Unplugged the MAF and it ran fine. After work started it up and it was fine. Plugged it back in and no love at all.

It "appears" that the sea foam and fuel treatment weren't related to the failure of a wonderful piece of remanufactured crap.

Which leads me to wonder, if it runs fine without the MAF in the loop WTF do I need it for? Unplugged the CEL is on but so what? Am I hurting anything to drive it without a MAF?

Kenny_McCormic
Kenny_McCormic UltimaDork
9/11/15 6:49 p.m.

In reply to KyAllroad:

It will run open loop, get worse gas mileage, lowered performance, etc.

Knurled
Knurled GRM+ Memberand UltimaDork
9/11/15 6:53 p.m.

Well, Ford builds redundancy into the system so if a sensor fails, the engine will still run.

Running without a MAF is removing one layer of that redundancy. It's like the saying "never be less than two errors away from getting killed" (or whatever the saying is, I don't listen too good).

We know for sure now that the engine is capable of running well IF it gets the correct inputs. Unplugging the MAF takes the MAF signal out of the equation. This means that either the MAF is bad, or the MAF isn't measuring all of the air going into the engine. Meaning it could still have false air or a vacuum leak.

ed. note: It is in my nature to be helpful and I really do want to help, but much of the reason I stick around this thread is, what does TIA mean?

chili_head
chili_head New Reader
9/11/15 7:13 p.m.

Transient Ischemic Attack?

ebonyandivory
ebonyandivory UltraDork
9/11/15 7:26 p.m.
chili_head wrote: Transient Ischemic Attack?

That's what I thought at first but as I kept reading I thought "Truck Is Awful".

KyAllroad
KyAllroad SuperDork
9/11/15 7:35 p.m.

Ha! Sorry about the TIA reference. Dr. Boost had a thread about his recently and I thought that my allusion to "stroke-like symptoms that seemingly resolve themselves" was pretty clever.

Thank you guys so much for all the assistance, my medical skills appear to be stronger than my automotive ones and sometime I need help.

So upshot is that I can drive the truck as-is until such time as I find a good MAF sensor and swap it in?

Knurled
Knurled GRM+ Memberand UltimaDork
9/11/15 8:12 p.m.

That is technically correct. Which is the best kind of correct!

But I'd still hunt for vacuum leaks and stuff. Or loose pins on the MAF connector. Connectors are generally only good for four connections, after that all bets are off. And a lot of times they "wear out" just being on the car.

Which incidentally makes me REALLY hate the '08-up Impreza airbox design. You MUST unplug the MAF to check or replace the air filter, the way everything is laid out. Very dumb. And the WRX models seem to eat air filters every 5,000mi because the ducting sucks air straight from the grille with no "crud trap".

maj75
maj75 Reader
9/11/15 8:17 p.m.

Yeah, I'm not sure why you are certain it's the MAF and not the wiring? Check the pins and see if you can find the specs for each wire and test them with a meter.

Kenny_McCormic
Kenny_McCormic UltimaDork
9/11/15 11:54 p.m.

Knurled reminded me of the word we're looking for, "pin tension". Sometimes you can take the connector apart and tighten up the pins. Packing it full of dielectric grease sometimes helps too.

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