Okay guys any help would be appreciated here. I'm stumped and can't seem to find any kind of answer elsewhere. Working on my '01 f150 with the 4.2. The short and simple version of a long story would be I was sitting at the bank idling and out of nowhere started running like ****, no power, missin bad, just runnin like all around ****. Happened out of nowhere. So my first thought is MAF, or something to do with it. Even though I was pretty sure it wasn't the maf itself I replaced it with a new spare I had, as expected no change. So I started testing the wiring. So first I tested the red (power) wire, all good, getting full 12v. Next I test the black/white wire (common ground) all good, when grounded out to pin and hooked to 12v I get a full 12v. Next was the tan/blue (ground to ecm) and here's where the problem is. So on this wire (with key on so ecm is on) I should be able to ground out to this pin and connect to a 12v source and read a full 12v. But I am only reading 5.30v when grounded out to the pin and I have done the text multiple different times and ways and confirmed its only handing just over 5v instead of ~12v. Just for the hell of it I grounded it out to the pin and tested with the key off as well (yes I know that isn't how it's tested) but with key off it reads ~12v. So I need some advice, is there an underlying issue here that I'm not seeing? Did the ecm **** the bed? Let me hear your ideas cause I'm at a loss right now.

 

Try following this.....

http://easyautodiagnostics.com/ford/...sensor-tests-1

 

Brand new person here, first post - shouldn't there be an OBD code? That's what on-board diagnostics are for, aren't they? So you don't have to guess.

Guess - how about a bad O2 sensor? Water in the fuel?

 

I agree get the codes read first.

 

Doesn't sound like you have a CEL.

Personally I'd just follow by-law diagnostics and leave the MAF alone, unless you have a DTC.

By-law, - Fuel first always. Check your pressures, - that makes more sense than anything I've read here.

 

I didn't try and diagnosis his problem, I just gave him a link to find out how to check the MAF that he was having problems checking. Of course checking the CEL is first. I preach that like I preach doing compression checks on high mileage engines when tuning them up.

 

Sorry for the late reply here. Never got a notification of any replies. Yes I already read for codes, yeah it's throwing codes but for things completely irrelevant and things that don't affect driveability and are proven not to affect driveability. Have also been driving with them on for over a year now with 0 issues. I agree, codes are always first. That's why the first thing I did was plug in my scanner. Have not checked fuel yet but I highly doubt that is the issue as it happened just sitting at the bank idling. I think there is a misunderstanding here? On my post I stated that there is an issue with the wiring for the maf, I am only able to handle 5.3v when I ground out to my pcm ground instead of 12v like you should be in that exact write up that I have been through multiple times. How would fuel having water in it or anything else cause a grounding issue in the harness or somewhere in the computer?

 

Are you joking? This has to be, no ones that....

 

Please enlighten me on how the egr being removed and properly blocked off and tuned to not run an egr and how the evap system being removed and properly blocked off causes an issue with maf wiring in the computer or harness if im that ignorant. And how even if it's completely relevant to the maf (it's not in any way) it doesn't present an issue until over a year later

 

Sorry for your luck, unless your into calling yourself names. I'll pass on the rest.

Post those codes and you just might get some help. I mean that's what they're there for. It also helps us help you. IF that's what your here for...really.