7.4L MAF Issue?

[Tom P]

Yeah I'd really doubt it to be the coil. I hadn't really considered the effects of the trims. Did you try running with the o2s unplugged? That should throw it into an error state and keep it open loop, correct?

Ran them unplugged for about 4 hours worth of towing my travel trailer ~5000lbs. No change

Again though trims apply in open loop. If he could clear his trims then run open loop that'd give us a better idea. I have a Harbor Freight scanner that displays PIDs. That's what you're after. The ability to monitor ECT, IAT and **** like that.

Pardon my ignorance but could you explain PID, ECT and IAT?

 

[Tom P]

Just Ordered my own OBD2 scanner. Should have it tomorrow.

 

[Christian Steffen]

Ran them unplugged for about 4 hours worth of towing my travel trailer ~5000lbs. No change



Pardon my ignorance but could you explain PID, ECT and IAT?

Parameter ID's. Engine coolant temp, intake air temp.

I think simply disconnecting the battery erases the long term trims, right?

 

[Supercharged111]

OBDI yes, OBDII it's not supposed to work that way.

 

[Christian Steffen]

OBDI yes, OBDII it's not supposed to work that way.

Interesting. Apparently I don't know **** about fuel trims haha

 

[Tom P]

What about disconnecting the positive and negative battery terminals and touching them together for 30 seconds? Heard that one some where once.

 

[Supercharged111]

Yeah, that or unplug the batt and turn the headlights on for a few minutes. Supposed to drain the capacitors in anything that has them. Forgot about that one.

 

[Tom P]

Well tonight is going to be an interesting test. I have to haul my brother in laws tractor back that same 15 miles. The only difference is ill be starting out cold. Wish I had the scanner now to check the live data but I'll get more chances for that. Going to quick throw on the new coil before I go on the off chance that is the problem although now you both have me feeling stupid about it. Tonight I'll probably get my prep torch out and see if I can loosen those dam o2 sensors after the trucks been good and hot. I really hate working with exhaust.

 

[Supercharged111]

Just try the ghetto pcm reset and unplug the front o2 sensors and see what happens.

 

[Tom P]

I'll give that a shot.