Strange miss solved
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From: Ishpeming Mi.
Strange miss solved
I posted quite a while ago that my truck would seem to shut down for maybe a quarter second or so and then start running again. I never recieved a real reply on the cause of it although I've seen the question posed on this and other forums, all with no explaination, just comments from others suffering from the same malady.
Doing my hypermiling I do a lot of coasting and my engine has an annoying habit of stalling, presumably because of my bad MAF sensor. A friends son who was at one time a Ford Mechanic suggested unplugging the MAF sensor to possibly cure the problem. Well it didn't. What it did do, though, was stop the sporadic shutdown of my engine.
Now the how's and why's involved I haven't a clue, I just know my truck hasn't 'hickupped' since.
Doing my hypermiling I do a lot of coasting and my engine has an annoying habit of stalling, presumably because of my bad MAF sensor. A friends son who was at one time a Ford Mechanic suggested unplugging the MAF sensor to possibly cure the problem. Well it didn't. What it did do, though, was stop the sporadic shutdown of my engine.
Now the how's and why's involved I haven't a clue, I just know my truck hasn't 'hickupped' since.
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From: SW Va
I posted quite a while ago that my truck would seem to shut down for maybe a quarter second or so and then start running again. I never recieved a real reply on the cause of it although I've seen the question posed on this and other forums, all with no explaination, just comments from others suffering from the same malady.
Doing my hypermiling I do a lot of coasting and my engine has an annoying habit of stalling, presumably because of my bad MAF sensor. A friends son who was at one time a Ford Mechanic suggested unplugging the MAF sensor to possibly cure the problem. Well it didn't. What it did do, though, was stop the sporadic shutdown of my engine.
Now the how's and why's involved I haven't a clue, I just know my truck hasn't 'hickupped' since.
Doing my hypermiling I do a lot of coasting and my engine has an annoying habit of stalling, presumably because of my bad MAF sensor. A friends son who was at one time a Ford Mechanic suggested unplugging the MAF sensor to possibly cure the problem. Well it didn't. What it did do, though, was stop the sporadic shutdown of my engine.
Now the how's and why's involved I haven't a clue, I just know my truck hasn't 'hickupped' since.
I doubt he meant to drive it with the MAF unhooked, just as a troubleshooting method to see what effect it would have on the condition.
I agree, don't expect good mpg or driveability with it disconnected, as the computer expects to have it's input to help adjust & maintain ideal fuel trim, as we drive..
If you don't want to spring for, or can't afford a brand new MAF right now, maybe consider a reman, or low mileage salvage yard MAF sensor.
On the engine stall while drifting in "N", maybe have a look at the IAC, as it's often a culprit in off throttle & idle problems.
Edit: Reviewing & noticing that you have a vintage 4.0L I'd add vacuum leaks to your idle problem suspect list!!!!
More thoughts for pondering.
Former ******
Joined: Nov 2004
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From: Salt Lake City, Utah
Actually, the MAF does not change the fuel trim, but rather acts as the primary reference for fuel trim. If you had a vehicle with no O2 sensor and just a MAF, fuel trim would always be zero. The O2 sensor is used to adjust fuel trim.
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From: Ishpeming Mi.
23.9mpg on my last fillup with no MAF hooked up and I was missing my oil filler cap. Stranger and stranger. I tried the test using propane and detected no aparent leaks.My MAF sensor hasn't been plugged in for the last 3 weeks. Other problems have to take precidence at this time over a replacement sensor. I just got a spare for it, something it has never had since I got it last Sept.
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From: SW Va
If you tried the propane "sniffer" test, when the oil filler cap was off & the MAF sensor was disconncted, everything may have been so unbalanced, that the propane vacuum leak check may have been invalid.
The PCV valve is a calculated for, PCV system vacuum leak & will be grossly uncalibrated wthout the oil filler cap in place.
With the MAF sensor disconnected, the engines air flow isn't being properly monitored, so the computer has reverted back to it's canned program to operate the engine, so all this may affect the sensitivity & results of a propane sniffer leak test imo.
You must have a bit of a mess underhood, if you've been driving without a oil filler cap!!!!
The PCV valve is a calculated for, PCV system vacuum leak & will be grossly uncalibrated wthout the oil filler cap in place.
With the MAF sensor disconnected, the engines air flow isn't being properly monitored, so the computer has reverted back to it's canned program to operate the engine, so all this may affect the sensitivity & results of a propane sniffer leak test imo.
You must have a bit of a mess underhood, if you've been driving without a oil filler cap!!!!
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From: Ishpeming Mi.
The mess, oddly enough, is over by the power steering pump. I made a posting about how rough Red road was, well it literally loosened up the cap on the pump.
The test using propane was done back in early May when the engine was still capped off and plugged in. It's possible that with the engine cold instead of up to full running temperature some demands where the leak could be weren't being made yet. With a known bad MAF, which I'll be replacing on my next paycheck, I'll try the test again with the propane.
The test using propane was done back in early May when the engine was still capped off and plugged in. It's possible that with the engine cold instead of up to full running temperature some demands where the leak could be weren't being made yet. With a known bad MAF, which I'll be replacing on my next paycheck, I'll try the test again with the propane.
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From: Ishpeming Mi.
Addenum, I do have a dirty mess on the oil filler side as well. Oh, well, time to clean the engine compartment.
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From: Ishpeming Mi.
Replaced the MAF sensor over the weekend, No more CEL and the truck has stopped stalling when idleing. I wonder how this will help my hypermilage mpg? I do now have an erratic miss, which suggests that it's time to tune it up. Alas it's summer tax time on me casa so that will have to wait a couple of weeks.
Cargo Master
Joined: Apr 2004
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From: Golden, CO
Keep your throttle less than three-quarters open and the beast should stay in closed loup, which is what you have been missing out on.
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From: SW Va
If you didn't do it while installing the new MAF sensor, be sure to pull the B- battery cable for say 20 min or longer, or just leave a door open. or some other electrical load on, to wipe the the computers memory more quickly, so it can begin to relearn the things it needs too, with the new MAF sensor in place.
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