Computer keeps throwing maf codes

[Jesus Freak]

If thats the case let's loop @Jesus Freak in here for one of his classic stories of "Wha' happun'd"

Here goes:

And his good friend and neighbor across the street installed a ZF-5 obtained from a local junkyard for cheap, while him and his wife cleaned and fried catfish for all the wonderful helpers......... and they lived happily ever after....... without a turbo charger...... running his truck on waste oil........ and diddling with his ATC250ES Honda Big Red.......

P.S. that's the best I can do guys, I'm E4OD illiterate.

 

[TheMadHatter]

I apologize for my lack of updates the truck is also my only income currently and still out works most new trucks. I have checked the ground the 5volt reference and the signal line the map (maf) sensor is working as designed yet the stupid transmission will lock into limp it does it probably three times a week the harness has been checked it is just a annoying that I can’t come wt the solution. I keep telling myself that I did buy it as a unfinished project out of a field but for a basic obd1 truck it should not be this aggravating

 

[Jesus Freak]

I apologize for my lack of updates the truck is also my only income currently and still out works most new trucks. I have checked the ground the 5volt reference and the signal line the map (maf) sensor is working as designed yet the stupid transmission will lock into limp it does it probably three times a week the harness has been checked it is just a annoying that I can’t come wt the solution. I keep telling myself that I did buy it as a unfinished project out of a field but for a basic obd1 truck it should not be this aggravating

Nice rollback. Can't the brake lights being bad make those transmissions do something stupid? If so, could the extra lights on your truck be an issue somewhere......just thinking out loud.

I did have a friend give me a bunch of mullet this afternoon, of which I cleaned and fried for dinner. There wasn't any transmission swapping involved though. Good luck with it, man.

 

[TheMadHatter]

That hadn’t occurred to me I just walked out and verified my hand drawn wiring schematic to what I setup on the truck. The deck is wired to the trailer lighting harness while the lower lights are wired to the truck oem harness. I left this out before just due to forgetfulness when I bought the truck the dashboard transmission computer and the transmission was changed from the original with a “REBUILT” more like Craigslist rebuilt transmission and I am now wondering if they were chasing the same issue but the guy just said it wasn’t shifting properly so the changed the transmission. On a same yet different question has anyone ever tried wiring in a GM three wire map sensor into one of these trucks just a quick look as specs from the oem to a three wire gm,they both run on the 5+ volt and the same +/- signal ? I appreciate your time and feedback

 

[DirtyWood]

Bad brake lights can make the E4od act up. Any chance you have LED brake lights? If so then they might not draw enough current to let the system know they are functioning.

 

[TheMadHatter]

The lights are incandescent, i truly wish I either could find a mechanical automatic or it’s getting to the point that finding a manual 5speed and chopping the floor etc. tonight it decided that it was going to continue to drop into limp mode repeatedly. So in true fashion it would have highway running to do. If there was a repeatable fault, temperature, rpm,load,etc but it might do it at 3mph or 60mph could be loaded or empty, temperature, humidity etc I have to be missing something obvious but thank you folks for your time and input

 

[Rdnck84_03]

when I bought the truck the dashboard transmission computer and the transmission was changed from the original with a “REBUILT” more like Craigslist rebuilt transmission

This statement makes me even more suspect of the tcm.

Also if you're truck had a factory third brake light it has to work or the transmission will not shift correctly.

Other common issues that come to mind are MLPS, FILP, VSS

James

 

[TheMadHatter]

That is a very interesting thought my cab is wired for a third brake light even though it was removed.

 

[Jesus Freak]

The lights are incandescent, i truly wish I either could find a mechanical automatic or it’s getting to the point that finding a manual 5speed and chopping the floor etc. tonight it decided that it was going to continue to drop into limp mode repeatedly. So in true fashion it would have highway running to do. If there was a repeatable fault, temperature, rpm,load,etc but it might do it at 3mph or 60mph could be loaded or empty, temperature, humidity etc I have to be missing something obvious but thank you folks for your time and input

It's definitely something simple and electronic. If you do swap it and you want an automatic, get some type of 4spd out of a school bus or something. I couldn't imagine a C6 going well in your application.

The ZF-5 will be great except reverse is WAYYY too high. I went from a ZF-5 to a T-19 in my wrecker and am a lot happier. (My wrecker is currently laid up waiting on an engine overhaul)

 

[Nero]

So you mentioned you checked the wiring, how can you be sure the sensor is working? Its easy to replace, I'd suggest dropping a new sensor in real quick.

 

[Black dawg]

What is the code# , and have you replaced the map sensor?

 

[TheMadHatter]

The map sensor has been changed three times tried oem ford from the stealership as well as aftermarket standard code 22 map out of self test range

 

[Black dawg]

The computer on these is pretty basic, I have seen more than a couple times, codes flagged that were not relevant to the actual problem.
I saw one that led several mechanics completely sideways, with an irrelevant code.

Problems almost always come back to tps, tach sensor, or speed sensor.
Tach in cluster signal comes from ecm, and can work pefectly even if the computer is getting iffy signal

Does the tach work while in limp mode, and what takes place for you to know it is in limp mode?

 

[Black dawg]

Does the port on the map sensor have a vacuum line on it?

 

[Nero]

Does the port on the map sensor have a vacuum line on it?

If it does.... It Shouldn't. Should only be measuring ambient air pressure, so vented to atmosphere.

It is possible the tcm took a poop out on ya, you can get a refurb unit fron O'Reilly for pretty cheap.