My Truck, a 93 e250 straight six with a e40d tranny, is missing on 3 cylinders my mechanic told me, he did all the basic checks and replacements, fuel pressure regulater, plug, wires, cap rotor, checked the injectors etc etc..

Finally he replace the ecu with one he had lying around, which made the engine seemed to purr, even under load. The down side was I had no first gear. I had to start off in #2 to get her going, in which the engine ran fine it seems.

So, Today I pulled my partners ecu out of his truck, (sister pair, from the same company, same models, years, engine and tranny) and did a swap out.

My truck once again is misfiring and has cylinders out again, BUT has first gear once again!

As expected, his no longer has first gear but runs .

Why would one computer make the engine run on all six ( minus 1st gear), while a known good ecu still let it misfire ( yet shift fine)??

I read in another thread it may have someting to do with a bad ground for the injectors? Maybe I have an open ground in the injector wire ground splice ( if there is one) and the second computer solves that? I dunno? I'm at a loss.
I'm an electrician for twenty plus years, so I think I can solve this with some help.

Wouldn't bad sensors be bad on both Ecu's??
Could the electronics on my trans be sending screwy signals and readings to both 'proper' Ecu's?

To quote Johnny Fontaine in The Godfather.... "I don't know what to do,I don't know what to do...................."

Thanks guys, i would really appreciate this!


Ralph in Chicago

 

Update. No suggestions?? Here's what has happened so far if it helps....out of frustration today I unplugged the large Pin connector atop the trans, the one that splits down the line and goes to each e4od connection point. The truck ran fine thru all gears. Of course it didn't want to budge. I quickly reconnected the plug and the engine went back to missing and sputtering. Anybody?

 

I think you need to check the computers. Something is not right as you've already noticed. Check the calibration codes on the door jam stickers on the trucks, then check the computers. It sounds to me like there are a couple different programs in them. Just because the two are identical the computers may not be. You need to pull the codes to find out what's going on.

 

Sounds to me like you have a short in the harness somewhere. You will need a wiring diagram and an ohm meter and ohm the harness between the computer and the transmission connections.

 

Thanks guys! As it stands right now, she's over at the trans shop that rebuilt her 3k miles ago, he's gonna pull the codes. He says he doubts its the solenoid pack, but is gonna check that out.

I find out at 3pm what the story is. I as thinking of checking the harness if he can't find any fault.

Very true about the computers, I was just told that this morning, about the programs. AGAIN, thank you for the help.

 

Just got a call from the trans shop! Said there was a short in the trans harness ( Bravo Clubwagon! ), three wires fried together which fried the solenoid pack. Which in turn caused the computer to go haywire, causing the misfiring. $300.00 bucks doesn't sound bad to me, gets me back on the road! Thank you guys for your input. Bless you all.

I'm going to pick it up with my fingers crossed!

 

OH MAN!!!

I love it when we pull off wins like this!!!

Glad to be of help.

 

Glad to hear you got it fixed. $300 is not bad at all. Sounds like he's not charging you labor for replacing it.

 

Yeah, when I got there, he told me he only charged like $50 bucks.
I do send and refer people to him often.

I appreciated your input, alot, I'm a 25 year commercial electrician, so, if I can ever return the favor...............................Just write me!