I am having issues with my computer on my 92 F150 Scab 5.0L AOD 2wd and need to replace it. When calling around I am told that there were 4 units used that year. My concern is that the computer may have already been changed and the correct one not installed. How does one find out for sure which one is needed, by the above info, the vin or other?

thanks

John

 

I don't know if there really is a way...the vin won't tell you. The only way I think you could do it is to look at a book of the computer #s and what vehicle they came on...or go to the dealer and ask them to help you.

Just be careful, the computers usually don't require replacement, so make sure you know it's the computer issues.

 

John, can you get to the computer to see what the calibration code is? If you can, you can try to cross reference the code here to see if you have the correct computer alrady: http://fordfuelinjection.com/index.php?p=17 . I also think it'll be for an E4OD automatic (you have the overdrive cancel switch on the shifter, right?) which doesn't seem to show up on that list for some reason. What problems are you having with the computer right now? What kind of codes do you have? I think the dealer should be able to tell you what computer is in the truck by getting the calibration code from the drivers side door jamb, but I don't know for sure.

By the way, I'm Eric, the guy from NC State who hangs around HRT all the time.

 

The calibration code is on a sticker, on the front driver;s door pillar which you can see when you open the door all the way.

If its not there, you can look on the computer itself. If its not the original computer, and the truck ran well, you can get the same one that is there now and call it a day.

The computer comes out through the firewall in the engine compartment. Two screws removes the seal, one screw removes the cable release, then you slide it all out.

 

Hello Eric, I will be over there today. The tranny is an AOD, just had it rebuilt at the same time as the engine.

Thanks frederic, but not quite so. I got the computer out about half way and it hit the inner fender. It has some weird size small bolts to get it loose and with a big black cloud overhead it was dark pretty fast last night. I didn't get it out.

Best I can tell the calibration code is 2-54J-R10 & F2AE6EO61 GKM on the door jamb sticker. I could not find any way to cross reference this code at the site lhat is linked. I was able to see U2D on the puter and it matched it to a 5.0 & AOD.

I bought this truck off Ebay last fall with 244,000 miles. I had to rebuild the engine and then the tranny. The truck had been running fine but the check engine light kept coming on, and I could only get about 12 mpg at best, and no punch at all. I figured that truck should get 16-18 mpg on the hiway. I drove it to Advance Auto in Butner sunday a week ago to have the codes read. The guy hooked up his reader and it wouldn't come on. I saw that he had connected it backwards to the battery +/- -/+. He changed it, pulled the codes. It said that the MAP sensor was out of range.

Bottom line the truck wouldn't start when I was ready to leave, finally after 20 min. or so we got it fired but it was surging, and wouldn't take throttle. I was able to nurse the truck home, rolling it off idle.

We worked on it last sat changing sensors from another truck that I have, NOTHING. Finally we tried connecting another computer and the truck fired right up. I am able to drive it but it is running like a choke is on, the tail pipe is sooty & black.

The manager of the store claims that his reader will not fry my puter, even though everyone else including the Ford dealer service employees say not so.

thanks for the help

John

 

I have my old MAP sensor at the house if you want to give it a try. If the MAP is giving a false reading it can cause it to run rich and get bad mileage like you are experiencing. Usually those computers don't go bad, but if the guy hooked up the code reader backwards, that might have something to do with it. It sounds like the computer is the correct one for the truck though, so if they can cross reference the Ford part number, you should be back in business.

I don't know if I'm gonna be able to make it back to durham today, but maybe tomorrow for a little while. We just got a new motor for the race car, so we'll be working on setting it up today and tomorrow, and running it on the dyno a lot this weekend. Otherwise I'd get up to Durham and see if I could help figure out what is going on with your truck.

 

I'm suprised, because I took mine out of my F350 (same cab, different frame) and taking the two metric bolts out was all that was required. I did have to wiggle it a little, but I didn't have to move anything under the hood. I can't imagine my 93 is any different than any other 92-96 f-series, which is why I made it sound so easy.

I did struggle a little with the bolt that holds the cable on... but that was because the ratchet I had with me at the time wasn't clicking properly.

If you can't cross-reference the computer online, or mail order, take it (or the numbers at least) to the dealer, and get the Ford Part Number that matches what you have, then cross reference that number, to the source of your new ECM. I've run into disconnects with ford part numbers before, which always baffles me. If its 1234-5678. it should be 1234-5678. But your dealer can cross reference it.

Maybe, maybe not. My crewcab gets 14 on the highway, but it does weigh almost 7000lbs. There were a couple of threads on this forum about miles per gallon with the 351, and the mileage people were claiming were as high as 18 and as low as 8 (and the guys on this end were shocked). So 12, while not desirable, might not be "awful". But the fact that you have no power, and your check engine light on, certainly indicates to me there is something to be done that might effect future mileage.

Since you pulled the codes and found the MAP sensor was out of range, this could be for two reasons. First, the map sensor itself could be bad, or the voltage to the map sensor is wrong, not there, etc.

Take a volt meter to the map sensor connector with the sensor still attached (shove the probes into the wire entry points) with the key in the "on" position. You should have 5V on one wire, ground on another, and a smaller voltage around 1-2v or so if your truck is idling.

Other people here have not reported this problem, but my truck "eats" map sensors every 6-8 months. It always has, no one can figure it out (even me, and automotive wiring is a "thing" of mine). I have the right voltages on the connector, the map sensor isn't getting baked by exhaust, yet it still dies. Whether new, a junkyard pull, whatever. Maybe I've finally found someone who has the same issue?

New sensor out of range... that leads me to believe either there is a massive vacuum leak, or the voltages to the sensor aren't correct.

And to your dealer telling you that a code reader can hurt the ECM, that's not so. As I've experienced problems with my crewcab, I've pulled codes with a variety of things... from "Auto XRay" to a Snap On reader, to a paper clip and a red LED shoved into the connector... 330K miles and still going, my ECM is the original.

 

If the polarity is reversed when connecting the code reader, I'm sure it could mess up the computer - especially if the SIG RTN is grounded through the code reader - that would mean it put 12V on the signal return wire. The MAP signal wire will show 2.5 volts at all times - the frequency varies, so that will have to be read with a tachometer, or something that will show a duty cycle. John's truck is a 302, so it should definitely be getting at the very least 16 mpg on the highway - certainly not 12 - even with four wheel drive.

 

Thanks for the help guys, I spoke to the manager of the Hillsborough Rd store in Durham yesterday. They and the manufacturor of the reader are in denial about blowing it, but they agreed to replace the computer, and ordered one.

The little bolts holding the inner fender turned out to be 5.5mm. Just happened to run across a 1/4" drive socket that had come with Bronco that I bought a while back. That and prying the inner fender with a 2X2, I was able to get it out.

I have a 66 F100 FE C6 that got 13.9 (best tank run on trip) once while pulling a 18ft car hauler in the flat lands of S.C. near Charleston, and maintaining 75 mph. If 12 mpg is all this rig is gonna get, a for sale sign is going around it's neck. I aint putting up with a wimpy Ford truck getting bad mpg. I surely thought a EFI 5.0L would have more spunk that this one does.

John

 

Got the new puter in yesterday, took the truck out for a little test run, and it seems to be running much better than with the borrowed one. The check engine light is still on. We put a new ox. sen. on last week. Maybe I need to unplug the battery once more.

Getting the inner fender back in place is gonna be a bear. The cold wind was blowing to much yesterday afternoon for me to fight it.

Any ideas on improving the mpg? The engine/tranny has about 2900 miles on the rebuild now.

You can email me at my username ncfto dot org Eric, you might be interested in that site.

John