Hey everyone. I've been doing a bunch of work on my 92 F150 and she's running great for 300k miles. I still need to replace the EGR tube because I'm getting high when driving to work !! But, today I wanted to tackle the ECU (computer} and wasn't able to get the dam box out of the bracket so she soaking in PB Blaster at the moment. I'm gonna be smelling that stuff in the cab for months !

In the mean time I plugged in the new computer and guess what, the dam truck won't drive forward. She goes into reverse fine but in drive it feels like I don't have a clutch that engages the tranny. Also, the OD button / light doesn't work. I have a feeling Cardone sold me the wrong computer. Any thoughts ??

Thx ..

 

Verify the part number of what you got, and make sure that it crosses with the numbers on your old computer(once you get it out). Although the wrong computer shouldn't prevent the truck from going forward at all.

 

Hmm, interesting. she does go into drive, but the engine revs with very light engagement with the trans. I'll put the old ECU back tomorrow in and verify the issue. Ran out of time today. I noticed that the ECU that is stuck in the bracket has rounded corners on the enclosure but the ECU I got from Cardone has a square enclosure. In other words the box has hard / sharp corners. Like it's an older unit

Thanks for the feedback, will post my progress tomorrow !

Phil.

 

So I called the Ford dealer, got the ECM part number based on my VIN, then called Cardone and they confirmed that I have the wrong ECM. I then spent 4 hours looking for the correct unit with no luck. There was a 78-5238 on Ebay but not sure I want to go down tat road again. There's 20 ECMs that say they'll fit my 92 F150.

Anyone have a good source for ECMs ? Again, I need a 78-5238

Thx.

 

What exactly is wrong with your old ECU? The majority of ECU failures in these trucks are just caused by leaky capacitors, which aren't too hard to replace. You can get packs of these capacitors on Ebay for ~$10. If you aren't comfortable soldering them in, a local computer repair shop should be able to help.
78-5238 comes up as being for a '93 only, but you mentioned that your truck is a '92.
I would check with Blue Streak Electronics as an alternative to Cardone.

 

What's up Shagg, thx for the reply. My truck is driving fine after all the work I've been doing but in the effort of "dependability" I decided to swap out most of the engine related components. My rig has 320k miles so I figured this would be a good idea since I'm driving the truck a lot more. I did read up on the capacitor issue with our ECMs so replacing the unit seemed smart. So after fitting the Cardone 78-5345 earlier this week, which shows on the Cardone site as proper for my truck, I found the trans / clutch wouldn't engage fully. It felt like a manual trans with a slipping clutch. Fun to witness. Last night I swapped back to the original ECM and we are all good now.

Points of interest though, I called Cardone about the above issue and they ran my VIN and associated ECM part number and it showed my truck's correct ECM is the 78-5238 which as you stated Shagg is for the 1993. My truck build must be on the change-over year cusp. Also, the Ebay seller for the 78-5345 ECM said that I had to program the ECM and is why it didn't work for me. I thought all Cardone ECMs are pre-programmed ?

Anyway, I was able to find a 78-5238 ECM on Ebay and will plug it in and give it a try. The old ECM will stay in my garage, maybe I'll teach myself how to solder new capacitors into the board.

Thanks for the help !!

Philo.

 

Just an update, was able to get the old ECM out of the firewall pocket but only after sliding a hacksaw blade along the sides to try and free it from the bracket and then having a neighbor tap the back of the case with a long ratchet extension from inside the cab while I wiggled the box from the engine compartment. The outside of the ECM was really corroded and was pretty much locked to the bracket. I put the rebuilt ECM in and she runs great. Idles much better and seems to shift smoother. However still waiting to see if the idle-jump still happens. This is when I'm sitting idle in gear and the trans clutch engages for a second and the truck jerks lightly forward. Very odd.

I also opened the old ECM to see if the old capacitors were leaking and gosh they look brand new, the PC board looks new, Kind of odd. No stains around the capacitors, they are nice and shinny.

Thx for the support !!

Philo.