Engine locks up after cranking

Good point Mat.
So you're thinking hydrolocked when the engine won't turn over?

I read "all new fuel system" and assumed that included injectors.
Plus no mention of incredibly rich exhaust, or wet plugs.  

It's definitely something to look into.  

I'll check into the injectors once my capacitors arrive and I can finally reassemble the ecm.

Man I miss being able to walk into electronics stores and pick up capacitors and stuff, now there are basically nothing.

Did you find anything amiss in the ECM?
Deposits or corroded traces?
Electrolytics are basically eating themselves from the day they go into service.

I understand your feelings about brick & mortar electronics shops but we're already a couple of generations away from the days of thru-hole components and shopping for a Heath Kit.

Nothing really looked wrong in the ECM but I did spend forever trying to get one screw out it was way over torqued so I had to drill it out every other screw was easy to get out just the one that I struggled with, not to mention the wild goose chase I had to go on to find a socket small enough.

I'm just gonna replace it while I'm here, it wasn't too hard to clean out the through holes my parts should arrive tomorrow or Tuesday. hopefully it was just a faulty capacitor, surprisingly there was only one capacitor on the whole board.

I've been in a few '85 ecm's and have always found three capacitors.    

1) 67V 3.3uF  2) 10V 47uF

Higher voltage is fine (probably better) but the farad's need to be right
Be sure you install them in the correct polarity.
Look for the stripe on the side and match to the position of ones you remove. (I find it always helps to take pictures before doing anything)

Conformal coating comes off with a Q-tip wet with isopropyl alcohol or acetone.

Yeah I had just one 67V 3.3uF on the board I didn't see any others on it.IMG_20230520_140800.jpg

File too big for the forum software.




This is very interesting!  Though I messed with more Mustangs than trucks back in the '80's .

Can you post a picture of the catch code of your ECU?
Either my eyes are shot or the engineering number shows E8TF-12A650-A
(maybe both!  😄)

New capacitor is in and I'm still having the same problem.


ECM code is E8TF-12A650-AN1B



Here is a video with sound of the noise I'm hearing with pops/backfiring when revving

https://youtube.com/shorts/plkknfXmLsM?feature=share

After listening to all the injectors they all are firing normally and have the same amount of resistance of 15.6-15.7 ohms, I am wondering if you guys have any ideas before I send it off for a diagnosis.

After a diagnosis from a really good mechanic he found the vacuum leak from the pcv and then also used a different firing order(13726548) than on the sticker(15426378) it now has way better power and just takes off.

. I was under the impression that Ford had changed the 302 firing order by '86?

I know my '85 HO had the later cam.

Anyway, its great that you've found a good mechanic!  

Yeah it now drives like a dream and has plenty of power, it needs some front end suspension work but  other than that its a fun truck. Do you have any recommended brands of ball joints, tie rods, and shocks?