1990 5.0 F150 missing after rebuild
 

My sons 90 F150 with a 5.0 had a burnt valve. It ran good other than the missing cylinder from the burnt valve. We built another 5.0, bored, new pistons, heads worked and now it is missing like crazy. It will not pull a greased string from a cats butt.
We put plug wires on it before tearing it down so we didn’t renew them. I replaced the distributor since the gear on the old one was chipped and had a lot of wear. New plugs, water pump just about everything replaced.
If it were something other than all the electronic and fuel injection I probably could fix it. It will backfire some, not all the time. It misses sitting idling and when it’s revered up it sounds much better, but when trying to drive off it doesn’t have any power regardless of rpm.
The egr valve was disconnected when we got the truck and it appears it may have had a smog pump, but it too is no longer on it.
I have checked the timing and actually set it with a light. I think I have tried it anywhere from 0 to 10 degrees BTC.
If anyone has any suggestions, I’m listening. My son really needs his truck, but I’m lost as a ball in high grass.
Any help would be greatly appreciated.
Thanks

Did you replace the camshaft? If so, what was the part number for it and what manufacturer.
I ask because there are 2 different firing orders for windsors, and the cam may not be efi friendly

Didn’t replace the cam.

I used a 95 engine and heads. Both are fuel injected engines. Roller cams

Not sure if the 90 was the old firing order, but the 95 engine is. So if you used the 95 efi cam you have the 1-3 order if you used the 90 cam, you MAY have the 1-5 orderhttps://cimg2.ibsrv.net/gimg/www.for...1a5cc46ab5.jpg

That was the opportunity. I’ve been driving Rangers for 25 years now, back when I did mechanic work built a lot of engines, but this newer stuff. . . I struggle with them!

I’m down to an occasional miss if you’re getting in it. We cleaned the injectors, but I really think it’s on the firing side. Could have a wire breaking down I guess.

I really appreciate the help Big Guy.

Well, if you can run it long enough to get to operating temp try pulling codes. That may point in the right direction....
Also, did you use the 90 or 95 distributor? The 90 dist has to be used

Did you pull the "spout" before you set the timing? If you did not, then your timing is heavily retarded as you are setting the timing as the computer is advancing it.

Spout? Not sure what this is!

I did use the 90 model distributor. It seems to sputter/miss some from about 1,700 rpm up to about 2,500.

My son drove it to school today and to work tonight. He called me earlier to let me know the range the RPM was in when it was missing some. He also said it didn’t seem to have the accelation it did before building it.

The picture that 88 posted is the spout connector. Get it to operating temp, shut it off, pull the little jumper out, start it and check timing.
By reading that you weren't sure what it is, I'll bet the timing is way off.

I’ll try that tonight when I get in from work. I have turned the distributor while listening to it and also used a timing light.
Thanks for the info guys, maybe I can get it “healed” soon. I’m about ready to pull my hair (what’s left) out. I guess I shouldn’t gotten into the computerized vehicles way back.

Thanks again.

The computer advances the timing, even at idle...the spout connector disables the timing advance so that you can accurately set the base timing. It should be 10* btdc at best, if you want a little more power you can try bumping it more, but I'd get it running good first.