I have an 89 F 150 5.0. a week ago it stalled and wouldnt start. I wasnt getting current from the coil to the distributor. So I changed Icm and the stator. the truck started but wouldnt fire right - had a really bad miss. changed the timing chain. still the same problem. Engine acts as if there is a plug wire crossed. But theres not I checked them several times. when i check the timing with a timing light it is jumping all over the place. Also it wont stay running. runs for about 5 mins and stalls. plenty of fuel pressure and i checked each cylinder for spark and compression. I am absolutely lost at this point. any ideas would be great. I ordered a new PCM that was suggested for me to try.

 

That sounds more like a distributor with worn shaft bushings to me. What does the rotor and the inside cap contacts look like?

 

^^^^^^I'd have to agree with that. Until you get the timing to settle down, replacing the PCM is going to buy you nothing but a lighter wallet. I'd check the distributor shaft and the gear on it.

 

thats what i thought on the pcm. rotor looks fine. Ill check the gears and bushings thanks. let ya know how i make out

 

nothing wrong with the rotor or bushings. Still have no idea what is wrong

 

I'm thinking you did not get that timing chain replacement just right.

 

Ok, first, I would double check the plug wires. Firing order is counter-clockwise 1-5-4-2-6-3-7-8, with 1-4 on pass side and 5-8 on drivers side. Make sure none of the wires are laying across each other which could cause cross-firing.

 

scanner finally pulled up EGR valve. the air line from the intake to the EGR was cracked and leaking. waiting on part to arrive tomorrow and see what that will do. was running it for a while trying to play with timing, noticed the catalytic concverter and muffler were glowing red hot (litlerally). that is when i put it on the scanner. Im guessing it isnt getting rid of the exhaust causing it to load up, which is causing the time not to advance. thanks for all your posts, much appreciated.

 

Well now, that just narrowed things down. You are either running extremely rich(fuel pressure regulator blown/or stuck shut), or the cats are clogged up(due to a rich condition). First, remove the vacuum hose from the fuel regulator and see if gas is running out of the top of the regulator. If not, check the fuel pressure with a manual gauge. Should be around 35-45psi. If it is extremely high, you need to replace the regulator. If that's all good, unbolt the exhaust pipes and see if it'll run. One more thing, take notice if the egr valve is getting hot while it is idling--soon after startup. If the egr is open, it won't idle, but that won't make the cats glow!!

 

fuel pressure is fine. Regulator is fine. unbolted the exhaust and changed nothing. Now the scanner is showing MAP sensor and EGR errors. Thinking of ordering the EGR but hate to put another $100 into an empty pot. showing code 31 Thanks for your help big bronc

 

Try another MAP sensor. That will make it run rich. Forget about the egr for now. That's just a position code. You can unbolt and block off the egr ports with a piece of a can, and it won't hurt anything. Do it all the time.

 

sold the truck, sorry guys but im going back to chevy at least i know how to fix them