I have been conversing with some reputable member with my issue and I am stumped and I think they are too.

I have an 89 f150 with the 5.0. Its been hard to start lately, usually takes about 2 cranks to fire up and when it does fire it stumbles for a bit then revs up and smells awfully rich.

Once its started and idles down to normal idle speed, it has a miss that you can feel. At cruising speed its perfectly fine though. There is no codes in the computer in either KOEO and KOER. It used to have a stalling issue while driving. It used to cut out unitl I put some BG44k in. After that it was gone for a while. I have noticed though, the idle is getting progressively worse. I have replaced many sensors in hopes it was a bad sensor somewhere, and still nothing.

I did a fuel pressure test and got these readings:

36psi at idle with vac on FPR
40psi at idle without vac on FPR

It hold 38psi after shutting it off for a long time so the check valves are fine. I have bled the system out and did a prime with the key and it build 40psi first turn.

I am at a lost of what else could be causing a problem. I have new 4 hole injectors in hopes a clogged injector or many is apart of the problem. I have checked for vacuum leaks and nothing happens with carb cleaner anywhere. My only other options i think are, timing chain, valve problem (although that would be throughout the rpm range), or someother internal problem.

 

Have you checked your timing?

I've got an 88 - very hard to start, idled hard - timing was about 15 degrees off. rotated it to 10 and it was like a new engine.

 

Timing is fine and it doesn't jump around. Doubled checked all this because I thought timing chain might be an issue.

 

for the miss - have you tried to narrow down which (if one) cylinder it is?

pull one plug wire at a time till you find one that doesn't make much of a difference. Can be difficult if it's just an internmittent miss especially on a v8 - but probably worth doing anyways. (would also be a good time to be SURE all wires are routed properly)

If you CAN narrow it down to one cylinder - that'd certainly make things a whole lot easier. If not - it still gives you some more info to go on.

While on the subject of plug wires - run it at night - see if any of them are arcing out. Can cause weird hard to explain problems.

 

followed the correct wire routing. I know these are common for the crossfire issue. I have not pulled a wire one cylinder at a time because I did not think it was an ignition problem. I will try that today.

I have checked it at night before and I couldn't see any type of arcing.

 

Just by chance......

When you turn turn the key to on, does the fuel pump "prime itself" for a couple of seconds then shut off, or does it/they run continiously ????

This is a very important question that needs to be answered for any and all of us that'll try and help you.

Bob

 

It primes itself for about 2 seconds. I can hear the frame mounted fuel resevoir the loudest.

I don't suspect any fuel pump issues.

 

New 4 hole injectors came in the mail today. I should have those in by next week if these don't fix the idle issue I have no other idea on what could be wrong.

I did find some info on fsb and a few people reported that the eec-IV systems seem to only like the gray colored distributor caps. I don't know how much that proves true but I am running a standard motor products blue colored cap.

 

Well, I did the injector job over my weekend (tuesday-wednesday) and I noticed a nght and day difference. Much smoother idle, better throttle response and easier starts. I imagine since I had some very nasty and sludge filled 1 hole injectors I am getting some better gas mileage with these reman OEM ford 4 hole injectors.

So In short, it appears the injectors might have been the or one major culprit in why it wasnt starting and running right. From now on its just drive it and see how she does, so only time will tell.

Also, FWIW, I did do a fuel pressure test with a gauge and everthing seemed to read fine, but I came to the conclusion that since these trucks with SD bank fire, it wasn't showing a clogged injector as easily.

 

Good find!

 

The distributor cap is not what they're talking about.

It's the TFI (ignition) module on your distributor. Earlier EEC-IV systems like yours need a grey one, while newer ones use a black one.

 

Ohh... thanks, I've got the correct tfi.