1987 F150 I6 4.9
Starts and runs great. It will eventually die and not start until it has sat off for an hour or so.
Replaced: O2 sensor, IAC, TPS, Distro, PIP, ICM, Cap, Rotor, Plugs, Plug Wires, CPU... Other things I cant think of right now.
Something I should note: Even after clearing the codes I still recieve PIP codes. I dont even have to start the truck (Im hoping that its just cause the distro isnt spinning)... Please advise

 

Post the code number you get and be sure and include what type code it is, KOEO or CM?

Right off sounds like you have a bad wire someplace, one just hanging on by a thread or grounding out against something.

 

KOEO

I cant remember the code number right off hand but I know it something about no signal from PIP.

When shes not working she runs GREAT.

Oh and I also need to add that a couple of times I was able to floor it and keep it going. Ran like **** but it got me home.

 

Stated replaced the dizzy and PIP, assume the PIP was included with and preinstalled in the dizzy? Or did you replace it yet again after replacing the dizzy?

The new dizzy, where'd you get it? Some of them "auto super center" type places replacement dizzy's are a known problem right out the box.

 

I had a very similar problem that turned out to be nothing more than the passive tank select valve, our 88 f350 has 2 tanks. My valve always had a bad tank/pump selected. It worked best if you left the key in run for a few minutes. I think the tank pump would eventually pump enough to get the HP pump going momentarially. It would run out of fuel every 100 yards. Let it sit for 5 minutes and it would go another 100 yards. I ended up replacing both intank pumps and the passive selection valve.
Now it works fine from either tank.

 

When it won't start, has fuel pressure but it doesn't have spark right? Reason you replaced all the ignition related parts?

If not you need to start there, find out what preventing it from starting, lack of fuel or spark.... both?

 

I had the same problem a while ago with mine 91 f150 4.9 it turned out to be a bad pip bought from napa it would run for a while till it got hot when it cooled off it would run. i will not buy any more electrical from them ( no warrenty) went to auto zone and got another runs great

 

Many ppl here are pointing at an electrical issue, i say change the fuel filter, it's probably clogged.

 

Yep, dizzy came with the PIP. I wanted to go this route so I didnt screw anything up. I got it from Vatozone. Ill see what kind of warranty it has.

This one does have two tanks. But my step father said that he has run low on gas more than once and he just selected the other tank(s) and everything was fine. Would this be a sign of it working OK? And I thought you could actually run without the intank pumps (I know it would be more strain on the main pump, but just for examples sake).

Also this truck would go for miles then die. And then not start until its fully cooled down. If its cool out or at night, it seems it would run forever, but temp wasnt any different under the hood.

I had spark but it seemed irratic (Im not good at telling which is which), I used a cheapo timing light. I replaced ingnition parts for good measure. Not to mention the codes came up with PIP and many others said that PIP and ICM were prone to heat soak.

I have yet to check fuel pressure. How would I go about doing it on this truck?

Hmmmm, could be possible. I got her from AZ. Like said above Im going to check the warranty.

I have to find out, but Im pretty sure I was told it was replaced. How would this cause it not to start for a period of time? And then suddenly run great?

 

+1
Replace your fuel filter.

 

Yea replace the fuel filter, always a good idea especially if you don't know if its ever been changed, don't see it causing a heat soak problem though.

Heat may be effecting frame mounted high pressure pump, say cooler air / night air might be keeping it alive, delivering enough fuel pressure where during heat of warm day the pressure drops.

You should check fuel pressure replace the filter or not, you can rent a gauge from most auto centers or buy one fairly cheap.

Connect it to the valve on the fuel rail and see what it tells ya.

Engine off, key on = 50 to 60 psi.

Engine running, (vac line connected to fuel pressure regulator) = 45 to 60 psi.

Engine running, (vac line disconnected from fuel pressure regulator) = Pressure should increase 5 to 10 psi.

Low pressure in tank pump volume test = 6 oz min in 5 seconds.

Other testing can be done if a problem is found with any of the above.

You need to check for spark and fuel pressure when the truck acts up, might otherwise test as just fine.

Connect the fuel gauge and lay it safely under the hood, tape it off to something so when it starts acting up you can pop the hood and see it.

Carry a spark plug socket, when it acts up pull a plug and check for spark.

Until you know what system is causing the problem, it'll be a lot tougher to narrow down the exact cause of the problem.

 

I already have the fuel pressue kit. I just dont see (what I can see) where on the fuel rail to connect to. Ill also go ahead and hook up the timing light. Easy way to check for spark. Ill hook everything up and let it idle till it dies.

FPR: Where is it located? And how do I test it if the engine wont run???

 

You should find the FPR and schrader valve toward the back of the fuel rail.

You can test the fuel pressure when the engine won't run by simply turning the key to the run position, pumps will or should run for a second or two then stop building pressure.

Or by grounding fuel pump test pin at the eec test port with key in run postion, see >Ford Fuel Injection » How To Run a Self-Test scroll down page a little to see image of eec fuel pump test pin location.

 

my 87 4.9 is doing the exact same thing...

I've done Cap/rotor/wires/plugs/high pressure pump/fuel filter/fuel pump relay/tps/ cleaned idle air control. maybe it is the selector, it used to do this a while back and id switch tanks and it would go away, now switching doesn't help.

 

Hit 53 psi at prime and 45 while running

Couldnt get to the FPR, or maybe I could but I cant see back there. Why in the hell they put the shrader valve in the back Ill never know...

Unfortunately the truck never died so I wasnt able to fully test it under symptoms. Ill try again soon...

Might I ask what your doing with your old fuel pump (seeing how its not your issue)? Willing to part with it?