My son has a 1988 ford f150 4x4 that will start and run fine until it warms up. Then the truck will start sputtering, bucking and cut out. You can restart it just fine about half an hour later. We have replaced the distributor, coil pack, wires, plugs, rotor, front fuel tank, fuel pump, fuel filter (twice), put injection cleaner in it as well. We've dumped nearly $1500 into it and he can't get back and forth to school. Any help please!

 

Do you know the fuel pressure? And have you replaced the fuel pressure regulator yet? Also do you know if the fire is breaking down?

Two things that go bad on these model trucks, are the fuel pressure regulator, and the ignition module (located on the side of the distributor)

 

You need to determine if you are losing spark or fuel. I suspect it is spark, but more info is needed to help you narrow this down.

You stated you replaced the distributor, was it a new one or rebuilt? Many of the "rebuilt" units have bad PIP sensors in them which is the most common failure mode on this vintage trucks.

 

X2 on what RLA2005 mentioned. Also, the ICM located on the distributor would have been my 1st guess as these are more prone to damage than they're later counterparts. The later ones were addressed as the "Remote-Mounted TFI" systems being moved to the driver side fender well.

 

Well, apparenly with a quick water test we were able to determine that it has a leak in the intake and needs to be resealed. Will keep you posted if this helped at all.

 

That work was done a few weeks ago. It helped but did not cure the major problem. Any other ideas?

 

I think Posts 2,3 and 4 have direction as well as unanswered questions directed at you. No where have I seen a definitive answer from you where it was determined to be a loss of spark or loss of fuel.

We gave you direction before, it is your choice to ignore or keep throwing money and parts at it until you run out of funds, patience or time.

 

I believe the distibutor was rebuilt (got it from advance auto). I'm sorry I can't answer the fuel pressure question or about the spark. I am a single mom who relies on what her son or any random person is telling her when they look at it. I have had a mechanic tell me that it has a blown head gasket as well (which I do not believe). I have been told it needs a timing chain as well. If that was the case why would the truck run fine for about 10-15 mins then act up? I am pretty sure it is getting fuel, everything in the fuel system down to the front tank has been replaced. The truck sat for 5 years before we got it.

 

Ivy, as others have said spark is suspect here...try this, next time the engine dies, spray a little "starting fluid"(about $3.00) in the air intake tube. Then try starting the motor, then let us know here what happened with that...with these trucks the "PIP circuit"(inside of the distributor) and the "ICM" "Ignition Control Modual" also known as "TFI"(mounted on the outside of the distributor), are prone to failure do to heat (do a search on the forum here using one of those 3 terms for more info). Many times after cooling off for awhile, the vehicle will start again. It is possible that your distributor is fine, but the TFI needs replacing if you had not changed that out already. Generally speaking a re-built distributor is not heat tested before being offered for sale. You could buy a new distributor and TFI from Carquest, their distributors are heat tested, and I am using one of them right now. About $130.00, the TFI is about $100.00 ..You should be able to return that distributor that you already bought, if proven faulty...good luck to you
Ford Fuel Injection » Actuators

 

Chances are that if you replaced the distributor, and it didn't change the behavior at all, then spark is not your problem.

I'd be interested in finding out what the fuel pressure is at the shrader valve on the fuel rail (you can test it with a fuel pressure gauge). I'd also be interested in how much vacuum the engine is pulling. Also, have you pulled the codes? They may give you a clue that will point you in the right direction.

Unfortunately, diagnosing a vehicle requires some special tools that you often have to rent or buy in order to do the diagnosing yourself. That's one reason mechanics are expensive. They spend $2k or more a year just on tools.

 

Did you ever fix the issues, does the truck run good yet?

 

The throttle body was replaced a couple of weeks ago, along with the leaky water pump. Seems to be running well while sitting. I turned the tags in a while back so it hasn't been driven anywhere that amounts to any distance yet. I will let you know once its back on the road in the next couple of weeks.

 

We retagged the truck last week. My son took it to the gas station and filled up the front tank. When he got back gas was pouring out of the rear tank. He removed the nozzle and it exploded out. The front tank was emptying into the rear tank. So a nearby mechanic completely voided out the rear tank. He got a windshield wiper motor to put in it. When testing that, the truck wouldn't start anymore. He used a screwdriver on the starter and was able to start it. Apparently theres a solenoid in the clutch that connects to the starter. So thats where everything stands right now.

 

First: I believe the fuel from the front take in going into the rear because the tank selector valve is stuck.

Second: There is a starter solenoid on the passenger side corner panel, under the hood. Its a simple fix. Either the solenoid is bad, or voltage isn't coming from the key pulling in the solenoid. Most likely the solenoid.

 

Im the spoken of son.The truck not starting with the key i have no idea whats wrong with that.The solenoid is good,Ive looked at the clutch switch,ignition switch,and on through.So i just took some wire and put one end one the solenoid where the little wire supplies the voltage just for the solenoid,and put the other end in the sprayer motor plug since the motor didnt work.So now i got push button start.The fuel selector valve is bad it got stuck since the people that looked at the truck replaced it with a used one for no reason.the throttle body was not the cause as it does that bucking again.I just drove the truck from md where it has been and brought it down to sc where i live and it ran great not a problem.today i went out to mess with it and did fine for awhile then it started to just stall when i gave it fuel it will idle for a little bit but everytime i give it fuel it tries to stall.At idle it will eventually die and wont start again.All the advice has been great,but it is not spark.Its got to be fuel.The problem is it somehow gets air in the fuel rail.I cant get out after it dies and bleed the line of air get back in and fire it up.wait a little bit and repeat the whole process again.
What can cuase it to not get air and all of a sudden fill the rails?