1991 Ford f150 3.0L Ignition Problems

[Cofe]

My beater truck warms up, and then starts misfiring until it dies. Let it cool off a little and it starts and runs good until it heats up again... I replaced the ignition module fuel filter, and that didn't fix it. Any Ideas Oops.....EDIT... 5.0 302 ford motor

 

[MTboatguy]

Re: 1991 Ford f150 3.0L Ignition Problems

Does it have Fuel injection? If so, you might check the MAP sensor, if it is carb vehicle, then it probably needs to be rebuilt., as it is probably Fuel injection, it is probably that sensor, by the way, Ford is not listing a 3.0L engine in the 91 F150, the 3.0L was installed in the Ranger, but yours should be 4.9L, 5.0L or 5.8L

 

[Gyrene]

Re: 1991 Ford f150 3.0L Ignition Problems

When is last time it got plugs and wires? Like chicken soup - can't hurt.

 

[Cofe]

Re: 1991 Ford f150 5.0L Ignition Problems

Re: 1991 Ford f150 5.0L Ignition Problems

Oops....got my 3.0 car mixed up with my ford 5.0L 302. I will edit the title.....:facepalm:

 

[Cofe]

Re: 1991 Ford f150 5.0L Ignition Problems

Re: 1991 Ford f150 5.0L Ignition Problems

New plug wires, cap, rotor, I haven't inspected the plugs.

 

[rbh]

Re: 1991 Ford f150 3.0L Ignition Problems

Just a thought, if this is carbed, as the motor warms up does the choke open?

Other thought the intake gaskets are leaking when the enrichment/choke comes off it leans way out.


As the motor starts to die spray the mating surfaces with wd40 and see if the motor picks up.

 

[Cofe]

Re: 1991 Ford f150 3.0L Ignition Problems

Throttle body fuel injected motor.

 

[hungupthespikes]

Re: 1991 Ford f150 3.0L Ignition Problems

Check the ECM 2-wire temp. sensor. Your gauge is the one wire temp. sensor so it's for you and the 2-wire is for the motor.

When the motor is cold it should be around 3000 ohms for 70 deg. F. more is colder.
Warm the motor up, shut it down then read again. should be around 500 ohms for 160 deg. F.

cheap fix/test is a 500 ohms resistor instead of the sensor. It will run ruff cold but fine warm.

huts :facepalm:

 

[82rude]

Re: 1991 Ford f150 3.0L Ignition Problems

possibility is the coil is failing when it warms up.just a thought; ive had it happen to me.

 

[Cofe]

Re: 1991 Ford f150 3.0L Ignition Problems

possibility is the coil is failing when it warms up.just a thought; ive had it happen to me.

My thoughts too 82rude. I thought I was for certain when I replaced the ignition module.....but no..., but just thought I would post this here as there are a vast amount of mechanics here with suggestions that cover a wide range. I am planning on getting a coil tomorrow in the am. 4/6/14 and try that out. "Just keep throwing money until it runs.."

 

[Bob_VT]

Re: 1991 Ford f150 3.0L Ignition Problems

Put a timing light on it and have someone rev the motor a bit. Wath the timimg mark and see if it moves. It should advance and if it is NOT moving then you have an ecm and ignition problem. I chased a similar gremlin in a Bronco once and mine got so bad it would break the roll pin on the distributor.

 

[dolluper]

Re: 1991 Ford f150 3.0L Ignition Problems

ECC power relay or pickup coil..
try this link for how to check
Part 1 -Ford EEC Power Relay Test.

 

[PiratePast40]

Re: 1991 Ford f150 3.0L Ignition Problems

I just had a similar problem with my 96 F250 with the 7.4L gas engine. It was an intermittent problem. Would start when cold but then after driving it and warming it up, wouldn't start after sitting for just a little bit. But it didn't happen all the time. Took the shop almost a week to figure it out but ended up being the distributor stator (pickup). They decided to just replace the distributor since labor was less than removing it, tearing it down, and then replacing the stator.

It was frustrating since it was an intermittent problem. They had it narrowed down to the distributor pickup, ignition module, or coil.

 

[Cofe]

Re: 1991 Ford f150 3.0L Ignition Problems

A new coil and ECC power relay did not work. Have narrowed it down to the pick up coil, but that will take a new distributor. I have been shopping around, and notice that they make a steel and a cast iron gear for these distributors. Which one do I have

Thanks everyone for the help.

 

[Cofe]

Re: 1991 Ford f150 3.0L Ignition Problems

UPDATE: The truck is now running. The problem was the TPS...Throttle position sensor. I found out that there is a way to make the check engine light to flash a code for diagnostics. Then there is this web site where I found with the codes. EEC-IV Diagnostic Trouble Codes - Diagnose problems in your Ford

 

[rivermouse]

Re: 1991 Ford f150 3.0L Ignition Problems

The ignition CONDENSER can cause this. They get hot and then cool off .

 

[dolluper]

Re: 1991 Ford f150 3.0L Ignition Problems

Well in 2014 or even in 1991vehicle manufactors don't use points and condensors anymore.....back in the 70's that was common