90 f150 wont start sometimes:[

[ogea123]

We got a 1990 ford f150 the fuel filter,both air filters, the plug wires, and the fuel and master power relays were changed. But the truck can be run fine for a while then sit and it will not start!!!! It has done it before and we keep replacing parts on it and we cant afford to keep replacing different parts on it. Does anyone know why the truck is doing this could it be the computer?? We really need to find out because we need a vehicle to drive.

[bluebuick91]

what does it do exactly? Will it turn over, but not fire? Or will it not crank over at all? Could be a few things...Our starter and solenoid went out also, there was a small piece in the column It was the same way, sometimes it would start, sometimes it wouldn't. One quick way to tell if it is the ignition/column is to drop the column a little bit-just to get access to the rod that lays on top the column. If you can push down on the rod to start it and it will fire up and stay running, then it is the switch in the column. pull back on it to turn it off. The part itself is only 10-12 dollars, just doing the job is a pain...let us know what yours does...can offer more help later

[ogea123]

It does turn over it just wont fire and it only does it everyonce in a while. So tommorow it might start or it might not.

[mechhound]

Originally Posted by ogea123

We got a 1990 ford f150 the fuel filter,both air filters, the plug wires, and the fuel and master power relays were changed. But the truck can be run fine for a while then sit and it will not start!!!! It has done it before and we keep replacing parts on it and we cant afford to keep replacing different parts on it. Does anyone know why the truck is doing this could it be the computer?? We really need to find out because we need a vehicle to drive.

You could do a test when it won't start to see if you have an ignition problem or a fuel delivery problem. I know this vintage of Fords well enough to say 90% it's an ignition problem. One of these: 1. the coil 2. the ignition module, bolted to the side of the distributor 3. the PIP inside the distributor. I would start off by replacing the coil with a cheap one from Autozone if you have one near you. Post back with any questions.

[bluebuick91]

you can also try what we are having to do, have someone lay underneath and tap the fuel pump that is on the frame rail drivers side, under the floor board, you will see it in there...looks like a long can-have someone tap on it as you try to start it. Ours is sticking, causing the same symptoms as yours

[ogea123]

the fuel pump kicks on right away when the key is turned on? unless it still has problem like that??

[oldguyhd]

Definantly sounds like a fuel or spark problem. Next time it does it, pull a plug wire and try again to see if you got spark. I shove a small screwdriver into the end of the plug wire and hold it just off of a bolt to check for spark. If the spark looks hot blue white, probably good there. The fuel pump should kick on everytime you start the truck. You may or may not hear it in the cab. I had to replace one on my 87 f150 when I had it. Not a real bad job. It was raining and I just sat under the truck to work. I would really lean toward the pump. But check for spark first, it's easy and will tell you where to look next.
Mine also had dual tanks. Each tank had a fuel pump in it and they pumped it out to the booster pump on the frame through the tank switching valve.

[FNA]

"Definantly sounds like a fuel or spark problem" For an intermittent no start condition? Ya think?

Glad you suggested the OP look for a spark.

With a ford, if it is no spark, I would think more to module than coil

[ogea123]

well we will have to check it out and i will let you guys know whats wrong with it!!

[mechhound]

Originally Posted by FNA

"Definantly sounds like a fuel or spark problem" For an intermittent no start condition? Ya think?

Glad you suggested the OP look for a spark.

With a ford, if it is no spark, I would think more to module than coil

In reply to your last sentence. With these Fords the ignition module was mounted on the side of the distributor. When THIS ignition module died it usually died like most living things, dead meant dead. Unlike the coil and PIP,(my first and third choices) which would die and come back alive many many times. I have heard of these ignition modules(the ones on the side of the distributor) dieing and coming back alive, but it's very rare. So I still listed it as a possible culprit. The coil is much more likely the culprit than the ignition module in my experience. The reason I listed the ignition module as number 2 to replace, instead of number 3, is the cost and relative difficulty of removing(and mostly reinstalling) and disassembling the distributor to replace the PIP(choice number3). Now you know.

[FNA]

"The reason I listed the ignition module as number 2 to replace, instead of number 3, is the cost and relative difficulty of removing(and mostly reinstalling) and disassembling the distributor to replace the PIP(choice number3). Now you know."

The reason I listed the module as first, is that I have seldom seen an ignition coil go intemittent cold failure and CPU go/no go/go conditions are not uncommon. Now you know.

[mechhound]

Originally Posted by FNA

"The reason I listed the ignition module as number 2 to replace, instead of number 3, is the cost and relative difficulty of removing(and mostly reinstalling) and disassembling the distributor to replace the PIP(choice number3). Now you know."

The reason I listed the module as first, is that I have seldom seen an ignition coil go intemittent cold failure and CPU go/no go/go conditions are not uncommon. Now you know.

Well, let me put it this way I have driven Fords of this vintage a FEW HUNDRED THOUSAND MILES and personally done all the repairs on them. Also my closest neighbor had a 1990 F-250 which he drove 250 thousand + miles. One of MY above mentioned Fords was a 1987 Taurus, and it would just quit and then start after sitting a while, I finally figured out it was a bad coil. I had several ignition modules go bad on these Fords, and when the ignition module went bad, not one of them would restart even after sitting. My neighbors F-250 had two ignition modules go bad in his 250K miles, same deal there when the module died it was like a person dead. My vehicles were all 1990 and older with the ignition module bolted to the side of the distributor. Starting in 1992, I believe, they moved the ignition module to the fenderwell to get away from most of the engines heat. The story with the modules on 1992 and newer may be different. So I can say I KNOW FROM EXPERIENCE. Please understand I am not trying to argue with you, just stating the FACTS as I KNOW them.

[mightymouse466]

Try the ignition coil. The one on my 92 was a bit rusty and loose where the mounting bracket went through the middle. Sometimes it would start and sometimes not. It would even die going down the road. Cost me $35 to replace and never a problem since. And if it don't fix the problem, clean it up and take it back. Thats what I do.

[mechhound]

Originally Posted by mightymouse466

Try the ignition coil. The one on my 92 was a bit rusty and loose where the mounting bracket went through the middle. Sometimes it would start and sometimes not. It would even die going down the road. Cost me $35 to replace and never a problem since. And if it don't fix the problem, clean it up and take it back. Thats what I do.

That's a great idea on replacing the coil. That was my first choice suggestion. BUT most places have a NO RETURN ON ELECTRICAL PARTS policy. That is a good policy, in my opinion, so when you buy an electrical part you know someone else hasn't taken the electrical part and damaged or ruined it, then returned it. So when you buy a coil, realize you own it.