1987 f150 problem rough idle/hesitation/stalling.

primate · 03-15-2008, 09:07 PM

I just bought a 1987 f150 with 110000 OM(so the previous owner reported.)

When i got it like 2 weeks ago it was running great. The last couple days i've been having some problems though. The idle seems to be real rough. Also sometimes the truck will bog when accelerating as if it's not getting the correct amount of fuel. Also today i got to work and put the car into park. All the sudden, the engine starts revving VERY high. I put it into reverse and it went back to normal. Then back to park and it idled ok.

I'm not a huge mechanical guy, but my thoughts were:

-fuel pump(s)(the truck has 2 tanks one i know has a bad pump; The other one was supposedly fixed like 6 months prior to me buying it.
-Fuel injector(the previous owner told me 1987 was the first year they started putting fuel injection in these trucks.) i hope this is not the problem
-Some kind of throttle controlling element.
-I also read some other posts saying it could be a vacuum problem.

Thoughts? Advice? Suggestions? please help me!

thanks in advance.

-Prim

jonmark1985 · 03-16-2008, 06:14 AM

Its not a fuel pump or the injectors, don't go buying parts and changing those. The first thing to do is search for vacuum leaks and a sticking idle air control valve.

primate · 03-16-2008, 07:23 AM

new development. Went to leave for work today. Car started after stalling twice upon ignition. I pull out of my apartment complex. At the intersection i hit the heat; Immediately the car died. Put it in park and turned the key. Nothing...didn't turn or anything.

Any insights? Is this consistant with valve leak or idle valve? Just seemed weird that it isn't turning over. The truck has never had any problems turning before.

thanks again

distressed.

-Prim

trucker450 · 03-16-2008, 08:37 AM

Is the truck totally dead electrically or do you still have headlights? If it is totally dead I would look for a blown main fuse or fusable link. If you still have lights I would look for a bad solenoid, starter problem or low battery. If you try to start it and the lights stay bright look at the solenoid. If the lights dim down your battery is low or you have a starter problem. I dont know if your other problems are related but a short heavy enough to blow a main fuse would play hob with all your systems.

primate · 03-16-2008, 03:18 PM

The lights work fine. The battery does/did not appear to be low on juice.

-Prim

primate · 03-16-2008, 04:49 PM

Ok,so i just went and messed with it a bit with the bit-o-daylight i had. The truck turns over when i bypass the solenoid.I went and bought a new solenoid and installed it. Unfortunately it still doesn't turn at all. Also i checked all the dash fuses. all good.

So...i'm not sure where to go from here.....

suggestions?

thanks,

-Prim

jonmark1985 · 03-16-2008, 06:41 PM

Yeah there was nothing wrong with the solenoid, there never is. Check for 12 volts at the little wire on the solenoid (the trigger) when you have the key in the crank mode, if you don't have this you need to check your nuetral safety switch or for a broken wire.

primate · 03-19-2008, 02:13 PM

Ok. i'm only getting .2V at the solenoid trigger(the small boot that connects to the top of the solenoid.) I get the full 12.8 at the battery. I also get a full 12.8 on the large bolt on the solenoid.

Another question about the neutral safety switch. If the switch was faulty, would this prevent the car from starting when i jump the solenoid? It just seems weird to me that the electronics died and at the same time the truck will now not start when i jump the solenoid. Before the electrical failure the truck never had a problem starting.

So i think a problem that would cause both of these problems seems logical.

thanks..

-Prim

jonmark1985 · 03-19-2008, 05:57 PM

you got two different problems

when you apply twelve volts to the trigger on your solenoid your truck should crank, if it doesn't your have bad battery cables or a bad starter, the solenoid is hardly ever bad (you will hear a "thunk" in the solenoid when you apply the voltage). If you jump the solenoid using a screw driver across the two large terminals (which I don't reccomend) and you don't get a start its the battery cables or the starter, or the starter cables.

Apparently your not getting the trigger voltage, so you need to figure out why, whether is a bad fuse, broken nuetral safety switch, ignition switch, broken wire, or any other common wiring problem.

Don't jump the solenoid or make it crank any time you have the key in the run posisition, I have been ran over from cars that started that way. My suggestion is to set the parking brake, put the truck in park or nuetral, block the wheels, and put the key in the house, maybe even consider unplugging the coil, JUST MAKE SURE YOUR TRUCK DOESN'T START OR RUN YOU OVER!

BTW if you have a stick shift check the clutch safety switch.

wuddupb22 · 05-01-2008, 06:02 PM

Quote:

Originally Posted by primate

Ok,so i just went and messed with it a bit with the bit-o-daylight i had. The truck turns over when i bypass the solenoid.I went and bought a new solenoid and installed it. Unfortunately it still doesn't turn at all. Also i checked all the dash fuses. all good.

So...i'm not sure where to go from here.....

suggestions?

thanks,

-Prim

I think that itmight be you neutral safety switch, you can bipass it like i did, or you can buy a new one for like 40 dollars