'90 model F-150 Will Only Idle

[Rimjam]

My good neighbor bought a non-running, low miles (46K) Lariat w/ 5.0 eng. Been sitting about five years. Started throwing parts at it: fuel pump, fuel tank, injectors (2 sets). fuel pressure regulator, throttle position sensor, a known good distributor, MAP - trying to get it to run right but it will will only idle roughly. Will not rev up unless you play with the accelerator pedal very slowly (too slow to drive). It has good fuel pressure, is not showing any codes. Local indie mechanic is at a loss. I suggested we try my extra ECM for my '88 Ranger - possible we burn something up assuming the '88 ECM will even plug up? Thoughts welcome!

 

[Uncle Gump]

Have you ran a full compression test?

Put a vacuum gauge on it?

There is only one way to rule out mechanical issues.

 

[Eddo Rogue]

Might be the MAF sensor, or TPS.

 

[Rimjam]

Compression test not done. TPS replaced. Thanks for input.

 

[Rimjam]

MAF sensor replaced, I incorrectly called it a MAP in initial narrative.

 

[Eddo Rogue]

Might be somethin silly...forgot to connect a plug, maybe a missing/ broken vacuum line. Possible one of the parts you replaced was bunk. I have had bad luck with aftermarket parts lately. Pretty much anything not motorcraft or OEM doesn't work.

 

[dvdswan]

Air/fuel issue. Have you checked the simple stuff like clogged air filter or obstruction to t/body, or clogged fuel filter?

If it was sitting for a while animals like to find homes in the air box.

 

[Rimjam]

Hoses from air filter disconnected. Fuel pressure good. Eng will eventually rev up if you keep playing with the accelerator pedal. Gonna try ECM if Ranger will fit.

Keep those ideas coming.

 

[rubydist]

It will not run with a Ranger pcm, so that is a total waste of your time.

 

[franklin2]

You have changed the distributor. Have you set the timing? There is a certain procedure. If you did follow the procedure and set the timing correctly, what does the harmonic balancer look like? Is the rubber on the balancer all cracked up and or trying to come out? If it is, it could have slipped and the timing marks may be off. If that is the case, you could try and adjust the distributor hold down bolt so you can just turn the dist by hand, get it idling, and then grab the dist and turn it so the engine speeds up, and then see if that helps it. Just to get it running you can guess at it, but if the balancer is in bad shape you need a new one.

 

[Rimjam]

Good idea to double check timing & balancer. Local indie mechanic did the dist work & he's been at it for years, doesn't mean he's above errors.
I still wanna try the ECM swap just to test. Will my Ranger spare plug in? Will anything explode?

 

[franklin2]

Good idea to double check timing & balancer. Local indie mechanic did the dist work & he's been at it for years, doesn't mean he's above errors.
I still wanna try the ECM swap just to test. Will my Ranger spare plug in? Will anything explode?

Your ranger is a six cylinder? And the f150 is a 8 cylinder? Not going to work.

 

[Rimjam]

Hadn't considered that, thanks.

 

[rusty ol ranger]

Was it running good when parked?

Kinda sounds like maybe the timing chain jumped a tooth or 2.

Your Ranger ECM will not work.

Oh and make sure when your checking/setting ignition timing the SPOUT connector has to be unplugged. Otherwise youll end up with it way off

 

[Rimjam]

Indie mechanic wants to try ECM next...I'm looking for one.