91 F150 5.0 Have spark and fuel but wont start
Asked by Chuck Dec 08, 2015 at 12:24 PM about the 1991 Ford F-150 XLT Lariat SB
Question type: Maintenance & Repair
I have a 1991 Ford F-150 5.0. My fuel pump works, new fuel filter, new coil,
new plugs & wires, new entire distributor and still wont start. Before it shut off
on me it had really poor mpg's, shaky idle, and the rpm hand would act crazy
jumping all over the place. Any help please????
8 Answers
Check the timing it sounds maybe like the timing jumped. It could also be that the brain box for the dist is bad. On ur truck is there a gray box on the dist or does it have two plugs coming off the dist?
It has two plugs . I haven't checked the timing but would that keep it from not starting at all?
The timing will most deff cause it not to start, the two plugs should go to a silver box on the driver side fender. Pull the dist back out put a socket and a large breaker. Bar on the blot for the harmonic balancer wit some one at the top looking down at the engine u will need to do a TDC (Top Dead Center) that is when piston one is at its furthest reach inside the cylinder once u have it at TDC go ahead and put the dist back in and try that
Jim And Tara answered 7 years ago
Cps(crank position sensor) bad. Use OBD plug with an engine analyser, code will tell you if sensor is bad.
Jim Carlson, I have the same problem; 1999 F-150 V6 suddenly died coming down a hill and won't start. I can hear the pump humm when I turn the key to start. I sprayed starting fluid in the air intake and it starts for a bit, so I know it has spark. I searched the web and Youtube videos and most of what I see and read points to a bad crank position sensor. I'm going down tomorrow to get a replacement and putting it in and then we'll see if that is the culprit. I'm also waiting for a scanner I just purchased just in case ;)
Chuck did you ever figure yours out? Mine is doing the same exact thing