Engine won't stay running.

[Range98]

Got the engine all hooked up a few days ago and it fired in half a turn but it will not stay running. It starts perfect but when it starts coming down in the rpm's it stalls out every time. I checked fuel pressure, vacuum lines, my coil pack, and the timing was at 8 degrees. I'm running out of ideas. My next leads are my crankshaft position sensor or my MAF. When I give it just a tiny bit of pedal it will idle but is VERY rough and feels like a timing problem. It has very slow throttle response and surges. Any ideas out there!? 1997 mountaineer engine into 1998 ranger.

 

[snoopjonnyjon]

Not sure if this is your problem or not, but when you first turn the key on, the fuel pump runs for 3 seconds and then shuts off. After that, the ECU requires a signal from the distributor to continue running the pump. If there is something wrong in that circuit, the truck will start, but will not continue running.

 

[Range98]

I checked fuel pressure during the stall and it was fine.

 

[nine-teen91stxranger]

.

 

[Range98]

well I was out all afternoon and I discovered my spark plugs are firing very sporadically and at different speeds. I'm replacing the crankshaft position sensor tomorrow hopefully that will fix it.

 

[Range98]

not the crankshaft sensor. I'm clueless

 

[Psychopete]

Pull codes

 

[Range98]

I've tried I bought a scanner and the computers not throwing any codes.

 

[doorgunner]

hope you figure it out (stuff like that is why I have a carb & distributor on my ngine now)

 

[hoosier1104]

well I was out all afternoon and I discovered my spark plugs are firing very sporadically and at different speeds. I'm replacing the crankshaft position sensor tomorrow hopefully that will fix it.

Your last sentence does not make sense logically. The crankshaft sensor should not control duration of spark. I would look at your coil pack, that connection, plug wires and the plugs themselves.

 

[Rowdy Fitzgerald]

Possibly the module on the side of the dizzy? Maybe it just needs to be cleaned and new dielectric grease put on?

 

[Range98]

i took a vacuum pressure gauge and found when it stalls it's at not even 2 lbs. I started searching for big vacuum leaks and found one right after my throttle body. Half the gasket is missing so I have that all apart and going to seal that and see what happens. Not sure on timing anymore. Going to get vacuum pressure up and go from there

 

[Rowdy Fitzgerald]

There's your problem! I'm betting that'll fix it.

 

[Range98]

I'm hoping! We'll find out in about an hour I'll let ya know

 

[Rowdy Fitzgerald]

Saweet!