351_f150_4x4

Hi, I am also new to the forum. I just picked up an 88 F-150 4x4 with a 351. Seems to me that we might have the same problem. I too can't get my engine to fire eventhough it seems i'm getting efficient fuel, spark, and air into the motor. I'm pretty sure that not having the egr canister or a smog pump will not at all affect you engine's ability to run. I removed both off of my 1990 5.0 mustang and i dare to say it runs better. I also have some sort of sensor hanging around my intake manifold not connected to anything. Rather strange. I'll be sure to keep an eye on this thread as well as inform you of anything intresting I may find. Good luck.

nastnaso

Hey glad to hear Im not alone that sensor may be the MAP sensor hanging in the back which shouuld be plugged in and have a vacuum hose going to the intake. But I have tried and looked at everything on this truck and it is beginning to be a pain in my ***. Im about to switch it all over to carburated. Good luck and I will keep you in mind if I find anything.

nastnaso

Ok so here we are at the final conclussion and question. I have run all checks timing is right on (distributor and cam) The noid light reveals all injectors are getting a pulse. Spark is present at all cylinders and compression is at 140psi for all. I do have some backfiring of the engine when cranking and I can see a flame coming out from between the upper and lower intakes. So I know there is a leak there but I also feel the engine is not getting enough fuel from the injectors. The injectors are good the TPS was replaced and the idle control valve is good. There are no emission control objects on this motor at all. And fuel pressure stays at 40psi when turned on and a long time after problly like 20 minutes. My question is what can cause there to be not enought fuel getting into the engine. MAP Sensor? Can a vacuum leak be causing it that bad? Please I am at a loss here

351_f150_4x4

Have you tried replacing your ignition module on the side of your distributor. That sends a pulse wich effects your injector pulse. If that goes then it could inhibit fuel flow.

351_f150_4x4

did you figure it out? I decided to hell with it. I just bought a Permformer intake, carb, and distributor. Looks likes it time to swap.

nastnaso

I have'nt really messed around with it for a while but i think a large vacuumn leak may be causing the no start. I know there is one between the intakes now so Im gonna reseal that and see what we get.