OK folks, I have been lurking, searching, reading, and in the end, confusing myself on this one. 89 f250, 4x2, manual trans, 351 engine. In frame fuel pump is working, but maybe weak. It will run off of either tank but sort of misses and you don't dare touch the throttle. My fuel pressure tester has a larger female fitting than the schrader valve that is on the fuel rail. It does have pressure at the valve but not alot. My question is, will the intank pumps have enough pressure to feed a week in frame pump to let it idle for 1-2 minutes, then when it dies, you have to turn the key off and on 4 or 5 times(hearing the inframe pump each time) and it will start back up. I read somewhere on here that the inframe pump should be around 40 psi? It seems that would be enough to shoot fuel up on the hood? It only squirts up 4-5 inches from the valve? I know I need to test fuel pressure but I do not have a way to adapt down to the standard valve size. Thanks in advance for any help. I don't have much hair left to pull out!!!

 

I think I've had it with this 89 and my 87 f350 dually 4x4. Both have the same problem and neither one is a dependable vehicle. I'm tired of throwing money at these 2 trucks. Think i'll do myself a favor and have the scrap guy come and get both of them. At 111,000 on the 89 and 82,000 on my dually, they should be something I can get in and drive without having to worry about them making it home.

 

Same problem here only mine starts fine and idles fine but give it gas and it spits and sputters and backfires through the intake. Someone suggested timeing to me but I don't see how timing could be just all of a sudden. Hope you find a cause.

 

I just dont know??? I'm at the end of my rope with these 2. I've tried every trick/test/stand on my head and point 1 foot at the north star tactic I've read on the net. My 87 has good fuel pressure but it has a carb, no fuel injection. I think I'll just scrap the 89 since it's 2wd and buy a different brand truck for a daily driver. This is ridiculous!

 

I would get a fuel pressure tester that works so you can test the pressure and go from there. I assume you have changed the fuel filter?

I'm sure the problem is something simple, it's just a matter of figuring it out. Don't get one of those other brand trucks or you may have to go back to that other forum, ha ha. I remember seeing you there years ago. Oh, and greetings fellow South Dakotan.

 

How the heck are ya? Yeah, I know........i'm just wore out with these 2! I'm going tomorrow to get the adapter to use with my gauge. I dont care to fix it but it just seems to snowball. I pushed the clutch in earlier and the plastic bushing fell out in 2 pieces. LOL! I just put new wipers on it.........maybe I shouldnt have!!!

 

Ok, got the adapter for the ford rail. From plugging the gauge in, you have to turn the key off and on 11 times and needle then stops at 40psi. While cranking, it stays from 30-40psi. Turn key off and within 45 seconds, it's on zero. You can hear the frame pump but it sounds awful loud. Any help would be appreciated. ( checked fuel pressure regulator, no change in pressure other than it takes longer to build up, no gas in vacuum line) When it does finally start for 30-45 seconds, it does not smell flooded like theres fuel in a cylinder from a leaking injector???

 

But it does run like it's hitting on 4 cylinders. I assume this is from lack of fuel pressure?

 

Take off the vac line to the FPR, cycle key on and off making pump build pressure, any fuel leak from the vac nipple?

Yes, replace the FPR.

No,

Take a pair of vise grips and set them to pinch down the fuel return line (rubber section of course), limit the fuel allowed to return to the tanks, see how it runs.

Run better? holds fuel pressure return line pinched off? (don't want to prevent all fuel from returning to tank doing so, adjust amount of pinch via vice grips until reads at/near spec at gauge, close as you can get it a minute)

If that makes the difference in fuel pressure reading/it runs better, replace the FPR.

 

Thank you danr1, I will go do that right now and let you know what happens.

 

danr1, pinched the rubber portion with vise grips. 2 turns of key and it's up to 40 ish psi, stays there while cranking. No start. I checked spark and it is bright and strong.??? Still bleeds off pretty quick but that has slowed down as well.

 

If you have good fuel pressure and good spark, then somehow fuel is still not entering the combustion chamber. Test to see if the injectors are pulsing. I use my noid light set but I've seen many other ways of testing them online

 

Yeah, this thing has me stumped. I tried a noid light last night on all injectors. Steady then pulses on each one. Compression is good, if I remember right, 130-135 or so but that may be off, notes are out in garage.

 

Did you check spark at the plug wire or the coil wire?

 

I have one of those adjustable tools you take the plug wire off and clamp to plug and plug wire on other end. Also pulled each plug, nice tan burn, each one fires nice.