Okay here is the deal. Had a 1982 ford box van (uhaul rental truck) It had the inline six. It died so I was able to aquire a 1989 f150 with the inline six but fuel injected. So I swapped everything over. Including the dash so the harnesses all matched. I added a return line to the tank as well as an in tank pump. It started up and life was good. Then all of a sudden the dreaded sputtering and barely running scenrio kicked in.

Took a bit of searching to find out about the correct timing marks, but its spot on. Doesn't flutter. I have replaced spark plugs, wires, cap and ignition module. Did a fuel pressure test. 53psi If I remove the vacuum to the regulator it jumps up about 5-10 psi. I did a volume test on the frame pump and it took about 18 secs to fill a pint bottle. I have all the sensors connected. Sometimes it runs like a champ and then all of a sudden it will sputter but will clean itself out. I pulled the injectors and cleaned them and added new o-rings.

Two scenerios I am curius about is one....the computer is mounted on the inside fender well which is rubber, but it is grounded to the body, which is grounded to the motor which is grounded back to the battery. I have connected all the grounds that were in the original harness.

Scenerio two is that the f150 donor truck was a manual and the engine is now mated to an auto. Would this make a difference to the comp?

Sorry for the long post but I am trying to give as much info as I can. I have seen that this seems to be a common problem, but I think I have covered most of the solutions that have been given. Can the fuel pump still be going bad even though it passes the volume test? I drove it around with the pressure gauge taped to the window and on acceleration it rises a psi or two but stays pretty steady.

Thanks in advance.

 

Your fuel pressure is way too high. It should be around 35 PSI. Now you have a place to start.

 

WRONG.

the I6 runs a higher fuel pressure with smaller injectors.

your pressure is fine.

one of the problems with your truck is the engine computer runs off the vss in the rear axle. and with it being in a older vehicle without vss the computer doesnt know that the vehile is moving when your driving. basically the computer just thinks you sitting there reving up the motor.

 

See, That is why I come here. Learn something new everyday. Thanks for the lesson Fordtrucknut.

How would a guy solve the vss problem?

 

get a later model axle with the vss/ abs in it. they both use the same sensor.

or you can rig some crap up i've heard of people welding the tone ring that is inside the rear axle to the pinion then making a bracket for the vss sensor. but that seems to me like to much work.

and some company called california prefun (909) 845-8820
???? makes a kit for the 4x4 transfercase.


got this info from serious explroation a ford exploder site.

 

so what does that do? just take out the front axle or something?

 

its for if your running a rear axle that doesnt have the vss in it. the engine management and trans(if your running a computer controlled auto) and the factory abs system.

 

I still have the donor truck. I'll take a look at the rear end and see what its got. I do have the rear abs light that comes on. Wow never would have thought of that. The donor truck was a manual. Would it be better to get a computer for the auto? Its the older auto so it wasn't computer controlled.

 

you need to stick with the manual trans computer. if you put in an auto computer your going to be runing even worse.

i'm not sure if the vans and the f150's axles swap out without redoing mounting brakets. never looked under a van lol

 

Darn it. I trimmed the wires at the tank. Does anyone have any idea what colors those are? There are two that are twisted together. Guess its off to PNP to get a new connector and do a rear axle swap. Oh the joys of fuel injection. Although when it runs great its 922% better than the motor it replaced. Is that only 4.9l that is affected like this? I swapped axles in my bronco (1989 351) when I did dana (60 front and 10.5 rear) I never connected any wires to the rear and it never ran like this.