4d55 fuel delivery problem?

[swamijake]

I have an 86 ford ranger with the 4d55. It starts and idles great. no smoke, no funny sounds. if not moving it revs freely and builds to about 10-12 psi boost.

On the road it seems to have no power. It can barely get above 45 mph. I'm thinking it could be a constriction in the fuel pipe, the ford has an electric feed pump that could be dead, or it could be the timing is off?

Any ideas?

[swamijake]

I should mention that I replaced the pre lift pump filter and the pre injection pump filter.

[camoit]

It sounds like you have an air leek in there some where. There could be somthing wrong with the filter gasket.
Was it having the problem before you made the changes?

What were the filter numbers? Did one filter have a glass bottom? If so then the upper and lower gaskets are swapped around.

[swamijake]

Thanks for the feedback. The problem was there before I changed the filters. It doesn't feel like an air in the lines problem as it starts easy and idles perfect, just feels like there is not nearly enough fuel going through the pump.

[camoit]

The first thing I would do is check the pump in the tank and make sure it's working. Once you know it's not fuel related we can work from there. We have a lot of .pdf manuals. Look in the manual section > over162 manuals > 4d55

[swamijake]

Here is an update. I took the fuel feed line off from the injection pump and turned the key on. No problem with fuel flow to the injection pump.
I think it is problem with the LDA on the injection pump. I hooked a vacuum line to the bottom air vent and things seemed a little better. Does anyone have a vacuum hose diagram, or a close photo of the later 4d55 injection pumps? I've gone through many manuals and can't find anything that shows me what everything on this pump is for. I understand the cold start device, but there is another thing on the side of the pump with a disconnected vacuum pump that doesn't seem to do anything.

[wrngwae]

http://gnarlodious.com/vanagon/bosch_pump/-Rebuild
http://www.dieselbookmarks.com/bombers/VEPump.pdf
not a novice type job. but doable. just google Bosch ve pump. there is lots of info.

[swamijake]

Thanks. I've actually been through a bosch ve a few times. I'm pretty sure my pump is fine, but that I have some sort of either pressure leak out of the top of the LDA, a split diaphragm (although I could see any issue with the diaphragm when I looked at it) or there is some other system on this particular pump which isn't hooked up properly. It has an odd ball thing on the side of the pump that looks like it should create a high idle, but doesn't seem to be hooked up to anything. It's right above the cold start device. I have nozzles on the way so will rebuild the injectors and keep poking away at the pump.