Lack/Loss of power, maybe??

[Silver91Hatch]

I have a 86 F-350 with a 17ft JerrDan Alum. rollback body on the rear, it has a 6.9 with a 4 speed manual 2wd. I don't know of the gear ratio, but here is my question...

It runs good, pulls great but I'm always wanting more. I drive 6.4, 6.0 and 7.3 PSD trucks everyday at work and they make great power, but my truck, well, not as much. When I drive it normally its fine, but if I go to wide open throttle it loses power, kinda like my 2.3 ranger, if I let off of the throttle about an inch it pulls harder, if I push down harder it slows down. Does anyone have this issue, is it normal?

I guess it sounds like I need propane, or more fuel? Anyone?

 

[TWeatherford]

Somebody else likely has a far better guess than me but here goes...

maybe with the increased throttle and subsequent increased demand you're opening up an air leak in your fuel system. Wouldn't think that would really happen that way but it did in my old Mercedes. Although if its instant I dunno.

 

[funnyman06]

It might have to due to the relationship between the throttle and the injection timing. As throttle increasing im pretty sure the timing retards. So as such, too much throttle and you loose your valuable timing.

 

[dyoung14]

i would say that your timing is probly to low, and another thing im going to ask any idea how old the injectors and injection pump are, a new pump and matched set of injectors along with proper timing can usaully wake these old beasts back up to good power

 

[Agnem]

What was said is correct. If you lay your foot into it hard at lower RPM's, your retarding your timing pretty badly. Best to let the engine spool up some before laying it out. Another bet is that your timing is not set properly to begin with. All these trucks will retard with wear, and they need to be re-timed at least every 50,000 miles.

 

[Silver91Hatch]

Well its got 4K miles showing, lol. Beings its a Rollback since day one I am willing to bet it has 204, 304 or 404K miles. I just bought it and it had the incorrect IP on it as it has a VRV on it and its a 4 speed manual truck. I am looking into replacing or atleast pop testing the injectors and seeing if I can get my hands on a timing light. Right now it runs fine, other than being hard to start below 15 degrees, rolling blue smoke until warmed up and driving like a 4 horse wagon its fine.

 

[dyoung14]

Well its got 4K miles showing, lol. Beings its a Rollback since day one I am willing to bet it has 204, 304 or 404K miles. I just bought it and it had the incorrect IP on it as it has a VRV on it and its a 4 speed manual truck. I am looking into replacing or atleast pop testing the injectors and seeing if I can get my hands on a timing light. Right now it runs fine, other than being hard to start below 15 degrees, rolling blue smoke until warmed up and driving like a 4 horse wagon its fine.

what do you mean incorrect ip? all ip will interchange on all 6.9 and 7.3 idi, pop testing injectors would be a good thing to do and see if they need replacing, and timing needs to be right to get decent power, if you really would like more power you could find a used turbo kit and that would make that truck really happy when you had a load and was heading for hills or mountains

 

[kas83]

what do you mean incorrect ip? all ip will interchange on all 6.9 and 7.3 idi, pop testing injectors would be a good thing to do and see if they need replacing, and timing needs to be right to get decent power, if you really would like more power you could find a used turbo kit and that would make that truck really happy when you had a load and was heading for hills or mountains

VRV indicates the pump is from an auto truck, so it's not in the correct swap application. They are interchangleable, but that's a great tip off that it's not a new pump.

 

[dyoung14]

VRV indicates the pump is from an auto truck, so it's not in the correct swap application. They are interchangleable, but that's a great tip off that it's not a new pump.

the pump on my truck is origanally an auto pump but its that caus emy origanal pump was very rusty inside and it would have costed a fortune to rebuild and i had a pump on an auto truck that was in great shap and i took it and had it rebuilt and had a few things done to it,

 

[kas83]

the pump on my truck is origanally an auto pump but its that caus emy origanal pump was very rusty inside and it would have costed a fortune to rebuild and i had a pump on an auto truck that was in great shap and i took it and had it rebuilt and had a few things done to it,

That's YOUR truck. He threw that bit of info out, and it's a great indication that the pump was just swapped with what was laying around to keep his truck running.

I'd go for a good reman'd pump and set of injectors to freshen the fuel system up on that truck IMO.

 

[Silver91Hatch]

This is my basic bare bones cheap-o rollback. I spend $$ where its needed. So far I have changed the Autolites for Beru's and bought a radius arm bracket, yet to change it, but atleast I got a new one. I have heard that the injectors for these are VERY cheap, but I haven't did any research on the pumps. I have a local diesel rebuilder that does pumps and injectors that I might call to get some prices. I have I have 1 injector return line leaking that needs to be replaced, I will do that with the injectors. I am used to PS part prices being I am the Parts manager at a Ford dealership and sell a LOT of 7.3/6.0/6.4 parts and used to seeing $290-350 injectors and pumps near $800. If anyone recommends any pump rebuilders over any others. Also I just found my pop tester at work today, still in the package, never been used

 

[kas83]

MWFI, Pensacola, Diesel Injection Service offer reman'd pumps. Others will chime in for sure on where to get one at.

FYI, a full set of NEW Delphi injectors from Pensacola is $156 shipped. They aren't balanced, but if you have a shop local that can do that fairly cheap, or do it yourself, you might come out way ahead.

 

[dyoung14]

MWFI, Pensacola, Diesel Injection Service offer reman'd pumps. Others will chime in for sure on where to get one at.

FYI, a full set of NEW Delphi injectors from Pensacola is $156 shipped. They aren't balanced, but if you have a shop local that can do that fairly cheap, or do it yourself, you might come out way ahead.

agnem offers great injection pumps pm him for info, he also offers injectors and so does typ4 i bought a set from typ4 a few months back they have been great to me havent had a single problem they were all matched pop pressure when i got them