First let me say I'm lousy at this forum stuff. I was on the old Ford Truck list and I'm better at the e-mail thing but here goes.

My 88 SD had been stalling on hot starts. I figured there was an air leak somewhere so I was happy to find a major split in the return line. I got the kit and redid the return lines and the connectors plus I had the injectors out to replace the o-rings and the copper washers.

The truck seemed to run fine but I hadn't really gone any distance. This morning I headed to an out of town job and got a surge as I switched tanks. As I drove on it got worse and worse and the truck lost power and would barely run and was idling terribly. I turned around and limped it home at 45 mph.

I've been running straight bio diesel so I figured it was time for the fuel filter replacement. I replaced it and the truck started ok and ran decently for maybe 5 miles. Same thing, no power missing like crazy and trying to stall. I decided I must have gotten the return lines wrong so I took the steel lines off and reinstalled the injector caps making sure everything was seated on both o-rings. Started it up and got maybe 5 miles, bucking, missing trying to stall and white smoke. It acts as if it's out of fuel. Which I guess could be an air leak, the injector pump, the transfer pump, what else? I have read back through a lot of the forum posts but so far nothing seems to really strike a bell.

What's odd to me is it starts out ok, not perfectly, maybe a little rough on the idle and a tad down on power but 5 miles later the truck is just not running at all. Any help greatly appreciated. I think it's going to the International dealer on Wednesday if I can't figure it out. I know that's cheating but I have to make a living and without the truck I can't.

 

Are you running B100 or 100% biodiesel?
How long have you been running biodiesel?
How much fuel in the tank?

There is a screen on the bottom of the pickup tube on my 86, if your 88 has that it could be blocked with stuff the biodiesel broke loose from the tank if you just started running biodiesel.
Also if you just started running biodiesel straight, it could have attacked the seals in the IP or broke some crud loose in the fuel system that is blocking a passage somewhere.

 

I'm running B99 which is what they call what used to be the 100 here. If it's blended they get their tax incentive up front instead of waiting a year. It could be the tank pick up screens but both tanks at once? It could happen but it's not likely. I do think it'll end up being an injection pump issue but I'm hesitant to blame the B99 upfront. First I've read tons and tons on the issues with running it and never once heard it kills the IP. It sure is acting like air on the high pressure side though. The miss fire expecially, the injector nozzles won't time correctly if there's air in the lines. It can't be a lot of air though because the truck runs. I'll be curious to see how bad it is to start this morning.

 

It sounds like your lift pump may not be working properly and the injector pump is just siphoning fuel out of the tank. When mine went out the truck would start and idle fine but if I was driving is would sputtur if I needed to accelerate but would return back fine while just coasting down the road. I figured it out when I changed the filter and it wouldn't start. There was no fuel flowing up to the filter.

 

Funny how that works, it is the lift pump and I just now figured it out. It's actually spraying a fine mist of fuel out underneath the truck. I'd had so much spilled fuel from the filter chanhge and the open return line that I missed it until now. Thank you very much for the confirmation it's so symptom specific it has to be it. I'm relieved to not be looking at buying an injector pump because this motor is pretty tired and I'm shopping drop in replacements for it and it would be a shame to end up with a new injector pump that would go away when the new engine gets installed. Any tricks to getting the pump out, it looks like 2 bolts total. I'm thinking of pulling the alternator and the vacuum pump for access unless I can get it out without removing them.

 

I think it was just two bolts. Didn't have to remove anything out of the way. I pulled mine from under the truck. Some have a redesigned arm on them that are installed a bit different. Can't remember what the difference was off hand. Should be on the directions or you could search cause I know it's been mentioned before.

 

Yeah the arm is different, it's annoying to start the 2 bolts but other than that an easy enough job. Mine's a Superduty and there is a lot of suspension in the way so I did go ahead and pull the alternator and vacuum pump for easier access from above. I also found a cracked hose so I think it was sucking in air which was why it was misfiring so terribly. The new pump is supposed to work with gasahol so that will eliminate another bio diesel point of failure. I need to track down a source of non vulnerable fuel lines eventually. Anyhow it started right up and I could tell the difference immediately. The miss is gone and it comes off idle a lot more crisply. No apparent leaks, time to go to the car wash for an engine bath. Successive failures are tough to diagnose. First the return lines then the pump. The guy who owned this truck before me was bad to it, he spliced everything instead of replacing it. Including the main positive cable across the front of the truck. Thanks for the replies.

 

Final follow up. Days later the truck is still running just fine. amazing what a constant fuel supply not entrained with air will do for the performance of a diesel truck. My truck hasn't idled this smoothly in months. I think the return lines were sucking air for awhile. A bonus is that I had a wicked oil leak from underneath that I always assumed was from the oil pan, turned out to be the lift pump gasked on the side of the block.

 

Fixed the oil leak and fuel problem at the same time. That's even better.