6.2 stalled, UPDATE: Got it!

[mechted]

Just finished swapping out the 4.3/700r4 in my brother's '85 C10 for a 6.2/th400 out of an '88 R20 Sub. The Sub ran fine before we pulled everything, and it was running fine in the truck before we got the driveshaft in (was being lengthened). When we first backed it out of the driveway, we found a fuel leak and dropped the tank to check. We replaced the hoses and reinstalled the tank. Then on it's first test drive, it started out fine for the first few minutes, then began losing throttle response and stalled about 15 sec later. Now it doesn't want to restart. We've only been able to start it back up a few times, but it always stalls again after only a few seconds.

It has new batteries (which we've been charging as needed) and 7 new Quickheats (one had swelled and wont come out). We bled the fuel filter and injectors several times, pulled the cover on the IP - full of fuel, and blew air through the fuel return line to see if it was blocked. We also jumped the glow plug controller with no luck.

Is there anything we're missing/forgot to check?

 

[maynardogle]

Well...kinda sounds like a fuel starvation problem...mechaical or electrical (?) fuel pump springs to mind....Are you pretty sure there is good fuel pump pressure to the back of the injector pump? That would be my first suspicion. The injector pump generates a little suction on its own but not enough to suck dielsel all the way from the tank...Did you accidently kink or crush a line when you put the tank back in? If all else fails put some diesel in a can and drop a short hose from the suction side of the fuel pump and see if that helps...

 

[mechted]

Im getting fuel to the filter... so i dont think the pump is shot. If I had to guess I would say there may still be air in the injector lines... how much cranking does it normally take to get this things bled?

Do diesels require a sealed fuel tank or something weird like that. Most of the bleeding has been done with the fuel tank lowered from the vehicle so we knew absolutely that it wasnt leaking there anymore (or any kinked lines)

 

[maynardogle]

To the fiter...but through the filter? If you unhook the clean side of the filter , just bebore the IP, cranking shoud fill a beer can in ten seconds...at least that was the old rule of thumb. If you got significant air in the lines, it can take alot of cranking to purge all the way through the pump (several minutes in 20 second shots) depending on how much air you got. If you think you got a lot in there unhook the line between the IP and the fuel filter and crank fuel into a bottle an make sure no more bubbles were being pushed out. After you are sure the fuel pump and filter are working OK push fuel from the tank into a bottle on top of the engine using compressed air forced into the tank...no more than about 5 psi...just stuff a short piece of air hose into the filler and use a rag to make a seal around the fill hole, and squirt air into the tank until the bottle fills without bubbles. If you use a big compressor go slow or you will squirt fuel all over the engine. I use one of those little $10 compressors that take 30 minutes to fill a tire.

 

[colbystephens]

what was the year of the engine? 83/82 fuel systems are slightly different from the rest.

 

[mechted]

what was the year of the engine? 83/82 fuel systems are slightly different from the rest.

its an 88

 

[mechted]

My brother got it today (finally ) turned out to be more air in the fuel system, just needed more bleeding

thanks for the help all (did a lot of searching for this) it really helped