Engine/Transmission (1998.5 - 2002) Hard start after injector swap?

[EBung]

Well decided to step down to some Mach 1. 6s so I installed them with some new connector tubes and o-rings. Got the job done left some lines loose fired it up tightened everything down checked for leaks,found none and went for a ride. Drove about 10 miles ran it up to 100mph came home got out and found fuel from the fuel neck back to the tailgate . So today I had a sneakin hunch ol #6 didnt go in right so I pulled it and the copper washer was black around about half of it. Replaced washer and o-ring on that injector,reinstalled and no more fuel tank grenade. But now I have long crank hard start if it sits more than 5 minutes have to cycle Fass to get it light then it runs fine. I wonder if the pressure from the washer not sealing blew somthing out or ruined the o-rings on the connector tubes or what the heck I should do now. Could it have ruined the relief valve on the VP return line?

 

[EBung]

So I am the only one to screw up this bad? BUMP bump

 

[PC12Driver]

I'd agree with your thoughts on it being the relief valve (assuming that you don't have any other leaks in the fuel supply side of things). The compression pulses leaking from #6 could have blown it out, and now the fuel is just draining back to the tank. If it was a high pressure line, I'd expect the truck to run rough at startup and take a while longer for it to have a hard start.

 

[EBung]

I think their is an o-ring at the tank for the return line and was thinking about putting air pressure to that line when I replace it and see if I can hear a leak. That and maybe replace the relief valve. If that dont do it off with air horn and replace the new connector tube o-rings with newer ones.

 

[PC12Driver]

The connector tube o-rings don't seal any of the suppy fuel, just the stuff that drains out the back of the head and back to the tank. A leak in those o-rings won't cause the fuel system to loose its prime, just ooze some fuel around the crossover tubes.



If there is a leak in the lines pre-liftpump, you'll suck air and the truck won't run/won't run right. If it is post-liftpump, you'll get a drip with the truck running. Either way, you'll probably get a puddle as the truck sits. No puddle = internal leak, and that puts you right back at the relief valve (imo).

 

[EBung]

Well the relief valve was not the culprit and I have seepage at the head visible now so I guess its tube seals? The connector tubes are new I wonder if I should put the old ones back in. I HATE diagnosing this stuff, until its fixed that is. I guess the pressure must of ruined the seals but is that the air leak too?

 

[PC12Driver]

Huh, I would've guessed it was the valve. But I guess if you now have seepage where the fuel lines hit the head, then it is something in the high pressure side of things. Still, the o-rings wouldn't cause fuel leakback in the system, so it has to be in one or more of the fuel line/crossover tube or the crossover tube/injector connections. There are no seals or o-rings that keep the high pressure fuel in, just compression fittings. Nick the smooth surfaces or over/under tighten them and you'll get a leak. How much are you tightening the fuel line nuts at the head? (spec is 28 ft/lbs)