So last Saturday I finally installed my boost and pyro gauges (which were in a box for a year), then test drove. They worked great. Sunday, I installed my 366 spring and turned the fuel screw 1 turn CW. Sweet! At full throttle highway speeds (70-80) it was at just over 20lbs of boost and 900 degrees. I think that's good, but you'll all know best.

I also turned the smoke screw CCW 1 turn because my truck seems to have a lot of black smoke under med-full throttle before the turbo spools up (thick black smoke). I have the 21cm turbine housing, so I was thinking the slow spool was the reason. The truck has smoked like that since I did the Denny T fuel pin about a year ago with no other mods (by the way, I love the Denny T, but it definately has a large gouge in it like I've seen others say).

Anyway, truck drove great for 3 days, then last night it started sputtering and just got worse and worse, to the point where I can't drive it and I had to be towed. It breaks up under throttle, and a little while idling. It looks like there is a small leak now near the pump top on the back side, but it could also be coming from the fuel return line (it is fully tightened) or that breather hose from the AFC. It's not a drip-drip leak, but most of the back of the pump is wet.

Yes, I know I am an idiot for not installing new pump gaskets while I had it pulled apart, and kind of deserve to pull it apart again to teach me a lesson.

My question is this, could a small/minor leak like I've described above cause the truck to completely not handle any load like I've described above. The way the truck is acting is very similar to when my fuel filter was completely clogged, but I replaced the filter under 1k miles ago. My lift pump (advance auto sourced) has under 5k on it.

Could it be the FSS? I know that the 2 wires are connected to it. I mean could it have failed like others have said when they turned in the fuel screw? I thought 1 turn CW was nothing, and didn't expect it to fail this early.

I'll try to get some pics up this weekend of the leak. I'm ordering the pump seal kit today, and an extra fuel filter just to rule that out.

As you can see from my signature, I haven't installed the fuel pressure gauge I bought yet, so I don't have those readings.

Also, you are all right, I shouldn't have messed with the truck, cause I'm addicted now. I'm trying to get the GDS upgraded 60mm compressor (sold out) and a 16cm housing. When I reassemble my pump I'm going for at least another full turn of the screw (removed the collar). Let's hope the original clutch holds out.

 

I would try the fuel filter first you may have 2 seperate problems. Contact Dennyt he is a great guy and will replace your gouged fuel pin.

 

tape a baggie over the vent tube and take it for a short drive. if a few drips are coming out of the rubber vent tube on the back of the pump its not an emergency. the tiny o-ring around the fuel needle tends to need replacing, epically once a new fuel pin is in and the pressures are turned up a bit.

a few drips is no major deal, just rust proofing for the area under it. if its more than that you should consider resealing it sooner rather than later.

and Bill is right, the first thing to do ANY time there is fuel involved is change the filter

 

You may have bad connection on the FSS terminal causing it to lose power for a split second, causing the power to break up.

My truck does this sometimes.

 

I got a better look at the truck when I got home from work today (got towed at midnight), the problem may be worse than I thought.

In the first pic, you can see a few problems with my IP. Circled in red is a bolt on the delivery side that completely worked itself free, the bracket just happened to keep it in. I'm not sure yet if other bolts are missing. How many should be on that side of the pump like that one? Circled in yellow is what looks like the pump splitting itself apart. I assume that is a natural seam (two parts typically bolted together), but that it should not be visible. If you look close you can see blue fuel right through the pump. If I manually pump the lift pump fuel drips out the bottom like in the pic.

In the second pic, it is the bottom of the IP. Circled in orange is 1 on two bolt holes that I don't know what they are there for. It looks like something might have been there but fell off, I don't know. I wouldn't think those are the bottom of threads for something bolted through above, but maybe it is. I did remove a couple of things so the pics wouldn't have any wires in the way.

Any ideas on how this happens? I didn't touch this part of the pump. Did the increase in pump pressure cause this to happen?

Before I noticed this I tried starting the truck and it was worse than ever, sounded like it was idling at 50 rpm. I shut it down after about 15 seconds.

Thoughts? Anyone seen or heard of this happening before?

 

That is the head of the pump, I took my buddy's pump apart last week and I think it was leaking in the same place from what he said. There is a big green O-ring on the head side that seals that. Looks like your allen head bolt came loose and caused the leak and the O-ring may be okay, But I would pull the allen heads out, pull the head off and check it just to be sure. Be careful taking the head off and don't lose any parts and make sure everything is where it was then tighten it all back up.

As for the holes on the bottom of the pump, those holes I think are to put it on a test stand, but they don't have anything that goes in them when installed on the truck.

 

Thanks smokin. I assume I can leave the pump on while removing the injector head? I'll look for other threads on here that explain head removal, otherwise I'll figure it out as I go. I'm hoping nothing internal caused this to happen. It's just odd it was only 3 days after my first big mods to the pump.

 

There are 4 bolts holding the hydraulic head onto the pump housing. Tighten up the one that worked itself out and check the remaining 3 bolts if you can. I'll bet you just might get lucky when you tighten up the bolts and the leak stops. But as Austin said, it's not really that big of a deal to replace the o-ring. Just take your time and don't try to break any time records.