Surely a kit should be complete, from source to pump.

If there is a breakdown anywhere in between.....the kit should be fixing that ?

It should have proper wiring, connectors right from source to the pump itself.

 

I'm saying it's not a kit, I just added the wiring that would normally be in a kit, I was just dumb and didn't do the ground correctly.

 

Confused - Running pressure drops to 40psi. Turn engine off and then key on to prime pump it goes back to 50psi? Doesn't make sense since pump supply voltage with engine off should be < than running voltage although your gnd circuit is not clear so could have voltage drop on gnd side when running and other accessories consuming current.

Next - not sure I understand your ground setup. Maybe pic or drawing to clearly show gnd connections. If using hanger and tank to gnd pump, I would not expect a reliable gnd circuit. Use a dedicated gnd wire from pump to clean gnd point

 

Priming the pump KOEO takes 3 prime cycles to reach 50 psi. 1 prime only gives me ~18 psi.

I'm going to redo the pump ground now that I realized my mistake so we can remove that as a variable. Just picked up a new tool and playing ATM so will update tonight or tomorrow when it's cooler.

 

Was KOEO test done immediately following KOER 40psi pressure recording? Not concerned so much about # of prime cycles required to obtain peak pressure as compared to what the peak pressure is. Get gnd sorted out and see if pressure drops.

Suggestion - diagnosing problems should start with being able to duplicate the problem. When you have a clear approach to duplicate the problem you can then start considering what test(s) you should/need to run to isolate root cause. The test plan (how you will test) is just as important as the test measurement results. When diagnosis and repair is done, retest using the clear approach identified earlier to reveal the problem to confirm you can no longer duplicate the problem and problem is resolved. Hope this makes sense.

 

Yes KOEO test that achieved 50 psi at 3 primes was done right after 12 min idling that dropped FP to 40 psi.

I agree that having a good plan of attack and being methodical to troubleshooting is key. Perhaps some of what I've posted hadn't seemed that way, but it has in my head, just not down on paper. With the back and forth over the last few pages I've ruled out several things. Hopefully with the ground fixed I'll see positive results.....OR it'll be a good indication to swap back in the 255 and see if the 450 pump itself is the issue. Either way this has been good because I've cleaned up the fuel system and wiring and have a boost referenced external regulator now as opposed to the factory one that is in tank, all of which will help when I want to turn the boost up some more.

 

Leaking or sticking injector(s)?

 

45 min cruise had pressure holding steady. Only seems to happen with stop and go/start stop/idling. We'll see if fixing the ground to the pump had an impact.

 

105a at max output. The rpms would be too high for it to full field at wide open throttle. Plus there are other current loads. But amps arent the issue volts are.

Also racetronix says 30amp fuses in their hotwires for 340 and 400+ pumps. Not the 20 that come in them. Ive measured 16 to 18 running but those are on real and fresh pumps. As any electrical part gets warmer itll pull more current and as they get older also. This is why pump quality is important but also why a venturi is important.

Trying to run an inductive clamp for current on a vehicle at wot can be basically impossible also unless you use peak and hold or min max and a trap door. The equipment has to at least be capa of that.

 

I have a 25 amp in mine. Not all electronic parts pull more current when warmer, all depends on the type of load. I was under the impression that even the upgrade kits on 98s didn't come with a Venturi, only 99+s, is that not true? Im to the point if fixing the ground doesn't resolve the issue I'm yanking the pump and replacing it. I see you sell 340s, not sure that'll be enough when I turn it up. Do you sell 450s?

 

Just log it if you want, it's easy.

 

Well grounding better may have helped SOME but not much. See log pic over ~12 min cold start idle. FP started out at ~51. Battery voltage started at 13.5VDC AT THE PUMP. It slowly dropped to 13.1VDC over the time. Something interesting is that rev'ing the motor didn't change the battery voltage at the pump which seems suspect. Tempted to wire a charger straight to the pump directly outside the car and see if it holds pressure steady. Otherwise, think I'm ready to yank the pump.

 

Most battery charges would barely offer 1 or 2A. Maybe not much point doing that.

When you revved it, did battery voltage change ?

I guess at this stage, despite it being a hassle it's worth trying another pump

 

Voltage at the pump didn't change and based on the log it doesn't look like the battery PID showed w change either. Ive got a charger with a 2/12/75A setting. Could run the 12A setting but not the 75 since it's just for cranking.
On the plus side I made some idle changes in the tune which helped my cold start idle surge since I scaled the tune.

 

I really don’t see a 1 or 2 volt drop making any difference in the fuel pressure. I think there’s something wrong with the fuel pump motor or a leaking injector. I’m interested in seeing what the culprit is. Why not go ahead and swap pumps out real quick?

what kind of clamps did you use on the hose from the pump to the hat? Worm drive hose clamps or pinch clamps?

 

I'm with you. I just ordered a new 450 from @Summitracing . Was going to order from Ws6store but it wasn't on their site and Racetronix was out of stock. Least it's from a site sponsor and they were on sale for $89, good deal. Picked up some misc fittings to make 100 and get free shipping too.

Only worm clamps on the feed hose fr the pump to the bulkhead.

 

worm drive clamps are ***** for small stuff, and should not be used for small diameter hose.

Although if it's external, you'll at least see them when they leak. If internal....you wouldnt.

 

The reason I asked is I had a problem like this years ago. Turns out it was the clamps and I even double clamped each connection. At the least, a screw tightened pinch clamp should be used but I use the factory type crimp clamps. They are awesome except you have to cut them off if you need to remove.

At this point it could be a pressure leak at the connection or a bad pump. Don’t chance using those worm drive clamps again. I know people have certainly gotten by with them, but they are far from ideal.

 

small diameter worm drive clamps do not close round. They are totally inappropriate.

 

Interesting, first I've heard of that. Using the small diameter worm clamps and would give a good pull on the line after tightening and feel pretty good it's not the clamps. Guess I could always switch when the new pump arrives. Should arrive mid next week.