I have an issue with my water injection that has me stumped. It is a homemade kit with a shurflow pump and Devils own nozzle & tubing that's set up with a manual on/off switch and is running only water (no methanol).
The issue is that the truck will stall/stutter when I shut off the water injection. I think it's an electrical issue, but I can't figure it out. The dash flashes "water in fuel" and MIL light for a split second (during the sputter) and shows a code when it stalls completely, but the code clears as soon as I restart the truck (I can't read the code because my scanner won't read when the truck is off and the code is gone when I restart the car...)
It only has the issue if I leave the water running for longer than a few seconds (less than about 5 seconds and is fine).
It doesn't seem to have any correlation to boost level (at on or off), engine temps, speed, etc.
It doesn't seem to correlate to nozzle size either. The issue happens with 8, 5, and 3gph spray.
It DOES seem to be less likely to happen if I let off the throttle BEFORE I shut off the water (regardless of the boost level when I do it).
What I've checked:
I checked the nozzle spray and it did shut off a bit slowly (spray decreased for about 1-2 seconds before totally shutting off). I changed the spring in the checkvalve (devils own) and the spray shuts down immediately (no period of decreased spray where the droplets aren't fully misting). The checkvalve is about 1/2" from the nozzle holder and it doesn't let any water through when the pump isn't on (at least when I check it...)
I checked all the wiring, re-grounded the negative leads just to try that, and changed the positive connection from the starter battery to the other battery...but the issue persists.
I even tried moving the nozzle location from near the AIH port in the intake manifold to the IC pipe.
It's a simple relay set up running through a keyed source with a manual on/off switch, so there really isn't much to check on the wiring. I used the same set up on my previous truck (6.5l '98 Chevy) and never had an issue. I ran it as high as 10gph for minutes at a time and went through a period where I ran it at 3gph any time the engine was on, and everything in between (water only and up to 25% meth), so it got plenty of use.
My apologies for the long post, but it's driving me crazy and I wanted to give as much info as possible. It seems like it has to be an electrical issue, but I don't really want to drive around stalling out my truck trying to pin-point the issue more specifically.
Last edited by Troponin; 08-01-2013 at 10:07 AM.