Alright, so recently installed a airdog II 4g 165 pump and new 45% sac injectors. When the job was done, the truck is commanding 5k at idle but actual is around 10k...then sometimes would creep down to 5k, sometimes it wouldn't and just stay high. My mechanic thought the lift pump was putting out too much pressure so hooking his guage up pegged his 10psi guage. Unhooking the lift pump and the high rail pressure would come right back down. So put on a whole new filter base and regulator from air dog that they supplied to help our problem and the truck still has a problem with actual rail pressure being at 10k at idle. I don't have a pressure guage to check the pressure but could it be my fpr is going bad not able to withstand a lift pump? The truck does not lope at idle or anything weird that way. Or does having sac injectors affect my fuel pressure regulator somehow?
Fuel Rail Pressure Probs...new lift pump and sac 45% inj
- Thread starter joelykool
- Start date
The pressure should be around 8psi, too much pressure & fpr doesn't like it
One of trucks was like that especially when the engine was cold & at idle
One of trucks was like that especially when the engine was cold & at idle
You can either turn down the lift pump pressure, or increase regulator current. On all my AirDog installs, I've found adding 50,40,25 mA to the first 3 cells of the regulator current table fixes the high pressure at idle issue.
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I'll be honest I've had my 30 pound gauge peg out an rail was nvr an issue. It wa alike that the whole time on my cp4. Put cp3 in an was at 30, was very loopy. Anything over 15 to be exact. I've got a fads 260 it was a pain to get it down as far as it would keep dead heading an blowing fuse. I've got it down to 11 after going to hardware store an getting new springs. There isn't much spring left in there being at 11.
That's a big lift pump for the mods you have listed, only really see those on heavy fueled builds & competition trucks
I agree I was dumb to even buy it but have it now so bad to utilize it. I hate it it's loud an I mean very loud. When it lets me down fads can turn it into a 220 that's as low as I can go though.
I just had a customers truck with the same issue. It was a lml and we out a 4G 165 in it. He had a fuel line blow off a couple hundred mikes away from home and then the filter pressure switch/fuel filter minder started leaking. I had him. Ring it back and found the pressure set to over 45 psi. Someone at Airdog just has been slacking when setting the regulator pressures. So now I have to check behind them in all pumps.
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Think I fixed my problem. Took out the regulator spring and cut 2 rings off the spring with it backed all the way out. No more problems now. I have to find someone with a gauge to see what my pressure is now, but it took care of it. You'd think with these pumps being so pricey, it's have the right pressure. Thanks for all your help!!
I don't know what their pumping out for product volume but with different engines needing different pressures I'm sure there's chances of pumps get sent out with the wrong regulator springs
Makes me glad I have a Kennedy pump. It moves alot of volume, but not much pressure. The CP3 already has it's own supply pump, so it's volume you need to it, not pressure. You just need positive pressure to the CP3 supply, the internal pump will do the rest. My single Kennedy moves well over a gallon a minute at the CP3 supply line, that's more than enough fuel for what I'm doing.