Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
10-05-2007, 12:18 AM
#21
0.0 BAR
Join Date: Dec 2002
Posts: 0
Re: Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
Originally Posted by 88dx
nope i sold them before i knew of this problem 
I dont see how injectors would make fuel pressure drop off in boost but who knows 
I dont see how injectors would make fuel pressure drop off in boost but who knows Thats true but odder stuff has happened ya know.
10-05-2007, 02:54 AM
#22
3.0 BAR
Thread Starter
Join Date: Nov 2003
Posts: 5,838
Re: Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
Originally Posted by MADMAX
The current injectors might not be 550's.
Seen it before. If the injector scaling is way off, you can tell.
10-06-2007, 02:00 AM
#26
3.0 BAR
Thread Starter
Join Date: Nov 2003
Posts: 5,838
Re: Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
Originally Posted by fe3tcourier
no, but as the revs climbed, at some stage they'd max out and you'd go lean. i think thats what hes getting at.
Originally Posted by fe3tcourier
do you have some logs of duty cycle?
what ecu is this?
what ecu is this?
10-06-2007, 02:22 AM
#27
3.0 BAR
Join Date: Feb 2006
Posts: 3,906
Re: Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
Just a thought, some guys where having trouble with the sock on the pump. maybe yours has started?
1, fix the head.
2, put a flow meter on the pump or run the pump and measure what it puts out. This will eliminate the pump for flow problems. like the other guy said 2.2l+ min? search for it.
3, if the pump is good, he only other thing that can be the problem is the return system or fpr
If the injector was leaking it wouldnt go lean, so the only other place for fuel to go is back to the tank or out a line.
pump, return system, or maxing the fuel system enuff that it cant supply enuff flow to create preasure.
1, fix the head.
2, put a flow meter on the pump or run the pump and measure what it puts out. This will eliminate the pump for flow problems. like the other guy said 2.2l+ min? search for it.
3, if the pump is good, he only other thing that can be the problem is the return system or fpr
If the injector was leaking it wouldnt go lean, so the only other place for fuel to go is back to the tank or out a line.
pump, return system, or maxing the fuel system enuff that it cant supply enuff flow to create preasure.
10-06-2007, 04:55 AM
#28
1.5 BAR
Join Date: Jul 2007
Posts: 752
Re: Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
it cant be the return line. if that was blocked you would get too much pressure.
it can be the pump, the reg, the feed line, or insufficient supply.
you did say that its not the HP version. you are trying to boost. boost + base + restrictions is what the pump sees. that could be like 90psi or so.
if you have an adjustable reg, pull the return hose off, feed it into a bucket, turn on the system, watch the flow, turn up the pressure, if you see it visibly decrease, then the pump sucks. otherwise its because as the flow through the reg drops off as the injectors open, it isnt restricting flow back to the tank enough.
fred.
it can be the pump, the reg, the feed line, or insufficient supply.
you did say that its not the HP version. you are trying to boost. boost + base + restrictions is what the pump sees. that could be like 90psi or so.
if you have an adjustable reg, pull the return hose off, feed it into a bucket, turn on the system, watch the flow, turn up the pressure, if you see it visibly decrease, then the pump sucks. otherwise its because as the flow through the reg drops off as the injectors open, it isnt restricting flow back to the tank enough.
fred.
10-06-2007, 10:33 AM
#29
3.0 BAR
Join Date: Feb 2003
Posts: 1,625
Re: Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
where are you measuring pressure? my friend had a problem with fuel pressure for quite a while, and he almost sold the car because of it. turned out it was the fuel dampener on the end of the fuel rail that was bad and was causeing his pressure to drop off at the rail in boost. it would drive just fine NA, but when you started to make boost, it would lean out. his also was fine when he had 450s and a stock pump, but started acting up when he dropped in his 680s and walbro. its super simple to change, and you can pick up 4 or 5 at the junkyard.
10-06-2007, 12:23 PM
#30
1.5 BAR
Join Date: Jul 2007
Posts: 752
Re: Fuel pressure drops off in boost. :::::::::::::HELP::::::::::::
i dunno about honda dampers, but the mazda ones are just a sprung mini accumulator with a path for the fuel to flow through. i assume the others would be similar. other than blockage, i cant see how they could mess up.
