losing fuel pressure ?

ok ive been havin issue with beeing lean ,had allen retune ,too make rich purposely ,it was for an hour ,then now its going lean again.i put a pressure gauge on sure enough its losing press.its dropping from 55 psi to 50 causing it to break down.i have an elec aeromotive fuel pump setup feeding off my stock tank,with 2 100 micron filters and a pump speed controlllerthat is supposed too at 3k kick it up to 58 psi..i was just trying to get some ideas were to start looking first.for losing pressure .would a dirty filter cause this?give me some ideas guys.it has been slowly proggressing for over a month.started just going lean then 1 night i really hammered her and its been worse since then,it started skipping mildly,then progresses to skipping and popping now .and obviously loss of power.i do keep getting po174.code.could be unrelated.thanks ahead guys.
o i have already changed plugs and wires.

It's probably the fuel pump. Go get a Walbro 255lph pump and go back to a stock fuel filter arrangement.
And if it surges to 55 then back to 50, the filters might have something to do with it... I'd check the filters first before I go off and redo my fuel delivery system...

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Originally Posted by txarkitekt

It's probably the fuel pump. Go get a Walbro 255lph pump and go back to a stock fuel filter arrangement.
And if it surges to 55 then back to 50, the filters might have something to do with it... I'd check the filters first before I go off and redo my fuel delivery system...

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i used walbro went through 2 of em ,junk in my book .i had to do the work ya know .i wanted accesability.ive got a 1500 dollar pump setup im not going backwards.if you drop a few tanks it pisses ya off.dont mean to sound like a jerk i appreciate the help.it does surge though .maybe i collapsed a filter or it is dirty .ok keep em coming.

oh yeh i forgot too mention when i initially turn the key on it rises slowly too 55.b4 it shot right up !

Oh...and you don't have to drop the tank every time. Go get a friend and take the 8 bolts off the bed and lift the bed off. Easier than dropping a tank, IMHO.
You must have got a few bad Walbros...they usually are the best high flow fuel pumps. But I would go check your filters...

what size injectors do you have? is your IDC getting above 100%?? sounds like bad filters to me .... Is it an A1000 pump?....

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Originally Posted by ramsey rider

i used walbro went through 2 of em ,junk in my book .i had to do the work ya know .i wanted accesability.ive got a 1500 dollar pump setup im not going backwards.if you drop a few tanks it pisses ya off.dont mean to sound like a jerk i appreciate the help.it does surge though .maybe i collapsed a filter or it is dirty .ok keep em coming.

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there are Walbro knock offs out there. I can only recall one that gave up on us.

definetly sounds like a filter, my a1000 has done this to me on my pro-street
s10. Had to go to a bigger filter. which aeromotive are you using?

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Originally Posted by trtturbo

there are Walbro knock offs out there. I can only recall one that gave up on us.

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were i got mine said the same thing guess its just a freak thing..

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Originally Posted by casey23

what size injectors do you have? is your IDC getting above 100%?? sounds like bad filters to me .... Is it an A1000 pump?....

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42lb .part#11104 aeromotive.and would bad filters cause it to skip like hell when you lightly press the pedal.?

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Originally Posted by TurboMic

definetly sounds like a filter, my a1000 has done this to me on my pro-street
s10. Had to go to a bigger filter. which aeromotive are you using?

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aero 11104 pt# im using 2 100 micron filters.cant imagine them beeing that dirty already,but i guess its poss right.seems like thats what everyone thinks,itll hit and miss under accellaration.like a bad plug or wire.thinking of taking off the speed pump controller.

Could be a bad ground or not enough power.

ground on what and not enough power were?

Maybe a loose or faulty ground connection on your speed pump controller or electric fuel pump. The power he is talking about is in the wires. You may have too small of diameter wire to supply voltage to either of the two pumps...

:imwstupid:

The voltage could be dropping below 12 volts which will cause all kinds of problems

ok i checked the filter and indeed it was full of all kinds of sht.somehow ithe guy that changed the fuel pum when it was intank left behind the shrink tube from wires,black tape,silicone,and some gel ,alll i can say is thank god for that 100 micron filter,cleaned it spotless,reinstalled 2 nd 1 in line was totally clean,put back together.i raised the f/p while i was under there to 60 psi for the 42 lb injectors only a few psi.started back up 80 percent better .i still have a little skip and ive gone lean from before filter cleaning,,allens tune was super rich,but the pcm kicked it lean,should i reinstall to richen or am i really still lean,the weird thing is it was rich for a couple hours.so im asssuming the pcm kicked it lean.and the fp gauge raised very slowly when i turn on the key,it used to fly up then drop till i started it ,i have a bypass regulator on it .weird it goes up slow then when i start it it flies up normal.any explanations for slow rise?and because its only 80 % beter i still have a little skip,what should be my next step?i thought my injectors might have gotten dirty or clogged when i saw that mess in the filter,but filter 2 was spotless,so i dont think the inj are clogged any sugg of what now.thanks ahead.i love this forum everyone is there for ya for opinions.sometimes you dont think of the littlelest things.thanks guys

Maybe you have a large pocket of air in the lines.

How are u running 15psi with 42lb injectors??

How much horsepower are you running? Where is the pump located(distance from tank)? What size lines in and out of the tank to the pump and from the pump to the engine? Filter arrangement? 1 before the pump and one after? Where is the fuel pressure regulator located(distance from fuel rail)? Are the fuel rails aftermarket or stock? Do you have a tuning program, hptuners, etc? If you do post up the log file and I will have a look. RC

Ah I missed that in his sig. I'm running 16psi and I'm running 73lb injectors at about 75% duty cycle. I had similar issues with my engine running with Corvette FlexFuel 42's on 12psi.

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Originally Posted by casey23

How are u running 15psi with 42lb injectors??

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all i can say is ive not really had any issues until this point.idk i accidently put this pulley on and its been fine and it is badass when running properly.its just the last month or so its been acting up.what size should i run with this much .i was actually trying to get 11 psi when i got 15 psi didnt realize the paxton nov 2000 i had too put on was 1500 cfm vs the vortec 1000 cfm.

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Originally Posted by RedHeartbeat

Maybe you have a large pocket of air in the lines.

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and red how would i get that out?

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Originally Posted by richardacampbell

Ah I missed that in his sig. I'm running 16psi and I'm running 73lb injectors at about 75% duty cycle. I had similar issues with my engine running with Corvette FlexFuel 42's on 12psi.

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im with you guys on the injectors but y have i been able too run it for months like this runnin like a banshee with no issues then all of a sudden,the last month or so it has progressively gotten worsh.i dont think thats the inj. causing this particular problem.ill see if i can figure out how to post my recent tune the other day i sent too allen ,yes i have hp tuners and a unlocked pcm.

crack the filter loose and run the pump until no air runs out of the filter? Haven't had to fight that battle before. You can stand the filter on end with the out end upwards to send the air bubble up the stream.

RC Fuel Injection

Per this calculation, not knowing your numbers exactly.

Here is what I put in:
600HP
8 Injectors
.575 BSFC
.70 Duty Cycle
43.5 psig

It returns:
61.96Lb/hr
651cc/min

My choice would probably be 60's. If your fuel pressure regulator is not boost referenced I would probably upgrade that as well. This will allow you to set your fuel pressure at 45ish without boost and under boost it will increase 1:1 for every psi. RC

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Originally Posted by richardacampbell

RC Fuel Injection

Per this calculation, not knowing your numbers exactly.

Here is what I put in:
600HP
8 Injectors
.575 BSFC
.70 Duty Cycle
43.5 psig

It returns:
61.96Lb/hr
651cc/min

My choice would probably be 60's. If your fuel pressure regulator is not boost referenced I would probably upgrade that as well. This will allow you to set your fuel pressure at 45ish without boost and under boost it will increase 1:1 for every psi. RC

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by boost referenced do you mean the vaccuum line on it ?i do have that but allen said i dont need it .if so were do i run the vacc.from ?just a regular vac off the intake?thanks.let me know please its not working right i know it the pump is making all kinds of low and high noises.

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Originally Posted by ramsey rider

by boost referenced do you mean the vaccuum line on it ?i do have that but allen said i dont need it .if so were do i run the vacc.from ?just a regular vac off the intake?thanks.let me know please its not working right i know it the pump is making all kinds of low and high noises.

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o also how do i kow if i spend the money on inj.if there going to be to big and is there such a thing ,would i be chancing it ?or is there math to knowing if there going to be too big?thanks again

With the pump making all kinds of low and high noises I would have the pump and/or the controller checked. Some of them are sensitive to fluctuations in voltage. Injectors can be too big. Maybe someone else can shed some light on this but I was told that as long as I stay within 60-80% duty cycle I will not have any issues. If I go lower I will have difficulty at idle and low rpm. If you go too high you will run out of fuel at high rpm and potentially run lean and damage your motor.

Yes, that would be correct, the vacuum line on your FPR. That goes to any vacuum port in your intake. I have mine coupled with my magnavolt voltage regulator. I could go into the whole math of it but basically the more boost you have the less fuel you will get out of your injector which is why the boost referenced FPR is nice because it somewhat compensates for the extra pressure needed under boost to make you injectors perform the same as if they weren't under boost. Just my .02 RC

I just don't see how you could be running that thing "like a banshee" and then it just leaning out all of a sudden. I CAN see that the clogged-ass filter had something to do with it, but like you said, it was probably running REALLY rich from the last tune. I would assume that the PCM is trying to "learn" this new inlfux of fuel and is voluntarily cutting it back lean. I would try and email Allen your log tables and see if he can recommend something for ya... Then he can tell you how to log everything in with your HPT...

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Originally Posted by txarkitekt

I just don't see how you could be running that thing "like a banshee" and then it just leaning out all of a sudden. I CAN see that the clogged-ass filter had something to do with it, but like you said, it was probably running REALLY rich from the last tune. I would assume that the PCM is trying to "learn" this new inlfux of fuel and is voluntarily cutting it back lean. I would try and email Allen your log tables and see if he can recommend something for ya... Then he can tell you how to log everything in with your HPT...

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it has been running just fine and performing fine till this last week it had all kinds of power ,no skipping no nothing i thought it was just my w/b was screwing up again,because i didnt have any performance issues.that i know of,it felt the same as usual.then within a week it started popping and skipping.idk.im really getting discusted.i did send allen a log and he says he dont know what to tell me because its not in the pcm,its mechanical if it didnt help when i loaded my recent scan,the other day.today i hooked up my boost vac ref on my regulator for the hell of it and it did go rich,but its not running much better still skippin,but popping is gone especially when i lug it down ,it runs alittle better in tow /haul.cause it doesnt lug down as much.idk.im discusted.

Since you have HPT, go and pick up some reading material and see what you can find out about tuning it yourself. There are some pretty good books out there from what I have heard for LSX motors. You can even take classes for it. Try and get the fuel delivery issue solved and see how you can tune it yourself.