Fuel Pressure Problem, Need Help Please Options

[Lil-Joe101]

So I received a phone call from the shop that has been helping me with the rest of the swap. For some odd reason the car idels normal when both my electronic fuel pressure gauge and their fuel pressure gauge measured directly off the fuel filter reads "0". As the fuel pressure climbs to normal operating pressure the car begins to idle rough, almost to the point of dieing. Both gauges have the exact same reading simultaneously so I know our gauges are reading properly. Im stumped because if both gauges read "0" the senerio should be reversed. Also the pressure isnt staying steady. It raises, drops and raises and drops. As I said as it drops idle is better as it raises it worsens. Both the shop and I believe it to be a bad fuel pump. Need a second opinion on this matter. Has this happened to anyone else during there swap or at all. What could be the reason behind this. NEED HELP ASAP.

[Bitter]

You can not have zero fuel pressure and a running engine. They're doing something wrong.

[Lil-Joe101]

Yeah I know. All they did was start it and had me watch both fuel pressure gauges. As both read 0 she idled fine, the moment the pressure built she idled rough.

[Lil-Joe101]

Soo out of the 15 who have viewed this, no one can give me an opinion. Come on I need your help here guys please.

[Malek]

Sorry I'm not up to date with your swap. Are you using the Fuel Pump Relay box with your swap or did you bypass it running constant high pressure?

This almost sounds like an ecu type issue. I don't think voltage at the pump changes as the car warms up.

Or..faulty fuel pressure regulator? Which regulator are you using? The pressure might build because the regulator is restricting it too much and is not allowing sufficient flow to the injectors, starving it. 0 psi could be a relative measurement meaning that it is reading whatever pressure it is at idle as 0 and builds from there.

Plot twist: This may very well not be a fuel delivery issue as much as a mixture issue. Don't get tunnel vision and focus on one thing (gauges) that doesn't seem right.

Just throwin out ideas. Good luck to you man.

Edit: I've had my fair share of fueling issues ranging from pump voltage to clogged filter to fuel pick up...more often than not (basically every damn time), the thing I believe is causing the trouble turns out to be perfectly fine and I end up fixing more things that don't need to be fixed.

This post has been edited by Malek: Feb 11, 2014 - 10:44 PM

[Lil-Joe101]

Im useing the original fuel pump relay with the walbro GSS342 fuel pump. The fuel filter hasnt been changed that I know of since before I owned the car (4years). So that is a deffinite option. Im also useing the original fuel pressure regulater, rail and injectors that came with the engine. What would cause the fuel pressure regulator to become restricting? Possibily practicals not caught by a bad fuel filter maybe, or could the regulator just be bad from normal wear and tear?

[njccmd2002]

not an expert, could your fuel lines be clogged, and filter from ethanol gas, and sitting to long? start with the gas filter, and go from there.

[Smaay]

i dont know whats going on with your swap, but its impossible for your fuel pressure to go to 0 and the car run. either the gauge is hooked up wrong or they are taking a reference from something else.

and fuel pressure doesnt really climb, its there almost instantly.

where are you getting fuel pressure from the filter? that makes no sense. fuel pressure should be read from either at the rail, or the regulator.

[Lil-Joe101]

My electronic gauge is reading off the rail and they're mechanical gauge is reading off of the filter. Both have the same readings while the car is on. I know this situation sounds weird and I'm stumped myself. The needle on both gauges jump around. From normal operating pressure to zero. At normal operating pressure on both gauge readings she bogs but when both gauges drop to 0 she idles beautifully. Yes I know its impossible for the car to run at zero pressure. But this is the reading the shop and myself have seen when she idles perfectly fine. The perfect idle lasts only a few seconds till she starts bogging again and at that point both gauges jump to normal operating pressure. The bogging and perfect idle fluctuate between each other after a few seconds.

[Galcobar]

Erm, I know this is going to sound simplistic, but if you have good gas delivery when the gauges read 0 and poor when the guages read normal...do you have the gauges installed in reverse?

[Lil-Joe101]

Thats what I thought too. But I know for a fact my electronic gauge is installed correctly. Now as far as measuring pressure off the fuel filter properly Im not entirely sure. From what I saw, the shop has their mechaincal gauge installed on top of the filter itself where the banjo fitting would normally go and the banjo fitting on top of their fitting so the fuel flows through both, giving them a reading through their gauge as the fuel travels.

[Bitter]

They're not tapped into the return line or have the pump running backward do they?

[Lil-Joe101]

How do you run the pump backwards if you dont mind me asking sir?

[Smaay]

have the leads wired backwards

[Bitter]

Same way you have a car running with zero fuel pressure. **** if I know. If they had the pos and neg swapped on the pump it would spin the wrong way and wouldn't pump but would make noise like it was running or it would make barely any fuel pressure, I've never goofed that up so I don't know.

So what size injectors are you running? How are they set up for fueling maps? Maybe theres just WAY too much fuel being dumped bu the injectors and so even just a tiny bit of fuel pressure is all you need. Maybe the FPR is leaking raw fuel into the intake?

[Lil-Joe101]

The injectors are stock. I haven't swapped them out or even replaced them fire to the little time I had to work on it because of the deployment that just passed. I do know that my fuel pump was faulty so Im replacing it. I might just have to replace all the components even if they are good, this way I wont have to deal with them going faulty anytime soon.

[3WayStunna]

The leads could most deffo be backwards....Buuut..This might sound insulting, but have you checked to make sure that the fuel is getting to the injectors? Also have you checked the lines thourougly as well? I know this sounds simple, but its always the simple things that give the biggest problems...

[Lil-Joe101]

Good point. Ill check with the shop tomorrow with all the thoughts and opinions that everyone has giving me. All your answers mak for good troubleshooting on this situation. Thanks so much guys, and if you have any or thoughts or opinions please please please let me know.