Symptoms of Low Fuel Pressure

[RWinzen]

I'm hoping someone can help. I'll start by saying I don't have a FP gauge or warning light. I have an in tank pump (I know, I've read all the comments), I'm even on my second. (warranty) I haven't changed it out yet because I haven't notice any issues until now. First, can anyone tell me what symptoms I might get from weak pump?



I've taken the Smarty off and running with everything else in my Sig. On a WOT, it accelerates smoothly until the RPMs get near 3k. Then it feels a little like a gasser with a miss, very slight w/out the smarty, very heavy with it. It does it in all gears and speeds. I know I'll think of more once I post this, but any help would be greatly appreciated.

 

[RWinzen]

I knew I would think of something else. If I had a low pressure warning kit like the one from Genos, do you think it would show a problem or do you think a gauge is the only option? Thanks in advance.

 

[steved]

I knew I would think of something else. If I had a low pressure warning kit like the one from Genos, do you think it would show a problem or do you think a gauge is the only option? Thanks in advance.

While a light won't provide you exact numbers, it will show you if you are having trouble.



If pressure is good, the light will stay off.



If pressure is low, the light will illuminate.



If the CP3 is pulling more fuel at high RPM than the pump can supply, the light will illuminate at higher RPMs/loads as pressure drops due to demand.



I only have a light in the cab and a mechanical guage under the hood... the light works fine for letting me know if there is an issue that needs further scrutiny.

 

[AH64ID]

Are you sure its a miss and not just the defuel that happens above 2900 rpms?

 

[cerberusiam]

Are you hearing what sounds like a popping noise from under the hood when this happens?



Off hand I would say you are draining the rail. Even without a power mod the 50 HP injectors can cause fuel delivery issues with a stock LP. Just not enough fuel there to supply the needed volume at higher rpms.

 

[RWinzen]

Thanks for the quick response. That was the input I was hoping for. I like the idea of the mechanical guage under the hood. I don't hear any popping, but I really haven't left my foot in it when it starts. I'm ordering the warning light. Keep you posted.

 

[CKelley1]

skip the light get the 1 1/8" test gauge from geno's and a $7 oil pressure gauge kit connect it with a banjo bolt from genos to the cp3, the cp3 can deliver full rail pressure with the lp pressure at 0 psi i know look at my sig

 

[RWinzen]

Update: I've been running with the BD fuel pressure lamp for about a week now. It test ok as you turn the key, but doesn't come on when I push it hard to get the 'miss'. I guess maybe a different description of what I'm feeling is if your driving along and hit something really slick, tires spin, then grab dry ground, then spin, then dry ground. The RPMs fluctuate about 200-300 RPMs. It's very 'jerky'. You can keep pushing it and when it shifts, it grabs firm and accelerate smooth until the RPMs get up there again. I did install a Goerend VB last weekend. Everything was very clean, shiny pan and the magnet had very little on it. Trans temp never gets hot. In fact, I've never seen it about 220 while towing. Any ideas?