Alright guys, I've been kind of out of the loop lately. Been very busy while I'm relocating out of state this month to Northern VA, if any of you hot rodders are in that area shoot me a PM.

Here's the problem. My car will not deliver fuel under boost, very scary. The car will hit 4-5 psi and still be at 14.5:1, not cool. I've dove into R4 program which I'm very familiar with and tried adjusting my aux fuel pump settings as far as when it comes on. Should I maybe try setting the start pressure, run time, or startup time. I talked to vortech and they said the first step should be to buy a hand pump and simulate boost to see if the aux. pump turns on. I will be trying this in the couple of days. I had the dealer check the plugs and injectors and both check out ok. The car has been also going very lean near the 0psi range with mild throttle. Guys I'm really lost here but I have not jacked up the car to look at the hoses and wires. If anyone has any fuel or fuel delivery issues with the Vortech please chime in, pm me, or call me 813-340-1775.

Thank you,

Craig

 

Hey, try taking the fuse out of the aux. pump line and see if anythign happens. If it stays the same, then you know something is wrong with the pump. If not, try checking the FMU and see if the lines are kinked or anything to see if it is reading boost.....thats all i can tell ya for now......

 

Thank you for the quick response, I'll add these suggestions to my list of test points.

 

There are quite a few Z's and G's in NOVA, where exactly are you going to be at in NOVA. I actually live down south but i work up there. Good luck with the problem.

 

Like jdm3fiddyZ said, I would check that the fuse is OK and see if the problem exists with the fuse removed although I suspect that the pump is working. If the pump was not adding fuel, I would think that you would be much leaner than you are now. What gauges do you have? There are a few things that must be changed in the R4 software when you create a new customer. Are you aware of these?

 

Craig...If your aux. pump , or FMU are bad . Let me know . Mine are no longer on the car and will be selling them shortly . That would be my guess , fuse , kinked vacuum line , loose wire to the pump . Hope you find it...Bill

 

What indications are on your dyno run? At what rpm does all this happen? I had a similar problem, as did two others. Everything was fine until it got to 4500 rpm's. The AUX pump was not delivering fuel. The two wires on the pump were reversed. Did not discover the problem until a meter and pressure gauge were put on the pump. In my case, something so simple made me feel so stupid. It is a very easy mistake. The pump is marked + and -.

 

This is not a new installation, the s/c been on the car since July. I'm going to check it out on Saturday to see if anything looks strange. As far as the vacuum line being kinked, I've watched the boost live in R4 and it reports boost in the box. I have a FP gauge currently mounted in the engine compartment for dyno testing, I'm going to bring it up and out temporarily to view while driving. Other gauges are a:f and boost inside the car. Anyone know where the fuse would be for the aux pump? Anyone tried inducing boost with a handpump before? Thanks guys for the feedback.

Moving to the Alexandria area, Fairfax county where I'll promptly buy a winter car.

 

Inducing boost with a handpump this will make your hand hurt!!!!Just joking you could do it with a pump but a better way is to just hook a air line up to a air regulator set it for X psi and hit the lever....This will give you a constant amount of pressure to test if the aux-pump kicks on........Here is how I would test is though get her on the dyno and run it with the aux-pump wired with a toggle switch and flick that ***** on do the run while watching the A/F ratio.....This will rule out the pump and your tune in you ECU and narrow it to either the original wiring or the FMU....Also check your FMU's lines for cracks and all your vacuum lines for leaks...
Later

 

It is a blue fuse inline with the red power wire to the pump. It should be under the battery cover access panel somewhere.

 

gspot35...

If it's not an issue with the fuse or fuel pump itself, check your FMU.

After mine had been on the car about 7000 miles, the float in the FMU seized. This prevented fuel from getting to the pump. Wound up having to rebuild the FMU. Not expensive, but very disturbing. In my case, the car would not run at all.

 

Did your car act up when not in boost? Mine will go extremely lean at normal-moderate acceleration. I gues the real question is, does the FMU/Auxpump interrupt or parallel the stock fuel system?

 

Ok guys, the saga continues.

When I applied compressed air to the vacuum line, the pump turns on. The split-second box reports exactly what the gauge does meaning there should be no kinks in the vacuum line. I also watched the fuel pressure gauge and it shot to over 100psi when the air was applied.

Here's more info about the problem. A:f is 12:1 or so at 0psi, then as soon as the car goes into boost it shoots to 14:1 or so. My mapping is very close to 9.5's and 10's in the fuel map so I don't think that is the problem. The mapping hasn't changed in a while. This one is driving me nuts guys!

Thanks for any info in advance.

Craig

 

Craig....did you ever figure out your problem ?

 

i have a question about this, got my r4 software to work last night, but when i pull a reading from the fuel map, it shows 10.2 across the board, and if i rev it will go up to 11.4 or so, completely different than what is reading out on my aem wideband a/f gauge, does this mean i probably have a kink somewhere ? thanks in advance.

 

The values in the R4 software have no direct conversion to your A:F reading. As far as the R4 software is concerned, a value of 10 means that your FMU will use a 8:1 fuel psi:boost psi if that washer is installed. Any less of a number than 10 the FMU will restrict, and any higher than 10 the FMU will allow more fuel.

Hope this helps,

Craig

 

Hmmmmm...I miss understood how it work also then . I thought the FMU raised fuel pressure , and the r4 fuel map controlled the injector pulse. Well I sure hope the r4 controls the injector pulse or Im in trouble . I have the return fuel system going in along with 550 injectors . And that means I will no longer have a FMU or aux fuel pump

 

So at 8 psi I we should see 64 psi of fuel pressure?

 

. The FMU raises the fuel pressure at a rate of 8 to1 over the stock fuel pressure . So if you are at 8psi of boost your fuel pres. should be 64 psi over the stock fuel pressure [ around 115 psi ] . Then the R4 fuel map controls the injector pulse. A 10 being no change in the pulse and less than 10 ...a shorter fuel pulse