All right the problem I've been having is getting into boost. As soon as I get a little bit above 0 vacuum I experience what feels like a fuel cut. After talking with Reese, NOTA944, he told me to look at my Accelerator Pump Values. Mine were set at basically nothing around 1. My question is how big is the difference in fuel required from vacuum to boost. Because every time that I've tried to get into boost it's been very slowly, bascially getting the pressure to just build up. This is all below 1 psi. So if the difference for boost, compared with vacuum is fairly great, than I might just not be getting enough fuel when I get into boost. If not than I just need to keep searching for the problem. I ask this because I am still waiting on a coolant hose, so I can't go out and test this immediately, and also because I want to know how this all relates to each other.

- Steiner

 

Um, isn't the throttle pump RPM dependent only?
0-1500, 1500-3000, and 3000+?


-Ted

 

Yes it is, but as long as I am trying to get into boost within the ranges of those rpms it would have some affect, because it should be adding more fuel. I didn't mean that the accel pump is coming on at the staging line or when I get into boost, it's coming on beforehand, because I slowly move into boost, so it uses the evens the constant throttle pump values. It will use these until I left off or slam it. I just don't know if the the amount of fuel requirements is that much greater as soon as you get into boost.

- Steiner

 

sounds like you need to bump up the 1st bar in boost a tad

 

I have. When the car was running we tuned on the road, and jumped the first three bars of boost up a lot. It still did it, so we removed a lot of fuel, same thing. Once I get the coolant hose back on, I'm going to move the staging bar and see if that does anything, but I am still unsure of what is causing this.

- Steiner

 

Had the exact same problem, what is your fuel pressure when this happens? I raised mine to 42psi at idle and at 1-5spi of boost its at 50-53 pressure. I think what happens is when the secondaries turn on the atomization suffers. Im not sure if this will fix your problem but it fixed mine. Ive since mounted a fuel pressure gauge ontop of the cowl, this way i can keep an eye on it.

mike

 

Can you change fuel pressure through the Haltec? All I have tried so far is adjusting injector output. I don't have any aftermarket fuel parts aside from 720 secondaries. No money and no need with a blown stock turbo. Let me know how to change it and I will see if that helps. Thanks man.

- Steiner

 

No, cant change fuel pressure through haltech. youll need a ajustable regulator prefferably a 1-1 rising rate. This will raise fuel pressure 1 psi per psi of boost. Put a guage on your car and see what its doing, you can use a test guage and tape it on the windshield will driving so you can see whats happening.

mike

 

Okay thanks. There is a page in the software to adjust pressure I saw that. I won't mess with it though, since I won't know what I'm doing. Eventually I will try and raise the pressure, just short on cash right now so no boost. thanks.

- Steiner

 

Haltech wont control fuel pressure just on and off of pump, so whatever page you were looking at is something else. The throttle pump circuit acts like a accelerator pump on a carburator. If your easing into the throttle its not using the throttle pump map, if you smack the gas, its using the map but still will only run on that map for the rate of time you have entered. Tune your car before messing with the throttle pump circuit, its just going to take longer if your compensating for crappy fuel map by raising the throttle pump circuit. Maybe post your complete fuel setup would give me some ideas ie: pump, injectors, yadyad.

P.S. I dumped my trailing ignition again, with the MSD dis2 its even more impressive under boost.

mike

 

Well my friend Reese just gave me the Accel pump values that he had on his 13bt with stock ports, so that is the map I'm running for accel pump. My complete fuel set up is as follows: stock fuel pump, stock lines, stock fuel rails, 550cc primaries, 720cc Secondaries. I can get into boost now. When I hit .1 bar it feels like a very small stutter, but it doesn't fall on it's face like it has in the past. So now I think the accel might have been part of the problem. Next week some time I'll hopefully hook up a wideband and tune on the street, until I can go to the dyno.

- Steiner

 

I don't supposed your staging bar is set at that boost level?
Sometimes if you're too lean and you're driving with very low load, you won't feel the hesitation.
But, if you're WOT, you might feel it just then.


-Ted

 

No my stagin bar is still set at stock, I think 11. I ment to play around with that. I'll do that tomorrow night. Currently staging is right at 0 Vac. I can still feel the hesitation both when I am barely on the throttle, and also when I am hard on it (still haven't been full throttle, never since I've owned the car) I will move the bar up 1 and down 1 and see how it reacts to that. But I also have a stutter at .5 bar, which I am attributing, for now, to running rich. I'll find out for sure next week when we hook up a wideband.

- Steiner

 

Well after some fooling around, the acelerator pump was part of the problem, I can boost now. I'm running rich as hell up there though. Hopefully I'll scrounge up enough money to actually get to a dyno and get tuned so I can stop wasting so much gas.

- Steiner