foru2nv4

I have done lots of research and not getting no where with my D&D. I took a stock saleen mustang GT added a salen series IV supercharger and water cool for supercharger bigger fuel injectors 42Lbs. smaller pulley 2.73 inches, bigger throttle body, and 4.10 gears to car. Sent my computer to saleen to be programmed before I had these upgrades listed above. The program thinks I am still runnin stock throttlebody with 3.27 gears and saleen pulley that is 3.10 inches. I just purchased a sniper tuner recon and had to have the guys in charge of making sure the sniper is workin for your car build me a stock tune cuz suppossely u cant build a tune from the saleen tune that was installed in my car after I got computer back from saleen. So he sent me a stock tune to build from and wiped out the saleen tune since I have alot of upgrades. Right now car is idling very low every time I build a new tune from stock but its funny while Im building the tune it asks me n the tune "If I have an FMU present?" its always checked yes. If I leave it on yes and then go thru tune saying I have 42Lb injectors 4.10 gears it idles really low as if it wants to die and throws check engine light but when I check no for FMU present it idles much better but still low when I build another program from sniper but still get check engine light. Ok my question is if the FMU is always on yes is the dude that sent me the stock program to build from thinking that this car should or does have an FMU present, So if I buy an FMU for a supercharged 42LB injected car would it solve my low idle problem and if so what FMU and who do I buy it from. Im thinking this guy knows sumin about supercharged 2003 mustang GTs and thats why on the stock file yes is always checked yes for FMU present. Thanx need help.

945LSTANG

Sounds to me like you need to stop fiddling with mail tunes and go get a custom dyno tune.

And no, don't buy an FMU. Someone correct me if I'm wrong, but I'm pretty sure those are one way to tune fuel on an OBDI car. As I'm sure you know, your car is OBDII. Not sure you would have one on your saleen blower.

Dave19525

Unless you have changed your fuel system from the non-return type to the older style return type you do not have an FMU. Some guys with really built motors have converted over to the return type system. But if you haven't done this you don't have and can't use an FMU.

Dave19525

+1 945LSTANG, go get a dyno tune and call it good.

LilRoush

You don't have a FMU.

Maybe I'm not reading right, but are you saying you had Saleen tune BEFORE your mods or FOR your mods when you got it done?

As posted, get a real tune. You spent a lot of money on that set up, why ruin it with a cheap mail order tune?

foru2nv4

your right lilroush I had the PCM sent to saleen after I put saleen series IV SC on and water/air coolant all stock in a crate sent from saleen. But since then I have upgraded to bigger injectors bigger TB and smaller pulley. I do have 2003 mustang GT yes it is OBD II if your right I will not buy an FMU for car. So my question is why is car idling low no matter what tune I put in from sniper special forces? What or where should I be looking to get the idle back to idling normal? But you guys could be wrong cuz they do make FMU's for 1999-2004 mustangs look at JEGS and SUMMIT RACING $600 item.

foru2nv4

Do you all think maybe my fuel pump is going out? Hard time starting when engine cold have to pump pedal while turning engine over. Should I have a pressure check on fuel rail? if its still running at stock do I need to upgrade to sumin special since they are 42Lbs injectors instead of saleens 30LBs injectors? According to my D&D online it says 42Lbs injectors should have 60 psi going to them instead of my stock 40-70 psi on SOHC according to looking in haynes manual when testing fuel pressure. Would kenne bell boost-a-pump work or sumin else?

sv650lex

I agree with above you need to bring it into a good tuning shop. The idle should be able to be ajusted seperate. i have a hot wife

P.S. were drinking.

LilRoush

I wouldn't try to retune a canned tune from Saleen with a Sniper. You'll need to account for the injector change and other mods, though.

I highly suggest getting to a dyno with it and starting fresh or having Saleen account for the changes in their tune.

945LSTANG

You need to stop taking shots in the dark and just call your local tuner. He will strap it to the dyno, datalog it, and be able to tell you the issue on the spot.