I NEED S/C HELP

[curtis]

I HAVE A YSI KIT ON MY STROKER ENGINE WITH 60 LB INJECTORS AND PRO M 80 MASS AIR...I WAS RUNNING 42 LB INJECTORS AND THE CAR WAS RUNNING GREAT , BUT WAS LEANING OUT ON TOP END., DSO THATS WHY I WENT TO LARGER INJECTORS....NOW THE CAR IS SURGING AT IDLE AND RUNNING REAL REAL RICH...THE PLUGS ARE BLACK..I HAVE THE F/P AT 40 PSI AND 13 DEGREES OF TIMMING....I STILL HAVE THE STOCK COMPUTOR....ANY ONE GOT ANY HELP ON HOW TO GET IT NOT TO RUN SO RICH AND SURGE? SEND TO CURTIS@INETGENESIS.COM THANKS ALOT, CURTIS

[frdfandc]

OK, first off you are going to need an injector driver. The 42# injectors are high impedance, which will work fine with the stock computer. The 60's are low impedance, and they are not compatable with the stock EEC unless you are running an injector driver.

Also, is your MAF calibrated for the 60's??? if not, that is also part of the problem.

[regattacoupe]

Darin, they make high impeadance 60's now so i'm sure thats what he meant by the stock computer.

Curtis, I hate to be the bringer of bad news but you're probably going to need a tuning device or a chip burnt of some kind to fix the issue. You can send the meter back to pro-m and tell them to "lean it up" some but it may or may not be enough.

[curtis]

ok...any one else got any answers...thanks

[curtis]

i dont under stand..i have 60 lb high ind. injectors...

[BLOWNBY]

i dont under stand..i have 60 lb high ind. injectors...

Try backing the fuel pressure way down see if that helps the idle(Like mid to low 20's). See if that helps, than bring the fuel pressure up till it begins to surge. It will give you an idea for now as to what is Going on.

We just had the same sort of problem on a buddies car. With the bigger injectors your squirting a lot more fuel in the intake than with the 42's. You're probably going to need to have it tuned and a chip burned.

[curtis]

it want hurt it to run the fuel pressure on 20 psi?

[Alex]

At idle, no.

[BLOWNBY]

it want hurt it to run the fuel pressure on 20 psi?

At idle or just putting around no. But don't get on it. This will just help to narrow down your problem. If this works than you need to get it tuned and a chip burned and this should be your only problem. If adjusting the fuel pressure doesn't help than you probably have other issues.

[BLOWNBY]

ok...any one else got any answers...thanks

Any results yet? Did you try and lower the FP. Did it help??

[stevieturbo]

You cannot fit larger injectors to a car, and expect the fuelling to correct itself.

The ecu will need re-mapped to suit the larger injectors.

[curtis]

what do you mean by re-mapped

[stevieturbo]

re-mapped, new chip, whatever way you want to put it.

The fuel settings will need adjusted for teh new larger injectors.

The injector pulse width will altered throughout the revs so that your AFR's are what they are supposed to be for a given throttle/boost/rpm site.

You have suddenly went from feeding fuel into the engine with say a hose, to throwing buckets of fuel at it, without making any attempt to control the fuel delivery.

[curtis]

i tried to turn my fuel pressure down to 34 and the srew that turns out is all the way out and the lowest the fuel pressure will go is 36 psi i have a paxton regulator...is this normall....do i need to buy a regulator that goes down to 30 psi....thanks for any help

[stevieturbo]

You are trying to steer around the problem. Fuel injection systems are designed to operate at around 40-50psi, so that the fuel is sprayed/atomised properly at the injector.

Lowering the pressure will create injectors that squirt drops of fuel.

By lowering the pressure, you will to an extent reduce the amount of fuel the engine receives, but this will be the same throughout the rpm range, entirely defeating the purpose of fitting them in the first place. In fact, it will have been a major backward step.