If you could simply tune this car for me you would become my very best friend in the world It's a customers car, and I'm at my wits end with it. LT1's are normally pud to tune. But this one is giving me nightmares! I didn't work on it today though just because it's too frustrating. I might try it again for the last time tomorrow. Thanks for all the help. Appreciate it much.




Chuck

 

If I were you I would set the maf tables back to stock. Use them for tuning part throttle blm's if you choose, but I've found that if you get the injector constant right for the injector you're using and the fuel pressure you're running...that the stock maf tables work fairly well.

How much boost are we talking?
What size injector?
Is the fuel pressure regulator a boost referenced unit?
What ratio fmu?
Is an fmu even required with the amount of boost and injector you're running?

There are quite a few things that factor in here...

 

haha, it's got stock injectors (24#). I bet that's the problem

The customer purchased the kit, we only did the install. It's a Procharger D1SC, but has a big pulley. We haven't hooked a boost guage up to it yet, but I assume it's around 7 psi. Couldn't tell you what fmu it has, or what the ratio is. It's got a stock fuel pressure regulator as far as I know..

Thanks for the help Dan. You made the ol light bulb light up

Chuck

 

I'd be willing to bet you're out of injector.
Find out what size injector you could go to and be able to get rid of the fmu.
Old technology. It works, but a big injector is the way to go IMHO.

 

the OPEN LOOP vs TEMP vs MAP is the table refered to in WOT mode when in open loop. The VE tables also play a roll in all open and closed loop fueling but the specifics are complicated and not believed by some. And I do not want to start something here. Also since he boosting hes going beyond 100 KPA sooooooo the VE tables are very inccorrect and would be better if he didnt touch them.

 

Well after a week of replacing parts, we're still in the same boat! Brand new SVO injectors didn't fix it, and a brand new Walbro 255 in tank pump didn't fix it. Fuel pressure goes from 45-60-back down to 45 (which is when it starts to cut out real bad.

Chuck

 

Starting to sound like you may have some ignition problems as well as the fueling problems that you've taken care of. You already know the biggies I'm sure.

1) Fresh Optispark
2) Fresh Wires
3) Colder Plugs - to avoid blowout
4) Bad MSD box if your using one - I've heard of a lot of problems with MSD's

Also: What kind of Duty Cycle are you seeing right before it starts breaking up now with the larger injectors? What the heck would cause the FP to drop back down to 45? Probably loosing boost when it starts to break up, then mainifold pressure drops, and thus FPR lowers FP. Just thinking out loud here.

Good luck.

Steve

 

Starting to sound like you may have some ignition problems as well as the fueling problems that you've taken care of. You already know the biggies I'm sure.

1) Fresh Optispark
2) Fresh Wires
3) Colder Plugs - to avoid blowout
4) Bad MSD box if your using one - I've heard of a lot of problems with MSD's

Also: What kind of Duty Cycle are you seeing right before it starts breaking up now with the larger injectors? What the heck would cause the FP to drop back down to 45? Probably loosing boost when it starts to break up, then mainifold pressure drops, and thus FPR lowers FP. Just thinking out loud here.

Good luck.

Steve