cnichols

iTrader: (23)

Stock 98 LS1 w/ full exhaust and a Painless Perfect Computer.

I've asked Painless and they don't seem to think it's in the tune, but rather something wrong with my setup.

Things to remember...

-98 injectors were ~28.5 lbs/hr, correct?
-Using a Corvette filter/regulator...what pressure does it maintain?
-There is no MAF sensor...this is a speed density system.

Having said that, my best guess is that it's either a fuel pressure problem, a MAP/air temp/O2 problem, or it's simply in the tune. Since I don't have the ability to tune it yet (Painless won't release the software), I would like to eliminate any other possibilities.

hpmotorsports

iTrader: (5)

Don't know much about the painless setup,but usally it is in the tune, if all the sensors are good.

cnichols

iTrader: (23)

Well, there is a wire that is either grounded or left alone depending on which injectors you have. I was thinking that if my fuel pressure is too high, I could unground the wire, causing the computer to think I had smaller injectors, and therefore fixing the rich condition.

But, not exactly what I want to do. What is the best way to test the MAP sensor?

And, if the MAP sensor is slightly "off" or damaged, will it still function so well? Basically, I'm asking is there an "in between" for a malfunctioning MAP or is it mostly just working/not working?

bczee

iTrader: (12)

suggest you move this to the PCM Diag / Tune forum. maybe one of the Mod's will move it.

whiteLS1

iTrader: (15)

numbers look good for a 98 with full exhuast. any chance the dyno could have been off i would bet that the a/f gauge on the dyno is off. remeber 98's made the least amount of power of all the ls1's

just throwing that out there

hpmotorsports

iTrader: (5)

can you log any data with that setup

cnichols

iTrader: (23)

Forgot to add that I have an FJO in the car. It matched the dyno wideband. Even if it didn't, the fact that I've had numerous people tell me I'm shooting fireballs pretty much dismisses the possibility that the Wideband is off.

Yeah, I was happy it made over 300. The Carbon Fiber driveshaft, longtubes, and intake probably allowed it to do that.


Hell, it may. But Painless is dragging their feet on releasing their software.

lt4malibu

iTrader: (39)

are you running rear 02's?

cnichols

iTrader: (23)

No, the Painless has no provisions for rear 02s.

I am leaning towards a faulty MAP sensor or my fuel pressure being too high as I am using a Walbro in tank 255lph pump. Anybody think that might be overpowering the Whorevette filter/regulator?

lt4malibu

iTrader: (39)

if you arent using them, and the PCM thinks you should be, that could be a problem(just throwing it out there). any DTC's?

kansaschity

iTrader: (1)

there is no pcm, he's using the painless perfect computer

lt4malibu

iTrader: (39)

wow... would help if i could read...

Kamin

you probably have another 10-20hp on that setup chris, thats WAY rich at peak power.

fouz65

just guessing but, the curve on the sheet looks choppy. check your plugs for cracks or change them. guy that tuned mine said if their cracked it will show choppy on the curve (im not sure how much). dunno if that would make it run rich by not burning all the fuel. just an idea. cheap and easy to do. might have a little crack when you was messing with the headers? maybe someone that knows can put their 2 cents in.

memphiss13

yeah i was going to say the same thing. your problem looks like bad plugs or improperly gapped plugs probably. what about your wires? are they new?

exodus

iTrader: (15)

I have heard a lot of people say this. I must have had a "factory freak" car. I put down 312 rwhp and 322rwtq with my 98 when I got it. This car was literally 100% bone stock from the factory this way.

cnichols

iTrader: (23)

There is no smoothing on the graph, but yeah, I'm going to swap out plugs (been running that rich the entire time) and get new wires. Those don't explain the problem of the air/fuel ratio though. Will be upgrading to the MSD packs soon and will do it all then at once.

I replaced the MAP vacuum line and also the brake booster line so any leak should be fixed. We'll see what happens.

mattmartindrift

if you've ever seen the "tuning bell curve" fuel does not give you much power between 11.5-13:1 is a very minimal difference, and it's often safer to run rich. Power is most of the time in your timing map.