KILLER-LS1

iTrader: (18)

So here is the problem im having. the car goes super lean at part throttle only when the engine is at operating temperature. WOT the car runs great, and it idles great. its only at part throttle/ cruising speeds. The car has an SD tune programmed to run open loop. its an ebay kit, but has been modified to take a 50mm turbosmart wastegate and 76mm .81 a/r turbo. im running 7-8 psi.

fuel is walbro pump, stock lines, edelbrock fuel rails, 50# injectors.

we tried to fix this on the dyno but had no luck tuning it out. I have no knowledge about tuning, so if im leaving out any important info let me know.

the gauge only reads to 16 but on the dyno it is actually leaning out to 20:1 which is why the motor is running so crappily as you can hear in the vid

http://www.youtube.com/watch?v=GGvHxObI5lg


any ideas,????? my brain is fried after troubleshooting for a week!

.

KILLER-LS1

iTrader: (18)

forgot to mention:

using HP tuners.. has a 2 bar MAP from a colbalt

ive tried disconnecting the WG, i get the same AFR readings even with no boost.
disconnected the tube going to the TB, same AFR readings w/ no boost
ive swapped coils, bought new wires, and new TR6 plugs gapped at .035" and the problem is still there.

69LT1Bird

iTrader: (1)

Post the tune file

KILLER-LS1

iTrader: (18)

I dont have those, the tuner does...

69LT1Bird

iTrader: (1)

Well there isn't much people can do without the file. Get the tuner to post the tune if he needs help or find a different tuner who can figure it out.

Slowhawk

iTrader: (12)

Don't know if it's the problem but I hate 50lb injectors.Always had problems tuning them.SD tuning is pretty basic.Just as long as the STFT and LTFT have been shut off to verify.

KILLER-LS1

iTrader: (18)

yes, i did notice that, and the fuel trims have been turned off.

do you think the car would need a crank sensor re-learn via Tech-2? it has an eagle crank in it...

white2001s10

iTrader: (4)

That sounds terrible.
Check the VE table in the low RPM (where it is happening), medium to high load range 40 - 80 kpa.

Those VE values may have to be increased by 30 - 50% or more.

At WOT your PE may be saving you - covering up a lean VE table.
It might help you to lower your PE to something like 10% across the board, then get the VE table in better shape. That way there will be less transition to PE, and you can add a little low RPM PE to simulate more pump-shot.

This is very common after adding heads, cam, exhaust, and/or larger intake manifold. The actual VE at part throttle is much higher than that predicted for a stock engine. Add fuel in the right places and it's done.

darkhorizon

I liked my 50's, never had a problem with them.

I find it funny this "tuner" let you leave when it was running like that. Got any names or whatever of this tuner place?

KILLER-LS1

iTrader: (18)

no, its a very reputable shop in the area, i know they know their stuff... there wasnt much else he could do so i just towed it home

Slowhawk

iTrader: (12)

You can't always blame the tuner.Sometimes there are other problems.

hymey

Does it sound like its running on 7? Injectors aren't the issue there easy to sort. turn the STFTs on and do a log. It will sit on 14.7 until PE drive it around for 20 minutes or so and fill the log up in the tune.

Make sure in the STFT map you change the source from "sensor" to "pid" I have had dicky readings with HPT otherwise if you are using efilive its not an issue.

The motor should sound smoother whilst driving and the log will highlight leanspots simply copy then past and multiply to your VE table, Go for another drive in OL and see what happens, it should be close if not its not a tune issue. Possibly ignition somewhere.