Need Help With Turbo Tune (Tune and Log Inside)

[mikeyayell]

I have a 370 cubic inch InconTT car. Car has a small cam and is on 10lbs of boost. I had the WOT tuning done at a local shop and the car made good power for a break in "safe" tune. My problem is that the car breaks up badly at 3500-4000 rpms. I dont have a wideband on the car and the AFR on the dyno was 11.5 WOT. The car is also getting KR and I dont know why. Also, I have 2 intank Walbro 255s and 60lb injectors and the car is running out of fuel. The pumps are wired together, so they're working constantly. The car is on a 1Bar SD tune right now. Car was tuned with Efilive. Can anyone look over the tune and see if they can find anything. Any help greatly appreciated.

[Stealth97]

I'm limited in my knowledge but I'll help you brainstorm.

Have you checked your spark plugs? The car may have been running perfectly on the dyno day and might now have fouled the plugs. You could have been rich while tuning, and 11.5:1, while not excessively rich (at high RPM), could have still fouled them. What is the gap on the plug? Are you flowing so much air and making such a big spark that it is blowing out? Try gapping down and see if it helps.

Post back after you check the plugs and ask questions if you don't know what you are looking at (Are the plugs white and hot or black and dark?).

Eric

[mikeyayell]

TR6's at 0.30. How does the log and tune look? I still cant figure out how its running out of fuel.

[mikeyayell]

Here is a run down of the car:

Engine:

370 Cubic Inch Iron Block
9:1 C/R
Stock 317 Heads
GM MLS Gaskets
222/222 114lsa Cam
ls6 Intake
Stock TB
ARP Everything

Fuel:

Dual Intake Walbro 255s
60lb Injectors
PP Fuel Rails
V6 Fuel Lines with Return
Boost Referenced FPR
Methanol

Drivetrain:

T56
Textralia Twin Disc Clutch
Moser 12 Bolt

Incon Stage 3 TT Kit

[Stealth97]

I forgot to address the issue of running out of fuel. How do you know it runs out of fuel? Does the wideband go lean at 3500-4000? How lean and does the spike coincide with the breaking up?

Did you check the plugs to see if they are currently fouled? Sometimes you can take a badly running turbo car, change the plugs, and it is smooth as butter afterwards.

I have not looked at the tune yet. Again, I'm an amateur, but willing to help and listen.

[SS2win]

does that log really say it's commanding less than 8:1 when you floor it?

[nevinsb]

Do you have a fuel pressure gauge on it? Does it lose rail pressure when it "runs out of fuel"?

[mikeyayell]

FP is 55psi idle and 70psi WOT and does not lose pressure.

[SS2win]

without a wideband you're just pissing in the wind.

[joecar]

Some comments:
- Do you have the manifold-referenced FPR...? If so, then B4001 is wrong.
- B4001 IFR doesn't fit your 60 lb injectors.
- B0101 VE table looks wrong.
- MAF sensor is not working.
- MAP sensor is pegging at 104kPa, shouldn't it go higher...?
- If IFR, VE, MAF are made to work right, then AFR and INJDC will come good.
- Wideband is required.

[mikeyayell]

I understand you guys say I need a wideband. It was just tuned on a dyno with 11.5 AFR across the board by a reputable shop. It is a SD tune, I have 60lb injectors. The car also cuts out in neutral or if you are steady at 3500-4000rpms. It sounds like it has a 2 step. It does not do it if you hit it at idle or less than 3k and stay in it. Any ideas?

Thanks

[Stealth97]

Read this thread on why a MAF is better than a Speed Density tune. I just read it.

http://forum.efilive.com/showthread.php?t=1811

Cliff Notes: Speed Density is great for precise weather conditions. Change temperature, humidity, etc. etc. and the tune goes wacky lean or rich or both depending on how far out of wack constants and other values are.

It may have been "tuned to 11.5 on a dyno with an SD tune", but was it thoroughly road checked and tuned for different atmospheric conditions? You already know the answer or else you wouldn't be here.

Simply put, your tune still needs a lot of work. I'd take the suggestions of fixing your IFR rate to match 60 lb. injectors and retune the VE table. Having IFR wrong caues a lot of problems, I've been down this road before.

Do you own EFI live? Get the wideband and do some AutoVE tuning with it.

You might be able to do STFT tuning using Jesse/Wait4me's tuning trick with the narrowband O2 sensors but I have not checked out how well it works. I'm just testing it out this week. I'm waiting on my LC1 and sLC1 TAQuickness cable.

One thing that is cool, if you had the car running okay before, you can get it back there and make it stay there, it just takes work. Good news is the spark timing table should have been tuned on the dyno for good power and you should just need to get fuel in line and she should MOVE OUT.

I'd play with 3 tables. IFR, VE and MAF.

Eric

[SS2win]

Any ideas?

Thanks


Yeah. get a wideband, hook up your tuner and start figuring it out. No one on here can tell you what to do without accurate data. Saying it was tuned by a reputable shop is as good as saying my Aunt Effie tuned it via the Internet using a trojan backdoor program in my pcm.

[LS1Nova]

How did you ever make out with your tune??
I'm just throwing this out there, but don't you need a 2 bar map sensor for boosted applications less then 15psi? I would imagine the ve table is setup for the way the turbo built boost on the dyno, but on the street it will build boost differen, hitting different cells that you may not have tuned from the dyno session.