Cwarta

iTrader: (12)

Have a question that has been bugging me since the day I first used HP tuners. Everytime I flash the tune in, I have to turn the switch on, then off, then on, then off and then start it, and pump the **** out of the gas pedal and it will stumble around 2,500 rpm and catch and then its fine, no more issues with the car.

If I do not cycle the key first several times, it will start and immeadiatly die if you try to rev it up a little. If you let it idle, it will idle for around 5 seconds and then die. Then you will have to go thrue the key cycling process to get it to start up, and then all is well.

What gives? Im thinking maybe its a fueling issue? Im not sure, the only thiong I can think off that would be affected by the key cycling would be the fuel pump and related pressure? Any insight is greatly appreciated, Chris

joecar

What happens if you flash in the original tune...?

Cwarta

iTrader: (12)

Same thing, no matter what changers are or arent made in the tune.

edcmat-l1

iTrader: (10)

What are you tuning, and is it a custom OS or a speed density tune?

Cwarta

iTrader: (12)

Well, it didnt matter when when the car was exhaust only to what it is now, it was stock OP then, now its 2 bar speed density :/ But im still running the stock LS1 map sensor

James@ShorTuning

Sometimes on a sd car it takes a few seconds for the MAF to fail completely. Try inputting 10-12g/sec in the first few cells of the MAF table. Also make sure you have failed the MAF with 0hz in diagnostics and fail on first error. To keep the light off you can uncheck SES. The SD OS's for the 04 GTO were a little odd compared to the 0411's.

If that isn't it then verify good fuel pressure on the rail under all conditions. Verify bleed down isn't excessive on the fuel pressure after the pump is off. Other than that its probably a tune issue.

wait4me

iTrader: (10)

Make sure your car reads 100kpa when the key on engine off. Maybe since you are running a 2bar with a 1bar it is wrong on the ve tables. Not sure if they fix the map sensor calibration automatically when you apply the custom os. In efilive the value to check would be table C6301 Map sensor Scaler For the stock sensor should be 94.433594

wait4me

iTrader: (10)

These are the maf sensor fail settings I do for no maf sd.

{C2901} MAF High Frequency Fail 1 0.000000 Hz
{C2903} MAF High Frequency Fail Limit 1.000000 Failures
{C2904} MAF Low Frequency Fail 1 1300.000000 Hz
{C2906} MAF Low Frequency Fail Limit 1.000000 Failures
{C2907} MAF Test Min Engine Speed 100.000000 RPM
{C2908} MAF Test Min Run Time .1000000 Seconds
{C2909} MAF Test Min Batt Voltage 8.000000 Volts
{C2910} MAF Test Max TPS 99.000000 %

edcmat-l1

iTrader: (10)

Might wanna post your tune. If you have a 1 bar sensor and a 2 bar COS, and you didn't swap the MAP linear and offset back to stock, that could be a contibuting factor. If you haven't failed the MAF correctly, that could be a contributing factor. If you've done both correctly, there are still other things that can be done (as James mentioned) that can help it fail the MAF quicker.

Cwarta

iTrader: (12)

I follwed a write up to fail the maf, it is possible that its not correct.

SInce the day I went SD I have had a picture of my car on the message center with a wrech in it saying service soon or something, cant get it to go away.

Im going back to 1 bar OS tomorrow to eliminate that.

Russ K

iTrader: (1)

Thats because you need to uncheck the Maf code boxes. And I set my Maf codes to 2-no mil light.

Russ Kemps

Slowhawk

iTrader: (12)

Just unplug the MAF.

Make sure the MAP settings are right by doing what Wait4me said- 100kpa ignition on,engine off.
If those are done the VE or injector scale are way off.

Sunny

After each flash on LS1 GTOs I turn the key back off and disconnect from the diagnostic port. Then take the key out of the ignition and open and close the door then wait 10 seconds. This seems to give a clean flash and the car always starts right up.
I’ve only experienced this on LS1 GTOs while using beta. Others have had the same occurrence.

wait4me

iTrader: (10)

Interesting, It sounds like the bootloader in the pcm is still being ran and not flushed after the reset. By doing what you are doing, you are allowing the pcm to go into a shutdown sleep state, which is probably flushing that bootloader finally allowing the pcm to then perform as normal without modified loading code.

Cwarta

iTrader: (12)

Sunny, are you stating that if you try and start it right away it does the same thing as I am stating, but by doing it your way it starts first try? Intersting if so.

I have asked several other local GTO owners about there cars and If they experience this. All have said no, BUT all are LS2 GTO`s so it may be an 04' Thing then.. Thank you!

Cwarta

iTrader: (12)

Also waitfor me i will double check all my settings as you discribed above and hopefully that works. I am looking at updating to the LS3 card MAF as ill be spraying shortly.