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I have recently completed a blown V6 tune on the dyno.

It's a VP V6 , decompressed, stroker crank, H beams, forged pistons, ported heads, etc running a V7 vortech blower with a water to air cooler.

Pretty impressed with it as it made 460hp and 470 ft/lb at just 5000rpm! Had to stop it there as it was running too much boost (17lb) and rapidly running out of injector.

Anyway, the engine goes in the car and it had trouble starting. It's really rich, so much so that it's fueling up the sump.

I have tried everything I can think of to reduce the cold start fuelling. I am starting to think that it may be an air temp issue.

I did manage to get it running with a std V6 OSE tune runnning a 1 bar sensor. As soon as it got some temp into it, I swapped back to the 3 bar sensor and the 3 bar tune.
Started and ran fine. This one has me scratching my head. It does not seems to respond to any attempt to reduce the cold start fueling.

I did notice also that when I got it to run, it was trying to idle at 90ka? So, I enabled the closed throttle VE table. No real change.

Any assistance would be appreciated.

can you clarify what you mean ....

does it start and run just pig rich or does it not actually start and floods ?

does the car have a wideband in it ? can you get a log or anything ....

also which map are you using in the tune map a or b ? it looks from what i can see theres been more work on the map a tables so im guessing that its the one.

It will start, but runs rich until it fouls the plugs and won't run.

It would initally not start at all. I greatly reduced the coolant corrections , post start and crank fueling ( bearing in mind I had already reduced the crank fueling due to the larger injectors)

The weird thing is, on 1 bar, using a std tune ( updated for the 42lb injectors) it starts and runs cold with no change to the cold start other than reducing the crank pulses. Seems as soon as I change to 3 bar sensor and bin, it goes stupid cold, but is fine hot.

It's on map A. No wideband in the car as yet. Logging not possible at the moment, I don't have the car in my possesion.

Yeah would be interesting to see a log done with 1 bar and then 3 bar if you can next time you have the car.

how sure are you that its a 3 bar sensor? whats kpa does it sit on when keyon but engine not running with the 3 bar snesor in it?
if its really a 2 bar sensor but youve got it set to 3 bar, then it would run real rich.

Yep, checked the sensor, it's the right one.

so.... what kpa does it sit on at keyon in the tp5 dash screen?
how do you know its 3 bar? got a part number to look up?

Reads 110kpa using the 3 bar sensor at key on. The same sensor and bin saw 220kpa on the dyno. Have tried 2 different sensors, same result.

I managed to log 1, 2 and 3 bar sensors.

Tune was not changed, only the map sensor selection.

Used the correct adx for logging 1, 2 and 3 bar petrol.

The 3 bar setup sees 20kpa more than the 1 and 2 bar when the engine is running.

2 and 3 bar see 110kpa at key on. 1 bar sees 103kpa.

Thanks for the really good logs The key on MAP reading variation from 1bar to 2/3bar is much more than I would have expected, should be very similar to the 1 bar. And can see post start the MAP readings are pretty different with the 1 and 2 bar sensors. Are they genuine GM sensors? The calcs I used are from the factory code so should match factory sensors - and am pretty sure others that have swapped 1 to 2 bar saw only a very small change in the key on reading.

No probs. Nothing beats good data!

I believe that the 1 bar sensor is GM and the 2 and 3 bar are aftermarket but are the same style sensor.