MSefi.com read only forum (Jan.15,2018)

MSII 2.886 v2.2 P&H board

I've been battling a minor hot Idle issue for a while. My truck has a 5.7SBC TBI. Overall drivability is good.
Very pleased. The weather has been good here lately and an anoying issue is bugging me lately.

When my Intake air temp raises above 110 degrees I loose Idle quality. Not real bad but it's noticable.

I have a factory ECU that I run sometimes that doesn't do this. Same Harness, just an ECU swap.

So I set out for a day of experimenting. I have played with IAT fuel correction many times and made some improvements but it alway just got a little rough when underhood is extremely hot.

Out of the blue I decided to try Injection delay just to see what it would do and If I would even notice anything.

Oddly enough above a 20% delay there was a noticable improvement in Idle qaulity. Didn't seem to change any after 50% but made an improvement after 20%. I wen't back and forth a couple of times between 0% and 50% just to make sure it did change. I don't seem to have any side affects from doing this. I plan to put some in traffic miles on the truck this week so I'm interested to see if this affects any thing else.

So, it's a wet intake with TBI. Does anyone think it's the actual fuel pulse timing that makes the difference or is it something electrical that's making the improvent. Changing the distance between fuel pulse and ignition.

I have good clean sensor signals, I'm running a crank trigger 4x hall. Good clean signal, good grounds.

So, anyone have any Ideas about injector delay?? Or is my improvement in the same catagory as 'sacrificing a chicken'

Thanks,

Joe

Fiddling with the injector delay helped smooth my idle right up too. I don't believe, however, that this has anything to do with problems while running hot. Check your temp values for timing and fuel.

Now that I've had a few days to drive I have to say It improved my overall Idle quality Hot and cold. It was surprising to me.
It now has the OE feel to it that I have always been missing. I am very pleased, I was mainly just chasing the hot issue because my idle quality started to deteriorate. Not real bad just noticable. Very happy overall. Wish I would have tried this a long time ago. Learning new things is always interesting.


Joe