cliffyk

We had been discussing this in an earlier thread that had gotten off track so I thought I'd start a new one.

My '03 GT had been doing this (hot start requiring some cranking and throttle play) since I got it with 30k miles in December of '06.

It has always started eventually after the very embarrassing "I ain't gonna' start in front of your friends and all the other people here at the Wednesday night get together at Hooters", however for obvious reasons (even for a geezer like me) that was a less than desirable outcome.

In any event, a while back I got the Sniper Commando upgrade for my Special Forces tuning package--which lets you "modify/alter/edit/delete/screw around with" just about anything there is in the EEC-V programming--and while poking through the 73-1/2 zillion changeable things I found a function called Crank A/F Ratio that struck me as very intriguing.

Crank A/F Ratio is a function that maps ECT against AFR for cranking purposes. I saw that at 200° ECT (which would be just about after the big "engine just stopped heat soak" started to go away) that the AFR was set to 13.81:1.

Knowning that the engine seemed to be not starting because of being lean I bumped this to 13.25:1 and guess what?

After driving for a couple weeks it would seem that the problem is gone. I have not babied it in any way as has been suggested by myself and others (turn the key on and wait a bit, "floor it", or any of the other improvisations), and it has started better then ever after stopping to buy beer, etc.

YMMV, but it seems to be the cure for me...

amoosenamedhank

I really wish I would have purchased that software from the beginning. It just seems like you can do anything with that sniper program. Seems like some really cool stuff.

blstoff

yeah , I had the same problem . there are a few parameters that deal w/ crank fuel . the 2 major ones are " Crank ISC Duty Cycle " & " Crank Lambda " . most people w/ FI have to richen it up 10-20% . for me , I had to add 8% at 150* & up . & I added 15% at 125* & down . now it starts like it did when it was stock .

EDIT : a little more info . Crank ISC duty Cycle controls the initial flare up . I have mine set up to flare to about 16-1700rpm . if I wanted it to flare higher than I would just add more air . but if you add more air into the crank isc duty cycle then it would lean out again so you would need to add more fuel in crank lambda also to keep the a/f where you wanted it . there is also a parameter called " Crank Fuel Multiplier w/ Time " that plays a part too , it's a function of ECT & PIP (Profile Ignition Pickup ) . there is also "Cranking Spark " & " Spark when Exiting Crank " . I use SCT's software so I'm not sure what parameters you have access to .