I'm having issues with my truck running right when its cold. I have a speed density tune from allen tuned in San Antonio right now. I have driven this truck to West Virginia for work, and now I drove it all the way up to Wyoming. Zero problems on both trips. I was using my truck for work while im waiting on a company truck. It was starting great for 5 days or so. One morning I started it and it ran great in -10 weather, went to location and parked it. Started it at 5:15 to leave and it was warmer and it was idling like crap. The a/f was real rich and the idle was rough. I let it idle for a few minutes and it died. Started it back up and it idled a little better so I walked inside and 5 mins later its dead again and wont start at all. Ended up having to get to towed to Rock Springs to a dealership. They parked it inside over the weekend and started it monday and it started right up. All this went down last friday by the way. So they added some fuel addative thinking there was water in the fuel somewhere and it froze. I had the coolent changed to the stuff needed for the weather up here. The tech said he drove it all around town and it ran great, idled great and everything. I went to go pick it up yesterday and started it up when it was 6* outside and back to the idling like crap and idling rich. Let it warm up a little and leave and its way rich while driving. Around 10.0- 11.0, I was hoping it would warm up and get out of the closed loop and be alright. Anyway, I gave it a little gas to go through a light and the a/f would go lean when stepping on it instead of rich. It would go up to 13-14. I was in the process of turning around and heading back to the dealership when it died at a light and wouldn't start again. Had to get a tow with my tow strap to the dealer. They were closed already so I didnt get to talk to anybody. Called them this morning and let them know what went down. They don't even know how to diagnose the problem since it doesnt have a maf sensor. Seems it runs fine when its a little warmer in the day and like **** when its cold as hell. It was -22 here this morning. My question is, is this a problem with the speed density tune since it was tuned in San Antonio, Texas at a low elevation and now the trucks at 7000ft and ALOT colder. I called Allen and hes gonna call me back about it when he gets a chance. If anybody has any input on this it would be appreciated. I just need to get it running good enough to get it home when I go on days off. Sorry to be so long winded but I wanted to explain it well. Trucks mods are in the sig by the way.

Thanks,
Sam

 

With the changing of the weather and the SD mine would do the same thing. Weird random idle surges, died sometimes at the light. This is just me thinking but possibly since there is no MAF its not able to adjust for extreme temperature changes.

 

Base running air flow idle tuning will fix that problem. You have to be scaning the truck at those low temps to get the right info.

 

Or just run a larger MAF and be done with it. There are plenty of builders making well over 900 HP with a MAF

 

Iv seen alot of draw thru maf's boosted apps working well but not to many blow thru over 6psi.

 

I'm running 12-13 #'s blown through my stock MAF.The MAF is at it's limit at 4800 rpm's, then the PE tune keeps it safe until my shift points [6000 rpm's].

 

That way works but itS not fueling for your real airflow. Its rpm based so if you ever see more boost at say 5900 your going to go lean since the VE table flatlined at 105kpa and is now X rpm=X fuel and will not account for more or less fuel at that rpm under boost. It dose work so I'm not saying itS wrong as long as your happy at the end of the day it's just not for me.

 

If I was to get a re-tune to get the truck home, then I could go from there. Would that work? If I woulda known speed density was gonna do this I wouldn't have done it. Then again I didnt know I was gonna be taking my truck across half the US.

 

Do you sell the larger mafs blownchevy?

 

HA...I was having the same probs with my retune from BlackBear. Since I know nothing about tuning I have no idea what he did, but I did some data logging at idle and WOT and he sent me a reflash and its pretty much cured...give him a call and he'll answer the question I'm sure. R/