PDA

View Full Version : Truck dying on slowdown



haynss
April 20th, 2006, 08:28 AM
hello,

here is some background on the truck:
408 with STS GT70
240/240 550ish/550ish 114 cam

While we were tuning the truck we were trying to figure out why it seemed so sluggish. Before this everything with the VE tables were good and the truck was seeing the proper a/f. Then we found a table that had the piston protection come on if the temp of the truck was above ~170. Well most of my tuning was done with the truck at ~190-193 so we were always in this protection mode. We then upped the temp to 260 or something like that and that is why my truck started to no want to idle.

I was hoping to get some help or an idea of where to look. My truck keeps dying in the < 1000 rpm range. My idle is set for 1000. The WB02 was reading high 10.9-11.4. So anytime i was stopped or was slowing down i would have to brake and hold the gas pedal in so i wouldnt stall. I thought it was like this becasue i was too rich. So i leaned it out a bit, and the problem seemed to go away (80 degrees outside) in the afternoon.

So now this morning (52 degrees) the truck starts fine and i notice that im pretty lean (19.0-20) and goes down the street without me having to drive with 2 feet, then all of a sudden at the next stop, back to 11.8-12.2 ish. Now im driving with 2 feet again in traffic :bawl:

I just got back from driving out side (78 degrees) and I am still having to drive with 2 feet.

Everything is good (other rpm ranges are in the 15-16 range) besides when i take my foot off the gas and roll, the rpms drop to below 1000and the truck stutters and wants to stall and idles at 500ish if i dont give it gas with the WB02 reading 11.2.

Is there somewhere that I could take a look that could be causing this? I've had a couple people look at the tune, erik aka turboberserker, but they think things are looking ok.

sorry if this doesnt make that much sense, it did in my head when i was typing it :)

thanks for any help you can provide.
makani

TAQuickness
April 20th, 2006, 08:34 AM
anychance you are still using the MAF? If so, have you recalibrated it?

haynss
April 20th, 2006, 08:38 AM
no MAF, I believe the my tuner recalibrated it, as things were running ok up until that piston protection parameter was changed.

haynss
April 24th, 2006, 06:37 AM
ive just verified with an older table on some settings that were made:

The B3607, B3610, and B3655 tables were changed.
B3607 went from 1.0 to 1.1
B3610 went from 1800 to 1600
B3655 went from to 80 to 115.5.

The one I have the biggest concern for is the B3655 Piston Protection ECT Limit. How will rasing this from 80 to 115.5 affect this? I ask because that is the last change my tuner made besides to the VE table before I stopped being able to idle properly.