PrestigeBass

Hi all.
I am learning about chip burning, and diagnostics and such, and noticed an odd occurence. I have a 5 speed RS with an LO3, and I have noticed that whenever I stop, the RPM's are high for a second(around 900) and then drop down to regular 650. I was trying to figure out what factored in at idle, and I assume its only SA, VE, INT, BLM, and IAC when in closed loop. In the datalog from WinALDL, I noticed that my o2 readings sometimes go to 0. The BLM and INT don't change by much between the time that there is voltage, and then 0, and afterward, but, I noticed that it happens at different times weather I am moving, or stopped. As an example, it will read .77 then 0 then .81, .81, .14, .47... My question about that is if that means I have a potential bad connection, or the wire may be grounding for a second. When it idles while parked, the o2 voltage is around 0.7 going up and down a bit. The sensor is new. Other than that, I don't know if the idle while stopped during driving is effected by the o2 or not because I don't know what all controls the idle. Also, I don't know if the o2 reading 0 will effect anything. When it reads 0, I get data from everything else in the row, its just the o2 that reads 0.

Thanks for the help.

PrestigeBass

I still don't have complete understanding of how all of this works. I was thinking that since I have my idle set at 650 RPMs, that changing the IAC would cause it to idle at a different speed(RPM). I have TBI on it still, and just put the TPI air filter box on it with the caddy elbow for cold air intake, soon to be ram air from the fog light ports. The IAT is much cooler now which is making the engine run a bit cooler, but it hasn't effected the issue.

DENN_SHAH

iTrader: (1)

on the higher RPM coming to a stop, i believe your seeing the stall saver kick in. it does what the dash pot did for the carbureted motors.

the O2 bouncing down to zero isn't unusual, if it goes there & stays, that can indicate a problem unless your in fuel cut mode when coasting down from high speed.

PrestigeBass

denn_shah, Thanks. I tried to post the datalog, but it didn't show right. I have to review some of the logs, but I noticed it was 0 for mabey 8 rows on the log. Since my car is manual, would DFCO still be applied? Sometimes I'll Jake-brake it, so I don't know if that changes things... I also don't know if it does DFCO whin it's in neutral because of it being a stick.
Thanks again for the help, and hopefully I can return the favor.

DENN_SHAH

iTrader: (1)

no problem
im not certain, but i believe DFCO can kick in sitting still when you rev it.