PDA

View Full Version : A tough ?



glhs875
09-22-2006, 02:02 PM
I've been working on getting my car tuned in for a 3bar map. What could be making my car lean out under low boost (1 to 7 psi) at light-part throttle, and only in 1st gear while being driven only. It doesn't lean out in that range while power braking it through that range, or in 2nd and 3rd gears at all. And if I lay into in first gear right after startup it's fine. It happens only after the car is driven some. This has me puzzled. I can get the chip corrected, but I really don't know what to ask for to be corrected! Any suggestions or ideas? Right now to cover up the problem, I have my alky kicking in sooner, and that works great. But I really don't want to kick it in until 10 to 12psi or so. I may just have to have the cal richened up in that range, I don't know? Does the speed sensor have any effect on the fueling?

ShelGame
09-22-2006, 02:27 PM
The speed sensor has no effect on fuel.

What do you mean by lean? The computer tries to get as close to 14.7:1 as possible at part throttle. That could be what you're seeing. You shouldn't be in boost at part throttle.

Also, on startup, extra fuel is added. It goes away as the engine warms up.

glhs875
09-22-2006, 03:41 PM
The speed sensor has no effect on fuel.

What do you mean by lean? The computer tries to get as close to 14.7:1 as possible at part throttle. That could be what you're seeing. You shouldn't be in boost at part throttle.

Also, on startup, extra fuel is added. It goes away as the engine warms up.

Well, for right now anyway, to help narrow down the tune, I'm running my car in open loop. It was actually leaning out worse in closed loop. And with the S3 cam, my car actually likes things to be a little richer than 14.7 to 1. In other words, my car runs WAY better in open loop (everywhere), things are that close to being right for my combo, and also coolant temps are 20 to 30 degrees cooler when crusing at higher rpms and when pulling mountains while in open loop. It is defintely going into boost at part throttle. When I say lean, the 02 volts drop way low, and at times even a lean misfire even occurs during the lean out range. But like I said, I've gotten the tune down to where this only happens in 1st gear. It's like the map sensor isn't seeing all of the boost pressure unless there is enough of a load on the engine, or air weight related occording to throttle opening position. It's weird! While power braking into boost during this range, and then after I get traction and the throttle is nailed, things are perfect. And if I lay into the throttle hard in first gear during driving, not necessarily WOT, things seem fine. It's just happens at a light throttle opening when the boost comes in. I'm lost!!

ShelGame
09-22-2006, 03:55 PM
Well, for right now anyway, to help narrow down the tune, I'm running my car in open loop.

How? Just unhooking the O2?

glhs875
09-22-2006, 05:56 PM
Yes. by unhooking the 02. Any ideas on what to change on the cal. yet?