Running Lean at Low RPM Load
Discussion
The car is a Toyota Starlet Glanza V.
I have a wideband and can see that when i pull away from a standstill, if i give the car alot of throttle, it will go full lean and bog down. The only way i can pull away is if i feather the throttle up till around 4000rpm, at which point the car goes fine.
So far ive tried, with no effect, a new TPS, o2 sensor, and FPR.
Cheers
I have a wideband and can see that when i pull away from a standstill, if i give the car alot of throttle, it will go full lean and bog down. The only way i can pull away is if i feather the throttle up till around 4000rpm, at which point the car goes fine.
So far ive tried, with no effect, a new TPS, o2 sensor, and FPR.
Cheers
Pasteurised said:
The car is a Toyota Starlet Glanza V.
I have a wideband and can see that when i pull away from a standstill, if i give the car alot of throttle, it will go full lean and bog down. The only way i can pull away is if i feather the throttle up till around 4000rpm, at which point the car goes fine.
So far ive tried, with no effect, a new TPS, o2 sensor, and FPR.
Cheers
Rather than changing parts at random...how about testing ?I have a wideband and can see that when i pull away from a standstill, if i give the car alot of throttle, it will go full lean and bog down. The only way i can pull away is if i feather the throttle up till around 4000rpm, at which point the car goes fine.
So far ive tried, with no effect, a new TPS, o2 sensor, and FPR.
Cheers
Does the TPS work properly ? ( measured both at sensor and ecu ) Is fuel pressure normal and doing what's expected in line with intake pressure ?
Is there a map sensor, and if fitted dos it work properly ?
Try the following test:
1) stick car in 3rd at say 2500rpm (whatever road speed that equates to)
2) Using your left foot on the brake (to keep the road / engine speed constant) slowly, over say 5-10 sec, tip in (open throttle) progressively until you reach WOT (try to keep a constant road speed by applying more brake pressure simultaneously.
See what the AFR does when you do that, then:
3) apply more brake pressure once at WOT to drag the speed down, until say the rpm gets down to approx 1000rpm.
See what the effect of that is.
(by doing these things at a fixed throttle opening (and you can do it at less than WOT if you have a steady foot too!) you are taking away any transient effects. This will tell you if your "base fuelling" is correct as a starter.
1) stick car in 3rd at say 2500rpm (whatever road speed that equates to)
2) Using your left foot on the brake (to keep the road / engine speed constant) slowly, over say 5-10 sec, tip in (open throttle) progressively until you reach WOT (try to keep a constant road speed by applying more brake pressure simultaneously.
See what the AFR does when you do that, then:
3) apply more brake pressure once at WOT to drag the speed down, until say the rpm gets down to approx 1000rpm.
See what the effect of that is.
(by doing these things at a fixed throttle opening (and you can do it at less than WOT if you have a steady foot too!) you are taking away any transient effects. This will tell you if your "base fuelling" is correct as a starter.
Your transient fuelling is all a-cock then!
You need to add more fuel to the injection events after a sizeable tip-in (to replace the volume of fuel that is "lost" to the puddle mass in the intake system as the pressure rises)
If you're on an aftermarket ecu, this should be an easy cal change.
if you're on a std ecu it perhaps suggests your throttle position sensor is either broken or badly adjusted.
You need to add more fuel to the injection events after a sizeable tip-in (to replace the volume of fuel that is "lost" to the puddle mass in the intake system as the pressure rises)
If you're on an aftermarket ecu, this should be an easy cal change.
if you're on a std ecu it perhaps suggests your throttle position sensor is either broken or badly adjusted.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff