Houstonderk

iTrader: (3)

So i got the engine running decent, and just need to work out some accelerating hesitations and was looking at the pump settings. Is the inc increase and sus sustane? Basically its alright easing in the throttle but giving extra gas theres a hesitation all through the rpm range that I cannot get rid of. I only found that the first two are around idle, second two are 1500 to 3000 and the third two are above.

Claudio RX-7

iTrader: (1)

Yes, throttle pumps will fix this. The Increment will add fuel on top of what the maps are doing, the sustain will hold it and slowly withdraw until its back on the maps. This is very vehicle/engine specific, so you will have to play with it untill you get it right.

Here's what i do. Start with the car idling, no movement, as you slowly step on the throttle you see the RPMs come up and its all nice, when you do a sudden blip of the throttle its crap, there's either bogging or stumbling, if there's stumbling, its too rich and you need to revise your fuel maps, if it bogs then its leaning out all of a sudden and you need to add extra fuel to compensate. Please note, that sometimes its just better to add Increase and leave the sustain low, unless you feel that that alone its not working then you raise the sustain to keep the fuel going, but this might also mean you need to still do a little more road tuning to get it nice and good before continuing to tweak the throttle pumps. Also, very important, you MUST HAVE your TPS properly calibrated before playing with the throttle pumps, any recalibration done afterwards may affect throttle pump funcionality.

So, start blipping the throttle and raise the increase and sustain on the 0 and 1500 RPM bars. Then when you clear that up rev the engine to about 1500-2000 rpms, then blip the throttle to take them higher (past 3000) and then raise the 3000rpm bars.

The next step is to go on the road, find a road with NO traffic, since you will be basically stopping short in the middle of the road to get going again, as the car sits there idling with your rpms around 800-1000, put it in first gear and simultaneously let go of the clutch and press the gas at the same time, mind you we dont want to launch the car, we just want to create the same conditions as what i was describing before. Raise the bars to compensate for the bogging if there is any until you get good throttle response and a good sprinting movement of the car.

Next, roll the car to around 30mph hold the rpms at around 1500 in say 1st or 2nd gear, and step on the gas again (this time you wont have to have your foot on the clutch), and raise the bars if there is still some bogging when you do this, and finally, do the same thing, in say 3rd gear at around 40mph holding 3000rpms and mash the throttle again, and tweak as needed.

This is what i do with all the cars i tune and its the best solution to the throttle pumps that i can think off. Hope that helps.