SLIGHT HESITATION

[MANDALAY]

MR2 with a Rotrex SUPERCHARGER.
Its had some serious hours on the dyno .All is good except there is a slight hesitation when pressing on the accelerator.
If i slowly push on the accelerator all is ok when i tap it it feels like it wants to bog down rocks the engine recovers quickly and the revs go up.
This only occurs when the engine has settle down to idle , warmed up ,that is 900 rpm.
When the engine is cold and idling around 1200 for warm up stage tap the accelerator goes up with no shaking.
It feels as if timing isnt right on ? Or the fueling aint right because of the mad rush of air into the engine when the butterfly is opened quickly and the MoTec isnt reacting fast enough
Any comments as its frustrating me , especially when trying to park
oh BTW should point out that i have the M800'

Hate to think it cant be resolved as i spent a lot just to have the MoTec and was told this is one of the major grips with the MoTec as opposed to another ECU ?

[Holmz]

It might need acceleration enrichment, but probably easy to tell with lambda or trial and error (or when no-error then you will have solved it).
Have you tried that?

[MANDALAY]

I have to admit i really dont know much at all about ECU's. I have the M800 , knock sensor, wide band O2 , etc.
First tune , run in the engine.
Wasnt producing the PSI it should , had inlet pipes too small.
Upgraded the inlet and now have full boost 13.9 psi.
Car runs , drives really good only when i blip the throttle its annoying Makes a hard drive.
Will be on the dyno again but posted now as im trying to see if there is something that needs to be looked at that someone has had experienced this.
Also looking for reassurance that it can be fixed as my builder is a Autronic tuner and says this is very common with MoTec as the autronic has better logrythmics ?

All double dutch to me

[yotamhks]

autronic? logrythmics ? well, no.
but, accel enrichment is complecated in Motec in comperation to other ECU's.
so it might be more difficult to a non motec tuner,
but i am sure if you puch him to the edge he will recover and solve your problem, since if he doesn't
you should replace him..

i tuned autronic, motec, haltech, and you can alaways get it to work as you want.

[MANDALAY]

Its something i noticed the following day as i didnt drive the car home it was towed.
So is it just another dyno session to fix it ?
He is a well aclaimed MoTec tuner BTW

[yotamhks]

you might not need a dyno session, this can be done on the floor,
especially saying it happans in neutral.
all is needed is a lambda sensor plugged in.

but all what said and done, you got a tuner, what ever he says it should be performed.
anyway, hesitation on throttle response isn't about the Motec,
it's about the tuner, or mechanical matter (more rare)

[MANDALAY]

Will do.
BTW ive got logging , correct me he can down load that and see whats happening ?
Pardon me i dont know much at all.
Also i have a wide band O2 sensor and also the MDD . Cant i see the lambda ?
At idle i see a figure of around 0.95 and goes up as you accelerate.
Any links where i can get a better understanding would be helpfull.
Many thanks

[Holmz]

Will do.
BTW ive got logging , correct me he can down load that and see whats happening ?
Pardon me i dont know much at all.
Also i have a wide band O2 sensor and also the MDD . Cant i see the lambda ?
At idle i see a figure of around 0.95 and goes up as you accelerate.
Any links where i can get a better understanding would be helpfull.
Many thanks

(Disclaimer) 1st I am no expert in any of this


2nd:
I have seen numbers like 0.95 to 1.0 for cruse values for Lambda.
And WOT numbers like 0.87 for NA, and 0.83-0,85 for forced induction.
If the Lambda is going up under acceleration, then we have solved the causal mechanism that is producing the initial stumble. It should be going down into the 0.9 or less - not up.

[MANDALAY]

Will get back at the tuner hopefully this week.
Also noticed something, unlike a std oem ECU i cant push down on the throttle and hold a certain rpm like 2,500 rpm. As it goes to 2,500 gets there and drops then i have to push more then drops then i have to push more ?

[Holmz]

Will get back at the tuner hopefully this week.
Also noticed something, unlike a std oem ECU i cant push down on the throttle and hold a certain rpm like 2,500 rpm. As it goes to 2,500 gets there and drops then i have to push more then drops then i have to push more ?

Sounds like how my bicycle works.