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Discussion Starter · #1 ·
Every since i had my MAP ECU tuned, now and again i had a very slight hesitation in first gear (auto). Its something i never got round to getting sorted.

Yesterday i installed a PI3800 and the hesitation problem is worse. If i stomp on the gas from a stand then as soon as i get to around 2750rpm and get to 0.0bar boost the car hesitates a couple of times and then manages to get past the problem area and boost normally.

This only happens in 1st and i have to be on at least 3/4 throttle for it to happen.

Ive searched the board and tried changing the TPS% values on my MAP-ECU but it has not changed anything.

Anyone know what the problem could be?

PHR stage 1
Stock fuel (upgraded pump and reg)
Stock ECU (MAP-ECU piggy)
AVC-R

My wideband reads major lean at the point of power cut. Only for a split second though as the power comes back on quickly.

Scott
 

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Discussion Starter · #3 ·
I found this on the forum. Can anyone shed any light on this?

Here's something strange... I've got a 3000 stall Level 10 converter (and trans) in my car and noticed when the rpms exceed 2700 (stock stall), below 10mph and above 3.5v throttle angle, my ECM will actually try to bring in the second turbo. This causes the boost to dip a moment and the car will hiccup and drive through it. Kinda crazy. I can design a logic gate to get it to stop because it bugs me when it does it.
 

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Lemme guess. You are using an OBD-II ECU? If I am correct, switch to an OBD-I ECU and your problem will go away. OBD-II ECU's are very very very finicky with MAP ECU, just ask PHR. What exactly is you setup?
 

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Discussion Starter · #5 ·
not sure which ecu im on. My car is a 1995 UK. Id guess its OBDI

Im running a PHR Stage 1 with a MAP ECU.

Scott
 

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i always say toyota !
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sward42 said:
not sure which ecu im on. My car is a 1995 UK. Id guess its OBDI

Im running a PHR Stage 1 with a MAP ECU.

Scott

the label on the hood says if its obd 1 or 2.
 

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Boost4fun
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Have you tried to modify the MAP table around that area. I mean when you are experiencing a lean spot you can try to clear that out by increasing the values in the affected fields of your MAP ECU.
Put the laptop in you car and activate the "follow me" functionality. Then you can easily see in which field you have to do something..
Gerd
 

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Discussion Starter · #9 ·
I had a look at the map on the laptop whilst driving and played with the TPS% figures but with no luck.

Not confident enough to play with the figures in the map. maybe ill take it back to the mapper for this.

I have a feeling that its not the map and its this problem i posted from another member.

Scott
 

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Boost4fun
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Forget about the %TPS thing. This comes only into play when the accelerator is being adjusted fast. If you stay on it continiously it will not affect anything.
Try, as I told you, the "follow me" button on the table page of the soft. Watch for the moment it comes to the lean spot. Maybe there is a wrong value in that affected particular field in the map?! You can see that easily if the figure differs very much from the one before and after... It´should be a continiously increasing value.. You can also see if there is a peak when you go on the visual 3D graph page of the soft...
Give it a try and let me know..
Gerd
 

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Discussion Starter · #13 ·
Dude, you have given me confidence :) , ill give it a go and check the figures.

Hefti2 said:
Forget about the %TPS thing. This comes only into play when the accelerator is being adjusted fast. If you stay on it continiously it will not affect anything.
Try, as I told you, the "follow me" button on the table page of the soft. Watch for the moment it comes to the lean spot. Maybe there is a wrong value in that affected particular field in the map?! You can see that easily if the figure differs very much from the one before and after... It´should be a continiously increasing value.. You can also see if there is a peak when you go on the visual 3D graph page of the soft...
Give it a try and let me know..
Gerd
 

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Boost4fun
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Cool,
just check it or you can shoot me a PM at any time. It is really not hard to understand the map. If you have questions just let me know..
Gerd
 

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sward42 said:
Interesting reading. I had my throttle housing stripped apart and polished some stime ago, could of displaced something i suppose!
If you'd taken of the throttle housing then I'm 99% sure your TPS adjustment is off. Follow the TPS calibration thread and correct it. Then fine tune the lower part of the map and you'll be set.
 
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