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throttle body closing while wot

Posted: Mon Mar 09, 2015 7:10 am
by beq696
hi guys, im having this problem with one of my customer's car.
It"s a fd2r with forged internals, cams and afew plug and play mod ie headers, air filter and exhaust.
The car was dynoed afew year ago without any problem and the rev cut was set to 9500rpm.
After afew years of usage then the problem suddenly appear.
The car drives fine on the road but it just wont rev pass 9000rpm anymore.
It will throw codes and the car will stall with no response to the throttle pedal.
i've done everything i could think of that is related to the problem but still the problem persists.
things ive done :
1) changed the throttle body.
2) changed the throttle pedal unit
3) changed the alternator ( been reading that this problem is due to low voltage)
4) add more grounding
5) changed the ecu and different flashpro unit
6) check and recheck the wiring

ive attached a datalog file to explain the situation.
any kind of help would be appreciated.
many thanks in advance

Re: throttle body closing while wot

Posted: Mon Mar 09, 2015 1:02 pm
by Spunkster
Post the calibration used when the datalog was made.

Re: throttle body closing while wot

Posted: Tue Mar 10, 2015 1:50 am
by beq696
here it is

Re: throttle body closing while wot

Posted: Tue Mar 10, 2015 11:50 am
by Spunkster
Is this a stock Wiring harness in the car?

Can you post a picture of the Engine bay?

IS this an OEM throttle body, or has it been modified or is it from a different vehicle?

Re: throttle body closing while wot

Posted: Tue Mar 10, 2015 2:36 pm
by beq696
stock wiring,
stock tb,
ill take some pictures tomorrow,
just dynoed the car just now after changing to yet another throttle body and another alternator.
1st few runs the car still goes to limp mode when hitting around 8500rpm.
so i just tried clamping a jumper cable from engine ( ground terminal near the intake ) to the throttle body and another from battery to the engine.
surprisingly it rev past 9000 all the way to the rev limit.
datalog showed there are still glitches in the throttle body opening angle but it didnt go to limp mode.
after afew more runs have concluded it could be grounding issues.
untied the car from the dyno, made afew large grounding cable to the said locations.
i drove the car back today and thought id give it a go at the free way but sadly after afew pulls it happens again.
cel light on, no throttle. :(

Re: throttle body closing while wot

Posted: Thu Mar 12, 2015 12:29 pm
by beq696
Hi Spunkster,
Any idea what could be wrong?

Re: throttle body closing while wot

Posted: Thu Mar 12, 2015 2:17 pm
by Spunkster
You still have not posted pictures of the engine bay

Re: throttle body closing while wot

Posted: Fri Mar 13, 2015 3:47 am
by beq696
sorry i forgot
here it is

Re: throttle body closing while wot

Posted: Fri Mar 13, 2015 4:19 am
by beq696
closer look

Re: throttle body closing while wot

Posted: Fri Mar 13, 2015 9:23 am
by Spunkster
I would get a factory service manual and verify all the factory ground locations and make sure they are all secure. Additinoal grounds are not recommended.

The only difference is that you may want to connect the main ground which is part of the injector harness to the stud on the valve cover.