HELP - P0068 at key on.

[oztracktuning]

We are one day away from our LS1 Nationals in Australia and ive had a heap of trouble with my friends VZ LS1 thats just had a M122 Magnacharger style SC fitted. The car is running nicely except for one problem - everytime we turn it off and wait for while then key on - it goes into limp mode and throws the P0068 code.

I have done all the usual things and there are no issues at all under boost and even when the car is turned off and restarted straight away. But if we wait for a while and key on we have a siatutaion where it generates the codes immediately.

The SC system has an aftermarket TB with the inners of a normal style ETC TB (that we had to transfer) along with extending the wiring. The electronics are also on the other side of the TB which means the TB blade opens backwards.

Please help - at the moment the only way the car can be restarted without issue is if at key on the codes are cleared. Then they dont return.

The engine is using the last of the 1MB PCMs custom OS 0414003. It is running in speed density mode with a 2 bar tune.

I have also disabled two other codes from being set but (im not sure if that helps) but they were
P0120 Throttle position sensor 1 circuit
P0220 Throttle position sensor 2 circuit
P1516 TAC Module - Throttle actuator position performance.

The car needs to be driven 9 hrs in 2 days time to a race meet.

regards
Steve

[oztracktuning]

At this stage
C3901 to C3907 havent been changed from stock.

I wonder if this might help?.Im hoping that Disabling the TPS tests might help. I wonder is it because the table C3907 is 2% at 1200rpm and the TP is in zero position at that rpm. The car is trying to idle at about 800-1000rpm.

[ntae]

sounds like the TB stopers needs seting up , is it a TBA unit ?

[oztracktuning]

Its a PWR TB - we already tried shifting the stopper since it tends to try to shut at key on and can jam the butterfly in the TB. But shifting the position didnt help.

[ScarabEpic22]

Dang, sorry man. Ive heard for my 4.2L I6 the 'other' tuning software has a P0068 Rationality Test that allows you to set the rpms at which the code is allowed to run (say rpms have to be more than 800rpm), wonder if there's anything like that in your tune.

[ntae]

shuting on key on is a self test i believe

With a TBA unit it's all about setting up the right readings at the right time

Chipmaster & Power torque have help me out in the past try them


Its a PWR TB - we already tried shifting the stopper since it tends to try to shut at key on and can jam the butterfly in the TB. But shifting the position didnt help.