Nistune Forums

Just after some help with diagnosing a problem with my (and many other peoples) R32 GTR.

I have a R33 GTR engine with the R33 GTR ECU. Whats happening in either cold or stinking hot weather, the car goes into some sort of limp/safe mode where it retards timing and reduces the boost. Throttle response is also very poor. If you turn the car off then on again it is fine for a little while till it happens again. In regular 25degC weather it doesn't do it.

I'm thinking its AFMs or knock sensor related. I have resoldered all the dodgy joints in the AFM's twice. The first time it fixed the problem for quite some time, but after the second resoldering, no change.

I have had a pc plugged into the car via the consult port and nothing is out of the ordinary, only a small difference in AFM voltages, nothing alarming. No error codes either.

I'm thinking putting a resistor in where the knock sensors go into the ecu to see if that rules out the knock sensor circuit.

Any other suggestions? Any idea what things can cause the car to go into the mode its in?

Regards

Josh

have a closer look at the AIT or CTS if the MAFS are ok.
Remove clean and reseat the connectors.

see if you can data log the same stretch of road before and after the problem occurs.

Both of those mentioned sensors are brand new. I noticed when unplugged, they caused the car to go into the same mode.

I will log a run tomorrow.

Before disabling knock sensor(s)...have you ruled out it's not caused by actual detonation ?
Does it seem to occur under similar circumstances, eg. when accelerating from lowish rpm under load.

You can try to retard the timing a few degrees (rotate CAS) and see if the problem disappears or becomes less frequent.

Yeah, I'm going to be careful about disabling the knock sensor just in case . I'm not keen on doing it though..

The test would go:

make the fault happen.
Turn car off.
disable knock sensors
turn the car back on and drive (carefully)
see what happens.

Once it goes into the "mode" it gets really sluggish, so I wouldn't need to drive it hard to tell if disabling the knock sensors worked.

Might try retarding the timing first, good idea.

I should mention this seems to be a common problem, there are various threads with people reporting the same problem.