R33 Gts-t Running Rough

[fEkuaR]

Hey Guys,

Have been having some problems with my car lately.

Relevant Modifications include;

Powerfc, Turbo back exhaust, split dump, hiflow turbo, front mount intercooler.

Normally when i start the car and its on idle the knock sits on 1. However lately its been intermittently on idle jumping all over the place up to 8 on the hand controller. Normally when doing this if i raise the revs up and hold in nutural at around 1500revs, the knock then stops and it sits on 1 and doesnt move. However when i did this yesterday the engine started surging at idle. When i looked at the handcontroller the timing displayed was jumping between 17 and 0 and the engine sounded like it was wanting to stall. Also whenever i have given the car any stick now the engine is knocking in the midrange even when it's running smooth. Highest reading ive seen is 61 knock in first gear. Normally it doesnt go anywhere near this.

Sorry about the big post but im not sure where to start looking to fix this problem. And im sick of babying the car around in fear of high knock. Im wondering if perhaps its the CAS but im not sure. Has anyone experienced a similiar issue to this?

Thanks for any help its appreciated,

Dan

[paulr33]

it would be looking at the afm. check the plug. check it works. try swapping with a known working afm.

even if the afm cuts signal ign shouldnt drop to 0. if you can replicate it watch ETC, SENSOR SW CHECK and look for any sensors that get highlighted in black.

if they do, it means the sensor is dead/broken/out of range etc. also knockign at idle is no problem as long as its low (under 10) it might not even be knocking.

i dont think its even possible to knock at idle

[fEkuaR]

It might not being knocking at idle. But i do think that its running rough enough for it to register noise. I think that this issue is magnified under load and is why im getting high knock readings. Do you think that a bad airflow meter would cause knock even if the engine is reving and behaving seemingly normal underload?

Thanks for the reply Paul appreciate it

[paulr33]

no i wouldnt expect so

it would cerainly cause the load to go spastic on map tracer however

the engine check liight should come on if the afm complettely fails too

[fEkuaR]

Is there a particular sensor that could be intermittently failing that has a degree of control of ignition that could be causing this problem? Other then the crank angle sensor of course.

[paulr33]

cas or TPS

[fEkuaR]

Noticed today at idle when it started to play up that the ignition was jumping around between 11- 15. So i am thinking airflow meter. I will try cleaning it this weekend and my tps and see how i go. Thanks again paul.

[paulr33]

when u see this problem sensor sw check or monitor, airflow and see if its bouncing

[fEkuaR]

Just to give an answer to this thread in case it ever comes up in someones searches. I changed my Crank Angle Sensor on the weekend. The highest knock level i have seen since saturday is 12.