Base Timing And Pfc

[Fry_33]

Hi,

I have just had a PFC installed on my R33 GTST series 2 and had an adjustable ex cam gear put on at the same time (set at 4º retarded). The car seems fine but I was working on the car and noticed the CAS seemed fairly advanced (turned anti clockwise). I checked the timing, after letting the car warm up, and it appears to be set at 25º BTDC. I used a timing light attatched to the white wire loop at the rear of the engine.

Now I don't want to stuff the PFC tune around so I thought I would find out whether I should just leave it or put it back to the standard 15ºBTDC. If I look at the hand controller it shows 15 in the ign map grid it is using.

So I was just after people's thoughts

Thanks

[blind_elk]

The handset shows 15 because that is what the PFC is programmed to run at that particular map point. However, you now need to make the crankshaft also show 15. But you need to be careful, because some timing lights somehow double the reading (so that 15 "real" degrees shows up as 30 on the crank pulley).

[Fry_33]

I ended up taking another reading with the pickup on the fattest of the 3 wires going to coil 1. I couldn't make it out properly as the marks were jumping all over the place. The reading was very clear going off the wire loop? I took a photo so that it would pick it up better than my eyes and appears to be at 15º going by the marks shown in the below pics (4th mark from the right).

This is with the timing light pickup attached to the fattest wire that runs to coil 1.

This is with the timing light pickup attached to the looped wire at the rear of the engine.

My CAS appears to be very advanced as I thought for 15º the bolts should be roughly in the centre of the adjustment holes.

I might put a lead in between the coil and the spark plug tomorrow, pickup off that and see if that cleans up the signal/light pulses.

Thanks for the advice, thanks for the PM grigor

Edited May 6, 2007 by Fry_33

[Kinks]

did you disconnect the bottom plug on your TPS? the timing will jump around a lot if you haven't done this.

25 degrees is a lot, but if your PFC was tuned like that then if you knock 10 degrees of timing out it will run like a dog. i am surprised your tuner didn't realise his ignition advance values were much lower than they should be and check the base timing though.

[Fry_33]

Thanks Kinks, I might have put that tps plug back on between attempts at measuring it.. probably just forgot to take it off again, derr me.

Will check again tomorrow, I'm not stressed about it as the tuner would have picked it up like you say.

[blind_elk]

My CAS appears to be very advanced as I thought for 15º the bolts should be roughly in the centre of the adjustment holes.

But don't forget you've changed the camshaft orientation with the adjustable cam gears, and the CAS drives directly off the camshaft.

[RB30-POWER]

it will be in a different spot because of the cam gear now, rotating the camshaft a few deg.

however, the powerfc and crank should be matched exactly, if it was originally mapped with the crank and powerfc not matched, when you match it back up, you could either advance or retard your entire map.

depends on if you know for fact it was originally tuned with it all sync'd together.