I have a '93, 98k miles, pfc, dp, custom cold air intake, and pfs intercooler. I am currently running the base maps. Anyway, here is my problem. I hadn't noticed anything abnormal about the car since installing the pfc, I checked the knock ocassionally and it seemed to stay below 50. Two days ago I ran into a guy who lives down the street from me on the highway with his 300zxTT. Anyway, needless to say some spirited driving insued. I smelled a gas type smell at one point during the event but everything seemed normal after stopping and idling. No lingering smell from the engine compartment or exhaust. I checked the knock and it had a reading of 68 which was the highest I had seen. I hadn't been checking it regularly though but I'm pretty sure it hadn't gone this high before. Anyway. The next day when I started the car there was a larger then normal cloud of smoke Then after taking it relatively easy on the drive to work I got a peak knock reading of 98 On the way home I monitored the knock reading real time and realized that it was happening when the second turbo was coming online ~ 4.5k under boost. The excess smoke at startup has subsided now but this high knock reading has me concerned. Could this just be a fouled plug. I realize this complicates things since I'm not 100% positive it wasn't happening before. The car still seems to drive and accelerate fine. I don't here any knocking. I have an appointment to have the pfc dyno tunned May 6th at kdrotary, there was a three month wait or I would have had it done by now. Should I do anything in the meantime besides just take it easy and take a look at the plugs? Thanks in advance for the help, sorry for the length but I wanted to list everything.

 

I forgot to say that the highest reading I saw when monitoring it was 159

 

Is that during transition only or all the time? If it's at transition, go into the fuel map and add lots of fuel in the transition point area, say upwards of 10-12 clicks and you should see lower readings. Bottom line, get to a dyno and test with a wide band. Add fuel everywhere if you're seeing knock at points besides transition. Then again, it could be something totally different but I highly doubt it.

Can't remember his name, but it was the Montego Blue car that ran the one lap last year. At MADS last fall, he was getting the same thing, lots of knock at transition. Amazingly, he knew nothing about the PFC nor how to tune it. He didn't even list his mods to the place he bought it from. So...I went in and dumped in a bunch of fuel at the transition point and viola, no more high knock readings.
Michel
Michel

 

Yeah, the spike does only seem to be occuring at the transition only. I will look into adding more fuel at the transition. I haven't messed around with the maps so hopefully it is easy enough to figure out. If you have any tips I'd appreciate it.

 

Well, transition occurs (depending on settings!) from 4200 to 4500. So start at say 4K at various pressure points from .75kg/cm2 up to whatever you run, say .95kg/cm2 (assuming you're fully modded) and look at the fuel maps on either side that you WON'T be tuning. So...you get to the first cell and say it's 1.22 or whatever...go to the next field and hit next which will allow you to enter the new number by clicking the up/down arrows. Go to a numerically higher number. FYI, I had to take out upwards of 16 clicks in some places to go from a 10.0:1 a/f ratio to 11.0:1 (or something close). It's always safer to add too much fuel than too little, no? So perhaps try going up eight individual clicks for each cell you need to tune and take a test run. If your knock goes down by say 50%, add four more clicks til it gets below a reading of 50. I usually never see anything higher than 20, with an occasional reading in the 30's which is probably caused by something else, not knock. The PFC manual also says that just because a number goes above 60, it's not necessarily knock. Make sure to read the manual too.
Michel