Relatively simple Apexi PFC questions
 

I have a MY95 STI RA, hence a MY 93-96 PFC and commander, mapped to 1.4 bar. During the mapping session, it was found that the MY97 MAP sensor I had fitted was not being read correctly by the PFC, since it was expecting to read the different scaled MY95 OE sensor. It was reading under, so we couldn't use the BCS for boost control.

So a Dawes device was used to achieve the 1.4 bar, still using the MY97 MAP sensor. When I'm at 1.4 bar, the PFC thinks its 0.95 bar. Not really a problem, but I hear an under reading MAP is not good for closed loop fueling. Having said that the car has been running fine for a considerable time now.

I have just found the MY95 MAP sensor (which I never knew I had :rolleyes: ) So my questions are:

Can I fit this and still use the Dawes for 1.4 bar, or will something happen when the MAP sensor maxes out at about 1.2 bar?

I know I could get a Apexi 3 bar MAP sensor, but how come that doesn't underread? I take it you plug it into another port on the PFC?

If so, can I plug the MY97 MAP sensor into the 3 bar port on the PFC? could this work? Or is it on yet another scale to the 3 bar sensor?

cheers :)

The MAP sensor has NO effect what so ever on closed loop fuelling.

The scale for the 3 bar Apexi sensor is different to the MY97 one, so it won't work where ever you plug it ;) . The boost control kit plugs into the side of the ECU, next to where the commander goes.

Yes, you can run the OEM MAP sensor and Dawes at 1.4 bar. Just set the commander options as if it were using the optional boost kit and set the boost to say 1.6bar and you shouldn't get any nasty fuel cuts.

Tony.

Did that, it worked but throws a constant CEL and of course the boost monitor maxes out at 1.23 kgcm2. So pretty pointless really.

Back to the MY97 sensor untill i get that ACVR I suppose.

I thought the fuelling issue closed loop is that if it thinks there is less boost then there is less fuel enrichment at mild levels of boost just before the crossover to open loop. But I may be talking rubbish :D

If it throws a constant CEL sounds like you have the boost control option the wrong way round. Whatever you have it selected at when it throws the CEL try the other one ;)

Yes, you are talking rubbish :D. Fueling is controlled by either the MAF or TPS (for enrichment). There is an option to choose the crossover point if you have datalogit. This is the number in the fuel map which causes the switch, so say the option is set at 1.037 then any fuel map points below this value will be closed loop, anything above open loop. MAP has NOTHING to do with it.

Tony.