Hello Guys

I got an MY2002 with J`racing Header, No cat and Mugen exhaust. I am running a basic Comptech SC kit, used. The fuel pressure was set to 67 psi according to Comptech instructions.


After installing the kit we did some run in the highways and before VTEC the A/F ratio was 11-12:1 once the engine enters the VTEC area the A/F ratio jumps to 14:1. A/F til 9000 rpm. A/F ratio has been measured unsing a plx wideband sensor attached to the header.

I am thinking to swap my ECU for a MY2001 to see if performs better rathewr than increase the fuel pressure. The othe rconcern that I have is the fuel pump, I bought it in Octuber in Ebay, new. and recently some owners has problems with the fuel pump because they were bad... how can I check if the fuel pump is the problem? before buying a new one?


Thanks


J

 

The pump may still be good. one of our members just got his tuned this weekend with a new pump and he was rich down low and lean up top. you wont be good all the way through without some kind of fuel managment, be it EMS or piggy back. you will also run lean because of your header, no cat and exhaust. with those mods it is most likely that you will need something to adjust your AF. if your at 14 at 9k your pump sounds to be fine, but if you are still concerned try to see if there are any shops around you where they can test it. I'm not to sure if there is a way to do it your self.

 

drk

I understand that the header and test pipe would lean the mixture, but it is only 5.5 psi, the FPR should be able to deal with it

what make me think about the fuel pump is the jump from 12:1 before 6000 rpm and when the VTEC kicks in it jumps to 14:1, there isn't a gradual change.

 

Same problem I'm having with my MY05 with same kit plus aftercooler. Similar mods too.

I've got a Emanage on loan coming in a few days, if not its going to be an AEM....

 

ussually A/C kits runs a bit lean but mine should not.

I increased the fuel pressure up to 75 psi and no change

 

Mine went up too 80psi to get it down to where it is now.....

 

i dont have a gauge to tell fuel pressure, but i turned the fpr clockwise and the APR's went down to about 12.5-13. I want it richer, but am still troubleshooting other issues (ticking from engine at idle). i get the same thing with my car... its really rich down low then goes up when vtec hits... as soon as i get the AF's to where i want up top, i'll just remove fuel downlow with my Vafc

 

Here is my take on the fuel pump problem:

The problem with the fuel pumps is related to maintaining high pressure with high flow. With an aftermarket EMS you can keep the pressure at a reasonable 50 or so psi and pump plenty of fuel by adjusting the injector pulse. Pushing the fuel pump to make high psi will expose the problem at high flow.

 

^^^thanks side. I choose the simplest SC kit to aviod this problem and the electronics, no experts here, but seems that I will end with a emange and learn to tune myself

 

^ The problem with the comptech kit is it works great if you keep things standard. But once you start freeing up the flow, it starts getting harder to keep safe af's as there's only so much you can get by increasing fuel pressure alone. There's a pretty steep curve of dimishing returns for increasing fuel supply via fuel pressure - as in it's not linear.

75-80 psi sounds way too high for static fuel pressure, you'd be pushing well above 100 psi through boost! I'm not an expert by all means but IMHO I'd rather stick the cat back or go with some sort of fuel management rather than run those figures.