Fuel Pressure issue at WOT
11-26-2012, 05:25 PM
#1
Fuel Pressure issue at WOT
Quick update, car is having issues around the 7300 rpm mark with fuel pressure, at 6000 rpm the FP starts to Bounce, the AFR continues to drop to about 12.6 at 7300rpm...We added a bunch of fuel up top and still going lean at that RPM and higher. Trying to get it figured out and back in line as it is leaving a bunch of power still on the table.
Best i can get out of it so far is 372 whp/ 290wtq @ 7250. Ill try a couple pulls up to 8000rpm but im worried about it leaning out even further.
Girlded ZZP Block, Diamond Pistons, ARP, Ported head, 82# valvesprings, TVS with 2.7
Car runs E85 all the time, it has Deatchwerks DW350 Fuel pump, OTTP RSFS and Siemens 80# injectors. Injector duty is only 53% when this occurs.
unrelated: my boost gauge stays pegged and will intermittanly quit working. im going to need a mechanical one. HPT shows 23psi of boost and climbing.
i still need to get my roll cage installed and fix a rattle in the exhaust, but one thing at a time.
Best i can get out of it so far is 372 whp/ 290wtq @ 7250. Ill try a couple pulls up to 8000rpm but im worried about it leaning out even further.
Girlded ZZP Block, Diamond Pistons, ARP, Ported head, 82# valvesprings, TVS with 2.7
Car runs E85 all the time, it has Deatchwerks DW350 Fuel pump, OTTP RSFS and Siemens 80# injectors. Injector duty is only 53% when this occurs.
unrelated: my boost gauge stays pegged and will intermittanly quit working. im going to need a mechanical one. HPT shows 23psi of boost and climbing.
i still need to get my roll cage installed and fix a rattle in the exhaust, but one thing at a time.
11-27-2012, 01:59 AM
#8
What is your base pressure set to? And is it rising correctly and steadily until it starts to bobble? Then does pressure flatline or begin to fall after that?
Either way good numbers so far, and it makes me excited because I have pretty much all the same stuff besides the built motor and ATI, but power wise its pretty much the sanme with the S2 cams going in soon
Either way good numbers so far, and it makes me excited because I have pretty much all the same stuff besides the built motor and ATI, but power wise its pretty much the sanme with the S2 cams going in soon
11-27-2012, 09:16 AM
#10
i just thought of this
the guy that ported your head runs e with his tvs and on a 2.8 80lb inj and at 7000 his idc is 110% i dont think that a rsfs will cut the idc in half (considering you are on a smaller pully also 2.6) your problem could be the injectors are going static causing the fuel pressure to drop off and and bounce around it may be time for some 1000s
the guy that ported your head runs e with his tvs and on a 2.8 80lb inj and at 7000 his idc is 110% i dont think that a rsfs will cut the idc in half (considering you are on a smaller pully also 2.6) your problem could be the injectors are going static causing the fuel pressure to drop off and and bounce around it may be time for some 1000s
11-27-2012, 12:00 PM
#11
Mr belvedere is probably right. The tuner probably didn't delete bank 2 so the idc's are averaged between the the bank you have and the missing one cutting your idc's in half.
Funny thing is there are many people running 42's that are over 100 with seemingly no problems. Don't know if they would show the same thing with a fuel gauge hooked up, if the 80's just go static easier or you have reached the limit of your pump.
Bad venting could also be the cause. If you are pulling fuel out of the tank faster than it is venting you will create a vacuum in the tank that will lower the amount of fuel the pump can put out. Easy to check just try a run with the cap off.
Last idea to throw out there. Not as likely but might be worth investigating since the tank is easy to drop. Restricted filter on pump intake could cause pump to cavitate when you pumping high volumes. Pump could be pumping much less than it's rated capacity due to such a restriction.
Funny thing is there are many people running 42's that are over 100 with seemingly no problems. Don't know if they would show the same thing with a fuel gauge hooked up, if the 80's just go static easier or you have reached the limit of your pump.
Bad venting could also be the cause. If you are pulling fuel out of the tank faster than it is venting you will create a vacuum in the tank that will lower the amount of fuel the pump can put out. Easy to check just try a run with the cap off.
Last idea to throw out there. Not as likely but might be worth investigating since the tank is easy to drop. Restricted filter on pump intake could cause pump to cavitate when you pumping high volumes. Pump could be pumping much less than it's rated capacity due to such a restriction.
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