Tue Mar 06, 2018 7:47 am |
Post subject: Impreza Fuel pressure |
Wull user

Joined: 19 Jul 2013 Posts: 273 Location: Killin
|
|
|
|
What should the fuel pressure be @ idle?
Car has 850cc injectors, afpr and as far as I'm aware....std fuel pump.
I'm not sure whether it should be different to a std car or not or what it should be, car was running perfect afr before making 11-12 on full chat but it's now doing 13's and I'm trying to suss out why the sudden change in afr as nothing has been touched.
O2 sensor was changed before the last mapping session but during that session the afr's were bang on, was consistently in the 11's to the redline.
Any ideas?
 _________________ ND spec'd Evo 8
Impreza bug sti track car
Wagon SL ppp |
|
Back to top |
|
Tue Mar 06, 2018 8:25 am |
Post subject: |
AK Site Admin

Joined: 27 Nov 2006 Posts: 19841 Location: Aberdeen
|
|
|
|
Can a standard pump do much more than that power?!
Base fuel pressure is normally 3bar _________________ Impreza Race Car - SLS/SMRC
Mini Race Car - SMRC
911 - 1981 Air Cooled 3.0
500 - 1969 Fiat 500 L
Toureg 262 RLine
Track Scotland |
|
Back to top |
|
Tue Mar 06, 2018 8:35 am |
Post subject: |
Wull user

Joined: 19 Jul 2013 Posts: 273 Location: Killin
|
|
|
|
AK wrote: | Can a standard pump do much more than that power?!
Base fuel pressure is normally 3bar |
That makes sense, my boost gauge shows -0.8 bar ish @ idle and my fuel pressure is @ 2.2 bar at this point.
Everyone is saying 3 bar set with vac line removed.
I’ll check it at some point today but it looks likely that the fpr is fine and the issue could be elsewhere, but I wonder if under load what is happening with the fuel pressure. It goes up when I touch the throttle body but I can’t simulate full chat or full boost. _________________ ND spec'd Evo 8
Impreza bug sti track car
Wagon SL ppp |
|
Back to top |
|
Wed Mar 07, 2018 7:03 am |
Post subject: |
Vroomtshh user
Joined: 23 Apr 2014 Posts: 162
|
|
|
|
If its the original fuel pump, theres a good chance it can't cope at full boost. It'll need to pump another couple of bar at that point and might just not be up to it. Ideally needs fuel pressure checking to see that it follows boost |
|
Back to top |
|
Wed Mar 07, 2018 8:47 pm |
Post subject: |
stuartjdm user
Joined: 06 Sep 2011 Posts: 207
|
|
|
|
the std pump wont cope id say i replaced mine before i got it mapped. _________________ Hawkeye STI |
|
Back to top |
|
Wed Mar 07, 2018 10:48 pm |
Post subject: |
Wull user

Joined: 19 Jul 2013 Posts: 273 Location: Killin
|
|
|
|
Some good points there.......
It did actually cross my mind but I thought I had seen that the std pump could do 400bhp.
I removed the vac line and it went to 3.2 bar.
I attached a line from the spare wheel which I set @ 1 bar and the gauge went to 4.2 bar so it appears that the fpr is working.
So fuel pump, fuel filter...... _________________ ND spec'd Evo 8
Impreza bug sti track car
Wagon SL ppp |
|
Back to top |
|
Fri Mar 09, 2018 5:25 pm |
Post subject: |
stuartjdm user
Joined: 06 Sep 2011 Posts: 207
|
|
|
|
My filter is on the end of the pump in the tank and was a bit of c*ck to do  _________________ Hawkeye STI |
|
Back to top |
|
View previous topic
View next topic
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
TrackScotlandv1.0 Theme created by TrackScotland
|
|