[s-cars] Found 10 PSI Fuel Pressure and .8 Volts

[Sean Douglas]

Good point Cody, I'm not sure if the injectors running makes a
difference.

It would be interesting if you could do the test using the same
methodology as I did to eliminate the variables.

Cheers.

Sean

> -----Original Message-----
> From: Cody Payne [mailto:cpayne at bconnected.com] 
> Sent: Sunday, November 06, 2005 7:59 PM
> To: Sean Douglas; Dave Forgie; s-car-list at audifans.com
> Subject: RE: [s-cars] Found 10 PSI Fuel Pressure and .8 Volts
> 
> 
> Hey Sean,
> 	Thanks for your data.  
> 
> At idle w/ vac I am at 62 PSI.  Under WOT around 5200 RPM my 
> boost gauge reads around 25 PSI...so I should see 87 PSI on 
> my fuel gauge..but only seeing ~70 PSI now vs. ~60 PSI before 
> the new relay.
> 
> So I am still short ~17 PSI.  So really the difference 
> between my test, is that my injectors are running high duty 
> as well as the loads on the alternator.  I would expect that 
> your expected and actual pressures would be slightly 
> different due to those 2 variables...but I could be wrong?
> 
> Cheers
> 
> cp
> 
> 
> 
> -----Original Message-----
> From: Sean Douglas [mailto:quattro20v at telus.net] 
> Sent: Sunday, November 06, 2005 8:41 PM
> To: Cody Payne; 'Dave Forgie'; s-car-list at audifans.com
> Subject: RE: [s-cars] Found 10 PSI Fuel Pressure and .8 Volts
> 
> Cody:
> 
> When you measured your fuel pressure at WOT, what manifold 
> pressure are you seeing? I only ask because the fuel pressure 
> is dependent on the manifold pressure and is controlled by 
> the fuel pressure regulator.
> 
> I did this last year, but did the test differently. After 
> relaying the fuel pump as per Dave Forgie's instructions, I 
> put a pressure gauge inline on the supply line, manually 
> jumped the fuel pump so it was on (engine off) and 
> disconnected the vacuum / boost line to the fuel pressure 
> regulator and pressurized this with regulated compressed air. 
> Starting at 0 PSI and going up in various steps to 28 PSI, my results
> were:
> 
> 
> 0 PSI, 57 PSI
> 10, 65
> 15, 70
> 20, 75
> 22, 77
> 25, 79
> 28, 83
> 
> By my calculations, I was 4-5% below the target fuel pressure 
> across all values. The voltage at the pump was 12.4 volts, 
> perhaps when the engine is running, the voltage will go up 
> and hence the fuel pressure.
> 
> The reason I did all this testing was because with the RS2 
> mods, I was running lean (pinging) and wanted to see if I had 
> enough fuel pressure. In the end I decided it was a software 
> issue and switched software (to
> Dahlback) and now the pinging is 99% gone.
> 
> Sean Douglas
> 
> > -----Original Message-----
> > From: s-car-list-bounces at audifans.com
> > [mailto:s-car-list-bounces at audifans.com] On Behalf Of Cody Payne
> > Sent: Sunday, November 06, 2005 6:21 PM
> > To: Dave Forgie; s-car-list at audifans.com
> > Subject: Re: [s-cars] Found 10 PSI Fuel Pressure and .8 Volts
> > 
> > 
> > For those who have a fuel pressure gauge on their 
> cars...what sort of
> > pressure have you seen from your stock fuel pump?
> > Can you get 86+ PSI WOT?
> > 
> > Granted the set-up I had today was great as I could drive 
> and view the
> 
> > fuel pressure gauge mounted on the hood.  But on the dyno 
> works great
> > too ;)
> > 
> > My stock fuel pump is about 3 years old.
> > 
> > Thx
> > 
> > cp
> > 
> > -----Original Message-----
> > From: s-car-list-bounces at audifans.com
> > [mailto:s-car-list-bounces at audifans.com] On > Behalf Of Dave Forgie
> > Sent: Sunday, November 06, 2005 7:10 PM
> > To: s-car-list at audifans.com
> > Subject: [s-cars] Found 10 PSI Fuel Pressure and .8 Volts
> > 
> > You're welcome Cody.  But at 70 psi you are still down at 
> least 16 psi
> 
> > from the minimum 86 psi you need at 28 psi relative boost  
> (58 psi (4
> > bar) plus 28 psi boost).  I suspect that your 091G is got a problem
> > -either its weak or its inlet is clogged.
> > 
> > Dave F.
> > 
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