Fuel pressure test

8bit

Active Member
Feb 11, 2010
3,401
3
Aberdeen
I know some cars have a point somewhere on the fuel system you can plumb in a gauge to test fuel pressure. Does the mk1 Leon (specifically the LCR) have one of these?
 

8bit

Active Member
Feb 11, 2010
3,401
3
Aberdeen
Hmm not sure, it would have to be pre-injectors, wouldn't it? Fuel coming back to the tank would be at lower pressure cos some of it would have been consumed by the engine.
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
you dont check fuel pressure by checking the return line :rolleyes:
you check feed line into fuel rail with a pressure gauge T'd in

it should follow boost in pressure terms, starting at its normal 3bar start point.. so 1 bar boost you should see 4 bar fuel pressure

there is no check valve to take this measurement on the 20vt fuel rail on LCR unfortunately








Have you logged lambda correction yet like I previously suggested?
 
Last edited:

8bit

Active Member
Feb 11, 2010
3,401
3
Aberdeen
you dont check fuel pressure by checking the return line :rolleyes:
you check feed line into fuel rail with a pressure gauge T'd in

it should follow boost in pressure terms, starting at its normal 3bar start point.. so 1 bar boost you should see 4 bar fuel pressure

there is no check valve to take this measurement on the 20vt fuel rail on LCR unfortunately

Have you logged lambda correction yet like I previously suggested?

Great, thanks for the info Bill. I haven't had a chance to log it yet, possibility I might manage at the weekend. I'll be sure and post it here if I do.
 

Gulfstream

Active Member
Jul 31, 2010
507
6
I hooked a gauge up on my LCR and showed steady 3.5bars running off boost and 4.5bars+ at 1bar+ boost.

So LCR has a higher oem fuel pressure regulator?
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
normally 3bar like it says on the fpr itself.. unless someone squezed it to get a little more out of it or the gauge is a little off?
 

Gulfstream

Active Member
Jul 31, 2010
507
6
Not sure what it say tbo. Will put on my glasses when I get home again. All I noticed it was solid at 3.5 bars.

Perhaps the gauge is exactly 0.5bar off.... Need to do a test on it.
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
I know a trick used by some is to squaeze the top of an fpr to make it a little higher..

not just me needs glasses to read small stuff now then :D
 

alias

Active Member
May 9, 2011
317
0
Essex
It depends on where you want to measure the pressure at. Assuming pre-injector pressure, you could take it from the FIP outlet onto the fuel rail.

Hydraulic pressure is equal inbetween two points (in and out, if you will) so any point should be fine after FIP and before fuel rail assuming there are no other exits (leak off, return etc.). I'm not savvy with how SEATs are plumbed in so take it with a pinch of salt. It should be fundamentally the same as Fords, which I am familiar with.
 
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