Fuel Pressure
 

Idle with FPR connected 50lbs
Idle with FPR disconnected....60lbs

Free Rev with FPR connected drops to 40lbs

Free Rev with FPR disconencted 60lbs


Does the lack of load account for the drop?

Re: Fuel Pressure
 

The idea of an FPR in PFI is to maintain the same fuel
flow across all MAP levels.

Re: Fuel Pressure
 

So faulty FPR? I would think if it were the pump, it would drop when the FPR was disconnected, same for the filter being clogged...

Re: Fuel Pressure
 

These numbers look great to me.
From memory mine were 49 and 55

Really ? 40?
Mine hits 44 but sometimes 43.

Re: Fuel Pressure
 

Hi Lee,

Yes, faulty fuel pressure regulator.

On an LT5 the fuel pressure should be 3 Bar or 43 psi at idle with the manifold vacuum on the regulator.

With the vacuum hose off or at WOT the fuel pressure should be 51 PSI +/- 1 psi.

In the range of 45 to 55 psi each psi of pressure changes the AFR about .1. At 60 PSI at WOT you could be running an AFR point rich.

Re: Fuel Pressure
 

Ray Bohacz says that port fuel injection has capability of 'Acceleration Enrichment', and 'DE-celeration enLEANment' (the dashpot, in the carb), and how to check it, as Marc is saying here (5th page, 1st column, in PURPLE) :

(and when you know it all, like most gurus here, sometimes the simple stuff gets right by you)

(every time I read this article, something in it comes to me, that I didn't get before)

(and never mind my notes, just ideas I had as I read and re-read)

http://www.thirdgen.org/techboard/at...l-tpi-tpi1.jpg

http://www.thirdgen.org/techboard/at...l-tpi-tpi2.jpg

http://www.thirdgen.org/techboard/at...ensor-tpi3.jpg

Re: Fuel Pressure
 

(5th page, 1st column, in PURPLE)

http://www.thirdgen.org/techboard/at...l-tpi-tpi4.jpg

http://www.zr1.net/forum/attachment....1&d=1379194846

Re: Fuel Pressure
 

and the last 2 pages

http://www.thirdgen.org/techboard/at...l-tpi-tpi6.jpg

http://www.thirdgen.org/techboard/at...l-tpi-tpi7.jpg

Re: Fuel Pressure
 

AE is a pumpshot in carb terms. DE is not to be confused w DFCO
cuts off fuel not reduces it.

Re: Fuel Pressure
 

At 51psi, 22.7# injectors will flow as 24.7#, at 60psi, they flow like 27#. So at least 10% richer all around. Your going from a hypothetical 12.8 to an 11.6AFR at WOT.