Ford Mustang Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter #1
I've just gotten an brand new electrical fuel pressure gauge installed (the sender is mounted where the schrader valve used to be located, on fuel rail). Upon startup the gauge read 18psi and would bump up to about 24psi under throttle.

I'm assuming this is a bit low for EFI. :)

So, I've moved adjusted my Kirban FPR a bit so that at idle I'm at 26psi and under throttle, it's about 35psi. Am I still too low for this type of setup? Keep in mind I don't remove any vacume hoses or do any other mods while attempting to get a reading.

Bob.
302 CID, E-cam, TFS TW heads, etc.
http://www.hotrodder.com/bhoffman67
 

·
Registered
Joined
·
655 Posts
Remove your FPR vacuum line with the car on and then check your FP. Then see what its showing, If I was you I wouldn't go anywhere lower than 35 psi. (vac off)
 

·
Registered
Joined
·
19 Posts
Discussion Starter #3
Without changing the AFPR setting and simply disconnecting the vacume hose, my idle psi jumped up from 18 to right about 36 psi.

Granted this is with (likely) a stock 88lph in-tank pump. I've got a Walbro 190lph replacement sitting on the shelf waiting for an empty tank before I drop it (the tank).
 

·
Registered
Joined
·
522 Posts
in the directions for the kirban fp regulator it explains how to set the psi. You disconnect the vacuum line and set the psi to 43. Reconnect the line and you will probably be around 34psi at idle.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #5
Interesting... it says to just set it at 43psi without taking into concideration compression, injector size, timing, etc.?
 

·
Registered
Joined
·
92 Posts
I still can not find a good setting for my fuel pressure...i see some people say to lower it to 36 and others say to raise it.....seems like on some days it runs better when it is higher around 45 - 46 and others around 38 - 40.....
 

·
Registered
Joined
·
522 Posts
Well im guessing that if you still had the stock fp reg on there and pulled the vacuum line--you would see 43 psi. I am not really sure though. My car is blown and definitely likes the extra fuel. I believe my original fp reg was weak because I never saw the fp get anywhere near 40 under boost!!!! No wonder I was pingin--bare with me here this is my first blower car. I knew the fmu was supposed to boost the fp but I thought something was wrong. So anyway--even when not under boost--if I just run her up slow the fp will rise to nearly 42-then if I hammer it I will see nearly 62. Runs way better--thinkin I gained like 20 hp by doing this. A stock car is supposed to run better if you run it a little leaner than factory so give that a try. You actually want to run a car as lean as is safe--most power that way. Some setups will run better with more fuel---as mine does at about 45 with line off--some will run better a little leaner. To the guy that seems he is running better one day than the other. I think all of us with a quick car experience that. However--i dont go and change anything if it feels slower one day. Cause Ill wake up the next day and it will feel quiker for some reason. wowowo sorry I just rambled huh:eek:
 
1 - 7 of 7 Posts
Top