fuel pressure questions

[lnewton1974]

I am planning on installing an afpr this weekend and was trying to figure out how much fuel pressure and where should i adjust it to run? Thanks for the help

 

[907dsm]

From my understandings for a 2g it's 43.5 psi.. and 1g's it's 37.5.

 

[Gstclipse69]

^^This is correct. Remember to set the base fuel pressure with the vacuum line disconnected.

 

[9!'clipseDOHC]

1G MT = 37psi
1G A/T = 43psi
1G NT = 48psi
All 2G cars are 43psi.

These are all with the vacuum line removed and plugged.

Check out this thread for more info: http://www.dsmtuners.com/forums/newbie-forum/359811-1g-base-fuel-pressure.html

 

[lnewton1974]

Thanks guys iwould never have known to adjust with the vacumn line unhooked. And i was not sure about the pressure setting. Im so glad to have a resource like everybody here to fall back on for help. Thanks for everything

 

[nwbDSM]

1G MT = 37psi
1G A/T = 43psi
1G NT = 48psi
All 2G cars are 43psi.

These are all with the vacuum line removed and plugged.

Check out this thread for more info: http://www.dsmtuners.com/forums/newbie-forum/359811-1g-base-fuel-pressure.html

Ok, thank you for the info. My question is I have 2G body with 6 bolt swapped. Does this mean that I still need to set fuel pressure to 1G base setting (MT 37psi)? I just wasn't sure if I should go with the body or the motor.

 

[donniekak]

Ok, thank you for the info. My question is I have 2G body with 6 bolt swapped. Does this mean that I still need to set fuel pressure to 1G base setting (MT 37psi)? I just wasn't sure if I should go with the body or the motor.

Neither. Go with what the ecu was setup for.

 

[nwbDSM]

Neither. Go with what the ecu was setup for.

I'm sorry, but how to check it. I have dsmlink v 2.5. Or do you mean that if it's 2g ecu, I should go with 42.6, correct.

 

[9!'clipseDOHC]

Go with 43.5 but make sure you input the proper settings in ECMlink so your globals are correct.

 

[chenk18]

Is the vacuum line on the afpr? And does it matter where the guage is, like does it need to be with the afpr or can it be about a foot and a half before the fuel rail? Btw my afpr is an older one and goes on the end of the fuel rail if it helps any.

 

[9!'clipseDOHC]

Is the vacuum line on the afpr? And does it matter where the guage is, like does it need to be with the afpr or can it be about a foot and a half before the fuel rail? Btw my afpr is an older one and goes on the end of the fuel rail if it helps any.

When measuring the base idle it is always with the vacuum line removed and plugged (You can just cap it with your thumb). It doesn't matter if the gauge is before the AFPR as the rail and feed line are both pressurized. My gauge is between the fuel filter and the rail.

 

[gyd23]

so your global on DSMLink is supposed to match the fuel on your FPR?
i have a 2G ecu but my global fuel is at 39.5 and the FPR is set at 45.

 

[Jon91TSi]

Yessir, otherwise your tune will be off based on your global fuel settings.

 

[gyd23]

Yessir, otherwise your tune will be off based on your global fuel settings.

oh, well crap.
i paid $700 for a dyno tune a couple weeks ago and all i've found myself doing is constantly going over things he changed and even some things he didn't even bother touching, such as the global fuel.
so much for a $700 tune

would these settings cause me to have an erratic idle? (such as an idle surge or even it never staying constant in one spot?)

 

[Jon91TSi]

oh, well crap.
i paid $700 for a dyno tune a couple weeks ago and all i've found myself doing is constantly going over things he changed and even some things he didn't even bother touching, such as the global fuel.
so much for a $700 tune

would these settings cause me to have an erratic idle? (such as an idle surge or even it never staying constant in one spot?)

One of the very first things you change is your global fuel settings to match your injectors and base fuel pressure, not sure why that was overlooked... I would find someone else who is more competent to tune your car... I wouldn't think being off being off a few psi on global from actual would cause those symptoms, but each car is different. I would follow the video how-to's on ecmtuning's website, or contact Tom for help to get your base fuel settings dialed in. You need to have that nailed down properly first, otherwise everything you do beyond that was a total waste...

 

[9!'clipseDOHC]

The Global Fuel takes into account the base fuel pressure, the injectors size, and the stoichiometric ratio. Global fuel shouldn't equal the base pressure.

 

[gofer]

gyd23 start a new thread and attach a log of your car idling completely warmed up (180*+ coolant temp) for at least 3 minutes. I'd like to see what the "tuner" did for $700 on a dyno...

If you've got a 2g (which you do gyd23) fuel pressure needs set to 43.5psi base, which is while the cars idling and the vacuum line removed and plugged. Fuel injector globals are mainly based on their size compared to stock, which are 450cc injectors. You've got 850's you take (450 / 850) - 1 to get your new injector globals, which after doing the math you'd find they would be -47%. The tuner that dyno'd your car might have noticed them flowing like a smaller injector (like a 750) which is why he set your globals to -39%.

 

[9!'clipseDOHC]

gyd23 start a new thread and attach a log of your car idling completely warmed up (180*+ coolant temp) for at least 3 minutes. I'd like to see what the "tuner" did for $700 on a dyno...

If you've got a 2g (which you do gyd23) fuel pressure needs set to 43.5psi base, which is while the cars idling and the vacuum line removed and plugged. Fuel injector globals are mainly based on their size compared to stock, which are 450cc injectors. You've got 850's you take (450 / 850) - 1 to get your new injector globals, which after doing the math you'd find they would be -47%. The tuner that dyno'd your car might have noticed them flowing like a smaller injector (like a 750) which is why he set your globals to -39%.

You mean like my issue

 

[gyd23]

alright Gofer will do once i get my car out to the base im currently located in..
i would upload the log he used when he tuned the car but he didn't save any logs neither did i before i left home. i do however have the tune saved on my computer.
but none the less in the next week or two when i get the car out here i'll do a log of it idling for you all to look at.

 

[chenk18]

When you do pull the vacuum line off of the afpr and plug it, should there be a dfference in pressure before and after you pull the hose?

And should it be in park or drive, I have an auto?

 

[TSiAWD666]

When you do pull the vacuum line off of the afpr and plug it, should there be a dfference in pressure before and after you pull the hose?

And should it be in park or drive, I have an auto?

If the car is idling, yes, it will be lower with the line on because your engine is in vacuum and so pulling on the fpr resulting in lower fuel pressure. When you pull the line it's returned to atmospheric pressure, and so the fuel pressure will go up slightly.

Park/drive, doesn't matter. You just need to be idling.

 

[9!'clipseDOHC]

And should it be in park or drive, I have an auto?

Park/drive, doesn't matter. You just need to be idling.

Park or neutral. If it's in drive then it's not idling.

 

[TSiAWD666]

Park or neutral. If it's in drive then it's not idling.

Eh, even if the brake is on? That's how I imagined him accomplishing being in drive. I haven't had an auto for 10 years now but I thought they idled when standing still.

 

[9!'clipseDOHC]

Eh, even if the brake is on? That's how I imagined him accomplishing being in drive. I haven't had an auto for 10 years now but I thought they idled when standing still.

Being in drive with the brake on isn't base idle. To set anything at base idle, the engine should be warmed up, all accessories should be turned off, the steering wheel should be in a neutral position, and the transmission should be in neutral.

 

[chenk18]

I just want to say thanks for the help. I adjusted it, but it didn't adjust near enough, so I guess I have a bigger problem than an adjustment.