fuel pressure Q's

[typhoonscuba]

ok i did search for the correct fuel pressure to set and i just wanted to make sure i was right. vaccum hose off and the truck started fuel pressure should be set at 40 PSI. does it matter if you have any mods on the truck? my typhoon has a crane cam, a 20g turbo. my buddys syclone that im trying to get running better has a stock engine with a 850 cfm turbo, air to air intercooler. i didnt know if i should bump up the fuel pressure because your trucks have bigger turbos or not? thanks in advance

 

[bigtime]

Re: fuel pressure Q's

You can't just throw fuel pressure at it. Do you have any type of data logger? You can get close by reading O2 voltage. you really need to pay attention as not enough will burn a hole...quick!

 

[SeattleSy#1255]

Re: fuel pressure Q's

you have not mentioned anything about what chip(s) are being used.

 

[typhoonscuba]

Re: fuel pressure Q's

my typhoon has a burned two bar chip but i dont really know whats on it. the last owner told me if i wanted to run more boost i would need a different chip and a 3 bar map sensor. the syclone i'm not sure if it even has a chip. no i dont have datamaster or any scan tools. thats my next thing im buying.

 

[SeattleSy#1255]

Re: fuel pressure Q's

well that syclone won't run without a chip.

probably the best thing to do is go back to stock on both of them and start there. could be the source of both them running like poo.

 

[typhoonscuba]

Re: fuel pressure Q's

it has a chip i meant that i think it is a burned stock chip in the syclone. the syclone has a 160 degree thermostat, no EGR, and a 3-bar map sensor.

 

[SeattleSy#1255]

Re: fuel pressure Q's

if you have a stock chip and a 3bar MAP sensor, then it'll run like crap, maybe not run at all...

 

[typhoonscuba]

Re: fuel pressure Q's

ok i found out what was on the chip that was in the syclone. the last owner sent me some basics on the chip that he had brian green burn for him.
-stock injectors
-T2 timing (from ultimate)
-no EGR
-no boost flag
-3 bar map sensor
-and should also be open loop
he didnt know the timing tables or fueling on the chip. i checked the fuel pressure and it was at 50 psi w/vac off and plugged. is this right? but that was at 15 inchs of vaccum if the autometer is still good. im going to change the vaccum line this weekend. would low vac affect the fuel pressure? i thought the fuel pressure whent up when you get into boost not less vaccum.
thanks

 

[dhorsman2000]

Re: fuel pressure Q's

50#'s of FP is good. if you have a FP gauge you can hook it up and read what you get when your driving the pressure should rise with a load, if I remember correct mine went to about 70 psi

 

[dgoodhue]

Re: fuel pressure Q's

i checked the fuel pressure and it was at 50 psi w/vac off and plugged. is this right? but that was at 15 inchs of vaccum if the autometer is still good. im going to change the vaccum line this weekend. would low vac affect the fuel pressure? i thought the fuel pressure whent up when you get into boost not less vaccum.
thanks

I am not quite sure what your saying about fuel pressure/vacuum & boost.

If you do have an open loop chip, you will really need to look at a scan tool to what it doing in normal driving condition. An open loop chip has no ability to compensate for rich/lean conditions like normal closed loop chip does. (This is not neccessarily bad, but you can't randomly change FP either)

What do have that will support the additional timing?