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fuel pressure solenoid delete

Jesh

Well-known member
Joined
Nov 12, 2009
Messages
282
Location
Soldotna, Alaska
what would happen if i deleted my fuel pressure control solenoid valve? and just ran a vacuum hose straight to the fuel pressure regulator and then the intake manifold. it will work the same, i'm just curious what this solenoid does? emissions i know... but will it make the ECM freak out?
 

nothing will happen at all if its a 1g. If its a 2g it will throw the CEL, but that sit...

...but wait for the theory gurus to attack me like a wounded gazelle in a cheetah jungle. LOL

EDIT: i didnt see the second part of the question, that solenoid is for hot starts, supposed to make it easier to start by adding fp. without it it might take an extra crank or two to start but who cares.
 
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Jesh

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Joined
Nov 12, 2009
Messages
282
Location
Soldotna, Alaska
haha... yeah they do that, but they just don't want anyone getting the wrong info here, which i can appreciate. but man some ppl on here just don't know how to take a joke :p and yeah its on a 1g #898/1000 i'm just trying to clean up under the hood in preparation for a stroker project. lucky me i have a spare block and head so i can still drive the car and build the motor, best of both worlds! /ubbthreads/images/graemlins/smile.gif
 

Haha no worries. See the second part of my first response, i forgot to answer the second part of your question.
 

Barnes

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Feb 9, 2003
Messages
6,249
Location
Richland, WA
Keydiver would be the one to really have this info for sure, but I was under the impression the solenoid opens during COLD starts to make things a bit richer. /ubbthreads/images/graemlins/crazy.gif
 

Jesh

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Nov 12, 2009
Messages
282
Location
Soldotna, Alaska
good to know, i've had a AEM EMS sitting on my shelf for over a year and i'm finally gunna install it next week so i can change any little problems then.
 

toybreaker

iconoclast
Joined
Apr 30, 2006
Messages
3,581
Nah, teh wounded gazelle got that one right, Jon

The fpr solenoid is comanded by the ecu to vent the fpr vacuum reference to ambient during hot starts. This increases the fuel pressure a schosche, and helps eliminate stumbles during hot starts.

On second thought, actually, he's more like a blind squirrell...

Like my grandaddy always used to say...

"Even a blind squirrel finds a nut every now and then" /ubbthreads/images/graemlins/wink.gif
 

^^ Yeah. Every theory nerd can go fast from time to time too.....i think. /ubbthreads/images/graemlins/wink.gif
 
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Jesh

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Joined
Nov 12, 2009
Messages
282
Location
Soldotna, Alaska
lol... hey since were on the subject, can i just run a hose from my pressurized side of my turbo to the wastegate? i'm not sure what all the other crap does but i'm having some problems keeping boost levels. it will be @ 10psi one minute and the next i'm hitting 15psi. very annoying, just trying to troubleshoot it, and i would like to get rid of the rest of the hoses.... /ubbthreads/images/graemlins/smile.gif
 

toybreaker

iconoclast
Joined
Apr 30, 2006
Messages
3,581
You'll be running wastegate pressure at that point, and will actually lose some boost.

The ecu cycles the wastegate solenoid under optimal conditions allowing for more boost.

Any knock shuts that system down, and you'll be running on the 'gate.
 

Jesh

Well-known member
Joined
Nov 12, 2009
Messages
282
Location
Soldotna, Alaska
thats fine by me. until i get this thing dialed in i only wanna be running 10psi. the only reason is because of this boost pressure fluctuation i don't wanna raise my boost to 17psi and then have it randomly go to 22psi... i doubt it would, but i'm not the kind of person who takes that chance. i just wanna do it the right way.
 

Brunoboy

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Joined
Apr 25, 2008
Messages
2,880
Location
San Bruno,CA Home of SFO
can someone please take a picture of this FPR Solenoid? Thanks, because I dont even have one connected I dont think. =/
-shane
 

atc250r

Staff member
Joined
Sep 11, 2003
Messages
13,235
Location
Orange County, NY
I always thought it was the other way around. It stopped vacuum from reaching the FPR on a cold start to richen up the mixture kind of like a choke mechanism would.
 

turbowop

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Apr 29, 2001
Messages
11,971
Location
Yakima, WA
I was always under the impression it did it on hot starts to combat fuel vapor in the lines/rail.

The FIAV was for the cold starts.
 

atc250r

Staff member
Joined
Sep 11, 2003
Messages
13,235
Location
Orange County, NY
But the FIAV bumps the idle speed up, it doesn't richen the mixture. I doubt you'd have a vapor lock problem since there is a return line the fuel doesn't stay in the rail long enough to get that hot.

John
 

turbowop

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Apr 29, 2001
Messages
11,971
Location
Yakima, WA
I would think that the ECU could control any richening of the mixture during cold starts without needing to bump fuel pressure via a solenoid though. I'm still confident that it's in place for hot starts. /ubbthreads/images/graemlins/smile.gif
 

atc250r

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Sep 11, 2003
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I never stop learning.
 

CarRacer

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Jun 28, 2007
Messages
4,371
Location
Shakopee, MN
Me neither, I couldn't remember what the correct answer was so I had to search for it.
 
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