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3800 N/A with supercharger fuel pump by vamper
Started on: 06-03-2008 08:02 PM
Replies: 9
Last post by: darkhorizon on 06-04-2008 08:26 PM
vamper
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Report this Post06-03-2008 08:02 PM Click Here to See the Profile for vamperClick Here to Email vamperSend a Private Message to vamperDirect Link to This Post
im almost done with the swap, im just trying to figure out what is wrong with the motor and why its running weak

So im messing with a few things and decided i was going to see what happened if i pulled the fuel pump relay
its a fuel pump designed for the SC 3800 and puts out 60lbs instead of 35lbs
so after i pulled the pump relay the car revs up and then idles really nicely until the pressure drops too much in the lines
what can i do to fix this?
I dont have my fuel return line hooked up, would this fix the issue?
anything else someone might have to help me out its appreciated

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darkhorizon
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Report this Post06-04-2008 11:20 AM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonDirect Link to This Post
what the hell.... you dont have the return hooked up? How is it working at all, and what are you talking about with this "supercharger pump" putting out 60psi? A fuel pump is a fuel pump, they are rated in flow not pressure.
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vamper
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Report this Post06-04-2008 01:43 PM Click Here to See the Profile for vamperClick Here to Email vamperSend a Private Message to vamperDirect Link to This Post
well i blocked off the return due to a rotten return line, and planned on hooking it back up but havent gotten around to it trying to trouble shoot this issue, i have had plenty of cars that run fine with the return blocked off. Im about 60% done with bending the new tubing and setting everything up but need to run to the parts store and grab some more fuel line. will keep post updated.
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Dennis LaGrua
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Report this Post06-04-2008 02:25 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaDirect Link to This Post
The return is there for a reason. If you block it, you will eventually toast the pump and maybe the engine.

------------------
87GT - 3800SC Series III engine, 3.4" Pulley Flotech Exhaust Autolite 104's 4T65eHD
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

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darkhorizon
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Report this Post06-04-2008 03:17 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonDirect Link to This Post
blocked return = insane fuel pressure... simple as that.
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Jncomutt
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Report this Post06-04-2008 05:33 PM Click Here to See the Profile for JncomuttClick Here to Email JncomuttSend a Private Message to JncomuttDirect Link to This Post
^ I LOL'd.

Put a return on it please. How do you think the regulator is supposed to work without it?
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vamper
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Report this Post06-04-2008 05:45 PM Click Here to See the Profile for vamperClick Here to Email vamperSend a Private Message to vamperDirect Link to This Post
return is on, car runs a bit better... but

the car starts and has a very high idle during this time i can rev the motor, after the idle levels out it seems to idle ok but i cant give it any gas or the motor will die out , if the motor does not die it will rev back up really bad then idle like normal.

also after the motor is warmed up it has a hard time starting and sometimes will not fire until i pull the fuel pump relay and crank it till it runs
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darkhorizon
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Report this Post06-04-2008 08:06 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonDirect Link to This Post
your fuel pump should not even work at all without a relay, something is really screwed if you can even run the motor in anyway without it.

x2 on the LOL'ing
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vamper
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Report this Post06-04-2008 08:23 PM Click Here to See the Profile for vamperClick Here to Email vamperSend a Private Message to vamperDirect Link to This Post
thats part of the issue, i shut off the fuel pump and the motor will run better until the fuel subsides.

not really sure what is going on
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darkhorizon
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Report this Post06-04-2008 08:26 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonDirect Link to This Post
ruptured fuel regulator causing 80psi of fuel pressure is my guess.
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