fuel pressure issues

Downtown02 · May 2nd, 2007, 09:43 PM

so i have a 99 gt sohc and i just replaced the fuel pump and my fuel pressure is very low now. i put in a ford gt fuel pump replacing the stock one. and now my fuel pressure sits around 10psi and the car has no power! any ideas to what is wrong or if i need something else with this to work?

ujslost · May 2nd, 2007, 10:23 PM

wow thats really weird

ChrisJ · May 2nd, 2007, 10:25 PM

I was under the impression that the GT pumps took some modification to the wiring harness...

Downtown02 · May 2nd, 2007, 10:37 PM

the stock pump had a two wire connector for pos and neg. the gt pump has two terminals for pos and neg on the top. i just cut the wire connector of and crimp on some stake-on to the wire to connect it to the pump.

ujslost · May 2nd, 2007, 10:39 PM

is the pump getting enough voltage then? thats my guess after reading that

Downtown02 · May 2nd, 2007, 10:48 PM

i haven't checked that out yet. i had to go to work. if the voltage is low what should i check next? it wouldn't be my fuel regulator would it? that should still maintain the same pressures right?

ujslost · May 2nd, 2007, 11:41 PM

yeah it should maintain. but the connections you said you made might not be good. bad ground maybe???? possibly a bad pump.

MustangMatt96GT · May 3rd, 2007, 01:26 AM

From what Chris has been saying, the GT pumps require a different set up with more modifications than what you have done! You might want to look into this in much more depth!

ChrisJ · May 3rd, 2007, 09:24 AM

You do not have a fuel regulator...

Fpdm and wiring...

You'll need to get a hold of someone to get your FMDP upgraded to handle the extra current these pumps will draw... The FPDM is in your trunk on the driver side opposite of where the gas tank filler would be... Black small black box with some 'L' shaped brackets coming off of it...

As far as wiring, you'll need to do some searching online to find out exactly what gets upgraded... but You'll need some 8 or 10 gauge wire (with either 20 or 40 amp fuse) going first to the FPDM, then to the pumps, keeping in mind you need to upgrade the ground wires too...

This is why your car is doing what it is doing...Or you can just go buy a SVT FOcus Pump and drop it in the basket and call it a day and not have to modify the wiring or FPDM...

ChrisJ · May 4th, 2007, 06:17 PM

Did this fix it?

Downtown02 · May 16th, 2007, 08:47 PM

i got a modified fpdm and did the wiring upgrade and even bought a new fuel rail pressure sensor. the car is still doing the same thing! i put the stock pump back in it and it still does it...i used a diablosport predator to datalog it. fuel press was from 29-32 psi with fuel pump duty cycle at 49.99%(stock fuel pump) and after a couple min the fuel pump duty cycle went to 25%. fuel pressure dropped to like 10 psi, then fuel pump duty cycle started to increase. got to about 30% but the car stalled by then. after that i got a code for fpdm offline or disabled, frps and frps ckt high input. p1233, p0190, p0193.

zkid01 · May 16th, 2007, 09:04 PM

Something is wired up wrong, double check your frdm.. im going to make a call too a budy and see if he has any ideas for ya.

Downtown02 · May 16th, 2007, 09:21 PM

i'll check it again. but i had this problem before the wiring upgrade and it didn't change at all after the wiring upgrade.

ChrisJ · May 17th, 2007, 09:19 AM

Check the automatic fuel cutoff switch located in the trunk...This can cause the p1233 code...

Also check the wiring at the FRPS. More specifically, check the voltage. It should see about 5 volts on the input side. If it is seeing more, you either have a short in the wiring leading to the FRPS causing it to see more than 5 volts (probably 12 volts) or the PCM is no good...This can cause the p0193...

The p0190 is for the FRPS so it cna be caused by the same things that cuases the P0193...

Hope this helps ya out...

banned · May 17th, 2007, 09:52 AM

Originally Posted by ChrisJ

You do not have a fuel regulator...

This is why your car is doing what it is doing...Or you can just go buy a SVT FOcus Pump and drop it in the basket and call it a day and not have to modify the wiring or FPDM...

+1000 on the focus pump - why make life difficult

Downtown02 · May 23rd, 2007, 02:44 AM

i figured it out! it was due to a grommet ripped and falling out. the grommet for the gas tank that the gas filler neck goes thru. replaced that and it's all better!

Downtown02 · May 23rd, 2007, 02:44 AM

weird how the i was getting the fuel rail pressure sensor code

02StangGToWNEr · May 23rd, 2007, 02:52 AM

Good to hear that ya got it fixed, and it's good to see another NYer besides me & neckbonekat!

May 2nd, 2007, 09:43 PM	#1
Downtown02 Newbie Join Date: Dec 2006 Location: Central, NY Posts: 8 iTrader: 0 reviews	fuel pressure issues so i have a 99 gt sohc and i just replaced the fuel pump and my fuel pressure is very low now. i put in a ford gt fuel pump replacing the stock one. and now my fuel pressure sits around 10psi and the car has no power! any ideas to what is wrong or if i need something else with this to work?

May 2nd, 2007, 10:23 PM	#2
ujslost MM Fanatic Join Date: Mar 2007 Location: Albertville, AL Posts: 3,920 Blog Entries: 1 iTrader: 1 reviews	wow thats really weird __________________ 1986 Mustang GT t-top time piece!

May 2nd, 2007, 10:25 PM	#3
ChrisJ RLY SRS Join Date: Aug 2005 Location: Ft. Meade, MD Posts: 36,743 Blog Entries: 4 iTrader: 9 reviews	I was under the impression that the GT pumps took some modification to the wiring harness... __________________ 2008 Acura TL Type-S - 2008 EB Ford Expedition - 2002 Boosted GT - Sold Facebook Google+

May 2nd, 2007, 10:39 PM	#5
ujslost MM Fanatic Join Date: Mar 2007 Location: Albertville, AL Posts: 3,920 Blog Entries: 1 iTrader: 1 reviews	is the pump getting enough voltage then? thats my guess after reading that __________________ 1986 Mustang GT t-top time piece!

May 2nd, 2007, 11:41 PM	#7
ujslost MM Fanatic Join Date: Mar 2007 Location: Albertville, AL Posts: 3,920 Blog Entries: 1 iTrader: 1 reviews	yeah it should maintain. but the connections you said you made might not be good. bad ground maybe???? possibly a bad pump. __________________ 1986 Mustang GT t-top time piece!

May 2nd, 2007, 10:37 PM	#4
Downtown02 Newbie Join Date: Dec 2006 Location: Central, NY Posts: 8 iTrader: 0 reviews	the stock pump had a two wire connector for pos and neg. the gt pump has two terminals for pos and neg on the top. i just cut the wire connector of and crimp on some stake-on to the wire to connect it to the pump.

May 2nd, 2007, 10:48 PM	#6
Downtown02 Newbie Join Date: Dec 2006 Location: Central, NY Posts: 8 iTrader: 0 reviews	i haven't checked that out yet. i had to go to work. if the voltage is low what should i check next? it wouldn't be my fuel regulator would it? that should still maintain the same pressures right?

May 3rd, 2007, 01:26 AM	#8
MustangMatt96GT Proud American 1996 Mustang GT 10.76 @ 122 with d/a of 8365 ft Join Date: Dec 2006 Location: Lakewood, CO Posts: 10,168 iTrader: 3 reviews	From what Chris has been saying, the GT pumps require a different set up with more modifications than what you have done! You might want to look into this in much more depth! __________________ RIP Travis Billings Special Thanks to: Andrews Racing Transmissions Baseline Suspensions Blown Small Block Ford with a hole in the block. 9.5 Dart Block 400 CI being saved for. Just because you can fuck a cactus doesn't mean you should. Never Lift Racecars

May 3rd, 2007, 09:24 AM	#9
ChrisJ RLY SRS Join Date: Aug 2005 Location: Ft. Meade, MD Posts: 36,743 Blog Entries: 4 iTrader: 9 reviews	You do not have a fuel regulator... Fpdm and wiring... You'll need to get a hold of someone to get your FMDP upgraded to handle the extra current these pumps will draw... The FPDM is in your trunk on the driver side opposite of where the gas tank filler would be... Black small black box with some 'L' shaped brackets coming off of it... As far as wiring, you'll need to do some searching online to find out exactly what gets upgraded... but You'll need some 8 or 10 gauge wire (with either 20 or 40 amp fuse) going first to the FPDM, then to the pumps, keeping in mind you need to upgrade the ground wires too... This is why your car is doing what it is doing...Or you can just go buy a SVT FOcus Pump and drop it in the basket and call it a day and not have to modify the wiring or FPDM... __________________ 2008 Acura TL Type-S - 2008 EB Ford Expedition - 2002 Boosted GT - Sold Facebook Google+

May 4th, 2007, 06:17 PM	#10
ChrisJ RLY SRS Join Date: Aug 2005 Location: Ft. Meade, MD Posts: 36,743 Blog Entries: 4 iTrader: 9 reviews	Did this fix it? __________________ 2008 Acura TL Type-S - 2008 EB Ford Expedition - 2002 Boosted GT - Sold Facebook Google+

May 16th, 2007, 08:47 PM	#11
Downtown02 Newbie Join Date: Dec 2006 Location: Central, NY Posts: 8 iTrader: 0 reviews	i got a modified fpdm and did the wiring upgrade and even bought a new fuel rail pressure sensor. the car is still doing the same thing! i put the stock pump back in it and it still does it...i used a diablosport predator to datalog it. fuel press was from 29-32 psi with fuel pump duty cycle at 49.99%(stock fuel pump) and after a couple min the fuel pump duty cycle went to 25%. fuel pressure dropped to like 10 psi, then fuel pump duty cycle started to increase. got to about 30% but the car stalled by then. after that i got a code for fpdm offline or disabled, frps and frps ckt high input. p1233, p0190, p0193.

May 16th, 2007, 09:04 PM	#12
zkid01 Enthusiast Join Date: Apr 2007 Location: Pearl Harbor, HI Posts: 606 iTrader: 0 reviews	Something is wired up wrong, double check your frdm.. im going to make a call too a budy and see if he has any ideas for ya. __________________ Work Hard....Play Harder.

May 16th, 2007, 09:21 PM	#13
Downtown02 Newbie Join Date: Dec 2006 Location: Central, NY Posts: 8 iTrader: 0 reviews	i'll check it again. but i had this problem before the wiring upgrade and it didn't change at all after the wiring upgrade.

May 17th, 2007, 09:19 AM	#14
ChrisJ RLY SRS Join Date: Aug 2005 Location: Ft. Meade, MD Posts: 36,743 Blog Entries: 4 iTrader: 9 reviews	Check the automatic fuel cutoff switch located in the trunk...This can cause the p1233 code... Also check the wiring at the FRPS. More specifically, check the voltage. It should see about 5 volts on the input side. If it is seeing more, you either have a short in the wiring leading to the FRPS causing it to see more than 5 volts (probably 12 volts) or the PCM is no good...This can cause the p0193... The p0190 is for the FRPS so it cna be caused by the same things that cuases the P0193... Hope this helps ya out... __________________ 2008 Acura TL Type-S - 2008 EB Ford Expedition - 2002 Boosted GT - Sold Facebook Google+

May 23rd, 2007, 02:44 AM	#16
Downtown02 Newbie Join Date: Dec 2006 Location: Central, NY Posts: 8 iTrader: 0 reviews	i figured it out! it was due to a grommet ripped and falling out. the grommet for the gas tank that the gas filler neck goes thru. replaced that and it's all better!

LinkBacks (?) LinkBack to this Thread: http://www.moddedmustangs.com/forums/99-04/21414-fuel-pressure-issues.html
Posted By	For	Type	Date
2nd try on getting a dyno tune today at 2pm cental! thoughts?! - Page 3 - SVTPerformance	This thread	Refback	July 23rd, 2010 06:25 PM

May 23rd, 2007, 02:52 AM	#18
02StangGToWNEr Hardcore Enthusiast 2006 Mustang GT Join Date: Feb 2007 Location: Upstate NY Posts: 2,698 iTrader: 0 reviews	Good to hear that ya got it fixed, and it's good to see another NYer besides me & neckbonekat!

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