P0193 fuel pressure at 90 PSI

ddaniels750 · February 27th, 2011, 09:32 AM

Well I recently purchased an 03 GT and had to iron out a few issues. One of them being a code for the FRPS. I can't seem to get this code to go away. I've replaced the FRPS,CCRM,FPDM, replaced all vacuum lines and checked for any loose connections at the ecu. When I hook up the Diablo Sport the FP reads 90 PSI no matter what and it constantly gets 5.00 volts(which would explain the 90 PSI) Has anyone else ever had this problem? I'm leaning towards the ECM being at fault. It seems that someone replaced the original one with one from 2002 Mustang GT 5 speed.
Any help would be GREATLY appreciated.
Thanks!

torkum · February 27th, 2011, 09:41 AM

A bad fuel pump can also cause this code. Do make sure you have checked all the wiring for rubs around the engine.

FoxHoss · February 27th, 2011, 11:28 AM

did you check the fuel pressure with a manual gauge?

depending on wether you have 90psi or your ecm is reading 90psi is two completely different things. if your ecm is reading 90psi but your actuall rail pressure is normal then i would look into a wire rubbed through somwhere or some corrosion in a connector. i wouldnt necessarilly jump to ecm replacment

ddaniels750 · February 27th, 2011, 01:04 PM

Very good question. Sorry I forgot to mention that the pressure at the rail is reading 39-40 psi. The Diablo is actually reading 90. I will have to go through and check the wiring more thoroughly.
I have also replaced the pump along with both internal filters as well as the external. The car had been sitting for some time and the fuel was somewhat dirty in the bottom of the sending unit. I have since run through almost 3 tanks of fuel and fuel system cleaner.

WickedSnake00 · February 27th, 2011, 01:36 PM

From a mechanical engineer in the automotive industry-

Sensors are typically designed to operate in the range of 0.5-4.5 V in range. That way, if the ECM sees below 0.5V or above 4.5V you should get a "failed high/low out of range" code. If it's below, it's probably grounding somewhere, and if it's high, it's shorting to source voltage somewhere.

In this case, it's failing high out of range, meaning it isn't a physical sensor problem, rather an electrical. If you've replaced the sensor I'd look for a short or mis-connection somewhere, likely to source voltage.

ddaniels750 · February 27th, 2011, 02:15 PM

That's definitely some excellent advice. I was also under the impression that it shouldn't read above 4.5 volts. It caught me by surprise to see a 5 volt reading. Does anyone have an ECM pinout diagram for 03 GT?! My next step is to check continuity between the sensor and ECM. On another note... I just pulled the connector off the FRPS with the key on and it still reads 5 volts?! This has to be a wiring issue.

WickedSnake00 · February 27th, 2011, 06:35 PM

That absolutely indicates a short to supply voltage. Somewhere in the wiring your sensor signal is shorting to a supply voltage. You might have to do some wire tracing.

Wish I could help you out with the wiring diagram.

FoxHoss · February 27th, 2011, 06:43 PM

i have diagrams im just having trouble posting them

FoxHoss · February 27th, 2011, 07:20 PM

here ya go. i think i got it.

ddaniels750 · February 28th, 2011, 06:59 AM

Very nice. Thanks! I'll be chasing down dome electrical gremlins tonight.

cliffyk · February 28th, 2011, 07:27 AM

Here are the output voltages for the FRP sensor, and connector info:

VRef should be 4.0V to 6.0V KOEO...

ddaniels750 · February 28th, 2011, 10:41 AM

Thanks guys! I really Think this will take care of the problem. I'll keep you posted for anyone that may have a similar issue.

ddaniels750 · March 1st, 2011, 07:45 PM

Well guys, I finally found the problem today and it turned out to be a problem in the engine harness. Specifically where it connects to the sub-harness that passes through the firewall into the ECM on the passenger side firewall. It seems as though someone was in a hurry and bolted the harness down and in the process they pinched two of the pins together in one pin socket. Therefore causing the brown/white vref wire to receive 5 volts at all times causing the FPRS to see 90 PSI.
Thanks again for all of your help.
Here's a picture of the harness... The second row up from the bottom, left side, third pin from the left.

http://s1119.photobucket.com/albums/...ls750/Mustang/

February 27th, 2011, 09:32 AM	#1
ddaniels750 Newbie 2003 Mustang GT 13.2@107 Join Date: Feb 2011 Location: Maryland Posts: 29 iTrader: 0 reviews	P0193 fuel pressure at 90 PSI Well I recently purchased an 03 GT and had to iron out a few issues. One of them being a code for the FRPS. I can't seem to get this code to go away. I've replaced the FRPS,CCRM,FPDM, replaced all vacuum lines and checked for any loose connections at the ecu. When I hook up the Diablo Sport the FP reads 90 PSI no matter what and it constantly gets 5.00 volts(which would explain the 90 PSI) Has anyone else ever had this problem? I'm leaning towards the ECM being at fault. It seems that someone replaced the original one with one from 2002 Mustang GT 5 speed. Any help would be GREATLY appreciated. Thanks!

February 27th, 2011, 11:28 AM	#3
FoxHoss Enthusiast 02' GT Join Date: Oct 2007 Location: Brooklyn, CT Posts: 907 iTrader: 0 reviews	did you check the fuel pressure with a manual gauge? depending on wether you have 90psi or your ecm is reading 90psi is two completely different things. if your ecm is reading 90psi but your actuall rail pressure is normal then i would look into a wire rubbed through somwhere or some corrosion in a connector. i wouldnt necessarilly jump to ecm replacment __________________ Nitrous is like a hot girl with an STD... you wanna hit it, but your afraid of the consequences 02' GT ~ Twin Screwed 469hp/493tq

February 27th, 2011, 01:04 PM	#4
ddaniels750 Newbie 2003 Mustang GT 13.2@107 Join Date: Feb 2011 Location: Maryland Posts: 29 iTrader: 0 reviews	Very good question. Sorry I forgot to mention that the pressure at the rail is reading 39-40 psi. The Diablo is actually reading 90. I will have to go through and check the wiring more thoroughly. I have also replaced the pump along with both internal filters as well as the external. The car had been sitting for some time and the fuel was somewhat dirty in the bottom of the sending unit. I have since run through almost 3 tanks of fuel and fuel system cleaner. Last edited by ddaniels750; February 27th, 2011 at 01:09 PM.

February 27th, 2011, 01:36 PM	#5
WickedSnake00 MM's king of Neon's 404 - car not found 17.81@87 Join Date: Aug 2010 Location: Diesel Engine Capital of the World, Columbus, IN Posts: 7,374 iTrader: 0 reviews	From a mechanical engineer in the automotive industry- Sensors are typically designed to operate in the range of 0.5-4.5 V in range. That way, if the ECM sees below 0.5V or above 4.5V you should get a "failed high/low out of range" code. If it's below, it's probably grounding somewhere, and if it's high, it's shorting to source voltage somewhere. In this case, it's failing high out of range, meaning it isn't a physical sensor problem, rather an electrical. If you've replaced the sensor I'd look for a short or mis-connection somewhere, likely to source voltage. __________________ Official Secondhand Snake Build Thread Here Looks Like a Cobra, Sounds Like a Cobra, Tastes Like a Cobra, Not a Cobra. For Sale: P71 Interceptor motor

February 27th, 2011, 06:35 PM	#7
WickedSnake00 MM's king of Neon's 404 - car not found 17.81@87 Join Date: Aug 2010 Location: Diesel Engine Capital of the World, Columbus, IN Posts: 7,374 iTrader: 0 reviews	That absolutely indicates a short to supply voltage. Somewhere in the wiring your sensor signal is shorting to a supply voltage. You might have to do some wire tracing. Wish I could help you out with the wiring diagram. __________________ Official Secondhand Snake Build Thread Here Looks Like a Cobra, Sounds Like a Cobra, Tastes Like a Cobra, Not a Cobra. For Sale: P71 Interceptor motor

February 27th, 2011, 09:41 AM	#2
torkum Newbie Join Date: Feb 2011 Posts: 4 iTrader: 0 reviews	A bad fuel pump can also cause this code. Do make sure you have checked all the wiring for rubs around the engine.

February 27th, 2011, 02:15 PM	#6
ddaniels750 Newbie 2003 Mustang GT 13.2@107 Join Date: Feb 2011 Location: Maryland Posts: 29 iTrader: 0 reviews	That's definitely some excellent advice. I was also under the impression that it shouldn't read above 4.5 volts. It caught me by surprise to see a 5 volt reading. Does anyone have an ECM pinout diagram for 03 GT?! My next step is to check continuity between the sensor and ECM. On another note... I just pulled the connector off the FRPS with the key on and it still reads 5 volts?! This has to be a wiring issue.

February 27th, 2011, 06:43 PM	#8
FoxHoss Enthusiast 02' GT Join Date: Oct 2007 Location: Brooklyn, CT Posts: 907 iTrader: 0 reviews	i have diagrams im just having trouble posting them __________________ Nitrous is like a hot girl with an STD... you wanna hit it, but your afraid of the consequences 02' GT ~ Twin Screwed 469hp/493tq

February 27th, 2011, 07:20 PM	#9
FoxHoss Enthusiast 02' GT Join Date: Oct 2007 Location: Brooklyn, CT Posts: 907 iTrader: 0 reviews	here ya go. i think i got it. __________________ Nitrous is like a hot girl with an STD... you wanna hit it, but your afraid of the consequences 02' GT ~ Twin Screwed 469hp/493tq

February 28th, 2011, 06:59 AM	#10
ddaniels750 Newbie 2003 Mustang GT 13.2@107 Join Date: Feb 2011 Location: Maryland Posts: 29 iTrader: 0 reviews	Very nice. Thanks! I'll be chasing down dome electrical gremlins tonight.

February 28th, 2011, 07:27 AM	#11
cliffyk Hardcore Enthusiast Join Date: Feb 2007 Location: Saint Augustine, FL Posts: 1,808 iTrader: 1 reviews	Here are the output voltages for the FRP sensor, and connector info: VRef should be 4.0V to 6.0V KOEO... __________________ -cliff knight- My Mustang 2003 GT, UPR X, 24lb/h injectors, Magnaflow, 180° stat, PP 70mm TB & plenum, DF Commando, Steeda UDPs, Ralco RZ_flywheel, RAM HDX clutch, WX EFX COPs 3.73s, 262 rwHP/305 lb-ft. Flex-fuel: burns gas and rubber...

February 28th, 2011, 10:41 AM	#12
ddaniels750 Newbie 2003 Mustang GT 13.2@107 Join Date: Feb 2011 Location: Maryland Posts: 29 iTrader: 0 reviews	Thanks guys! I really Think this will take care of the problem. I'll keep you posted for anyone that may have a similar issue.

March 1st, 2011, 07:45 PM	#13
ddaniels750 Newbie 2003 Mustang GT 13.2@107 Join Date: Feb 2011 Location: Maryland Posts: 29 iTrader: 0 reviews	Well guys, I finally found the problem today and it turned out to be a problem in the engine harness. Specifically where it connects to the sub-harness that passes through the firewall into the ECM on the passenger side firewall. It seems as though someone was in a hurry and bolted the harness down and in the process they pinched two of the pins together in one pin socket. Therefore causing the brown/white vref wire to receive 5 volts at all times causing the FPRS to see 90 PSI. Thanks again for all of your help. Here's a picture of the harness... The second row up from the bottom, left side, third pin from the left. http://s1119.photobucket.com/albums/...ls750/Mustang/

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