Losing fuel pressure

[fildrill]

Finally got my dream car about 2 months ago--woohooo; '97 gts blue w/ white stripes and I love working on it. Guy I bought it from didn't take too good of care of it and certainly didn't do any preventative maintenance. I've done new wheels, plugs, wires, O2 sensors, hub (not sure how he broke a hub but he did!!), cylinder pressure check (all 150ish-whew!!), fuel system cleanout, brakes, thorough buff, greased all fittings, just about there but its a bit tough to start so I'm replacing the fuel filter to start. When I went to depressurize the system by the port near the injectors, I found virtually NO pressure and no fuel released. So, basically I think the system is losing pressure when the car is off. Runs very good; except at three quarters to full throttle; feels like its being starved. NO CODES. Any ideas on where I go from here?

Thanks for any help,
Phil

 

[dave6666]

Fuel system cleanout? What did that consist of? Did you change the fuel filter after that?

And the fuel system will slowly lose pressure on it's own. How long after running the engine did you wait to depressurize?

 

[GR8_ASP]

If you have a faulty check valve the result will be lengthy cold starts. If you are not having that symptom the residual pressure must still be adequate. Pressure is an easy check though. Connect a gauge, turn on the key and wait for the pressure to stabilize. Key off and observe the rate of decay.

 

[fildrill]

Fuel filter being changed today; I waited about an hour to attempt to depressurize; I now know that the fuel system will depressurize on its own when off. Where would the check valve be? Do I connect a gauge through the SChrader valve?

Also, I'm going to change the stock thermostat. Should I go with a 180 or a 170. I'm using the car as just a weekend cruiser; no real racing

You guys have been great with info and I (and I'm sure many others) am VERY thankful

 

[bluesrt]

Finally got my dream car about 2 months ago--woohooo; '97 gts blue w/ white stripes and I love working on it. Guy I bought it from didn't take too good of care of it and certainly didn't do any preventative maintenance. I've done new wheels, plugs, wires, O2 sensors, hub (not sure how he broke a hub but he did!!), cylinder pressure check (all 150ish-whew!!), fuel system cleanout, brakes, thorough buff, greased all fittings, just about there but its a bit tough to start so I'm replacing the fuel filter to start. When I went to depressurize the system by the port near the injectors, I found virtually NO pressure and no fuel released. So, basically I think the system is losing pressure when the car is off. Runs very good; except at three quarters to full throttle; feels like its being starved. NO CODES. Any ideas on where I go from here?

Thanks for any help,
Phil

get a fuel pressure guage and drive it while watching it,when you gas the motor the guage should jump up in pressure,if it stays the same or drops it is definatly NO GOOD,also pay attention for the most when it malfuntions(the car) to the guage-if it doesnt drop at malfuntion,you need to start looking somewhere else,keep in mind a correct healthy pump should increase in pressure at gas up---

 

[Viper Wizard]

Phil Welcome and Congrats!


Forget the fuel gauge, I can tell you the check valve in your fuel pump module is bad. A lot of 97's have the same problem. Two choices, new fuel pump module at over $600 or get a hold of "Tom, F&L GoR" here on the site! Tom has come up with a fuel up box you can wirer in and save hundreds of $$!! Also do a on the subject here.
914-763-3136

 

[fildrill]

Thanks bluesrt and Wiz. The car is awesome- cockpit gets a tad hot at times. I've also found out that my Viper Tech Manual has a LOT of errors in it; like saying the fuel system will maintain pressure even when the car is off. I'm having a heck of a time removing the fuel filter with those stupid (NOT)quick-connect fittings not releasing. I'll get it. I'm assuming I have to access the fuel pump to address the check valve, right? I tried your "Search" button and it didn't work for me; I'll research it and contact Tom.

 

[Venomiss]

Thanks bluesrt and Wiz. The car is awesome- cockpit gets a tad hot at times. I've also found out that my Viper Tech Manual has a LOT of errors in it; like saying the fuel system will maintain pressure even when the car is off. I'm having a heck of a time removing the fuel filter with those stupid (NOT)quick-connect fittings not releasing. I'll get it. I'm assuming I have to access the fuel pump to address the check valve, right? I tried your "Search" button and it didn't work for me; I'll research it and contact Tom.

This was from search for you: put in fuel pump-and Tom's post is in there too.
If you are having problems with the search PM one of the moderators here so they can help you-kcobean or Lee00blacksilverGTS.

http://forums.viperclub.org/rt-10-gts-discussions/630284-troubleshoot-fuel-system-info-please.html

 

[Viper Wizard]

Thanks bluesrt and Wiz. The car is awesome- cockpit gets a tad hot at times. I've also found out that my Viper Tech Manual has a LOT of errors in it; like saying the fuel system will maintain pressure even when the car is off. I'm having a heck of a time removing the fuel filter with those stupid (NOT)quick-connect fittings not releasing. I'll get it. I'm assuming I have to access the fuel pump to address the check valve, right? I tried your "Search" button and it didn't work for me; I'll research it and contact Tom.

Your welcome Phil.

"I've also found out that my Viper Tech Manual has a LOT of errors in it; like saying the fuel system will maintain pressure even when the car is off"

This is NOT an error, when it does not.....bad check valve!

"I'm having a heck of a time removing the fuel filter with those stupid (NOT)quick-connect fittings not releasing"

DO NOT pull down on the filter when trying to disconnect!! You will break the plastic fuel line above or the fuel pump connector!!

If you want, give me a call. Maybe I can give some tips?
914-763-3136