Fuel Pressure Numbers
Thread Starter
Melting Slicks
Joined: Oct 2016
Posts: 2,024
Likes: 363
From: Central Alabama
Fuel Pressure Numbers
92 LTI, with Bosch IIIs.
Just installed a new Delphi with Strainer, removed pulsator. New GM fuel Filter.
After 5 ignition cycles 22 psi but it holds steady for a half hour.
Running is 38 (so slightly below what the FSM calls for). 56 with FPR disconnected No fuel in vacuum fitting.
As soon as you turn car off drops back to 22 psi and hold. Eventually drops to 10 after about 2 hours.
Little bit of a stumble at idle, hot days in traffic.
Is it time to replace the regulator?
Just installed a new Delphi with Strainer, removed pulsator. New GM fuel Filter.
After 5 ignition cycles 22 psi but it holds steady for a half hour.
Running is 38 (so slightly below what the FSM calls for). 56 with FPR disconnected No fuel in vacuum fitting.
As soon as you turn car off drops back to 22 psi and hold. Eventually drops to 10 after about 2 hours.
Little bit of a stumble at idle, hot days in traffic.
Is it time to replace the regulator?
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
92 LTI, with Bosch IIIs.
Just installed a new Delphi with Strainer, removed pulsator. New GM fuel Filter.
After 5 ignition cycles 22 psi but it holds steady for a half hour.
Running is 38 (so slightly below what the FSM calls for). 56 with FPR disconnected No fuel in vacuum fitting.
As soon as you turn car off drops back to 22 psi and hold. Eventually drops to 10 after about 2 hours.
Little bit of a stumble at idle, hot days in traffic.
Is it time to replace the regulator?
Just installed a new Delphi with Strainer, removed pulsator. New GM fuel Filter.
After 5 ignition cycles 22 psi but it holds steady for a half hour.
Running is 38 (so slightly below what the FSM calls for). 56 with FPR disconnected No fuel in vacuum fitting.
As soon as you turn car off drops back to 22 psi and hold. Eventually drops to 10 after about 2 hours.
Little bit of a stumble at idle, hot days in traffic.
Is it time to replace the regulator?
56 is high with the vacuum line disconnected.
Either the pump is putting out to much pressure or there is a restriction back to the tank for the return flow
With the vacuum line connected and you rev the engine half throttle for a second the pressure should jump to about 40. If you are much higher than this there might be too much instant pressure for the injectors hence making it to rich causing a stumble. Just a theory
1st Gear
Joined: Jul 2018
Posts: 1
Likes: 0
Hey guys new here and new vet owner got a 92 I’m having problems I’m getting around 34 pounds pressure starts and runs for a while heats up and dies not sure have replaced fuel filter and regulator not sure what next thinking injectors the ones in it the resistance on them is all I’ve from 11.93 to 12.21 any ideas ??
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
Hey guys new here and new vet owner got a 92 I’m having problems I’m getting around 34 pounds pressure starts and runs for a while heats up and dies not sure have replaced fuel filter and regulator not sure what next thinking injectors the ones in it the resistance on them is all I’ve from 11.93 to 12.21 any ideas ??
As to the injectors, if they are Multec, dump them. With ethanol, it could be an issue since the coil windings and ethanol don't get along and you will be forced to go to gas stations that have 93 octane 100% gas which will be a PITA.
