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cscrombie

1990 TC Fuel pressure bleed-off

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I need some help!

I have a '90 TC thats hard to start. I suspected a fuel problem, so I followed the manual instructions on the fuel pressure test. Fuel pressure is 48+/-2 psi while running, however, it drops to zero when I shut the car off. Watching the gauge while cranking, the pressure takes 5-10 seconds to build up, and the car starts once the pressure reaches about 30. This lead me to suspect a bleed-off issue after shut down. I pinched off the return line while the car was running and the pressure rises to about 70 psi, but drops to zero when I shut the engine off. This eliminated the FPR as a culprit. Next, I pinched off the main fuel line while running and immediately shut the engine off. The pressure stays steady at 48 psi. This eliminated the injectors as the culprit.

So, is the system SUPPOSED to bleed off ALL pressure once the engine is shut down?Or should some remain to ensure an easier start? Should the pressure be bleeding back through the pump?

I have found nothing in either the TC manual or Chilton's that describes this issue.

PLEASE HELP!!

Criss Crombie

817-715-4334

cscrombie@yahoo.com

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I need some help!

I have a '90 TC thats hard to start. I suspected a fuel problem, so I followed the manual instructions on the fuel pressure test. Fuel pressure is 48+/-2 psi while running, however, it drops to zero when I shut the car off. Watching the gauge while cranking, the pressure takes 5-10 seconds to build up, and the car starts once the pressure reaches about 30. This lead me to suspect a bleed-off issue after shut down. I pinched off the return line while the car was running and the pressure rises to about 70 psi, but drops to zero when I shut the engine off. This eliminated the FPR as a culprit. Next, I pinched off the main fuel line while running and immediately shut the engine off. The pressure stays steady at 48 psi. This eliminated the injectors as the culprit.

So, is the system SUPPOSED to bleed off ALL pressure once the engine is shut down?Or should some remain to ensure an easier start? Should the pressure be bleeding back through the pump?

I have found nothing in either the TC manual or Chilton's that describes this issue.

PLEASE HELP!!

Criss Crombie

817-715-4334

cscrombie@yahoo.com

Check the vacuum line at the pressure regulator if it's wet with gas, replace the regulator.

Pressure will eventually bleed off if the vehicle sits long enough, but imediate to [0] is way to quick. I'm no expert on these motors so I don't know without looking if the pressure test port is before or after pressure regulator and drivability is not my strong suit. Do know that pressure should remain in the fule line and if you plug the line between the pump and the engine, turn the key to on, wait for the fuel pump to stop running, turn the key off let it sit for about 20 min. and look for this: if you don't have gas on the ground and gas doesn't spray all over you when you remove the plug, your pressure is leaking back through the pump. Check the vacuum line first.

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