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This issue is a real challenge

VSS 4life

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I have a 95 VS SS Manual Sedan have owned for 12 years and just about replaced everything. But now I have an issue that I can't seem to figure out. So the symptoms first.

The car sometimes starts and idle fine but it's 50/50, if it doesn't start it just keeps cracking over but doesn't fire.
If it fires up and I start to drive it's 50/50 weather it will run for awhile or just a few metres before I lose all power a roll to a stop. Then it's a 50/50 If it's starts again.

So far I have replaced:
The ignition module, no good
The Coil, no good
Spark plugs and leads, no good
Dizzy including the hall effect sensor, no good
Disconnected the viper alarm, no good

I'm simply out of options as to what the issue could be. I'm open the any suggestions. Thanks in advance
 

DavesSV6Tonner

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Fuel pump?
 

Calaber

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I'd agree it's the fuel pump. I experienced similar problems in my VR years ago.
 

mechanic

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Stop replacing unnecessary parts and start testing.

But a cheap fuel pressure gauge from eBay and leave it connected. When the car dies check the pressure.

Feel all connectors and relays for heat and disconnect/reconnect them. Check the terminals for corrosion while you are there.

Wiggle all wiring in its place and see if it makes a difference.
 

VSS 4life

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Thanks guys. I replaced the fuel pump 2 years ago but maybe its faulty.
 

VSS 4life

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Stop replacing unnecessary parts and start testing.

But a cheap fuel pressure gauge from eBay and leave it connected. When the car dies check the pressure.

Feel all connectors and relays for heat and disconnect/reconnect them. Check the terminals for corrosion while you are there.

Wiggle all wiring in its place and see if it makes a difference.
Thanks for you assistance. Ive never fitted or know how to fit a fuel pressure gauge. Theres probably a video on YouTube.
 

immortality

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Or fuel filter or fuel pressure regulator. Either way, a fuel pressure test is a good start. A simple test would be to pinch off the fuel return hose and see if it fires (simple test of the fuel pressure regulator). A common failure of the Fuel pressure regulator is the diaphragm, when this occurs fuel enters the intake manifold via the vacuum reference hose. pull the hose off the intake manifold and check for fuel in this hose when you prime the fuel pump (and you can check the fuel pump does prime when the key is switched on).
 

VSS 4life

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Installed a fuel pressure gauge and is reads 40psi and up to 45psi when turning the car over.
 

immortality

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That is about right. Still no start with 40+ psi fuel pressure?

What happens to the fuel pressure when you stop cranking?

When you replaced the cap did you replace the rotor?

Have you checked voltage when cranking?

Clean and checked the earth connection on the ignition module? Also check/clean/tighten earth connections on block, chassis and battery terminals.

Switch out ignition relay with the horn or high beam relay as these are seldomly used and generally in good working order.
 
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