A new one to me - Fuel Over Pressure

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19 Oct 2010 16:23 #1712 by Rich928
A new one to me - Fuel Over Pressure was created by Rich928
My '87 928 S4 came to a sputtering stop last Friday. It would run for a bit and then stop. The fuel pump was making a strange noise.

I knew it wasn't my LH module - I have rebuilt it - and I had spark. So the next thing was to check fuel pressure, I suspected my fuel pump was failing. Much to my surprise, the pressure was pegged! The fuel pressure regulator was not allowing fuel back to the tank. I haven't seen this failure mode in the past, I've seen them leak and the pressure be too low, but not too high.

So, before suspecting your fuel pump just because of noise, check the pressure!

Rich
Charter Member 928 OC
www.electronikrepair.com

Rich
Membership Chairman
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1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast

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19 Oct 2010 19:44 #1716 by SeanR
Replied by SeanR on topic A new one to me - Fuel Over Pressure
When you say too high, how high are you seeing? And how are you measuring it?

Also, when a pump is starting to scream at you, it's time to change it.

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