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klefroid klefroid is offline
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Join Date: Jan 2010
Posts: 677
Originally Posted by JFairman View Post
If your car has two fuel pumps and two fuel pump relays the rear fuel pump relay also powers the heater elements on the WUR/CPR and the cold start aux air valve.

If the rear fuel pump relay stopped working the car will usually still run on the front pump only but then the heater elemenrt on the bimetallic spring thermostat in the WUR cools off and it lowers the control pressure which richens the AFR.

Just one of many possiblities with CIS... and it happened to mine while driving once.

I think your spot on, well almost!
The rear fuel pump is starting to make a strange and loud noise.
Should I replace both or would the noizy one be enough? If one fails most likely the other one follows or am I wrong?
I need to buy a cis pressure tester! it's all about money money money
Here's the sound, what do you guy's think?!
Pump sound - YouTube
Old 07-14-2014, 01:53 PM
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