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Discussion Starter #1
I installed a NAPA/Carter fuel pump several months ago to replace the OEM just for the heck of it. It has worked fine with no issues so far. In doing some testing while trying to diagnose a hesitation/sputter problem when the machine is cold, I found that it holds a steady 45 psi which is a little above spec. I did take into consideration that temp in the garage was kinda cool and the engine cold which may cause a little higher readings.
Does anyone know if slightly higher than normal fuel pressure could cause problems with say injectors and such?
AKStew?...You out there?
I've adjusted the TPS and cleaned the throttle body which seemed to do the trick but after it sat for a week it was right back to not wanting to idle cold without giving a little throttle. Idles fine after warm up.
Any ideas anyone? T-BAP? I'll be testing some more tonight and will post results.
 

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The fuel pressure being slightly high shouldn't make it sputter. The new fuel pump couldn't make the pressure too high, that's what the fuel pressure regulator on the pump assembly controls. On my machine the pressure regulator failed and the pressure was at 70 psi and it did no damage to the injectors. From what you've described I'd say T-BAP and or connector or maybe start w/ the ETC adjustment.
 

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Not exactly sure how the fuel injection works on the Polaris, but on a car there's a coolant temperature sensor that tells the computer that the engine is cold and to richen up the mixture. I have to guess there is something similar on the Polaris.
 

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Not exactly sure how the fuel injection works on the Polaris, but on a car there's a coolant temperature sensor that tells the computer that the engine is cold and to richen up the mixture. I have to guess there is something similar on the Polaris.
I've been wondering about that. I've got a new one in the shop and had considered putting it in just to eliminate that as a possible cause. I'll try it tonight to see what happens.
 

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Discussion Starter #5
fishhooker, what kind of symptoms did you have? In other words, how did you know something was wrong with the regulator. I didn't bother with the regulator when I change my pump and didn't think to test the pressure before the switch. I realize that the regulator controls pressure but some pumps put out more volume than others despite being the same physical size and thought the new one may be straining the old regulator causing the excess.
 

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I knew there was a fuel problem when I purchased the '04.5 700 efi (I got it real cheap because of this & bald tires). The previous owner was changing the oil every 20ish hours due to it being full of fuel. After I did a pressure test I got the Jeep pressure regulator and put it on. I did a bench test for pressure and it solved the pressure problem. I went ahead & put the Carter pump on while I had it torn down and it has been great. My current pressure is about 41.5 psi on average (40-43 during all my tests).
 
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