Voltage at FCA pigtail plug

Howling

Howling

Soot Sniffer
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Apr 30, 2006
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Trying to troubleshoot my dual cp3 controller

Curious if anyone knows what the voltage at the FCA pigtail is supposed to be. The readings I'm getting with the key on engine off is -

Top pump pig tail 0.002 Volts

Bottom pump pig tail 6.57 Volts

Top pump FCA 3.2 Ohms

Bottom pump FCA 3.2 Ohms
 
Top pump won't be fuelling. It takes voltage to open the FCA and allow fuel flow. Are there any perameters that controll fuelling on the dual controller for the top pump differently than the bottom? Like only bottom pump fuels while cranking to lessen the load on the starter?
 
I just checked resistance at each pig tail .

Top 5.5 Ohms

Bottom 9.8 Ohms
 
Zero voltage or unplugging the FCA will result in full fuel from that cp3. Rail pressure will be unregulated with the FCA unplugged. Not sure what the voltage should be tho. I'll see if I can find it in all data

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I realize it will go to max rail psi when unplugged.

I just pulled the belt and undid the extension harness and plugged the factory connector at the bottom cp3 FCA ,rail psi is normal again.

Looks like I might have a bad pigtail to the top FCA or a bad controller.
 
ShaferDiesel said:
Top pump won't be fuelling. It takes voltage to open the FCA and allow fuel flow. Are there any perameters that controll fuelling on the dual controller for the top pump differently than the bottom? Like only bottom pump fuels while cranking to lessen the load on the starter?
Click to expand...

You got that backward buddy. It takes voltage to make it stay closed.

Eric when i was testing my dual pump setup I would use T-pins and check the voltage while its idling 0-5 volts is about all you should see
 
Need to know which brand of controller. Different ones do things differently. Some will have a solid positive and pulsed ground, others a solid ground and pulsed positive.
 
I'm going to try a different controller tomorrow and see what happens, I can't see what else it could be. I pulled the rail pressure gauge, same issue. Pulled belt and plugged factory cp3 together and rail pressure was normal at idle.

It just puzzles me that it was perfectly fine on Friday night the Saturday evening bam high rail at idle.

I thought it had something to do with the lights I wired up since it was fine before.
 
ATS controller

I'm going to try one from Fingers tomorrow and get some next day aired from Dennis at TS on Tues.
 
From everything I have read you should have around 2 volts at both fca's with an ats controller. That is key on engine off. We are having the same issue, have 2 volts to the bottom fca and zero to the top. Which causes max rp at idle. I got to see if we can get a controller over nighted so we can make ts.
 
It just puzzles me that it was perfectly fine on Friday night the Saturday evening bam high rail at idle.

I thought it had something to do with the lights I wired up since it was fine before.[/QUOTE]

In my case we started the truck and it was at max rp, then shut it off and started it back and it was normal. I let it idle for 20 minutes and shut it off and started it again, it was fine. I took a shower went out and started it to leave and it was at max rp and has stayed that away. It's one of the stranges things I have seen.
 
I am having the same issue and a guy at ATS told me I should see 10 amps to each cp3... I just changed my box because the top had 4.5 and the bottom had .5. It didn't fix anything. New box had 8.5 amps going to top FCA after changing out ATS controller. Changing out the FCA's now.
 
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Tried a new harness today and everything is back to normal. I talked with Dennis Perry @ TS and he is going to overnight 2 controllers one for the truck and one for backup, since when they go out you are pretty much screwed.
 
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