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TECH SPECIALIST
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Discussion Starter #1
sigh... race day just went down the tubes...

toppex off the truck before hitting the road (8.9 gal), 85 miles out i stop @ a rest stop to empty the holding tanks & truck wont fire back up. intake temps up at 150+* so i figure its the tune nit compensating timing. while stuck here i do the obvious and check the fuel pump return flow & its good. then i take a wiff of the tank and it smells gas contaminated.

called the station where i filled it up to let them know and they are going to get someone out there to test the fuel.

so the question is, how much fuel contamination (if thats it) can the system handle before damage?
 

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TECH SPECIALIST
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Discussion Starter #2
Update... looked at ECM data with HPT & it looks like maybe a bad FCA or rail pressure sensor... rail pressure rises to 530 psi, commanded is 5.039k, fca actual = 14.8%, desired =38.3%. Crank sensor measures 198 rpms, cam sensor measures 198 rpms.

Unplugged the FCA and no change. I would have expected max rail pressure and no change, no start.

Thoughts?
 

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756 Posts
I had a bad rail pressure senor one time. It didn't prevent my truck from starting but it ran like crap. At fist it was intermittent then it acted up all the time. Didn't throw codes at fist but then it threw a low rail pressure sensor voltage and rail pressure to high.
I'm assuming that your truck has no code? I'm wondering if maybe the wiring to the rail sensor is bad? that would cause the truck not to see the rail pressure it needs..... if there is gas in your tank, cp3 might have grenaded but I would have thought there would have been warning sighs running like crap or knocking real bad. Just a shot in the dark, maybe remove the line that feeds the rail coming off the cp3 and see if theres metal in there. sorry man wish I could be more help.
 

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Premium Member
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Unplugging the fca and no change I’d put a different one in and see what happens , definitely get the fuel tested if your smelling gas .
 

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TECH SPECIALIST
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Discussion Starter #6
Well I sent it to a shop since I dont have a spot to tear it down... easily. What I grabbed last nite is all I know at this point. I did pull some fuel out of the bowl and there was no water and it did not smell like gas. I will toss some onto concrete and see if it lites up with fire applied. It is weird how it smelled at the fill tube.

The rail sensor, I would need to know what the FCA would be doing to know if the fca was behaving as it should have, commanded vs actual. Looks bad to me. CP3 has 250k or so on it. The fact that the rail did not spike with the fca unplugged tells me its stuck. I think I might have a spare under the back seat that was functional when I yanked it.
 

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TECH SPECIALIST
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Discussion Starter #7
Update...

pump inlet pressure = 18.0 psi, tech swapped the 3 mic filter at my request since it was due anyways (25k on it). After each event, still no start. He went back in to see if any codes were there and there now were 3.

P0480 | Cooling fan 1 control circuit / open (low speed fan relay)
P0483 | Cooling fan speed
P0251 | Injection fuel valve feedback circuit

Cleared the codes and now the truck starts as expected. WTH...? So, I had him yank the ECM connectors and clean them along with the fan plug that was oil soaked (was previously covered & at some point that cover was lost) and hook it all back up. Fires up as expected. Did some research and found a few threads with similar symptoms as what I had with a P0483 code. Someone suggested yanking the fan clutch fuse. However I think that fuse also is tied into the AC control some how.

Is it fixed??? IDK but it runs as expected. Will monitor for now, rebuild the trust in it and go from there.
 

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Good to hear, hopefully it is fixed.
 

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Sorry to hear the 'ol economy battle wagon let you down. Hopefully that fixes the problem though!
 

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TECH SPECIALIST
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Discussion Starter #11
Yeah now I need to build trust in it again. I need to find the fan clutch plug that I pulled off the old fan clutch when I yanked it for the e-fans and use that to seal that plug off.

Gonna have to do a "do-over" now at the track. Racing buddy reported his times & I think they would have been close head to head... however, he usually gets quicker when racing against me. :LOL: Cant leverage his bad habits anymore I guess :ROFLMAO:
 

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My plugs been just hanging for 10 years , it’s filthy and I thought about cleaning it up and getting the other side and sealing it up just never got around to it . You need to go into the dtc list and disable the fan codes
 
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