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Discussion Starter #1
I captured via log the moment my FiTech 600 Power Adder stalled on me while I was driving. I'm hoping somebody on here has seen this type of log behavior before.

I've been driving this setup for around 15 months now, around 8k miles. Only within the last two weeks has this thing shut down on me and this was my third time so it's time for me to get serious about diagnosing the cause. I thought I was having Fuel Command Center issues, and I might still be a fuel pump issue, but the engine temps and FCC were not very hot during this most recent stall so I doubt it was an FCC heat issue.

One of the items in the attached log clip is the AFR reading that went to 20 right as the engine starts to stall out. And when it is failing, the engine is trying to run, and barely holds on, before complete stall. Almost behaving like I was in fact out of fuel.


I'm open to suggestions on what to look for. -Thank you!
 

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Discussion Starter #2
Update:
Shut down again tonight. However, this time I was on a quiet road and could hear my fuel pumps while sitting on the side of the road. The update is, my Fuel Command Center was 100% out of fuel. Something on the low pressure side internal to my FCC is locking up and blocking fuel from entering. I need to learn how that low pressure side works and what would block fuel. I'm open to ideas from those of you who know what is on the inside.

Only recently did I start looking the the gauges on the FCC as why else would I? That thing is under the hood, out of sight out of mind... I started looking at it recently because the engine quitting on me. My low pressure gauge is sometimes on 4lbs but also sometimes bouncing on zero, or just zero. I assumed that is how this FCC is supposed to work. I no longer believe that. If your low pressure gauge is zero, take it from me, you really are not getting full fuel flow into the FCC. And this was after me installing a brand new Holley electric pump at my tank to feed the FCC.

Sitting on the side of the road, the FCC was very hot, as it has been since the day I bought it. Tonight I'm sitting there with all power turned off and then it happened, something made a "thump" and then I heard what pressure remained in the low pressure line flush into the FCC. That is why I believe I have an intermittent block happening inside the FCC. What was amazing is that within a second, the FCC was cool to the touch from all the new fuel that just got dumped into it. I immediately turned the key on and I had fuel pressure readings on both high and low pressure gauges. Fired it up and drove home.
 

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Update:
Shut down again tonight. However, this time I was on a quiet road and could hear my fuel pumps while sitting on the side of the road. The update is, my Fuel Command Center was 100% out of fuel. Something on the low pressure side internal to my FCC is locking up and blocking fuel from entering. I need to learn how that low pressure side works and what would block fuel. I'm open to ideas from those of you who know what is on the inside.

Only recently did I start looking the the gauges on the FCC as why else would I? That thing is under the hood, out of sight out of mind... I started looking at it recently because the engine quitting on me. My low pressure gauge is sometimes on 4lbs but also sometimes bouncing on zero, or just zero. I assumed that is how this FCC is supposed to work. I no longer believe that. If your low pressure gauge is zero, take it from me, you really are not getting full fuel flow into the FCC. And this was after me installing a brand new Holley electric pump at my tank to feed the FCC.

Sitting on the side of the road, the FCC was very hot, as it has been since the day I bought it. Tonight I'm sitting there with all power turned off and then it happened, something made a "thump" and then I heard what pressure remained in the low pressure line flush into the FCC. That is why I believe I have an intermittent block happening inside the FCC. What was amazing is that within a second, the FCC was cool to the touch from all the new fuel that just got dumped into it. I immediately turned the key on and I had fuel pressure readings on both high and low pressure gauges. Fired it up and drove home.
From my gathering, the FCC is nothing but trouble for most. Part of the reason I went with Holley sniper in the first place.
 

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Discussion Starter #5
Another one bit by the FCC it sounds like. Are you sure your pumps are actually pumping fuel to the FCC though?

While in my garage and with the low pressure gauge reading zero, I disconnected the line and it pumped full stream into my lawn mower can. Was the same result with the pump I replaced. Both had full stream.


I'm watching videos on youtube for opening the FCC unit. Looks easy enough. I need to figure out what is between that gauge and the fuel line, and where that float fits into the mix. I'm wondering if the needle and seat valve on the float is getting stuck. It is a holley style needle and seat so I do know that a single spec of sand can lock that thing up.


I'm open to ideas on what to look for from those of you had already opened one of these up.
 

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Discussion Starter #6
And there-in lies the decision to be made. If I'm going to crack this FCC thing open, I might as well remove the float and vent to create a surge tank style system out of this and take care of the heat problem.
 

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I went through this too. And my car is a project with intentions of replacing a lot of things. So I thought now was the time to parts blast the thing. I replaced the tank, pickup, fuel filter before the mechanical pump and even the high pressure filter after the FCC. With todays fuel sometimes it does too good of a job cleaning and dislodges debris. After the 3rd breakdown, I open the hood, lift up the FCC and it was light/empty!! Then I worked backwards to the mechanical pump, pulled the line, no fuel. As I was reinstalling the line I noticed the line that fed the mechanical pump was kinked and sucked flat. it was close to the engine so as it heated up, must have got more flexible and kinked. Just add this to my list of blaming Fitech when I'm the culprit.
My $.02, the FCC works, and has worked for your 18 months, so you have to figure out your fuel supply issue. I'd get that squared away before converting to a surge tank. If the FCC isn't getting fuel, neither a surge tank or sump tank style will work

just to add; since my gauges are broken, i've installed those glass inline fuel filters on my fuel feed and return lines and can see the fuel flowing in both directions.
 
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