FITECH Mystery solved

[jerry work]

Some of you will remember that the new owners of our Clasco experienced a no start issue following refueling south of Denver last summer on their way back to Alaska. They reverted to the carb and made the rest of the trip. At the time there was much speculation on this forum as to the root cause issue. Many speculated that it might have been too much heat for the throttle body mounted ECM, others that the high pressure fuel,pump inside the fuel command center might be bad, etc.

We are in Quartzite, AZ for the day and it turns out the new owners are as well and found us. It turns out the issue was an intermittent failure of a connection inside the main factory wire harness plug. He said he called the factory when they got back to AK and asked the FITECH guys what the problem might be with the throttle body. They had him reinstall the FITECH throttle body and it fired right up so the mystery remained. Later he said they experienced another failure after fueling. That time he rooted around under the hood and while moving things around heard a click. The FITECH fired right up again. He then could replicate the issue by squeezing that connector, one wire crimp was faulty inside the plug. No issues since.

Who would ever have thought a factory crimp could fail intermittently inside a factory plug.........

Jerry Work
The Dovetail Joint
Fine furniture designed & hand crafted
in the 1907 former Masonic Temple building
in historic Kerby, OR
http://jerrywork.com

 

[LarryW]

> Some of you will remember that the new owners of our Clasco experienced a no start issue following refueling south of Denver last summer on their
> way back to Alaska. They reverted to the carb and made the rest of the trip. At the time there was much speculation on this forum as to the root
> cause issue. Many speculated that it might have been too much heat for the throttle body mounted ECM, others that the high pressure fuel,pump
> inside the fuel command center might be bad, etc.
>
> We are in Quartzite, AZ for the day and it turns out the new owners are as well and found us. It turns out the issue was an intermittent failure
> of a connection inside the main factory wire harness plug. He said he called the factory when they got back to AK and asked the FITECH guys what
> the problem might be with the throttle body. They had him reinstall the FITECH throttle body and it fired right up so the mystery remained. Later
> he said they experienced another failure after fueling. That time he rooted around under the hood and while moving things around heard a click.
> The FITECH fired right up again. He then could replicate the issue by squeezing that connector, one wire crimp was faulty inside the plug. No
> issues since.
>
> Who would ever have thought a factory crimp could fail intermittently inside a factory plug.........
>
> Jerry Work

With my FiTech, I have high pressure pumps in the tanks feeding a pressure regulator and dead heading to the Fitech. I was having trouble with no
start after a hot run stopping for fuel. Hooked up a fuel pressure gauge and found that on shut off, the pressure burried the needle on the gauge. If
I released the pressure, I got immediate start. I'm speculating that the pressure got so high that it held the injectors closed for a no start.
Releasing the pressure allows for the pump to pressurize at normal 58lbs and allows a normal start. Currently thinking about adding another Fuel
pressure regulator at the output side of the FiTech to bleed pressure in excess of 70lbs or so, back to the fuel filler pipe. I did this when I had
the same trouble with my EBL system. Eliminated the no start issue. Just what I think.

--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

 

[justin brady1]

Good to know Jerry thanks for the update.

Larry, why would the pressure build past the regulator? The fitech already has a built in regulator, and you've added another. Curious where the spike
in pressure is coming from. Boiling fuel from heat soak?
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

 

[LarryW]

> Good to know Jerry thanks for the update.
>
> Larry, why would the pressure build past the regulator? The fitech already has a built in regulator, and you've added another. Curious where the
> spike in pressure is coming from. Boiling fuel from heat soak?

I have not added another regulator YET. Just considering putting another in because it worked so good with the MPI system I had. Yes, the Fitech has a
built in regulator. It works with the Fuel Command Center, regulating and returning fuel to that FCC. My Fitech is dead headed. The regulator is
located back at the tank and regulates and returns fuel before it goes to the TB. Boiling fuel from a heat soak builds pressure and since the TB is
dead headed, (no return line from the TB) and the engine is not running to relieve the head soak pressure, the pressure has no where to go, so builds
to a point that it holds the injector pintles closed, and no start for lack of fuel. Cracking open the plug on the TB relieves the pressure and allows
the pintles to open and engine to start. By putting another FPR on the output side of the TB set to 15 or 20lbs higher than the running pressure, it
allow s the engine to run normally. When heat soak occurs and the pressure gets to 70lbs or so, the return regulator bleeds off excess pressure
allowing the pintles to open and engine to start. It worked on my old system, should work on this. I've talked to tech support at FiTech and they
concur. Just my theory on what's happening here.
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.