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FiTech issue

BGBronco

Contributor
N A S H V I L L E
Joined
Jun 23, 2017
Messages
1,543
Loc.
Tennessee
302, Fitech, Dual Exhaust
Well, My FiTech has been running flawlessly for a long time but has an issue now. Very rough idle on startup and driving. Seems to be isolated on the driver's side of the engine based on exhaust popping and some smoke from the driver's side tailpipe.

I ended up getting stranded (luckily in a parking lot) when it died and would not start. Finally got it going but it was a rough drive home. Temp is hot here in Nashville but that hasn't been a problem before so I don't think it's a vapor lock issue. Also, the fuel pressure gauge is at 50 ish so that seems to be in good shape.

Here are some of my current Fitech readings. Thx in advance!
 

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.94 OR

Contributor
Bronco Guru
Joined
Jul 5, 2009
Messages
1,659
To me, the basics says the injectors on the side of issue are not getting fuel. Ignition should affect a single hole or all holes so I'd rule that out initially.

I had sent you a note a week ago or so dealing with mine. I was questioning why it ran so poorly so I yarded it off and pulled it apart as that always makes me feel better. Found the O-rings in the pressure manifold were starting to come apart and I was getting floaters in the pressure relief valve and apparently in the inlet screens of the injectors. $2.24 for 4 new fuel rated O-rings locally and a clean up, the thing runs pretty good now. I did a full relearn on mine for my reasons but I would think you could get yours clean and fire it back up.
 

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BGBronco

BGBronco

Contributor
N A S H V I L L E
Joined
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Messages
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Loc.
Tennessee
To me, the basics says the injectors on the side of issue are not getting fuel. Ignition should affect a single hole or all holes so I'd rule that out initially.

I had sent you a note a week ago or so dealing with mine. I was questioning why it ran so poorly so I yarded it off and pulled it apart as that always makes me feel better. Found the O-rings in the pressure manifold were starting to come apart and I was getting floaters in the pressure relief valve and apparently in the inlet screens of the injectors. $2.24 for 4 new fuel rated O-rings locally and a clean up, the thing runs pretty good now. I did a full relearn on mine for my reasons but I would think you could get yours clean and fire it back up.
I am running again but it's rough at idle / low speed. I'm assuming it's related to the AFR being below target in the first image as well as the IAC steps now being much higher than 10. I'd like to figure out of this is a fitech issue or an engine issue before I start taking things apart.

Sorry for the dumb question but where are the O rings located and where is the pressure relief valve? Thank you.
 
Last edited:

.94 OR

Contributor
Bronco Guru
Joined
Jul 5, 2009
Messages
1,659
In my picture, the fuel pressure regulator is the shiny cylinder on the left side. It resides between the throttle plates on the passenger side of the vehicle.

The fuel coming into the throttle body comes into basically a square plenum circling the venturies and if the pressure is too high and not consuming the fuel, the regulator opens and allows the fuel to the upper deck and out the rear port. On each side above the injectors is a metal manifold (my term) that has pressurized fuel available to the top of the injectors and is fed across to the other side through ports and channels. Where these side manifolds bolt up to the center body there is an O-ring at each upper corner.
 

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