Fitech back to Carb....

[vtboy51]

So I've had the Fitech installed for 4 or 5 years and I have never gotten it to run quite right. I've watch a ton of videos, asked numerous questions, and still I'm not confident in driving it. It will start every time when cold, but when warm it struggles to start which sucks when I stall at a stop sign or run into the store. I've seen many people post about this and I've tried the suggested fixes with no luck, very much could be my fault. At this point, unless there is someone in Vermont who would come tune it, I'm going to switch back to a carb.

The Fitech is running the timing, so I need to unlockout my distributor, and then what carb would you all suggest I run? Keep an electric fuel pump or put the manual back on? Thanks for any feedback.

 

[bronco italiano]

There are many "remote tuners" out there that may be able to help you out.
Going back to carb type depends on what you are going to do with your bronco. Off-roading, "Mall crawling", daily driver, etc.

 

[vtboy51]

There are many "remote tuners" out there that may be able to help you out.
Going back to carb type depends on what you are going to do with your bronco. Off-roading, "Mall crawling", daily driver, etc.

It's just a weekend driver, pavement and dirt roads but no off-roading.

 

[SteveL]

Q-jet works best for on and off road. If street only a performer is simple and works well

 

[gnpenning]

Qjet or motor craft 2100 series carb. The original is a very good carb. Manual pump or Carter .

 

[Madgyver]

QJet on my 393clevor runs well and I drive it all over the place with confidence.
I would have anxiety with running EFI and the cam that I choose to use.

 

[bsquared]

I am also a fan of the Q-jet carb and also had to trash an FI-Tech unit to go back to carb. VERY important step when installing that carb is to set the secondary air doors for the back two barrels to open up properly at wide open throttle. If you do not do this step, you might end up with a Car-B-Q like I did. After that I decided to go with the Explorer EFI stuff I had sitting in my attic. It's an expensive EFI system, but it is REALLY nice! You will need to go back to a low pressure fuel pump. Either go back to the original mechanical one or a Carter P4070 electric pump is a very good choice. Cheers, B2

 

[DirtDonk]

How does an improperly adjusted air door end up causing a fire? That sounds like a pretty important step!

 

[vtboy51]

Thanks for all the feedback. I'm going to go with the Q-jet and Carter pump. I just remember I also swapped in a new MSD distributor with the Fitech install years ago, so I either need to buy a new "Ready to run" distributor or buy the MSD box to work with my existing distributor.

Any options on which route to go?

 

[SteveL]

I prefer the. Hei distributor but if you go that route get the DUI dizzy. The cheap ones are just that

 

[gr8scott]

You don't need a HEI distributor to run HEI. This works very well with a Duraspark distributor.

 

[vtboy51]

You don't need a HEI distributor to run HEI. This works very well with a Duraspark distributor.

View attachment 942119

You mention a Duraspark distributer with this setup, I already have the 2 wire MSD distributor which I assume will also work with this HEI module...?? I Googled the HEI module, it's only $50 so that is clearly much cheaper than the $500 ready to run MSD distributor I thought I needed.

 

[DirtDonk]

Which exact distributor model did you get for the previous install? Maybe it’s already to run as it is?

 

[Johnnyb]

Hate to see you backing off of fuel injection. I have never personally known someone satisfied with FiTech, but there are great systems out there, per your preference and financial capability. My ProFlo 4 was basically turn-key and hasn't missed a beat since, 14 MPG on freeway!

-JB

 

[vtboy51]

Which exact distributor model did you get for the previous install? Maybe it’s already to run as it is?

Part number 85793, it isn't the ready to run version.

 

[ntsqd]

That distributor uses the D-S II pick-up assembly and reluctor already. Given that it is being used with computer controlled timing I'm sure that it has no mechanical advance. You should be able to buy the parts needed to give it that. If the rotor looks like this one: https://static.summitracing.com/global/images/prod/xlarge/msd-8467_xl.jpg then the mech advance system is right under the rotor itself and easy to get to. Unless MSD did something weird with the locked-out models.

The GM HEI module is a good module, I've been happy with those that I've used. Absolutely critical is that they be bolted to a heat-sink of some sort, AND that a thermally conductive grease is used to bed the module to the heat-sink. If you can find some, "Arctic Silver" is the best of these compounds. It doesn't take a lot of the grease, but you do need full coverage.
If you want to use a D-S II module you'll need a third wire going between the module and the distributor. It grounds the module to the distributor body and the system will not function without it.

I would suggest using the fuel pump that you have. You'll likely need to re-wire where it gets power from and how it does that. I'd add an oil pressure safety switch or an inertia switch to the control circuit. Use a by-passing type fuel pressure regulator, and put it as close to the carb as is reasonably possible. Doing this will help immensely with any tendency to vapor lock. I don't run dead-headed fuel supply systems anymore, especially not with a carb.

 

[vtboy51]

That distributor uses the D-S II pick-up assembly and reluctor already. Given that it is being used with computer controlled timing I'm sure that it has no mechanical advance. You should be able to buy the parts needed to give it that. If the rotor looks like this one: https://static.summitracing.com/global/images/prod/xlarge/msd-8467_xl.jpg then the mech advance system is right under the rotor itself and easy to get to. Unless MSD did something weird with the locked-out models.

The GM HEI module is a good module, I've been happy with those that I've used. Absolutely critical is that they be bolted to a heat-sink of some sort, AND that a thermally conductive grease is used to bed the module to the heat-sink. If you can find some, "Arctic Silver" is the best of these compounds. It doesn't take a lot of the grease, but you do need full coverage.
If you want to use a D-S II module you'll need a third wire going between the module and the distributor. It grounds the module to the distributor body and the system will not function without it.

I would suggest using the fuel pump that you have. You'll likely need to re-wire where it gets power from and how it does that. I'd add an oil pressure safety switch or an inertia switch to the control circuit. Use a by-passing type fuel pressure regulator, and put it as close to the carb as is reasonably possible. Doing this will help immensely with any tendency to vapor lock. I don't run dead-headed fuel supply systems anymore, especially not with a carb.

I did need to "lockout" that distributor since I was having the Fitech control my timing, so I will definitely need to undo that. I have seen others using the MSD Ignition control box in combo with the distributor I have. It is much more expensive than a GM HEI module, any benefits?

 

[ntsqd]

Not in my experience, no. For a really high output racing engine there may be an advantage to an MSD, but I have not found any advantage to an MSD on a mild street or off-road engine. I've not experienced a failure, but from reading a range of different forums over the years I don't think that they are as reliable as a good OEM ignition module.

 

[vtboy51]

Now I need some help on where to buy my Q-jet carb. I've looked on Summit and a few other sites and can't find one. Looking for one that will work with my Edelbrock intake (was needed for the Fitech setup), manual choke, and bone stock 289 (500cfm I'm thinking).

 

[ntsqd]

Q-Jets were never made that small of a CFM. I *think* a 750 is the smallest ever made. Due to the way that the secondaries work, it's not the problem that it would be if you were wanting to use a Holley that big.
A pic of your intake would be good, unless you know for sure that it has a spread-bore bolt pattern as well as the Holley/AFB 'square-bore' bolt pattern in it.

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