68 Cj5 Holley Super Sniper Tbi 2gc Or Howell Tbi

I did notice a change when I went to the 51 jets. The rear I have at 54. I had put an 8.5 power valve in and went back to the 2.5. That helped some.
I am thinking of a 6.5 power valve as that is what the 390 comes with. The 390 is plenty of carb if it gets dialed in. You could also add a rear metering block
with jets. Right now I am not making any changes until I put the AEM and vacuum gauge on. I would mod the 390 before going to the TA470 and it has
smaller primaries for a better vacuum signal. Another thing people are doing is using a fuel pressure regulator and turning the pressure down when going off road.
This puts less pressure on the needle valve to hold back the fuel at a time when not much fuel is needed. Fuel making waves in the float bowl have less effect.

 

I canceled the 450 as well as the crank trigger, and both companies were great about honoring my requests. I was tempted to keep the 450 coming anyway...

Replacing the rear metering block might be ideal for my 390. Any idea what that involves, or where to pick one up?

When I think back, this 390 was actually running pretty good when I pulled it out. I think I may have given it a bad rap prematurely before I went to the EFI.

BACKSTORY: I bought the CJ in February of '21 and started putting out the fires on multiple fronts. The carb was dying at the top of very steep climbs. I assumed it was the floats et al. I then had to mothball the CJ over the good weather months so I could tend to my real estate projects and get some fishing in.

Got back to it the following winter. Once the rig was approaching drivability, I ran it over to my mechanic to address some issues. Oil pan gasket, T-case gaskets, fluid levels, soft brake issue, and carb. I'd already tweaked the floats and idle mix screws, but he completely disabled the e-choke and messed with the floats a bit more.

After that it did run better, and even the cold start wasn't too bad since it started pretty good generally, even in cold weather (nothing like the EFI though). But it was still dying at the top of steep climbs.

It wasn't until AFTER I'd installed the EFI that I realized the fuel cell was installed improperly. The fuel line was coming out of the bottom of the FRONT of the tank, so with less than a full tank of gas the motor was starved for fuel after the fuel moved to the rear of the tank. Sucking air. I spun the tank around and ran the new lines and e-fuel pump from the bottom rear, and that likely cured the climb issues. I can't know since the EFI never worked well enough to run it offroad.

LOL, but now I'm going to run out of gas on steep downhill descents, losing my power steering and brakes! I may have to run an aux tank underneath somewhere...

It was after another breakdown last winter (early '22) while doing some test runs on the local bluffs that the FiTech was suggested to me by another mechanic neighbor who owns a CJ-7, and I decided the CJ was worth the investment since it had proven its offroad capabilities to me at that point.

So the 390 may have been taking heat for a completely unrelated issue!

I'll find out soon. New parts are on the way... In the meantime I'll stay on the list for the official Holley refurbished TA470 if one becomes available.

So you dropped the jetting on both front and rear of your 470? Interesting. The 6.5 may indeed be a solution. Curious to see what your new toys tell you. I think the 470 is a better carb, but am wondering if anyone is truly raving about theirs by now? I gave thought to looking for a Quadra-flush, as we used to call them, a 2100, and even looked at Toyota carbs earlier today. Never had issues with my 2-bbl on my early 4Runner, and I ran it everywhere.

The e-fuel pump I ordered runs 4-7 psi. Maybe it'll do the trick. Some guys have had problems with their fuel regulators, but it's an easy upgrade. But I think that TA offroad kit will make a ton of difference in itself. Time will tell.

FYI, up until a few years back, my folks lived in the Tucson area. I was down there many times, but never offroading. They lived west of town, over the mountain range and north of the Ajo Highway, IIRC. I remember you turn right at the McDonalds there at the top of the hill. I'm sure you are familiar with that area. Lots of places to have some offroad fun down there, in the winter...

 

A bunch of people like the 390 and the same for the TA470. It wasn't until fuel injection started to become more affordable that everyone wanted to make the jump.
Most run the high altitudes and FI is much more friendly in those conditions. I added an O2 sensor to my motorcycle [Cali models came with them] and an interface module.
I can run to the top of the mountain here , about 9000ft in high gear. No noticeable loss of power and that is just cruising.

I did re-jet the secondaries but was having other issues at the same time. Just working out the bugs. I decided the best way is know what you are dealing with exactly.
I go through phases of doing work on this thing. I can just close the door on it as I have other things I can be doing. In a pretty good phase right now.

I know the area where your folks live as I know every area. I worked all over town and the state. There is the mountain to go cool off and I know where the pools and
waterfalls are. The pools are year round but can become stagnant and the falls when it rains.

 

I'm not fond of climbing under the Jeep and rerouting fuel lines mounted above me. Plenty of room under there, just not a fan of it. I have a vehicle lift planned for my warehouse space once I get my inventory liquidated. What a difference that will make!

But last night that's where I was, hooking the carb back up to fuel and getting it ready for both electrical and mechanical fuel pumps. I was fortunate that I had enough of the EFI hose to get it to run to the carb fitting, and by chance, it is exactly 'enough' (tight line) to reach the stock mechanical fuel pump as well, so that leaves me two options.

I never pulled the mechanical fuel pump off the motor when I installed the FiTech. I just cut the lines and left it mounted. Figured I'd pull it at some point after the EFI was functioning properly. Of course that never happened.

So last night I ran that fuel line down to the mechanical pump and hooked it all up. Can you believe it worked? I pulled it off and checked the diaphragm and passages first, then mounted it and ran the three lines, including using the EFI return line to the mechanical pump seep fitting. Not the best fit because I had to run a vacuum hose over the fitting first, then my 3/8" high pressure EFI hose over that. Somehow it worked.

I cranked it a while but no response, so I shot in some starting fluid, to which it kicked right off. Soon the fuel caught up and it was running on its own.

DAMN!!! That thing purred like a kitten at idle, and around 600-700 RPM at that. That was SOOOO nice after dealing with that pulsing EFI for over a year. It just sounded HEALTHY. I can't tell you how warm and fulfilling that was! The carb had been sitting in a box for all of that time as well.

I took it out for a test drive at around midnight, not wanting to wait for daylight. Needed a refresher on any bad habits the carb may have had. I've probably had less than 10 hours on the carb since I bought the CJ altogether, so recalling exact behavior was a bit unremarkable in my memory.

The thing ran fine. The only 'habits' it had were when coming to a stop sign. The motor would just die. Easy start again. So I opted to try just a slow deceleration when coming to a stop, and the motor didn't die. It did that before as well, pre-FiTech. I may check into it, but first I have to check the timing.

You have NO IDEA how nice it was to have a 'normal' Jeep again. Starts, idles, drives, all of that. The FiTech was like a blindfolded madman. Completely unpredictable.

The low-pressure electric Holley fuel pump will be here soon. Curious how that's going to behave. From there I can start playing with some jetting and the offroad tweaks and the like.

Maybe there's hope for this summer after all! I'm going to have to hook the boat up for a test run as well. I think it will add stability to my ride. Our small town wants me to display them both in our annual founder's parade in a few weeks. That might be fun.

Because of the no-fuel issue, FiTech has instructed me to send the unit to them for a warranty repair. IMAGINE THAT!! I'll be updating the FiTech thread soon...

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Here's the motor when I bought the CJ. Holley 4160 390 CFM with Edelbrock air cleaner, mounted to Offenhauser Dual Port 360 intake manifold:​

Here's the FiTech Go Street 400 HP after install:



And now back to the Holley 390, plumbed a bit differently from the mechanical fuel pump, borrowing parts from the FiTech EFI:


​

 

I’m running the Holley 390 on my 225. It runs very well off road with no issues on hills, side or up or down. I am running a 5.5 power valve and #50 main jets, upgraded needles and seats with the springs. I changed the squirter to a #25 with 1 size smaller accelerator cam and the lighter spring in the accelerator pump, (not a lot of vacuum). Also running whistle on the metering block and an overflow tube from a TA470. It starts with 2 pumps on accelerator and turn of the key, doesn’t matter hot or cold. Idle set at 550-600. Floats are set with fuel just below the sight plugs. Mixture screws are set about 2-1/4 turns out. Averaging 18 miles per gallon on the highway at 65mph. I was getting a stumble on the road if I tried accelerating under a load, was able to smooth it out pretty well by going up on my squirter and down a size on accelerator cam and changing to lighter spring in accelerator pump.
Start with basic set up and make 1 change at a time until it runs how you want it. Sneak up on it.

 

That's some great advice. I was thinking about going to the 5.5 PV myself, based on the vacuum feedback that I was pulling on the FiTech handheld which ran around 12 psi with an occasional 14. I'll have to pickup a vacuum gauge.

The EFI did give me a great feel for what this motor can do with proper fueling. It had it's bright spots.

Did you replace the secondary metering plate, or did you just stick with the stock 60 jet out back?

Other than motorcycles, I'm a bit illiterate on the engineering of these carbs, so I went onto Holley's site today and did a lot of reading and watching videos. They do a great job! The interrelationship of the various components is much more enlightening for me now.

What elevation are you generally at when you're offroad? I see you're in Stockton, at sea level. Do you run up over the Sierras?

Which ignition are you running?

Here's Holley's page on power valve tuning. You can get a custom plate for changing jetting in that as well:

https://www.holley.com/blog/post/how_to_tune_the_power_valve_in_a_holley_carburetor/

 

I left the stock metering plate and stock 60 jet.
I’m at sea level here in town but run it up at 8k during the summer, able to maintain 55mph in the hills with the SM420 and overdrive with l 4:88’s and 33” tires.
I’m running the DUI electronic ignition.

 

I’ll have you sold on TBI after this year’s Rubicon run

 

I might haft to drag my JEEP filled with pop and good brown water up to your place for some time in your shop. I keep reading the threads on TBI, and am considering it. The simplicity of a carb is nice.

 

Remember the early 90’s???
The Chevy TBI trucks easily went 100k miles without issue…… fuel pumps were the most common failure.
I’ll raise you one…. My wife will show you how well TBI works when she drives Rubicon start to finish!

 

I watched all the videos of you JEEP in action on the Rubicon, and not arguing that it runs great, (especially after you figured out what manufacture couldn’t/wouldn’t do). It’s not the wiring or figuring out the fuel delivery, it’s the tuning and running down issues that has me a little scared.

 

And yes….I’m planning on watching in person your wife out driving me.. Gonna throw my hat in ring for Rubicon trip.

 

Curious as to which TBI you recommend.

 

I've never said that she will out drive anyone..... But she does take spotter directions better than 99% of men on the trail....
I attribute it to her initially being 100% out of her element and scared less. What else could she do other than listen and follow directions.

 

If I were shopping for a GM TBI system and I did not want to build a junk yard system, I would use Affordable Fuel Injection.
AFI is a little over $500 cheaper than the "H" place, AFI is more knowledgeable about TBI systems and has better/friendlier tech help. AFI was the only place that was honest and up front about the TBI system not working with odd fire engines without a crank sensor. You can have them build the harness with wire ready to add a crank sensor yourself. AFI will also burn the Scalded Dog tune for you when they ship your system.

That said, I can only recommend locations to buy parts. All of these GM TBI companies offer the same basic parts in the same configuration.
How well your GM TBI system runs depends on YOU the installer. If you do a install job then you will likely have a outcome and be frustrated.
If you think you are going to slap a GM TBI system on your jeep and never have to learn a little about how it works, you will be frustrated. It is no different than buying a new carb, slapping it on a jeep and not expecting to have to tune on it a little bit.
The "H" place has referred odd fire customers to me to help sort out their kits and walk them through crank sensor installs...... Very early on I realized that I needed to start out and ask for pictures of the installation and I could not proceed until I saw pictures. On more than a few occasions I have instructed the customer to remove the system and reinstall it properly before I can help them.
The GM system is very, very basic but needs proper care taken when installing to ensure the desired result.
Doesn't matter if your installing a GM TBI or doing a complete LS engine swap, a install is going to lead to a outcome.

 

AFI sounds like one of the better options. They have been doing it for some time and using a crank trigger to smooth out the irregular pulse of the odd-fire engine.
Here is a link from circa 2000: https://forums.off-road.com/threads/buick-v6-odd-fire-225-231-tbi-runs-great.38855/

 

There are a few odd threads out there on odd fire TBI systems, but no one ever actually documented the process or showed pictures. Just a few guys here and there who were 20 yrs ahead of me.
The goal with my thread was to dissolve the mystery around fuel injecting an odd fire engine and provide enough documentation for DIY'ers to tackle the project.
After competing my project and learning a ton of stuff, I came to the conclusion that the "H" place was considerably more expensive than AFI for the exact same product.
A few members here have bought kits from AFI and as far as I know they have been really happy with the results.

 

Which H place? The one with a W or the one with a Y in the name? Not that it really matters, but you have the W so it got me wondering.

The Affordable site doesn't list anything for the 225. I'd be curious as to what response they'd offer toward an inquiry.

https://affordable-fuel-injection.com/

The thing I liked about FiTech was its alleged pre-programmed V-6 ECU starting point, with a learning curve after that. Kind of a plug-and-play. It was pretty simple overall, once installed.

If only it worked--

 

AFI offers a Buick V6 kit..... You have to add your own crank sensor to make it work with an odd fire. Their kit comes with a chip burned for the V6 or I have an even better tune that was written on a chassis dyno. That tune is referred to as the Scalded Dog tune.