Howell flooding problem

Howell flooding problem


Maroa, IL
1985 CJ7
I have a 85 CJ7 that the previous owner installed the Howell system on. As of lately the engine is flooding on restart if it is a hot engine. If the engine is cold or just a little warm no problem on restarting. After driving for awhile, come out and she won't start....smells super strong of gas. Finally got it started with the gas pedal floored to go into "flood override mode. Any clues to why this would just show up as a problem? Howell is sketchy on the flood problem. Online manual states it could be a fuel return line problem. Not sure about that one.
She has left me stuck twice now and the trust is no longer there.
Thanks a million for any suggestions, help or advice.

For starters I would check the fuel return line. It is probably the original system and with the oem carb they did'nt get much use and could be clogged up. This would increase fuel pressure which should be set at 10-12 p.s.i. the fuel pressure is adjustable from behind the throttle body. A fuel return can be checked by removing the gas cap and blowing thru the fuel return line, which should be unobstructed, a visual inspection of it would be good also, checking to rubber lines and for kinks. You can make another one by purchasing compressed nut tubing sections at an auto parts store, some guys go to a 5/16 or 3/8 return line for a free flow. Howell does state that there should be 4-5 lbs p.s.i. at the return line So I think replacing with 1/4 line would be best. You should also have a check engine light on indicating a rich condition. I have a fuel pressure gauge on mine to keep track of things, since it does get a drop in pressure as it warms up. You can always call Howell Engine Developments since their customer service has been known to be quite good.
Thanks for the reply. Yeah my first check will be making sure the return line is clear. It is the original return line so it certainly could be getting gunked up. I'll be checking tomorrow. I don't have a check engine light coming on. One thought I had was the duraspark maybe going on the flaky side. Maybe when it's hot it is setting up some strange condition. Just a thought. Injectors have a nice mist and are not dripping on shut off, so I was ruling out clogged or stuck injectors.

A spark plug deposit inspection can tell quite a bit if you are running rich. As I recall you should not be able to see any spray, so you are probably in a rich condition. A spray can be seen with a timing light shown down the throttle body with engine running. The Duraspark ignition can be upgraded using the "Team Rush" upgrade and you already have the "Nutter Bypass" which means the computer does not control spark timing. It is best to get a remanufactured distributor since the timing advance is set up for the non-computer engines on those units. Where as the timing advance was controlled by the computer on your oem system.
TBI needs at least a 1/4 in. return line. Go with 3/8 if you can. The stock carb filter vapor line used as a fuel return is way to constricting. Mine was 1/8 in. what a joke.

Been there, done that. GM used 3/8 line on their return lines. TBI is GM's baby.

Make sure your tank vapor/ charcoal canister is functional as well. A pressurized tank can force vapor back through the regulator. This causes nearly a full bypass of the regulator, till all the vapor is purged.

This back pressure can also cause fuel pump drainback problems while off.

Vapor compresses, fuel doesn't. It's that simple. It's hard to purge the injectors, with little fuel pressure reaching them.

GM in-tank fuel pumps were designed to keep all this from occurring.

I have no problems with my CJ's TBI after doing the above. I'd teamrush your ignition as Torxhead suggested as well when you have the chance.
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I'm running a Holley, but there are common issues.

I'm running 3/8" fuel and return lines. Put a fuel rated pressure gage on both lines and see what's going on. 10-12psi in and 4-6 psi out. It is adjustable.

You might want to check your temp sender. If thats bad it can cause problems too.

Holley uses a timer on the 'choke' circuit. Every time you shut it off it resets regardless. Then the closed loop O2 sensor takes over and leans it out.

Not sure how the 'choke' circuit works on the Howell.
Put a fuel rated pressure gage on both lines and see what's going on.
Unless you just want to confirm the advice a few of us have given regarding return line size...

Messing around with the regulator isn't a worthwhile task until you have replaced the return line. It may run flawless after doing this one thing.

We've had the problems, or know someone who has. we've cussed, thrown tools, stared at the manual, troubleshooted with some buddies, checked and rechecked every factor involved with the TBI system.

Everyone's first answer has been fuel return line. You admitted it was stock. My stock was 1/8. Everyone here has gone to a larger line. That's the best first step. see what happens.

How the heck is your regulator going to send extra fuel pressure back to the tank, when the line is too narrow?

It's not. The pump keeps pumping, regardless of built-up pressure.

Adjusting the regulator will only cause you major headaches at this point.

Dropping the fuel tank isn't fun. but with a jack and some boards, it's an fairly simple, one man job. you want wider lines, all the way to the fuel sender assembly. there's a small segment of 1/4 steel line that's the "elbow" you connect to. Your system can overcome that small amount of back-pressure. Use 3/8 line, and a pair of Fuel Hose clamps, screw on the side, not the top.

The lines are safely run on the passenger side rail. I've seen people run fuel hose inches from their exhaust before. Not smart. It's a very fit running hose in this area, make sure you don't pinch a hose while re-installing. Go slow. Use a very bright flashlight or headlamp.

Now while you're under there...

Make sure your return isn't hooked to a "tank vent". Make sure you have good lines from the tank vents to the rollover and check valve area.(behind driver taillight) make sure this goes to the canister.

This (vapor check rollover system) can be a can of worms, since many Jeepers have disconnected them for whatever reasons. This is a project for another day, if you want. Make sure you have new vent lines from the tank, to this area, now.

Check your gauge sender ground and lead connection too. clean and put some dielectric grease on, too.
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Thanks for all the great advice and info. I put the compressor up to the return line and could hear air coming from the opened gas tank.
Could still be restricted tho since it is stock. I did a check on any trouble codes and 33 came up. That is the MAP sensor. Going to replace it since it doesn't cost that much. I will go from there. I am going to replace the return line even if this clears it up. I will repost the results. Thanks again for your time and wisdom.

The map sensor location is critical, The vacumn line must flow freely and at a downward direction into the throttle body, up above on the firewall is a good location. This is to let condensation in the line flow into the back of the t.b. or else it can give you problems if it freezes up. Using a blast of compressed air might not give you a correct indication of a restricted return line.
My MAP sensor was about an inch from the TBI, straight backwards. Could possibly be the problem? Replacement on it's way. I realize that a compressed air check isn't the end all to determining flow. Thanks Torx.
Iran my lines on the passenger side to keep it away from the exhaust. I used P clamps with a rubber insert to avoid any rubbing damage.

The electric fuel pump is tucked up back by the tank with a prefilter and a final filter up under the hood for easy access. I don't plan on changing the prefilter very often with a plastic fuel tank.
In the instruction manual for the conversion, which if you don't have it, is available on their website. It states "The Map sensor can be mounted in any convienient location on the firewall; however it should be mounted with the vacumn line pointing down, and level with or higher than, the tbi base. The Map sensor has its own vacumn tap at right rear of the TBI, and nothing should be tee'd into this line" FYI
What size and type of line did you run?

I ran aluminum fuel line with a 3/8" ID from Summit Racing. I put a reverse flare (brake flaring tool) on the ends and a rubber fuel hose to allow for the flexing at the tank end and front fuel filter. I put lots of P clamps and ran it on the top of the frame rail. 5 years and 1300 hard miles - no issues.

If my buddy can run aluminum on his nitro coupe drag racer its good enough for me.

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