vapor lock TBI on 350 small blk

[BGoodale]

Hi Guys; Thanks for all the suggestions. I'll make some more changes , such as upping the pressure,and insulating the lines. I even tried about a half of gallon of diesel in with the gas on last fill up. Haven't had a chance to drive it very much but runs a little rough. I'll keep working on it. Like I told my wife. Either I'm going to fix this thing or it will kill me. Brett

 

[BGoodale]

Hi Wygate; I was interested in your comment about a stock tbi pump into the cj tank. Tell me how you did it and do you think it helped or not. Plus, I think it is running lean since it really surges at higher elevations plus the plugs look like it's running lean but I thought the ecm etc. would take care of all the issues. Any thoughts, Brett

 

[Wayne M.]

Hi Guys; Thanks for all the suggestions. I'll make some more changes , such as upping the pressure,and insulating the lines. I even tried about a half of gallon of diesel in with the gas on last fill up. Haven't had a chance to drive it very much but runs a little rough. I'll keep working on it. Like I told my wife. Either I'm going to fix this thing or it will kill me. Brett

Good luck. Take it nice n slow, youll get it sorted out.
Definetly tap in a fuel pressure gauge before the regulator. I think it's important for it to have an isolator if you'll bring it in the cab. Also another thought, do you have a failssfe to cut the pump I case you got in trouble? IIRC, the original GM TBI circuit included the oil pressure switch to energize the fuel pump relay. Howell may have done this in their kit, but good to check. With this logic, if the engine were to quit for any reason, so would the fuel pump.
Please be careful about what you put in the fuel. You don't want to coat and damage the O2 sensor.

 

[BDaugherty]

First you need a fuel pressure gauge. It doesn't need to be in the cab, you just need to see if you're getting fuel when the problem comes up. Next you can route the return fuel through a cooler. Just make sure the cooler is in a protected area that gets some airflow. Last you need to use metal fuel line throughout with rubber only where needed for flex. Other thing to look at is if the exhaust passes anywhere near the fuel tank. If it does, wrap it to prevent heat transfer to the fuel system. I agree with upping the fuel psi a little... but you need to know where your vapor lock is occurring. Is it in the throttle body, tank, or lines? Are you running an ethanol blended gas? Ethanol boils at a lower temperature than straight gas does. Diesel fuel mixed with your gas will not have any benefit.

 

[SVick]

Hi BGoodale, I had the same engine in my CJ for years until 1-1/2 years ago when I dropped in a Vortec383 to replace the TBI 350. I was using the stock fuel injection which I believe is what Howell uses and I was using a Howell harness. I did not have the issue you have but I did have an issue with the fuel roll over valve leaking when I pressurized the fuel system for a Ca smog check. It is located behind the drivers side rear wheel up in the fender where the tail light wires go. I'm just thinking if it is not sealed tight, it may cause a similar issue. I bypassed mine since most of them leak. Hope this may help, good luck, Scott

 

[LNaugle]

Thanks LNaugle; It does not have a heat riser, but the next thing I'm going to do is buy 5 gaskets silicone them together and install them under the throttle body. Thanks, Brett

Are you sure? Most all pre fuel injection heads have the heat riser built in and you have to use special intake gaskets to block them off. I see this a lot! Also, put the pump in the tank. The frame rail mounted ones can cause issues.

 

[BGoodale]

Hi LNaugle; I've been gone for a few days so I'm interested in the heat riser issue. I didn't think I had a heat riser since I'm kind of old school , but maybe I do. How can I tell ? Also, is there a kit to put the pump in the tank? Thanks, Brett.

 

[LNaugle]

Pull the intake... its the ports between the intake runners. Unless they are tbi heads it is there. Not sure if they make a pump to go in the tank, we just make em work . you can get the wiring pieces or be creative, cut your pickup tube so your pump strainer is on the tank floor. Check out Gen-rite, they make tanks ready to go also.

 

[BGoodale]

Hi LNaugle; I was just passing thru your town today. So I'm traveling but appreciate your input. Thanks , Brett.

 

[LNaugle]

Hi LNaugle; I was just passing thru your town today. So I'm traveling but appreciate your input. Thanks , Brett.

Well too bad you couldn't stop by!