Vapor locking common?

[Green-Tonka-CJ5]

So my 1980 Jeep CJ5 with the 4.2 converted to fuel injection has what i can best describe as a "vapor locking" problem mid day in this weather. It will be going along and then seems to cut out/ lose power momentarily. Only happens when running hot, so i assume its the fuel line running near the intake/exhaust manifold area. So i re routed it, and insulated that area but still have same symptoms. Temp gauge reads under half warm on the dash, so the motor is fine, but engine bay seems hot.

Has anyone else had a similar issue or any advice where to tinker next? Thanks

 

[bryson]

I don't think vapor-locking is terribly common, but you are certainly not the only one that has the problem...

If that is indeed the problem, you're on the right track with re-routing and shielding your fuel lines. Make sure the sections along the frame aren't getting hot, like near your cat or muffler. Also, make sure your return line and tank vent are clear as well.

Next step might be to use a fuel pressure gauge to see if the pressure is dropping when it cuts out... could be a pump issue?

 

[jdub]

I've been through a pump on my kit within the last year. My pump died a block away, I was just telling someone how well my jeep was running and then nothing. Had to get a tow It definitely could be that, you also have a sensor on your crank as well as a throttle position sensor, Check those as your fuel pump will cost you ~80bucks. Those other sensors control the fuel mixture and throttle which both are issues you could have. Of the two times we went up af canyon it vapor locked the time that it wasn't super cold out <70* I still think that you need to chase the lines and see what could heat it up like Bryson said. Never thought about the return line, good idea. Something is getting hot, cause it works fine 9 months out of the year, mornings and evenings. Or just re-install the tow bar

 

[jdub]

Could insulate even the pump, just a thought. Filters are only $15 at hesco. I know it hasn't been changed, Maybe it is clogged and overworks the pump??? Pump does seem to work though in a vapor lock situation. But then again so did my bad one, Made the noise and gave pressure but couldn't continually push enough to keep the motor going. Scary thought, I ran the pump in my hand hooked up to wires to see if it was pumping. Gas+electricity=