help traded jeeps fuel injection problem

[wadeo5247]

Hey guys I did something last week that Im afarid that i might regret I sold my 76 CJ7 and bought a 84 CJ7 with pwr str pwr disk hard top hard doors and very little rust.... It runs really good to a point but it has fuel injection and I dont know which one or whos the po couldnt tell me... anyways it will run great for about 30 mins then it will just die let it set for about 20 min then it will fire right back up and run good again for about 30 mins??? I have tried repalcing the fuel pump relay fuel filter, have the after market fuel tanked droped now and tring to locate a fuel pump.. any other sugestions ( the po also said that he had already replaced the fuel pump ) but Im running out of ideas help!!!!!!!
thanks in advance.
wade

 

[wadeo5247]

forgot to mention that it is a 5 speed with a strait six I will get photos up this wknd

 

[mtnwhlr]

Sounds like a vaporlock make sure the fuel lines aren't by anything thats going to get them hot and that you have a good vent at the tank.

 

[wadeo5247]

the fuel line is coming over the valve cover actully between the cover and the firewall how do i check the vent

 

[mtnwhlr]

Right after it dies take the gas cap off and see if it sucks a lot of air and I would follow the gas line all the way from the tank to the motor and make sure it's not by the exhaust anywhare.

 

[Sasquach]

Open the hood and take a photo, then we can tell you what FI you have.
Both aftermarket makers have good tech support as long as it's not a 4.0 or GM home brew conversion.

 

[Old Dog]

I've seen ignition modules act this way when going bad.

 

[hole]

Ditto on possible vapor lock. It could also have a pin hole in the fuel line before the pump (providing it's not been converted to in tank pump) If it's a Mopar MPI there will be a shrader fitting on the rail so you can test psi. You can carefully bleed off air/vapor at this point as well. Pics of your set up will help

 

[wadeo5247]

I really appriciate all the help guys still havnt got to chase the fuel lines I know that it is rubber for a little ways then goes to steel then back to rubber then to the after mkt fuel tank.. I'm thinking of putting all new lines in when I replace the fuel pump the module is also new according to po it looks new too.. I am concerned with how close the module seems to be to the header though it seems to be fairly close, will heat affect this component as well?

I will get some pics up as soon as I get back home some time fri evening.

thanks again for all the advice
Wade

 

[hole]

My Dad was the PO of my 8, and the last 4-5 years he owned it he was afraid to go too far because the thing would just randomly die and then restart +/- 15 min later. It would do it very erratically, sometimes twice a week and then not do it for months. At first it was thought to be vapor lock, but after doing it a few times in cold weather he ruled that out. Dad tried all he could think of, re-route fuel lines,change fuel filter, pump, drop tank to check pu tube/sock, ect. He never found it, then lost his eyesight and passed his unfound problem to me . The 8 was his DD , but it's a play toy for me so I didn't worry too much about until it did it to me. Only it never restarted for me, good thing for AAA. After the tow home I fiddled with everything I could think of but still no fuel pressure at the rail. My buddies a mechanic and stopped by to help me out and was stumped too after everything seemed to check out, so he took the air hose and started pumping air into the tank. That's when I saw the drip on a section of steel fuel line just before the electric pump. A small pin hole air locked the pump.I changed all the fuel lines and haven't had ounce of problems since.

 

[AussieCJ7]

dieing when warm as well as the fuel lines I would also double check all my grounds sometimes as it gets hot and expands loosens the connection and cools and connects again

 

[Old Dog]

I am concerned with how close the module seems to be to the header though it seems to be fairly close, will heat affect this component as well?

thanks again for all the advice
Wade

Yes it can.

 

[wadeo5247]

thanks for the advice I'm planning on re doing the fuel lines anyways but went by the parts store today and the clerk said that the pump that the po put on was only good for like 4 to 5 psi so hoping that a new will fix that.. will post here with an update

 

[wadeo5247]

Ok well great news guys replaced the fuel pump with one that will actully pump the right amount of psi and guess what it works me and the family crusied around for a couple of hours yesterday, and no problems so thanks for all the help guys I will get some pics up soon to update and see if anyone can tell me what fuel injection I have..........

 

[hole]

Glad to hear she's a runner!

 

[jasonmark1993]

WTF Im surprised it even ran with a pump that would only push 4-5psi.