Fullcurl

Hi everyone, new to the forum, just bought a 2003 Jeep tj, 4.0 liter, guy that sold it to me told me that after the jeep has been shutdown for a couple of hours it is hard to start, he says turn the key on and let the fuel line pressure up before starting, or it does not start very well. I have done this and it seems to work fine, but sometimes i have a total lack of power from the engine, i can only do 30 -40 kms/hr. So i stopped and turned the engine off and turned the key on for 20 seconds before starting and the engine performed like it should, plenty of power. My thoughts are a fuel pump problem ?? Anyone have any suggestions ?

thanks
RL

herbie

I would hang a fuel pressure gauge on it to verify the pump

oldfart

I would change the fuel filter.

Fullcurl

The dodge dealership has since replaced the spark plugs and coil pack, the jeep will run for a day or two and then i will get the same misfire on cylinders 3 & 4, back to the dealership today to troubleshoot. Any thoughts, because they don't know !!

thanks
RL

Sid1966

The problem is in the fuel pump/regulator the fuel pressure regulator is in the tank.the fuel is draining bank to the tank.When you let the pump run before starting it pushes the air out,2 key cycles(key on wait for all lights and gauges to go out)are needed to complety purge line of all air.The problem might just be dirt stuck in the bottom of the pump, a leak in the line internal in the tank,(you didnt mention any leaks or smells to indicate an external leak) or the assembly could be bad.The fuel tank must be dropped to check these.Start with a fuel pressure check and more importantly a leak down test just to make sure before dropping fuel tank

Fullcurl

thanks Sid, have passed on to dealership !!

RL

Fullcurl

Fuel pressure is 48 psi, dealership says i need a new ECM, it will arrive next week for install, hopefully that does it!

Sid1966

I thought it was fuel related my Tj had a similar problem it would build fuel pressure but not hold it had to replace the entire sending unit had a crack leaking inside the tank

Fullcurl

New Ecm is installed and the Jeep has run good for 3 days, hoping the problem is solved !

Mr White

iTrader: (1)

Thanks for letting us know on the hopefully problem solved . :)