Not Starting Correctly

[jodomcfrodo]

Hi all,
So this has been an issue for a while now but it has just recently gotten worse. It is at a point where I'm actually going to fix it. When I go to start my 01', it cranks for around 10 seconds before it finally catches. Doesn't matter if it is out in the cold or in a heated garage (it has even done it when the engine is around 110 degrees), it won't start like it used to. I have tried pushing the gas pedal down a bit when starting and that hasn't fixed it either. Besides the starting issues, the engines runs perfectly. It's a 4.0 with around 192,000 miles on it. What could this be?

Thanks!

 

[Jerry Bransford]

If it is cranking normally but just not starting if it has sat for a while, but starts ok if it hasn't sat for long, that's caused by your fuel pump. There's a check valve in the fuel pump that when it leaks, allows the fuel to drain from the engine back down into the gas tank. The extra time the engine takes to start after it has sat overnight is the time it takes the fuel pump to get the fuel back up to the engine.

I'd replace it ONLY with either a Bosch or Mopar. Aftermarket brands like Spectra, Airtex, etc. don't last long and will just start causing the same problem in a year or so.

 

[jodomcfrodo]

If it is cranking normally but just not starting if it has sat for a while, but starts ok if it hasn't sat for long, that's caused by your fuel pump. There's a check valve in the fuel pump that when it leaks, allows the fuel to drain from the engine back down into the gas tank. The extra time the engine takes to start after it has sat overnight is the time it takes the fuel pump to get the fuel back up to the engine.

I'd replace it ONLY with either a Bosch or Mopar. Aftermarket brands like Spectra, Airtex, etc. don't last long and will just start causing the same problem in a year or so.

I just had the fuel pump replaced in November. I'm hoping that isn't it but you might be right. Is there anything else that it might be?

 

[Jerry Bransford]

I have had that problem enough times that I always think fuel pump. Some claim the fuel pressure regulator can cause that problem too but I'm not convinced. What brand of fuel pump did you install? If a shop did it, they probably just bought the first one they could find locally which was very likely a cheap store brand. Having installed brands like Spectra and had them fail prematurely, I'm sticking with Bosch (as I have been running a couple years now) or Mopar.

 

[jodomcfrodo]

I have had that problem enough times that I always think fuel pump. Some claim the fuel pressure regulator can cause that problem too but I'm not convinced. What brand of fuel pump did you install? If a shop did it, they probably just bought the first one they could find locally which was very likely a cheap store brand. Having installed brands like Spectra and had them fail prematurely, I'm sticking with Bosch (as I have been running a couple years now) or Mopar.

I had the local jeep dealer install it. I would assume that it would be Mopar. I'll have to go and find the quote. If I parked it on a hill with the front facing down and left it for a while, gravity would keep the gas in the block, right? Maybe I could test whether the valve is the issue that way.

 

[Jerry Bransford]

The last several feet of gas line run up from the chassis up to the engine so parking it facing downhill wouldn't help much.

Try this the next time your Jeep has been sitting a while and is likely to exhibit the slow-start problem. Turn the ignition switch on-off-on 5-6 times in a row with a second's pause between each time so the fuel pump will have more time to get fuel up to the engine before you actually turn it to the Start position. You'll hear the fuel pump turn on and then off each time, shut the key off and do it again 5-6 more times before turning the switch to Start which should help eliminate the slow start. If that helps, the problem is still very likely with the fuel pump.