99 XJ 4.0 - Sputter on start up.

[Macdaddy4738]

Takes a good 5 seconds to actually start up too. I think its the infamous fuel check valve problem, but Im not sure really.

Anyways, once it does start up, it runs like crap for about 10 seconds, then works just fine. Any idea what could be going on? I think its directly related to my gas mileage problem too. Im getting around 11 mpg city, and I know thats dead wrong as I am only on 31's....

 

[Jweezy]

tps? idle air control? fuel filter? mine did the same thing iac seemed to have fixed it.

 

[a_kelley]

CEL light on? if it is, 3 on-off- sequences (ending on) will spit the codes from the light.. chilton's or allpar has the codes. map sensor possibly..

 

[biggoofy]

cycle the key a few times then try and start it if it starts fine after you do that its most likely the fuel pump

 

[BenB90XJ]

cycle the key a few times then try and start it if it starts fine after you do that its most likely the fuel pump

x2 My 90 XJ does the same thing, it's the fuel pump

 

[advancedjosh]

fuel

we'll fuel pump possibly but I think you are right on with the check valve idea. its called a fuel pressure regulator I'm having the same issue with my wrangler don't try to install a check valve above the tank linnet's because although it will work the expansion and contraction of the fuel will bust the line off and dump fuel

 

[Hitchhiker]

Is that when the engine is cold, warm or both?

 

[Macdaddy4738]

Is that when the engine is cold, warm or both?

cold on the sputter.

But how long it takes to start up happens pretty much regularly.