Hard start up?

'98 4.0, it will crank for a long time on the first try, and sometimes starts. Here's the kicker, If you turn the key back it while fire right up on the second try. After the jeep has ran for awhile it will start up the next time. Its when it has sat for a longer time that it doesn't start on first try. Had shop check fuel pressure and it is fine. Any Help?

I don't know if this will help other people with hard to start issues...I installed a BMW check valve from BMAParts.com/1-888-BMA-3911...Forgot part number...Tell the part guy what you need it for...They get calls for this part all the time...It was used on BMW's that had check valve problem on there fuel pumps and this was used to save company from having to replace entire fuel pump...but It does work...It was 10 bucks and that includes Shipping...Shipped in 2 days...On my 97 Cherokee...And while I had the tank down I replaced the fuel filter/regulator at the same time...My hard starting which happens all day long and sputtering when it started in the morning...but it never sputters the rest of the day only in the morning after sitting for almost 10 hours...Is now I hope a thing of the past...It fires after only one revolution of the motor...Which is saving the life of the stater...If anybody tries to install the BMW inline check valve make sure the arrow on valve is pointing to front of vehicle...I double clamped check valve to fuel filter/regulator and the hard line going to engine...no leaks so far...It could have been the BMW inline check valve that fixed the hard starting or the new filter/fuel pressure regulator or it could have been a combination of both...I don't know...I hope this helps someone out...

John4wd

I experienced the exact same thing when I first got my '98 back in the summer of 03. I posted my problem here and the only response I got was to make sure and wait for the fuel pump to pressurize the lines (you'll hear it shut off). But that didn't always work for me. Last summer the CPS died and since replacing, I haven't had the hard start problems. I didn't do anything else to fix it so maybe it is a sign that the CPS is slowly starting to go. Just a theory.

Did you look for this in the OEM tech section? There might be an old post lurking in there somewhere, I don't know.
I have the exact same problem in my '92.
Found that if you turn the ignition on for a couple of seconds before you turn over the engine, it seems to start a little bit quicker.
Almost like the pump needs to prime or build up some pressure.
A lot of the time I get impatient or forget, so it does take quite a while for it to start sometimes.
I have chosen to ignore the problem until it gets worse.

I don't believe it has anything to do with the fuel pump even when you let it "prime" it doesn't start on the first turn. What and where is the cam position sensor (CPS)? What is the differance between that and the crankshaft position sensor (CPS)?

i had the same problem with my old 96 and my current 94, my grand father and the same problem with his 91. and they all had the same problem and it was a problem with the fuel pump. there are two little hose clamps that connect the pump to the sending unit, and they come loose all the time. what is happening is that the engine is not getting enough fuel because it bleeds through the loose clamp. hope that helps

and the difference between a cam position and a crank position sensor is that the cam position tells the computer where the cam is at all times, this is a timing device because the cam position sensor tells the computer when to fire the coils. the crank postion works only on start ups, it is a little magnet that tells the simply tells the computer which cylinder is at top dead center so it fires the right cylinder first