Hard starting (help me throw parts at my XJ)

During the summer I came home from a two week vacation to a dead battery in my 99 XJ. Jumped it and it started right up, however since that time it's been having a hard time starting when it had never hesitated before. Sometimes it took a few turns of the ignition to get it going. Well the battery is right at the expiration, so that must be it, weak battery right? I went to BJ's got a new Exide, installed it fully expecting the immediate firing of six cylinders, only to be disappointed with the same hesitation. Crap.

So I wonder what the issue could be. I've been wanting to replace the worn and badly oxidized battery cables with the heavy duty "Kelley's Works In Progress" cables for sometime, so maybe this is a good time for that upgrade. Hopefully it will help....Got the cables in the mail a few days ago (thanks Jon) and installed them today. I crossed my fingers as I turned the key and.....Same damn hesitation.

So the battery and cables/grounds are eliminated, what do I check next? Are there common issues with 99 XJ's I should know about? I thought it may be the starter, but in my experience with them they usually stick (then you use a hammer) or they die completely. Are Chrysler starters any different in this regard?

The fuel pump check valve is supposed to hold pressure in the fuel line while the engine is off. The check valve is located on the fuel pump and located in the gas tank. A failed check valve allows the fuel to drain back to the tank, slowly at first, and then faster and faster. This results in the following symptoms:

SYMPTOMS

·Longer than normal cranking times
·Never starts on first try, almost always starts on the second try
·Rough idle for a few moments of idling
·Rough running for first ½ block of driving
·Little or no fuel pressure at the fuel rail test valve similar to this -
1- Key in on position; fuel pump primes for 2 seconds then stops. 0 PSI
2- Cranking over the engine. 2-3 PSI
3- Engine starts and idles for 20 seconds. < 5 PSI
4- Engine idles and fuel pressure creeps up to 45 PSI.

POSSIBLE CAUSES

· Failed check valve on the fuel pump in the gas tank (1995 ½ to 2001 models ONLY)
· Leaky fuel injector(s)

Testing of the fuel injectors should show if any are faulty and are allowing fuel to drain into the cylinder. Either problem can allow heat soak to vaporize the remaining fuel in the fuel rail and you may be dealing with a bit of vapor lock as well, especially in warmer weather.

There are a few solutions to the problem –

1. Turn the key to ON for 5 seconds and let the fuel pump prime. Turn the key to OFF, turn the key back to ON for 5 seconds, start the engine.
2. Crank the engine for 3-5 seconds, pause, and crank the engine again. It will almost always start on the second try
3. Replace the fuel pump assembly in the gas tank. The check valve is not a separate part and cannot be serviced. This is both expensive and time consuming because you have to remove any hitches and skid plates and then remove the gas tank from the vehicle

You can use solutions 1 or 2 for as long as you want to, they do not harm anything and the fuel pump will continue to function for many more years.

Need clarification on the "hesitation" and "few turns of the ignition" you are describing. I re-read your post but could interpret it two ways. Which of these scenarios describe your problem:

1. Do you mean that you need to turn the key a couple of times B4 the engine turns over (a cranking problem rather than a starting problem)
2. The engine cranks over fine but just takes a longer time to start than normal?

If it is #2, then definitely follow Tim's lead on suggestions as the check valve is a common culprit. If it is #1, check to see if you have 12 volts or close to it at the starter itself. If you have full battery voltage there, suspect the starter. If you have voltage drop, start working your way backwards.

Tim_MN said:

SYMPTOMS

·Longer than normal cranking times
·Never starts on first try, almost always starts on the second try
·Rough idle for a few moments of idling
·Rough running for first ½ block of driving

Click to expand...

Welp. Pretty much exactly what's going on. Thanks for the tips on how to start it, at least I know how to properly deal with it now. As far as changing out the fuel pump, I have both a hitch and skid plate so that would be a royal PITA.

But I've been thinking of making my manual 97 XJ into a trail rig, and swapping all the skid plates/hitch from my 99 and making the 99 a daily driver. I'll probably switch out the pump whenever I decide to do that. Until then as long as nothing is being harmed I won't worry about it.

pump is going out

wolfpackjeeper said:

pump is going out

Click to expand...

Tim_MN said:

You can use solutions 1 or 2 for as long as you want to, the fuel pump will continue to function for many more years.

Click to expand...

3 + years so far

yes it will, It just got really annoying to me, and when I dropped the stroker I decided to go with a holly performance pump for a mustang. The holly was actually the same size and shape, and it was the same price as the OE jeep pump at like $80ish. Supports 350hp

wolfpackjeeper said:

yes it will, It just got really annoying to me, and when I dropped the stroker I decided to go with a holly performance pump for a mustang. The holly was actually the same size and shape, and it was the same price as the OE jeep pump at like $80ish. Supports 350hp

Click to expand...

Very interesting, I'll have to remember this when I go to change it out. And yeah, it's really annoying but at least I know what it is now, and I can take my time until I feel like fixing it which may be a while. I'm busy replacing the brakes and interior of my '97. :greensmok

replace your regulator when you do. This was on my 91 where it is on the rail. I used an OE one, but I will be going with the hesco unit soon.

The OP, Leica99XJ, has a 1999 XJ. The fuel pump assembly is located inside the gas tank. The filter, pump, check valve, float, and pressure regulator are all part of the pump assembly, in the gas tank.

right, and they expressed interest in the mustang pump. regardless of if it is all internal o not. they will need to check on the regulator while in there.

wanted to make sure he knew it was on a '91 when I did it

wolfpackjeeper said:

yes it will, It just got really annoying to me, and when I dropped the stroker I decided to go with a holly performance pump for a mustang. The holly was actually the same size and shape, and it was the same price as the OE jeep pump at like $80ish. Supports 350hp

Click to expand...

Do you have the specs on the Holley Pump. It sound like a better way to go than the Jeep Pump.

Your title is good -- throw parts at it. Or you could check fuel pressure bleed down to see if the pressure relief valve or injectors are leaking.