mikemcd2756

I believe my steering problem consists of what you guys refer to as "death wobble", it starts wobbling pretty good around 45 mph but cleans up as I speed up? Any troubleshooting help would be appreciated here, I'm a newbie.

Secondly, when I start my jeep after a extended cool down period it is very strained to start, im sure it's not the starter, battery or alternator. A friend said it could be the computer or a mis firing cylinder. Any experience or help is appreciated. Thanks.

ZINGGG

https://www.cherokeeforum.com/f51/di...-wobble-55021/

Read through this so you have an idea of what death wobble is. This link also has all the components listed that can contribute to death wobble.

As for your starting problem, how does it crank? Nice and slow? Or does it crank fast and just doesn't catch? Could be a problem with your battery, alternator or starter. Also could be tune-up related. Also could be a problem with the crank position sensor. NEED MORE INFO!

mikemcd2756

It cranks fast. I only say it isn't the starter, battery or alternator because after it doesn't the first time the second start is completely normal.

opie1988

if it clears up by changing speed, I would lean towards out of balance tires or bent rim. Rotate the fronts to the back and backs up front and see if it changes any of the characteristics

ZINGGG

How many miles are on it? Do you know if the crankshaft position sensor has ever been changed? It is a very common failure on our XJs and will cause a no start or when it starts to fail, will produce the same symptoms as yours.

Also, you should check your fuel pressure to make sure your fuel pump is working up to par

mikemcd2756

It has 112,xxx. Driving today and it only shakes from 45-50. That's it.

ZINGGG

Have a buddy get in your XJ, start it up and turn the wheel all the way right, and all the way left, over and over again, while you stare at each and every steering and suspension component. Look for excessive play or parts that are moving that shouldn't. Pay special attention to the track bar and ball joints.

As for your starting problem, get some fresh NGK Copper spark plugs gapped to .035. Also, run some sort of injector cleaner. I'm a fan of Seafoam. Then verify your fuel pressure. If that checks out as well, it may be time to dive into the crankshaft position sensor

tjwalker

You are describing two VERY common problems with the XJ.

Death wobble and the fuel pump check valve issue.

Because these problems are so common, I have a standard text in my computer files that I copy and paste whenever it comes up. Here you go. Hope this helps!
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My understanding of “death wobble” is this. Somewhere in the vehicle, one or more components is worn beyond tolerances, and when oscillation initiates from a suspension “traumatic” event (hitting a bump or a pothole) or also when a vibration reaches a certain point and harmonic at a certain speed, it causes the other components to react. This is called the “multiplier effect”, where one component affects one or more other components as the event travels through the front end of the vehicle.

Death wobble is not uncommon with the XJ. It is even more common with a lifted XJ. Finding the worn component or components is not always easy. It can sometimes be downright difficult. Sometimes it’s obvious, other times everything appears to be okay when you perform an inspection on a hoist, but getting the vehicle up in the air and going over everything with a fine tough comb is always a good first step. It is very helpful if you know exactly how to perform a comprehensive inspection of every single front end part, looking for abnormal wear and or play in that hardware. If you do not know how to do this type of inspection, pay an experienced professional to do it. Be sure to ask them if they are familiar with “death wobble”, as not all technicians are versed in this…..

Check out the below link if you would like some extensive reading on “death wobble” causes and cures. From my research, Kevin (the author of this tutorial) is possibly the best in the business with tracking down root cause of death wobble. He does offer hardware for sale that can help resolve death wobble, but even if you don’t buy any parts from him, you can still get some excellent ideas on what to look at in resolving your death wobble.

http://www.kevinsoffroad.com/how-to-...-death-wobble/

Possible causes of death wobble are listed below. Isolating death wobble is a process of elimination and the root cause is not always obvious and it can often be caused by a combination of things! From my personal experience, I would first concentrate on the track bar and the control arms and associated bushings.
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-Front tires out of balance (try swapping fronts to rear; see if symptoms change)
-Tire pressure. Don’t laugh. It’s not a root cause but can exaggerate the problem. Experiment with lower tire pressure to see if it helps
-Improper lug nut torque on wheels
-Front alignment out of spec
-Loose track bar
-Worn track bar bushings
-Worn track bar (check for play!!)
-Bad control arms and associated bushings
-Worn/damaged steering stabilizer (not generally a cause in and by itself)
-Worn/damaged shocks
-Worn/damaged tie rod end
-Bad U Joint
-Bad ball joint
-Loose frame mount
-Steering box loose
-Bad front hub assembly

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The check valves (there are two of them; one on the fuel pressure regulator and another on the fuel pump) are part of the fuel pump assembly on 95.5-2001 vintage 4.0 XJs. When a check valve starts to fail, it can reduce fuel pressure to a point where an extended cranking time is needed to start the engine. It is a very common failure. I experienced it on my 99 at around 75K.

A good (and simple) first step in helping you troubleshoot this problem is called “the poor mans prime”

1. Turn key to ON position (do not crank the engine!)
2. The fuel pump will energize and run for a couple of seconds
3. Turn key to OFF position
4. Repeat above steps 1-3 two more times
5. NOW crank the engine over

If the engine starts quickly and cleanly after performing this procedure, you may have a check valve issue. If it starts and runs poorly for a few seconds, it could also be a leaky fuel injector resulting in the fuel pressure leaking down and the subsequent stumble upon startup is the engine clearing the excess fuel that has leaked into the cylinder because of the faulty injector.

Also be aware that a bad battery can give you starting symptoms as well. Have your battery load tested (any parts store will do this for free) if you have any doubt; your XJ does NOT like low available battery voltage. Be sure battery connections and posts are CLEAN.

Some troubleshooting tips for extended crank times. You will need a fuel pressure gauge. Many parts stores will rent you this tool inexpensively.

*Hook up fuel pressure gauge on the schrader valve on the fuel rail under the hood

*Start engine and bring to normal operating temperature.

*Observe fuel pressure gauge. Normal operating pressure should be 49.2 psi (plus or minus 5 psi)

*Shut engine off.

*Observe pressure on gauge. Pressure should not fall below 30 psi for five minutes.

If pressure falls below 30 psi, it must be determined if a fuel injector, a check valve within the
fuel pump assembly, or a fuel tube/line is leaking. An adaptor tool/hose included with the fuel pressure gauge can help you with this. Consult the manual that comes with the fuel pressure gauge and the Factory Service Manual for your year XJ for more information on this exact procedure, but here is basically how it works:

*Turn the engine off and immediately clamp the fuel line at the adaptor hose. Watch the pressure gauge and see how long it takes to lose pressure.

*If the pressure remains at 49 psi for an extended period of time then the problem is in the tank – most likely a check valve. If the pressure falls below 49 psi fairly rapidly then the problem is probably a leaky fuel injector.

**Note. Where check valve is suspect, a quick loss of fuel pressure is often the fuel pressure regulator check valve and a slow loss of pressure is often the fuel pump check valve. But keep in mind that either or both check valves can be to blame.

You can limp a check valve problem along indefinitely if you like, as it doesn't mean the fuel pump itself is going to fail. Perform the “poor mans prime” before cranking to speed up your starts. However, if you have a check valve issue and want to resolve it, it is recommended that you replace the entire fuel pump assembly for two reasons. First, you have to drop the gas tank to access the assembly. Secondly, with two check valves, replacing just the fuel pressure regulator where one of the check valve resides may or may not resolve your problem; remember there are two check valves; the other one is on the fuel pump.

The fuel pump assembly consists of fuel pump, fuel pressure regulator, fuel gauge sending unit, fuel gauge float, pickup filter and pigtail wiring harness. If you do replace the fuel pump assembly, purchase a high quality unit; you do get what you pay for here. Some cheap aftermarket assemblies have been known to fail prematurely. I personally prefer Bosch fuel pumps as they manufacture the best fuel pump assemblies for the XJ. Carter is my second choice. Airtex is my least favorite choice and I will not recommend or install them.

Wonka1981

I agree, try the easy stuff before you assume its the deeper componants