Perrin Pockets

I have a 98 XJ sport. The first problem I'm stuck on is during startup. If it sits for more than 30min or so and I go to start I have to turn key, crank crank crank for a few seconds then stop wait and repeat and it will fire up on 2nd crank. I took the battery in figuring its time for a new one, (I just bought the jeep) had it tested and they agreed. Installed new battery recommended by adv auto parts. Still just as week on start. Any advice or suggestions?<br />
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Second and more alarming, is when braking. When I get bellow 10mph and almost to a stop there is a grinding sound that makes me think something is warped. It is From the rear end and is not consistent through the stop, the pauses between grinding increases as speed decreases. And the vehicle slows at an inconsistent speed, not a smooth stop it feels like I'm feathering the brakes when holding steady. Also I had new rotors and pads installed and drums cut thinking that would solve problem, no luck, it did reduce vibration when at 60+mph. <br />
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Any help on either problem will be a huge help! Thanks for your time!

Perrin Pockets

Also I know these questions may be answered somewhere else, I have been looking but am new to the site and am just using the app for the first time on my phone, it's a little different than the computer. If anyone has a link, thread, or hint in that direction that is also greatly appreciated.

tjwalker

1. For your starting problem, your issue is likely a "check valve" in the fuel pressure assembly. Very common on your vintage. More on that below.

2. For your braking issue, time for a thorough inspection of the rear brakes. I know you had them done recently, but that doesn't mean you can't have an issue. Inspection time; probably best to get a different set of eyes on it this time.
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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 about 2 seconds. Be sure to wait until it stops running.
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.

Perrin Pockets

Thanks for the advice, I'll be taking it to the Midas down the street in the morning and will discuss all of this with them.

Perrin Pockets

Got the Jeep back from Midas. 2 codes were reported, P0138 (O2 sensor) I cut the wires during exhaust job and spliced back together, this is when CEL came on. Second code reported was P0463 (Fuel level sensor) they said I need new fuel pump. When I asked about check valves they said there are none I need a new pump ($700+). As far as braking goes they said the shoes are saturated in oil, cylinders are leaking and brake lines need to be flushed. Their grand total to have my Jeep "safe" to drive home was $1700. I thanked them for their input on the situation payed the $90 diagnostic fee and have begun my search for parts.

Before I get to all these items does anyone agree/ disagree or have any other suggestions. A friend of mine suggested to start with spark plugs and wires, I just got the Jeep and don't know how old anything is so I would agree that I should change them being that its cheep but will this help with my starting problem? Thanks in advanced for all input and time!

cpttuna

You can get an inline check valve from NAPA. They run about $45.00. That'sall I know about them. I have a bad check valve and I just live with it.

tjwalker

You need to find another shop. Find one that employs ASE technicians for the best results. The training that ASE techs go through gives you your best chance of quick troubleshooting and getting things right the first time around.

There are 2 check valves INTEGRATED into the fuel pump assembly. There is one check valve on the regulator and one on the fuel pump, both of these are on the fuel pump "assembly" inside of your tank. For them not to know anything about check valves on a fuel pump doesn't give one confidence. Inline check valves are not recommended for your vintage.

Have you tried the "poor mans prime" that I outlined in my initial response? It is the absolute first thing you must try and it will take all of 2 minutes. It tells you a lot. I've worked on many of your vintage XJs with check valve problems. Including my own 99. But don't take my word for it. A search will verify this. Extended cranking does not mean the fuel pump itself is failing. It usually means the check valve(s) have failed; a very common problem. And if trying the poor mans prime allows for a quick start, you can either live with it or replace the entire fuel pump assembly (use Bosch). Follow the advice I gave you in post #3. It is the best advice I can give you and it is accurate.

As for your brakes, you need to find a reputable independent shop to take a look at them and give you an estimate. Brakes are not rocket science; any reputable technician will be able to figure out the root cause of your issues there.

Performing a tuneup would include fresh Champion copper plugs gapped to .035, quality plug wires, distributor cap and rotor. Never a bad idea for a "new-to-you" vehicle, but the extended crank time you describe is not likely related to tuneup hardware. It is most likely a check valve issue. Some of us have been running Jeeps since Shep was a pup and we know the common issues that the XJ experiences.

77olds

$1,700 for rear brakes and wheel cylinders?

I admit, drum brakes are a pain in the butt, but if you're at all mechanically inclined you could do the whole thing yourself in an afternoon. Flushing the brake fluid is easy too. Their prices are outrageous. That's the price you quote somebody when you want them to go away because you don't want to work on their rusty vehicle.

Anony

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PocketsEmpty

And that, ladies and gentlemen, is why I do not trust a single mechanic.

Perrin Pockets

I did the poor mans price both on the way to Midas and when leaving, at the shop the guys looked at me like I was crazy. But it fired right up great and right away after 3 primes (Sounded great with my new Flowmaster exhaust I just installed too) so I gave them a wave and wink and maybe a little extra tap of the gas petal and was on my way. I knew on my way there that I would not be having them do the work, I am no machanic but I have grown up with a good set of tools and a DIY attitude. I was just looking for a profecional diagnosis. They were actually not trying to scare me away with the price because they called me 6x yesterday to discus payment and even the owner called and gave me "10%" off, OOO how inticing! So I will be doing the work myself and have to piece it out over some time. Thank you all for your great words of wisdom, you have been much more help than the entire Midas shop.

PocketsEmpty

Congrats on your decision to basically flip Midas the bird! In PA, I can't get away from mechanics completely as PA requires annual state inspection (bastards), but this advice goes for anywhere -- stick to the local shops. They will be more willing to work with you and are generally more trustworthy (I use that term loosely).

As far as mechanical DIY work goes, my Jeep transformed me from computer nerd into a fairly advanced amateur mechanic in a matter of 5 months. I wouldn't dare let anyone else work on my Jeep (or my DD) for anything besides the inspection. The hardest part is simply getting started. Once you determine that you're going out to the garage (bring some beer!), and say "okay, I'm gonna do this thing" and start ratcheting, you'll be more interested in it, you'll learn a WHOLE lot, and you'll have a big sense of pride when the job is done--plus, you'll KNOW it was done right (maybe!), at least you won't have to guess about what some shady mechanic did. That's priceless to me! Plus the internet is amazing for support.

Also, instead of working on your drum brakes, might I suggest that you search around for a write-up on rear disc conversion. BEST mod I've ever done to my Jeep thus far, and fairly simple. It's involved, but as long as you carefully plan it out you'll do fine. It may be a little more expensive upfront, but the ease of doing maintence to your brakes over time will more than pay for itself. Drums suck!

Good luck!

dwright98xj

Lol, what would you kids have done back in the day of all 4 corner drums??? lol, 68 AMC Rambler, no vacuum assist either, careful adjusting/proportioning and it stopped as good if not better than any "modern" system.

Anyways, drums are extremely easy, you just have to be patient and detailed. Do ONE side at a time so that if you goof something, you have the other side as reference. With modern technology, take a pic with cell phone before diving in, again, in the event you forget which spring goes where. I usually lay them out in a replicated order of where they were oriented on the backing plate installed (yes, after 20+ years working on them, I'll occasionally throw myself in a loop, could've been the beer tho )

Just read up on it, and get yourself a decent brake drum tool set. Also, get yourself some flare nut wrenches!!! NEVER attempt to crack open a brake line or fuel line with anything else! You will kink it and be VERY sorry. Also, use some PB Blast or similar product in advance, you'll thank yourself later. Replacing ines isn't hard by any means, but it takes a little savvy thinking as pre-bent lines are 5x the cost of doing it yourself.

Bottom line, a chiltens or haynes manual will walk you step by step farely well, it's a job for the capable novice.

PocketsEmpty

Ha! I suppose I would've found a way to do a 4-wheel disc conversion then. That's terrible, seriously. There is nothing good that can be said about drum brakes--period. Especially on a Jeep.

also, I respectfully disagree with the Hayne's manual recommendation. That was the biggest waste of $20 I've spent towards my Jeep. No good information, firing order all wrong, no torque specs for intake/exhaust manifold, etc. I heard the Chilton's are a little better, though.

dwright98xj

I've found similar discrepancies among many makes and models in their books, agreed, for the longest time they had a completely wrong plug gap spec for the 3rd gen (82-92) camaros and firebirds.

In this instance tho, drum brake procedures are word for word in almost every manual out there as there is only two different types used over what 3/4 a century?

For a freebie, you could also use autozone online DIY guide.