Haulin

I just picked up a 2000 Cherokee with 167k and it starts in an odd way. Most of the time it cranks but does not start, but if you cycle the key again it starts right up. I have not done any extended cranking on the initial turn maybe 8-10 seconds. Any suggestions? I did search but didn't find anything. Thanks!

reddonkey

Mine does this. I have a leaky injector that lets the fuel leak out of fuel rail. I have to cycle the key to build up fuel pressure in the rail to get it to start. When it does start that injector causes a miss for a few sec then starts firing like normal. I don't know if that helps but that's all I could think of. I just cant seem to find any 703 injectors to fix it. But good luck to you.

Bigwillie

watch those leaky injectors. jeeps put the fuel rail right over the exaust manifold. causes alot of the to go poof!

purplegrocerygogetter

I call BS on u searched but no luck! A 2 second search turned me up this!
https://www.cherokeeforum.com/search...archid=3145722
Go read some threads! 248 of them to be exact!
Search its a awesome thing!

Haulin

Yep got the same list read a bunch but did not find anything that matched.

And thanks for the warm welcome.

And thank you to the other guys for their response

Haulin

Did you see these injectors?

https://www.cherokeeforum.com/f11/in...-30lbs-127580/

reddonkey

Yes every time I PM they are already gone.

Haulin

eBay but then your at almost $200 a set! Think Rock Auto has them for about $25each.

tjwalker

The check valve is part of the fuel pump assembly on 95.5-2001 vintage 4.0 XJs. When the check valve starts to fail, it reduces fuel pressure to a point where an extended crank 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) way to 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 a two more times
5. NOW crank the engine over

If the engine starts quickly and cleanly after performing this procedure, you may have the check valve issue. If it starts and runs poorly for a few seconds, it could also be a leaky fuel injector resulting in the bleed down and the 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 this symptom. Sounds strange but it definitely does happen. Have battery load tested if you have any questions; your XJ does NOT like low available battery voltage. Be sure battery connections and posts are CLEAN.

Some troubleshooting tips for extended crank times:

Hook up fuel pressure gauge on the schrader valve on the fuel rail

Start engine and bring to normal operating temperature.

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

Shut engine off.

Pressure should not fall below 30 psi for five minutes.

If pressure falls below 30 psi, it must be determined if a fuel injector, the check valve within the
fuel pump module, or a fuel tube/line is leaking. An adaptor tool/hose included with the fuel pressure gauge can help you with this. Consult gauge manual for more information on this 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 - possibly the check valve. If the pressure falls below 49 psi fairly rapidly then the problem is probably a leaky fuel injector.

You can limp a check valve problem along indefinitely if you wish as it doesn't mean the fuel pump itself is going bad. Normally, the check valve is replaced as an entire assembly as you have to drop the gas tank to access the assembly. Fuel pump assembly consists of fuel pump, regulator, check valve, filter. If you do replace the fuel pump assembly, purchase a high quality OEM style unit. Some cheap aftermarket assemblies don’t hold up and fail prematurely. I specifically seek out Bosch fuel pumps as they are the best in the business. Stay away from Airtex, as IMHO, they have a bigtime reliability problem.

Haulin

Tried the 3 turns of the key and it still cranked for 5-7 seconds and started. It does not seem to stumble or miss though. Shut it off and restart and it barely has to crank and it's running. Going to clean the battery terminals it a bit, but it does crank fast now.

BTW thanks tjwalker for that great post, I appreciate it!

Haulin

Pressure dropped to 10 in less than 30 seconds. I then tried to crimp what I thought was a rubber section of the fuel line for the rest of the test and quickly discovered I misunderstood when I broke the plastic line inside. So that was a $60 mistake and maybe a timely one too since nobody has one. Warehouse shows one so we'll hope it shows tomorrow morning if not its 3 days from some other warehouse. I'm guessing by the RAPID drop in pressure its the check valve.

tjwalker

The check valve is almost a certain fail for this vintage eventually. That is probably what is happening here. You can either live with it or if you want it fixed (as I did), drop the tank and replace the fuel pump assembly.

Do NOT buy an Airtex fuel pump as there is a reliability issue with them IMHO. My first choice for fuel pumps for the XJ is Bosch. Well worth the extra money in reliability AND longevity. Carter is my second choice.

Haulin

Well now with the broken piece of plastic line out of the way I have a piece of rubber in there I can crimp off to verify. The stupid mosquitos came out so I quit before I finished so tomorrow it is. Just curious where is a good place to get the bosch or carter pump? The Carter is $185 and the Bosch is $313 and Rock Auto.

tjwalker

Well for starters, check with your local parts stores. If they don't carry these brands, most of these stores can special order them if you don't mind waiting a couple of days.

I have seen a Bosch pump show up online once in a while. Check ebay. I see one on there now for $288. Entire assembly. Not cheap, but I think it's worth the coin.

Haulin

Found a carter for $160 shipped...