My Jeep starts... but it seems to hafta turn over about 4 or 5 times before she starts up... Usually just when its a cold start up! Is this normal? I had 14volts, good strong battery! Just curious why she hasta turnover so many times before starting.. Maybe Alternator is going bad? And it seems its a rough idle at initial startup. But then settles down again at cold start up.. Shuld I be worried about these ??
TIA

 

My '91 does the same thing, don't have the answer so I'm going to keep an eye on this and see if any tips come up. Coach

 

Have you tried tried turning key all the way over, to last position before cranking, and letting fuel pump prime for a sec? Or doing it two or three times before staring? If so, did it make a dif?

 

The check valve is located on top of the gas tank and 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.

 

I have done that. It helps a little, but still hasta crank over more then usual to fire up!!

 

Thanks alot man.. my jeep has 153k miles on it. It had the Fuel service done at 149k. Fuel pump, filter and etc done.. But doesnt mean someone could have messed something up. I will try and prime the jeep fore then once, since I have just let it prime only one for a out 8-10 seconds and it helped just a tad, thanks again

 

nice info on the fuel system...thank you...

 

Very good information in this thread. I have a similar problem myself. It became obvious to me that pressure isn't holding in my fuel system when I decided to change the fuel filter. While attempting to de-pressurize the system, I found there wasn't really much fuel pressure in the rail/lines when depressing the schrader/test valve. That said, I don't know if it's the check valve (which I assume is on the pump for a '90 Cherokee) or if it's the fuel pressure regulator. Is there any way to determine that with any degree of certainty?