jeep 4.0 hard start
11-05-2009, 10:32 AM
#17
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Year: 98' and 99'
Model: Cherokee
Engine: 4.0
Starter or One Way Check Valve
ive been reading alot of post and still cant find my answer
So in the morning i get long cranks and hard start, but after i started it once and turn it off its good untill it settles for a couple hours.
Ive been told by mechanics and alot of ppl that its the starter , but after reading post im leaning towards fuel system.
1) How can I check my starter to see if thats the issue?
So in the morning i get long cranks and hard start, but after i started it once and turn it off its good untill it settles for a couple hours.
Ive been told by mechanics and alot of ppl that its the starter , but after reading post im leaning towards fuel system.
1) How can I check my starter to see if thats the issue?
02-12-2012, 02:30 PM
#18
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Model: Cherokee
Im having the same problem and at first thought it was the starter, but replaced it and it is still happening. Like everyone else is saying that if it sits for a while then it does it but will fire right up if i start it right after i shut it off. I have also replaced the fuel pump and it continues to not start right. I hope you can figure it out so i dont have to spend money on a shop to fix it.
02-12-2012, 11:12 PM
#19
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Year: 1999
Model: Cherokee
Engine: 4.0
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.
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.
02-17-2012, 12:12 AM
#21
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Year: 2001
Model: Cherokee
Engine: 4.0
2001 4litre hard to start
Hey guys I'm new to this forum. I've read all the threads about hard starts but nothing fits mine. Let me give you some background info on my 2001 Cherokee Limited.
-Hard start in morning or after it sits more than 5 minutes.
-replaced battery
-replaced crank position sensor
-replaced fuel pump
-replaced fuel pressure regulator (checked pressure at the rail and it loses pressure)
-also the poor mans prime doesn't work to get mine started either
I haven't had a chance to check my pressures again but the long cranking and hard to start issue still persists. I've been reading up and the injectors my be leaking causing the long cranking time to clear the cylinders of fuel. I also was told to spray some throttle body cleaner into my intake just because the butterfly valves get gummy and cause starting problems. Any other thoughts or input would be greatly appreciated.
-Hard start in morning or after it sits more than 5 minutes.
-replaced battery
-replaced crank position sensor
-replaced fuel pump
-replaced fuel pressure regulator (checked pressure at the rail and it loses pressure)
-also the poor mans prime doesn't work to get mine started either
I haven't had a chance to check my pressures again but the long cranking and hard to start issue still persists. I've been reading up and the injectors my be leaking causing the long cranking time to clear the cylinders of fuel. I also was told to spray some throttle body cleaner into my intake just because the butterfly valves get gummy and cause starting problems. Any other thoughts or input would be greatly appreciated.
Last edited by Cherokee2309; 02-17-2012 at 11:01 AM.
02-20-2012, 11:20 PM
#22
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Model: Cherokee
good luck with that. i had this same problem. was told it was the check valve. so i decided to just replace the whole pump and entire assembly. well it still wouldnt start. so i checked for spark: no spark. ok lets test the coil, coil was bad. replaced the coil. now, after 3 days of throwing parts at it i decided it was time for the jeep to get a flatbed ride over to my mechanics garage... AAA picked it up about 10 minutes ago and im just waiting to hear what was finally the problem. but on the up and up hes installing my adjustable trac bar while its there, and hes going to check on the brake light/hazard problem ive been having as well. sometimes its just better to pay a couple bucks to have some things fixed. i hate that i couldnt figure it out but i only have so much knowledge and equipment. i hope for your sake you figure this out without any snags and without having spent too much moola. good luck 
12-06-2012, 02:41 PM
#23
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Year: 2000
Model: Grand Cherokee
I just joined the Forum, and found some good info in the Thread. I have a 2000 Grand-Limited with 140,000 and have the same hard/long starting issues. Not always but most of the time, and even sometimes it starts right up after a long sit? Have checked and replaced most what has been commented on. Has been doing this about 1.5 years now. No loss in performance or MPG. I think is about time I try the dealership; I will let you know the outcome.
12-06-2012, 09:53 PM
#24
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Year: 1993
Model: Cherokee
Engine: 4.0 HO
Ive learned to deal with the long start
let fuel pump prime before every start / turn of key method .. pulled my buzzer module out to hear it better
on this '93 .. long starts are less common w/ more than 1/2 tank of gas
hmm .. looking into that soon too .. new windshield tomorrow tho .. 150 bones done in work parking lot ..not bad i guess .. but should spend it elsewhere
let fuel pump prime before every start / turn of key method .. pulled my buzzer module out to hear it better
on this '93 .. long starts are less common w/ more than 1/2 tank of gas
hmm .. looking into that soon too .. new windshield tomorrow tho .. 150 bones done in work parking lot ..not bad i guess .. but should spend it elsewhere
06-02-2020, 11:09 PM
#25
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Year: 1988 2-door
Model: Cherokee (XJ)
Engine: 4.0
Just recently picked up a 1988 2-door 5spd 4.0 Cherokee Laredo Wagoneer with 159k. Along with your hard start, mine comes with gas in the oil but I'm still yet to figure it out. If you have, that would be awesome and if you could get back asap that'd be much appreciated, thank you.
06-02-2020, 11:10 PM
#26
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Year: 1988 2-door
Model: Cherokee (XJ)
Engine: 4.0
06-03-2020, 09:05 AM
#27
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Sounds like your injectors are leaking down when shut off.
You also need to go to www.cruiser54.com and complete Tips 1 through 5.
You also need to go to www.cruiser54.com and complete Tips 1 through 5.
The following users liked this post:
Spencer_P (06-03-2020)
06-03-2020, 11:46 AM
#28
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Year: 1988 2-door
Model: Cherokee (XJ)
Engine: 4.0
Injectors very likely
Sounds like your injectors are leaking down when shut off.
You also need to go to www.cruiser54.com and complete Tips 1 through 5.
You also need to go to www.cruiser54.com and complete Tips 1 through 5.
06-03-2020, 02:04 PM
#29
Old fart with a wrench
This is for the OP.
Yeah, if you turn on the key a couple of time before you start cranking it, that should prime the fuel rail for a normal start. If you decide to install an in-line check valve, it should be in the supply line back by the tank. That way it will hold the maximum amount of fuel under pressure until you start it the next time.
Yeah, if you turn on the key a couple of time before you start cranking it, that should prime the fuel rail for a normal start. If you decide to install an in-line check valve, it should be in the supply line back by the tank. That way it will hold the maximum amount of fuel under pressure until you start it the next time.
Last edited by dave1123; 06-03-2020 at 02:06 PM.
06-03-2020, 03:01 PM
#30
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Run nothing but 746 injectors in a Renix.