What could be causing my Cherokee to start so slow?
12-16-2011 | 04:36 AM
#1
Thread Starter
Seasoned Member
Joined: Dec 2011
Posts: 467
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From: Beaverton, Oregon
Year: 2001
Model: Cherokee
Engine: 4.0
What could be causing my Cherokee to start so slow?
I've got a 98 Cherokee I recently purchased and when you go to start it up in the morning it turns over but it cranks and cranks for a long time before it actually starts. The battery is brand new so it's nothing to do with that. Any input would be appreciated =]
12-16-2011 | 08:16 AM
#2
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Joined: Oct 2011
Posts: 763
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From: Warren, PA 16365
Year: 2001
Model: Cherokee
Engine: 4.0L
Have you changed the plugs, wires, cap and rotor?
Have you had the starter out and tested?
Have you cleaned the injectors?
How's the ground wire coming off the battery?
These are all things that may cause slow turn over/slow starting.
Have you had the starter out and tested?
Have you cleaned the injectors?
How's the ground wire coming off the battery?
These are all things that may cause slow turn over/slow starting.
12-16-2011 | 08:23 AM
#3
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,565
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Yep. The other end of those battery cables are just as important as where they connect to the battery. Engine to chassis grounds ever been cleaned and refreshed?
12-16-2011 | 09:10 AM
#5
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Joined: Mar 2011
Posts: 522
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From: Las Vegas
Year: 1992
Model: Cherokee
Engine: 4.oL H.O. 784 injectors, EV6 to EV1 connectors, APN header, Dynomax exhaust
Originally Posted by TheJerm
Try leaving the key at the ON position till you hear the fuel pump stop, ~10sec, then try to start it
12-16-2011 | 09:12 AM
#6
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Joined: Dec 2011
Posts: 467
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From: Beaverton, Oregon
Year: 2001
Model: Cherokee
Engine: 4.0
Also as far as the starter goes how do I test it? I was under the impression if a starter was bad it just wouldn't start period.
12-16-2011 | 09:13 AM
#7
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Joined: Dec 2011
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From: Beaverton, Oregon
Year: 2001
Model: Cherokee
Engine: 4.0
Trending Topics
12-16-2011 | 09:17 AM
#8
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Joined: Mar 2011
Posts: 522
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From: Las Vegas
Year: 1992
Model: Cherokee
Engine: 4.oL H.O. 784 injectors, EV6 to EV1 connectors, APN header, Dynomax exhaust
Originally Posted by PumpinIron
Funny you mention that. It hot starts perfectly fine but cold starts not so much. So you think that could be the issue?
How many miles are on it? How long have you owned it? Do you hear a whining sound from the gas tank area?
12-16-2011 | 09:20 AM
#9
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Joined: Mar 2011
Posts: 522
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From: Las Vegas
Year: 1992
Model: Cherokee
Engine: 4.oL H.O. 784 injectors, EV6 to EV1 connectors, APN header, Dynomax exhaust
There should be a schraider (probably spelt that wrong) valve near the fuel rail, it looks like the valve on a bike tire. Pop the cap and hit the valve core when its cold. If it has pressure and fuel it'll spray.
12-16-2011 | 09:35 AM
#10
CF Veteran
Joined: Jan 2011
Posts: 1,894
Likes: 4
From: Las Vegas
Year: 1999
Model: Cherokee
Engine: 4.0
This should help....
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.
12-16-2011 | 11:21 AM
#11
Senior Member
Joined: Apr 2011
Posts: 813
Likes: 1
From: Lansing, MI
Year: 2000
Model: Cherokee
Engine: 4.0
A general rule of thumb, if the engine still cranks at normal speed but doesn't fire, then it almost definitely has nothing to do with the starter, or the battery itself.
It's far more likely an ignition problem, and that could mean fuel, spark, or both if you're particularly unlucky.
Here are some things I would consider:
-A bad fuel pump, clogged lines, clogged filter, or clogged injectors could mean that fuel is taking a while to get into the cylinders.
-Leaking injectors could be flooding out the engine, and it won't fire until the extra fuel is worked out of the cylinders. I've heard that leaking injectors is a fairly common problem with these.
-A bad ignition module might cause there to be no spark during cold start-ups. I know it's a COMPLETELY different design, but my 77 Cutlass ran perfect one day, then wouldn't start the next. No spark. Tried it again later on after it had warmed up outside (and this was during the spring time, so it sat overnight in maybe 40-50 degrees), it would start like normal. Replaced ignition module, problem solved.
I'm leaning toward the leaky injector problem, though.
It's far more likely an ignition problem, and that could mean fuel, spark, or both if you're particularly unlucky.
Here are some things I would consider:
-A bad fuel pump, clogged lines, clogged filter, or clogged injectors could mean that fuel is taking a while to get into the cylinders.
-Leaking injectors could be flooding out the engine, and it won't fire until the extra fuel is worked out of the cylinders. I've heard that leaking injectors is a fairly common problem with these.
-A bad ignition module might cause there to be no spark during cold start-ups. I know it's a COMPLETELY different design, but my 77 Cutlass ran perfect one day, then wouldn't start the next. No spark. Tried it again later on after it had warmed up outside (and this was during the spring time, so it sat overnight in maybe 40-50 degrees), it would start like normal. Replaced ignition module, problem solved.
I'm leaning toward the leaky injector problem, though.
12-16-2011 | 12:07 PM
#12
CF Veteran
Joined: Nov 2011
Posts: 1,290
Likes: 0
From: phoenix az
Year: 1989
Model: Cherokee
Engine: 4.0l 6 cylinder
im having the same probelm as you it takes about 5 seconds for my car to start what i have replaced everything just as u have an i have a new starter but it still takes about 5-6 seconds to start
12-16-2011 | 01:01 PM
#13
Thread Starter
Seasoned Member
Joined: Dec 2011
Posts: 467
Likes: 1
From: Beaverton, Oregon
Year: 2001
Model: Cherokee
Engine: 4.0
The Jeep has 187k miles and runs perfect other than this. I have owned it for a month, that's it.
All of this makes sense though. There is no whine coming from the fuel tank but I'll start with a new fuel filter and then clean the injectors. If that doesn't help at all ill test out the fuel pump.
All of this makes sense though. There is no whine coming from the fuel tank but I'll start with a new fuel filter and then clean the injectors. If that doesn't help at all ill test out the fuel pump.
12-16-2011 | 09:51 PM
#15
Thread Starter
Seasoned Member
Joined: Dec 2011
Posts: 467
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From: Beaverton, Oregon
Year: 2001
Model: Cherokee
Engine: 4.0
I did as you guys suggested and let the fuel pump prime 3 times before I started it this morning and it started right up. It idles a little bit rough for the first 5 seconds once it starts but it definitely starts faster.
Is the fuel pump hard to get to on these cars? Do you need to drop the gas tank in order to reach it?
Is the fuel pump hard to get to on these cars? Do you need to drop the gas tank in order to reach it?