sputtering
12-13-2010, 04:24 PM
#1
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Year: 1991
Model: Cherokee
Engine: 4.0
sputtering
ok, so the symptoms first...sputtering while running down the road, NO POWER, popping out the intake, oil all over valve cover, oil in breather box, extremely hard to start...
the stuttering has been intermittent for about a week now, but now all of the other symptoms started and the sputting is constant... barely limped it home today...
please help, this is the only DD we have right now.
the stuttering has been intermittent for about a week now, but now all of the other symptoms started and the sputting is constant... barely limped it home today...
please help, this is the only DD we have right now.
12-13-2010, 04:43 PM
#3
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Year: 1997
Model: Cherokee
Engine: 4.0 H.O.
Well, start easy. Plugs, wires, distributor cap and rotor button. Then fuel filter, O2 sensors. Your oil issue could be your CCV valve is clogged possibly and mabey your PCV valve is clogged as well. Your CCV is the valve/ vent on the underside of your valve cover that attaches to you breather hose that runs to your airbox. Good Luck!!
12-13-2010, 05:51 PM
#4
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Year: 1999
Model: Cherokee
Engine: 4.0
I agree that you most likely need a CCV rebuild. (CCV=Crankcase Ventilation)
Search this forum, other XJ forums and the web for information on the parts you will need and how to do it.
I experienced this with my 88 Comanche 4.0. If you own an 87-90, sooner or later, most everyone goes through this.
Search this forum, other XJ forums and the web for information on the parts you will need and how to do it.
I experienced this with my 88 Comanche 4.0. If you own an 87-90, sooner or later, most everyone goes through this.
12-14-2010, 07:35 AM
#5
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Year: 1991
Model: Cherokee
Engine: 4.0
will a clogged CCV cause it to run extremely rough, have no power, and be super hard to start when warm?
i bought a DMM last night so i can test the sensors, going out in a few minutes to start doing that
i bought a DMM last night so i can test the sensors, going out in a few minutes to start doing that
12-14-2010, 09:35 AM
#6
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the clogged CCV isn't what is causing your issue, but is definitely something that needs to be repaired. You need to get new hoses from the dealership (~$15 for both) and 2 new valve cover grommets. If your existing grommets are very hard like plastic, you will need to literally break them off. The CCV fitting can be cleaned using carb cleaner (it's just a plastic elbow with a certain size hole in the end)
i would look into replacing your distributor cap + rotor first. Then your plugs and wires if the problem remains. Also clean the throttle body real thoroughly (avoid spraying directly into sensor holes) with throttle body cleaner.
It's also possible that you have a clogged fuel filter that needs to be replaced.
i would look into replacing your distributor cap + rotor first. Then your plugs and wires if the problem remains. Also clean the throttle body real thoroughly (avoid spraying directly into sensor holes) with throttle body cleaner.
It's also possible that you have a clogged fuel filter that needs to be replaced.
12-14-2010, 09:53 AM
#7
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Year: 1991
Model: Cherokee
Engine: 4.0
ok, when the intermittent problem started, i had hooked up some vaccum lines i found unhooked. they were to the EGR valve. i think someone had it unhooked for a reason because i unhooked them this morning and it runs a lot better. starts right up (or as fast as any Renix) and idles normally. could a bad EGR cause the symptoms i described?
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12-14-2010, 10:10 AM
#8
☠ CF Sheriff ☠
Originally Posted by Factory Service Manual
TESTING
EGR VALVE
Valve Opening Test
1) With engine at normal operating temperature and at idle,
rapidly open and close throttle. Open throttle sufficiently to obtain
at least 1500 RPM. Movement should be noticed in EGR diaphragm.
2) If diaphragm does not move, probable causes are: faulty
vacuum signal to EGR, defective EGR diaphragm or defective
backpressure sensor diaphragm (if equipped), or leaks in vacuum lines
or connections.
Valve Closing Test
1) With engine at normal operating temperature and at idle,
manually depress EGR valve diaphragm. RPM should immediately drop,
indicating that EGR valve is not leaking and had been properly cutting
off exhaust gas flow at idle.
2) If there is no change in RPM and engine is idling
properly, exhaust gases are not reaching combustion chamber. Check for
plugged passage between EGR valve and intake manifold.
3) If engine idles poorly and RPM is not greatly affected by
manually moving diaphragm up, EGR valve is not closing off exhaust gas
flow. Check for carbon between pintle, leaking EGR valve gasket or bad
EGR valve.
EGR VALVE
Valve Opening Test
1) With engine at normal operating temperature and at idle,
rapidly open and close throttle. Open throttle sufficiently to obtain
at least 1500 RPM. Movement should be noticed in EGR diaphragm.
2) If diaphragm does not move, probable causes are: faulty
vacuum signal to EGR, defective EGR diaphragm or defective
backpressure sensor diaphragm (if equipped), or leaks in vacuum lines
or connections.
Valve Closing Test
1) With engine at normal operating temperature and at idle,
manually depress EGR valve diaphragm. RPM should immediately drop,
indicating that EGR valve is not leaking and had been properly cutting
off exhaust gas flow at idle.
2) If there is no change in RPM and engine is idling
properly, exhaust gases are not reaching combustion chamber. Check for
plugged passage between EGR valve and intake manifold.
3) If engine idles poorly and RPM is not greatly affected by
manually moving diaphragm up, EGR valve is not closing off exhaust gas
flow. Check for carbon between pintle, leaking EGR valve gasket or bad
EGR valve.
12-15-2010, 03:35 PM
#10
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Year: 1991
Model: Cherokee
Engine: 4.0
CPS MAYBE?
i went out and tested it, the lowest setting for AC voltage on my DMM is 200 and it read 00.1-00.2 volts, it's supposed to be 00.5 or higher right? lunghd.com says replace if under 00.5
i went out and tested it, the lowest setting for AC voltage on my DMM is 200 and it read 00.1-00.2 volts, it's supposed to be 00.5 or higher right? lunghd.com says replace if under 00.5
12-16-2010, 12:24 PM
#11
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Year: 1991
Model: Cherokee
Engine: 4.0
ok so new crank sensor in and...NOTTA!
nothing changed. crank sensor make the injectors pulse, right? well i have injector pulse, but no spark...
nothing changed. crank sensor make the injectors pulse, right? well i have injector pulse, but no spark...
12-16-2010, 12:33 PM
#12
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Year: 1999
Model: Cherokee
Engine: 4.0 L
Have you checked the dist cap and rotor, plugs , fuel filter, fuel pressure as mentioned before? In my experience it is better to start with the simple cheap stuff first rather than to just start replacing random parts.
I had a s-15 jimmy that was missing real bad and running like crap,I couldn't figure it out then I decided to check the dist cap and what do ya know lol the contacts were burnt to oblivion. New cap and rotor and good as new.
If your egr has been disconnected thats probably a good sign that a po was too cheap to replace it.
I had a s-15 jimmy that was missing real bad and running like crap,I couldn't figure it out then I decided to check the dist cap and what do ya know lol the contacts were burnt to oblivion. New cap and rotor and good as new.
If your egr has been disconnected thats probably a good sign that a po was too cheap to replace it.
12-16-2010, 12:35 PM
#13
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Year: 1991
Model: Cherokee
Engine: 4.0
ok, so my TPS voltages are all out of wack...
A and C have .15 volts and B and D have 9.5 volts....
my understandign is that B is supposed to be the ground wire....
A and C have .15 volts and B and D have 9.5 volts....
my understandign is that B is supposed to be the ground wire....
12-16-2010, 12:38 PM
#14
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Year: 1991
Model: Cherokee
Engine: 4.0
i checked the cap and rotor, some corrosion but not to bad, cleaned them up and made no difference.
i havent checked/changed the fuel filter yet, but i am getting fuel to the fuel rail, i would think it would at least TRY to start...
i havent checked/changed the fuel filter yet, but i am getting fuel to the fuel rail, i would think it would at least TRY to start...