My woeful Jeep Grand Cherokee problems... Please help me!
Discussion
Good day all.
I originally posted this in 'Yank motors' but am yet to have any luck...
I have recently been ripped off in swapping my trusty old car for a 2001 Jeep Grand Cherokee 4.7 V8.
It managed 40 miles before it began mis-firing so badly that I had to get the RAC to come and tow me home.
Fault codes pulled at the roadside were for an intermittent Camshaft postion signal, and a primary/secondary circuit failure (ignition coil D).
2 days later, I removed the coils and cleaned them all with WD40, and also cleaned the contacts for the fuel pump and ASD relays, and it cured the problem.
5 days after this, I tried to start it, and the battery was dead.
(I did not leave anything on to drain the battery),
When I jump started it, the first 3 or 4 times it immediately stalled, but without misfiring, then after opening the throttle fairly brutally, the engine continued to operate, but at idling at 2000rpm, then gradually decreasing to 1500rpm.
While all this was happening, the alarm went off, and only stopped after I slammed the passenger door.
I am not a mechanic, but normally know enough to get by, and this has me completely stumped.
Could it be any of the following?
EGR valve, Stepper motor/Idle control valve, camshaft position sensor, O2 sensor, coils?
any help greatly appreciated as this is supposed to be my 'family' car, and so far we haven't been able to use it since we got it.
I originally posted this in 'Yank motors' but am yet to have any luck...
I have recently been ripped off in swapping my trusty old car for a 2001 Jeep Grand Cherokee 4.7 V8.
It managed 40 miles before it began mis-firing so badly that I had to get the RAC to come and tow me home.
Fault codes pulled at the roadside were for an intermittent Camshaft postion signal, and a primary/secondary circuit failure (ignition coil D).
2 days later, I removed the coils and cleaned them all with WD40, and also cleaned the contacts for the fuel pump and ASD relays, and it cured the problem.
5 days after this, I tried to start it, and the battery was dead.
(I did not leave anything on to drain the battery),
When I jump started it, the first 3 or 4 times it immediately stalled, but without misfiring, then after opening the throttle fairly brutally, the engine continued to operate, but at idling at 2000rpm, then gradually decreasing to 1500rpm.
While all this was happening, the alarm went off, and only stopped after I slammed the passenger door.
I am not a mechanic, but normally know enough to get by, and this has me completely stumped.
Could it be any of the following?
EGR valve, Stepper motor/Idle control valve, camshaft position sensor, O2 sensor, coils?
any help greatly appreciated as this is supposed to be my 'family' car, and so far we haven't been able to use it since we got it.
Given the considerable number of quite possibly unconnected faults and fault codes I'm not surprised no one wants to touch this because there's no way anyone can really tell you what's wrong. However I suggest you start by checking out the flat battery because very low battery or alternator voltage could cause all sorts of knock on effects including misfiring and the poor running when it started up.
Charge it fully off the vehicle, make sure it comes up to at least 12.6 volts, check the alternator output is up to spec (14v or so or whatever it's supposed to be for your vehicle) and clean and check all the connections. A current drain test would be wise to see if anything is draining it abnormally like a faulty alarm system given that went off unexpectedly or a courtesy light bulb stuck on somewhere.
Once you've done all that you can see if any other problems recur and then target them more specifically. It might be that doing the above will fix everything.
Charge it fully off the vehicle, make sure it comes up to at least 12.6 volts, check the alternator output is up to spec (14v or so or whatever it's supposed to be for your vehicle) and clean and check all the connections. A current drain test would be wise to see if anything is draining it abnormally like a faulty alarm system given that went off unexpectedly or a courtesy light bulb stuck on somewhere.
Once you've done all that you can see if any other problems recur and then target them more specifically. It might be that doing the above will fix everything.
After you have charged up the battery you should pull the camshaft sensor and the crankshaft position sensor, I'm sure these have both, with the crank sensor tucked away almost impossible to find high up close to the flwheel
The initial problem sounds as if the ECU isnt getting a clear constant firing signal
This can often be caused by foreign bodies gathering round the sensor tips
The crank sensor is specially attracted to clutch (and starter ring debris) materials thrown out centrifugally
I am not certain that the V8 Cherokee has these specific problems but they are generic enough to be worth a looksee
If it is the crank sensor it could be very hard to locate
The initial problem sounds as if the ECU isnt getting a clear constant firing signal
This can often be caused by foreign bodies gathering round the sensor tips
The crank sensor is specially attracted to clutch (and starter ring debris) materials thrown out centrifugally
I am not certain that the V8 Cherokee has these specific problems but they are generic enough to be worth a looksee
If it is the crank sensor it could be very hard to locate
quick update/brain pick of the ph massive...
Tested resistance in all coils, changed all the plugs, checked all for sparks, pulled cam, crank and o2 sensors, stuck on a new battery. Code still says primary/secondary circuit failure for coil 'd'.
Anything else i could try before torching it? I'm a bit desperate now guys...
eta...
car is now fine when cold, bt after 5-10 miles it cuts out even under load. Could this be the egr valve stuck open?
only getting co2 into the combustion chamber??
Tested resistance in all coils, changed all the plugs, checked all for sparks, pulled cam, crank and o2 sensors, stuck on a new battery. Code still says primary/secondary circuit failure for coil 'd'.
Anything else i could try before torching it? I'm a bit desperate now guys...
eta...
car is now fine when cold, bt after 5-10 miles it cuts out even under load. Could this be the egr valve stuck open?
only getting co2 into the combustion chamber??
Edited by big_russ on Saturday 16th October 15:49
Sounds more like a classic coil pack fault now, i.e. work when cold, stop working when hot, std coil pack failure, and, as the codes point towards this, i would suggest moving the coil packs around (if this is possible and they are induvidual packs) and see if the fault "moves" with the coil ???
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