Question about 1998 Jeep Wrangler

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03 JEEP wrangler Rubicon 4.0L missfire on cylinders 1,2, and 3!

2 new crank sensors, 2 new cam sensors and 2camshaft synchronizers, new PCM, new plugs, coil, all fuses and relays are good, timing is perfect, been checked by the dealer. This thing will idol all day long but as soon as you rev it to about 1500 rpm it starts miss firing and kills cylinders 1 2 and 3. check engine light comes on and even says miss fire on all those cylinders. Jeep dealership can't even figure this one out...had it for a month now and nothing, anyone have ideas?

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Bad fuel pump can cause this or plugged fuel filter but i believe they are one unit

Posted on Jul 30, 2009

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I changed the spark plugs on my 2006 rubicon now it feels like the timing is way off sputters and wont catch up to its self until 1500 rpm's anyone?

Posted on Aug 31, 2011


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Where is camshaft position sensor on 2002 Pontiac grand am se ecotec 2.2

This vehicle does not have a cam sensor .The ICM provides a synthesized cam signal to the PCM based on these inputs. The PCM uses the cam signal to synchronize fuel injection.

The powertrain control module (PCM) supplies a signal on each of the ignition control (IC) timing control circuits to the ignition control module (ICM). The ICM fires the correct ignition coil at the correct time based on the signals. The ICM detects if cylinder 1 or cylinder 3 is on the compression stroke by sensing the secondary voltage and polarity of each side of the ignition coil. The ICM detects this voltage with sensing circuitry integrated into each ignition coil. The higher voltage is on the compressing cylinder. This is called compression sense ignition. The ICM provides a synthesized cam signal to the PCM based on these inputs. The PCM uses the cam signal to synchronize fuel injection.
This system consists of the following circuits:
• An ignition voltage circuit
• A ground circuit
• A camshaft position (CMP) sensor signal circuit
• An IC timing control circuit for cylinders #1 and #4
• An IC timing control B circuit for cylinders #2 and #3

DTC P0340
This ignition system does not use a conventional camshaft position (CMP) sensor that detects valve train position. The ignition controls module (ICM) detects when #1 or #3 cylinder has fired on the cylinders compression stroke using sensing circuitry integrated within each coil. The sensing circuit detects the polarity and the strength of the secondary voltage output, the higher output is always at the event cylinder. The ignition control module (ICM) sends a CMP signal to the powertrain control module (PCM) based on the voltage difference between the event and waste cylinder firing energy. This system is called compression sense ignition. By monitoring the CMP and crankshaft position (CKP) signals, the PCM can accurately time the operation of the fuel injectors. If the PCM receives an intermittent CMP signal from the ICM, the CMP Resync Counter on the scan tool will increment. When the PCM cannot use the information from the CMP signal, a DTC will set. DTC P0341 sets when the PCM detects too many CMP Resyncs within a certain amount of time.

Jul 13, 2017 | Pontiac Cars & Trucks

2 Answers

Check engine code O2 sensor p0132

New PCM plugs and wires? hun?
new harness ,why? in a fire or wreck? running off road?
or did you mean, new PCM, new spark wires, and all new 02s sensors' It wont be a bad PCM , sorry, 99% are good.
the PCM never lies. it measure this and does a test and if it fails there is a circuit fault.
the why to understand, DTCs (have a FSM factory serv. manual)
and read how the test works. or do the tests it tells you do to
to discover true cause)
i have this car v6 3.8L: and 6speed and the FSM, book.
1/1 means bank 1 , front sensor (upsteam)
bank one means right bank, cylinder 1 side.
what does HIGH mean?

what is not clear is which side is failing, heater or CELL
this test is the CELL pin (oxy out)
pin 4.
the test (called a monitor) finds that pin 4 is stuck at 5v.
the o2 must be 0 to 1volt at all times.
if stuck at 5vdc then the ground is open to CELL pin 3 (wire cut)
or the 02 sensors is bad. (open)
do you know how to back probe? a skill that is must for all modern cars. use needles with your meter. (DMM) (leather needles work in a pinch sold at walfart for 1buck) needle probes are 10x better
key on and back probe pin 4, if at 5vdc or more(or near) it's wrong.
btw page 2891 shows what to do in the FSM. yah 7000 pages.
I think this pin floats to 5v if the wire is cut.

fail 2 is that pin 4 is shorted to voltage ,well , the heater runs off
of 12v and all cars (bad service) the 2 wires melt and short.

here ill list all 4 pins (key on)
1- 12v heater.
2- ground
3 - ecu quite ground to 02 (cell minus)
4- CELL + out (this is the oxy signal)

pin 4 must not be at 5v or 12v, but 0 to 1 volts.
at key on or running.

one more FSM quote
Measure the voltage in reference to ground, not the (K902) O2 Return Upstream circuit.

that means pin 3 to 4, is measured for best accuracy
but 5vdc or 12vdc is gross wrong .

if the o2 is new (is)
then this quote covers most fails on most cars
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact
in the Oxygen Sensor and Powertrain Control Module connectors.

here is the wiring.
if you need more photos full size or more tests.
or have questions, ask, i'm a retired ET, (controls systems , PLCs +)


see FSM here
on CD (best of best)

Nov 19, 2014 | 2008 Jeep Wrangler Rubicon

2 Answers


PCM= Powertrain Control Module. It is the brains of the car, it reads the sensor in put from all sensors including the cam shaft position sensor

May 14, 2014 | 2004 Toyota 4Runner

2 Answers

Crank sensor for 1994 jeep laredo

keep it simple first disconnect coil wire from distributor leaving coil connected, put a screwdriver in wire place it away from fan or other moving parts such as belt , and crank engine, u shld see spark. if not u found ur problem. coil needs to be replaced

Feb 14, 2014 | 1994 Jeep Grand Cherokee

1 Answer

Where is the bank 2 sensor 1 located on a jeep wrangler 2003 rubicon

Bank one is always the same side of the engine as the number one cylinder. Bank two is the opposite side of the enigine. Sensor refers to before or after the catalytic converter. Sensor 1 is before the cat and sensor 2 is after the cat. Let me know if you have any questions and I'll do my best to answer them. Thank you for using!

Feb 14, 2012 | Cars & Trucks

1 Answer

97 Jeep Wrangler sport- Cranks, will not

Fuel flow. Either simply, a blocked fuel line (debris / filter / fouled gas) or an electronic issue. Ever let this Jeep run bone dry on gas? Hopefully not, as doing so can draw a lot of crud into your fuel lines from the bottom of the tank. Electronically, if part of the Jeep "brain" has gone bad, there may not be any fuel being routed to the engine. This most likely needs a Jeep mechanic to repair.

May 15, 2010 | 2007 Jeep Wrangler Unlimited Rubicon 2...

2 Answers

Check engine light flashing runs rough not firing on all cylinder2000 lincoln navigator with large triton engine Hooked up diagnnostic and it said 1. system too lean bank #2 2. Unable to bleed up fuel tank...

you may try your rotor button and distributor cap. and spark plug wires. try your map sensor also they tend to cause a lot of misfiring if they go bad.hope this helps.

Apr 20, 2010 | Lincoln Navigator Cars & Trucks

3 Answers

P0308 cylinder 8 misfire detected? How to repair?

Fuel injector cleaner commonly has a low success rate, and will not help if it's more than one cylinder that is missfiring. The fact that you have a "rattle" noise, leads me to beleive the engine is not receiving fuel on one or more cylidners. If it is all the cylinders, than the fuel pump may be the culprit, or the fuel pump circuit. But if only one cylidner is missfiring than it is a possibly an injector. A code P0300 refers to all cylinder missfires, and any code between P0301-P0308 distinugiushes a particular cylinder.

1- a general electrical tune-up (spark plugs, wire set, cap & rotor) is a basic start to cure this issue. Wiggle the dist shaft while you are in there, if you have one.
2- Then a good carbon cleaning / throttle-body cleaning.
3- Vacuum leaks at any of the hoses that connect to the Intake manifold; especially the MAP sensor connection.
4- If that does not help then the O2 sensor could be bad or drifting.
5- Funky coil/coil-packs
6- Theoretically a microsecond glitch in either the cam or crank shaft sensors would cause this, but I am not aware of this as a typical cause.
7- Lastly a funky PCM but again it is not common for this to cause miss-firing.

Note for the V8 then also:
a) bad erg valve (this dilutes the combustion gases and hence raises the combustion temp
b) a leaky plenum/Intake manifold gasket. Leaking Intake gasket symptoms

Also can check the TSB 18-48-98 Ignition System Cross Fire/Secondary Ignition Wire Induction (Complete Version )

Hope help with this (remember rated this). Good luck and have a nice day.

Mar 05, 2010 | 1997 Jeep Grand Cherokee

1 Answer

Engine just stops for a few seconds off and on

There is a PCM update for that Have the dealership update the PCM to the latest software level for a rough idle/stumble condition.

Aug 04, 2009 | 2002 Jeep Wrangler

1 Answer

Dodge 5.9 pickup

check the flywheel for damage...these to cylinders are directly opposite of each other in tyhe firing order...also a bad distributor could cause it

Dec 12, 2008 | 1997 Dodge Dakota

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