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Donny
Donny, Shop Foreman
Category: Jeep
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Experience:  A.S.E. Certified A1-A8,L1,X1,T1,T2 Over 25 years Experience with Chrysler - Dodge - Jeep
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2000 Wrangler: Code reader says cylinder 3 fuel injector..connector

Resolved Question:

My 2000 Wrangler 4.0L has the engine light on, and engine is missing. Code reader says cylinder 3 fuel injector. How do I tell if it's the injector itself or the electrical connector?
Submitted: 6 years ago.
Category: Jeep
Expert:  Donny replied 6 years ago.

Hello

 

So you have a P0203 code or a P0303 code, here is some information for both

 

Check for a wiring rub through to the number three injector at the bracket for the throttle cable, if the injector connector is not turned towards the rear of the motor (2 o'clock position) and is facing up the wiring can chafe on this bracket causing the injector to not spray fuel at times or constantly

 

You can test the resistance of the injector coil with an ohm meter, and then test injector number 1 and 2 , they should all be almost exactly the same, this is the best way since resistance will change with temperature and this gives you a good base line to compare too

 

Also if it is worse after a hot shut down and a short soak you may want to try the bulletin

number 18-031-03

 

4.0L Rough Engine Idle After Restart Following A Hot Soak

 

Customers may describe a 20 to 30 second rough idle following the restart of a heat soaked

engine. This condition may be most noticeable when the engine is restarted following a

prior 10 to 20 minute heat soak in hot ambient conditions of approximately 32 C (90ºF)

or higher. This condition may be consistent with short city stop-and-go driving trips and

can be aggravated by the use of fuel with a high ethanol content. Depending upon

various conditions a MIL may occur due to DTC P0303 - Cylinder #3 Misfire.

This condition may be caused by heat from the exhaust manifold that following engine

shut down migrates to the area around injector #3 and causes fuel vapor to form

within the injector. This in turn may cause a momentary misfire of cylinder #3 until

the fuel vapor is cleared of injector #3. The insulator sleeve lowers the injector #3

temperature to a point below which the fuel will not normally vaporize.

 

Cut insulator sleeve, p/n 56028371AA, to make two (2) insulator sleeves

about 1 in. in length.

2. Install one sleeve around injector #3, with the slit on the upward facing side of the

injector. Install the other sleeve with the slit on the downward facing side of the injector.

3. Confirm sleeve is flush to intake manifold surface around injector.

4. Check injector #3 wire and ensure that the injector is rotated to a 2 o'clock

position (from driver's side of vehicle).

 

Let me know what you find and we can move onto more testing as needed

 

Thank you

 

Donny

Donny, Shop Foreman
Category: Jeep
Satisfied Customers: 828
Experience: A.S.E. Certified A1-A8,L1,X1,T1,T2 Over 25 years Experience with Chrysler - Dodge - Jeep
Donny and 5 other Jeep Specialists are ready to help you
Customer: replied 6 years ago.

I checked the injector resistance, and it starts with a very high number, then steadily decreases. Both #1 and #3 do this. I've driven it more lately, and it seems like it runs smoothly for the first 5 miles after cold startup, then starts missing and the engine light comes back on. I cleaned the electrical connectors, but the problem remains. The connector is clocked at 2:00, and I was unable to find any cuts or cracks in the wires.


 


Thanks again.


Paul


 


 

Expert:  Donny replied 6 years ago.

Hello


 


What are you getting for readings? for injector 1,2,3


 


You are testing across the two pins in the injector with the injector unpluged from the wiring harness?


 


Donny

Customer: replied 6 years ago.
Yes, my readings were across the pins. I cleaned the pins to see if that would make a difference, but the problem returned. I'm seeing numbers in the 30Mohm range that steadily degrade down. I didn't check #2, but I will.
Expert:  Donny replied 6 years ago.

Hello

 

If all of the injectors are giving you the same result, then most likley it is not an injector

 

P-0203 INJECTOR #3 CONTROL CIRCUIT

When Monitored: With Battery voltage greater than 10.4 volts, the auto shutdown relay

energized, injector pulse width less than 10ms, and engine speed less than 3000 rpm.

Set Condition: This trouble code takes .64 to 10.0 seconds to set when no inductive kick

is sensed 18ms after injector turn off, and with no other injectors on.

 

POSSIBLE CAUSES

AUTO SHUTDOWN RELAY OUTPUT CIRCUIT OPEN

INJECTOR #3

INJECTOR CONTROL CIRCUIT WIRING HARNESS INTERMITTENT

INJECTOR CONTROL CIRCUIT WIRING HARNESS OBSERVABLE

INJECTOR #3 DRIVER CIRCUIT OPEN

INJECTOR #3 DRIVER CIRCUIT SHORTED TO GROUND

POWERTRAIN CONTROL MODULE

 

1

Start engine, let idle for at least 20 seconds.

Key on, engine off.

With the scan tool, read trouble codes.

Is the DTC SPECIFIC GOOD TRIP counter displayed and equal to zero?

Yes Go To 2

No Go To 7

 

2

Ignition Off

Disconnect the Injector #3 Connector.

Note: Check connectors - Clean/repair as necessary.

Key on.

With the scan tool, actuate the #3 Injector.

Using a 12 volt test light, check the ASD Relay Output circuit.

Does the test light illuminate brightly?

Yes Go To 3

No Repair the open ASD Relay Output Circuit.

 

3

Ignition Off

Disconnect the Injector #3 Connector.

Note: Check connectors - Clean/repair as necessary.

Note: The next steps require an analog voltmeter.

Connect the positive lead to a good 12 volt source(B+) and the negative lead to the

Injector #3 driver circuit at the Injector connector.

With the scan tool, actuate the #3 Injector and observe the voltmeter.

Does the needle fluctuate?

Yes Replace the Fuel Injector.

No Go To 4

 

4

Ignition Off

Disconnect the Injector #3 Connector.

Disconnect the Powertrain Control Module Connector.

Note: Check connectors - Clean/repair as necessary.

With an Ohmmeter, measure across the Injector #3 Driver Circuit from the

Powertrain Control Module Connector to the Injector Connector.

Is the resistance below 5.0 ohms?

Yes Go To 5

No Repair the open Injector #3 Driver Circuit.

 

5

Ignition Off

Disconnect the Injector #3 Connector.

Disconnect the Powertrain Control Module Connector.

Note: Check connectors - Clean/repair as necessary.

Using an Ohmmeter, measure the Injector #3 Driver Circuit to ground.

Is the resistance below 5.0 ohms?

All

Yes Repair the Injector #3 Driver Circuit for a short to ground.

No Go To 6

 

6

If there are no potential causes remaining.

View repair options.

Repair

Replace the Powertrain Control Module.

 

7

Start Engine

Wiggle Wiring Harness from the Injector Connector to the PCM Connector.

Does the engine miss or stall?

Yes Repair as necessary where wiggling caused problem to appear.

No Go To 8

 

8

Ignition Off inspect the Wiring and Connectors.

Were any problems found?

Yes Repair as necessary.

 

tj003007

 

FUEL INJECTOR NO. 3 (4.0L) - BLACK 2 WAY
CAVCIRCUITFUNCTION
1DG/LGFUSED AUTOMATIC SHUT DOWN RELAY OUTPUT
2YL/WTFUEL INJECTOR NO. 3 DRIVER

 

POWERTRAIN CONTROL MODULE C2 - WHITE 32 WAY
CAVCIRCUITFUNCTION
B22--
B7--
B13--
B14--
B1--
B3--
B32--
B18--
B19--
B8--
B21--
B17--
B24--
B25--
B26--
B28--
B29--
B30--
B2--
B20--
B23GYY/YLENGINE OIL PRESSURE SENSOR SIGNAL
B27WT/ORVEHICLE SPEED SENSOR SIGNAL
B4WT/DBFUEL INJECTOR NO. 1 DRIVER
B15TNFUEL INJECTOR NO. 2 DRIVER
B5YL/WTFUEL INJECTOR NO. 3 DRIVER
B16LB/BRFUEL INJECTOR NO. 4 DRIVER
B6PK/BK (4.0L)FUEL INJECTOR NO. 5 DRIVER
B12LG/BK (4.0L)FUEL INJECTOR NO. 6 DRIVER
B9DB/TNIGNITION COIL NO.2 DRIVER
B10DGGENERATOR FIELD
B31VT/OR5V SUPPLY
B11OR/LGTRANSMISSION LOW/OVERDRIVE SOLENOID

 

Donny

Donny, Shop Foreman
Category: Jeep
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Experience: A.S.E. Certified A1-A8,L1,X1,T1,T2 Over 25 years Experience with Chrysler - Dodge - Jeep
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