Injector upgrade problems
Thread Starter
Junior Member
Joined: May 2017
Posts: 38
Likes: 2
Year: 1997
Model: Cherokee
Injector upgrade problems
Howdy everyone. 1997 Jeep Cherokee Sport -- 192,000 miles. I just upgraded my injectors to the Bosch 4 hole style. These were re-manufactured with a 5 year warranty, bought them off of Ebay. Before the installation the vehicle was running well accept for a Number # 1 misfire code. After the installation the vehicle ran great, very smooth, lots of power. After about 15 minutes of driving, however, it slowly started running rougher and rougher and the CEL came on with a whole litany of error codes: P0304, P0204, P0302, P0202, P0300. On a hunch I reset the PCM and again it ran very well for another 15 minutes, wherein the same symptoms and codes came back. I am sure this nothing new but I have had no success researching the problem online. I am not sure why this is happening or how to repair it? Any ideas? Thank you.
CF Veteran
Joined: Dec 2015
Posts: 2,139
Likes: 93
From: Syracuse, NY
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0L
You need to see what the computer thinks is going on. Get a BAFX OBD2 bluetooth scanner from amazon for about $25. Then if you or a friend has an Android phone, go get Torque from Google play (pay the $5 for the pro version).
This will help you to see the fuel trims, open/closed loop status, and other details about the O2 sensors. In near real-time.
My guess is that the fuel trims are probably all over the place. They (short term and long term fuel trims) should on a stock vehicle be near zero, or trying to work their way back to zero.
For anyone with a 96+ XJ, these little scanners are darn near a must-have item. Its the only way you can come close to knowing what the computer thinks is going on.
This will help you to see the fuel trims, open/closed loop status, and other details about the O2 sensors. In near real-time.
My guess is that the fuel trims are probably all over the place. They (short term and long term fuel trims) should on a stock vehicle be near zero, or trying to work their way back to zero.
For anyone with a 96+ XJ, these little scanners are darn near a must-have item. Its the only way you can come close to knowing what the computer thinks is going on.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,577
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
You need to see what the computer thinks is going on. Get a BAFX OBD2 bluetooth scanner from amazon for about $25. Then if you or a friend has an Android phone, go get Torque from Google play (pay the $5 for the pro version).
This will help you to see the fuel trims, open/closed loop status, and other details about the O2 sensors. In near real-time.
My guess is that the fuel trims are probably all over the place. They (short term and long term fuel trims) should on a stock vehicle be near zero, or trying to work their way back to zero.
For anyone with a 96+ XJ, these little scanners are darn near a must-have item. Its the only way you can come close to knowing what the computer thinks is going on.
This will help you to see the fuel trims, open/closed loop status, and other details about the O2 sensors. In near real-time.
My guess is that the fuel trims are probably all over the place. They (short term and long term fuel trims) should on a stock vehicle be near zero, or trying to work their way back to zero.
For anyone with a 96+ XJ, these little scanners are darn near a must-have item. Its the only way you can come close to knowing what the computer thinks is going on.
Senior Member
Joined: Nov 2013
Posts: 616
Likes: 4
From: Vernon NJ
Year: 1998
Model: Cherokee
Engine: 4.0
P0204 and P0202 are injector circuit malfunction codes. I would look at the wire harness and see if there is any wires that are frayed. I would also look at the plug on injectors 2 an 4 and see if there is any corrosion on the terminals. i would swap the old injectors back in wile you are trying to correct the problem. You may have 2 injectors that have a different ohm rating then the other ones. Pull them all and check the resistance against what the stock injectors are.