Unable to start 96 cherokee, guru's help
10-28-2009, 05:05 PM
#16
Newbie
Thread Starter
Join Date: Oct 2009
Posts: 19
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
Bump for more ideas.. I am stumped.. i have disconnected and connected every plug that my eyes can see.. LOL
I checked every fuse port for connectivity / voltage and it all adds up..
I reset the computer.. also
I still have not spark from coil and no fuel pump action...
I checked every fuse port for connectivity / voltage and it all adds up..
I reset the computer.. also
I still have not spark from coil and no fuel pump action...
10-28-2009, 05:25 PM
#17
Seasoned Member
Join Date: Sep 2009
Location: East Texas
Posts: 454
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1997
Model: Grand Cherokee
Engine: 4.0
That no spark and no fuel pump action now points to the CPS or PCM. I know you said you replaced the CPS but it may be the problem.
Did you try that link that I posted? It shows how to test CPS. I am trying to find another article on CPS but do not know where I hid it.
If the PCM does not sense the CPS the ASD shuts down ignition and fuel pump. That is how I understand it.
See this link.
Did you try that link that I posted? It shows how to test CPS. I am trying to find another article on CPS but do not know where I hid it.
If the PCM does not sense the CPS the ASD shuts down ignition and fuel pump. That is how I understand it.
See this link.
10-28-2009, 06:40 PM
#18
Newbie
Thread Starter
Join Date: Oct 2009
Posts: 19
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
That no spark and no fuel pump action now points to the CPS or PCM. I know you said you replaced the CPS but it may be the problem.
Did you try that link that I posted? It shows how to test CPS. I am trying to find another article on CPS but do not know where I hid it.
If the PCM does not sense the CPS the ASD shuts down ignition and fuel pump. That is how I understand it.
See this link.
Did you try that link that I posted? It shows how to test CPS. I am trying to find another article on CPS but do not know where I hid it.
If the PCM does not sense the CPS the ASD shuts down ignition and fuel pump. That is how I understand it.
See this link.
I have a voltmeter / ohmmeter and it has a red and black cable.. so is the red cable supposed to be on the B port of the plug and black on C or A?
Looking at the link you sent me... that is the plug i replaced with a new one from PEPBoys.. I can't imagine that the NEW plug can come damaged.. I mean is there a way to test the sensor itself?
10-28-2009, 07:55 PM
#21
Newbie
Thread Starter
Join Date: Oct 2009
Posts: 19
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
Nope.. i did not do a fuel pressure test but i do not hear the fuel pump kick in or nor am i getting a spark from the coil.
How do I do a fuel pressure test?
10-28-2009, 07:57 PM
#22
Senior Member
Join Date: Feb 2009
Posts: 811
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
the "no fuel pump" issue could be engine ground. when i did my engine swap, i forgot to hook that up and the pump would not run. maybe double check your connections between the engine and frame and battery.
10-28-2009, 08:13 PM
#24
Newbie
Thread Starter
Join Date: Oct 2009
Posts: 19
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
I will call PepBoys tomorrow and see if I can get an exchange but i doubt it since its a sensor and I could be wrong but they usually do not take something back that is electronic and put on the vehicle..
10-28-2009, 10:10 PM
#26
Seasoned Member
Join Date: Sep 2009
Location: East Texas
Posts: 454
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1997
Model: Grand Cherokee
Engine: 4.0
Ok, I looked at you measurements again. I took these as voltage measurements since you had the key on.
Reading that link that I posted, you set your meter to ohms and connect it to pin B n C. Which lead goes where does not matter. You should read an open, no measurement. If you read some ohms, the sensor is defective. You are testing the sensor. My manual shows the same test for the CPS. Check the connector and make sure it is clean. Trace the wiring and make sure all is good.
Unless Pep Boys is located far away, I would not call them. It is easy to say no on the phone. You might be better off going in person. Have them test the CPS. Just claim it was defective.
I can't think of anything else. Maybe checking the connectors at the PCM. Remove and reinstall them if not too difficult. Check the ground.
I think it is the CPS. If it is defective, the PCM will not read it and the ASD will shutdown ignition and fuel. These are the symptoms you are experiencing.
Reading that link that I posted, you set your meter to ohms and connect it to pin B n C. Which lead goes where does not matter. You should read an open, no measurement. If you read some ohms, the sensor is defective. You are testing the sensor. My manual shows the same test for the CPS. Check the connector and make sure it is clean. Trace the wiring and make sure all is good.
Unless Pep Boys is located far away, I would not call them. It is easy to say no on the phone. You might be better off going in person. Have them test the CPS. Just claim it was defective.
I can't think of anything else. Maybe checking the connectors at the PCM. Remove and reinstall them if not too difficult. Check the ground.
I think it is the CPS. If it is defective, the PCM will not read it and the ASD will shutdown ignition and fuel. These are the symptoms you are experiencing.
10-29-2009, 10:05 AM
#27
Junior Member
Join Date: Oct 2009
Posts: 64
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1990 Pioneer
Model: Cherokee
Engine: 4.0
couldn't it just be a worn out fuel pump. I have a 90 and can hear it before I crank it over. I have a 93 chevy as well and at about 200,000miles the fuel pump finally gave out.
10-29-2009, 07:15 PM
#28
Newbie
Thread Starter
Join Date: Oct 2009
Posts: 19
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
Ok, I looked at you measurements again. I took these as voltage measurements since you had the key on.
Reading that link that I posted, you set your meter to ohms and connect it to pin B n C. Which lead goes where does not matter. You should read an open, no measurement. If you read some ohms, the sensor is defective. You are testing the sensor. My manual shows the same test for the CPS. Check the connector and make sure it is clean. Trace the wiring and make sure all is good.
Unless Pep Boys is located far away, I would not call them. It is easy to say no on the phone. You might be better off going in person. Have them test the CPS. Just claim it was defective.
I can't think of anything else. Maybe checking the connectors at the PCM. Remove and reinstall them if not too difficult. Check the ground.
I think it is the CPS. If it is defective, the PCM will not read it and the ASD will shutdown ignition and fuel. These are the symptoms you are experiencing.
Reading that link that I posted, you set your meter to ohms and connect it to pin B n C. Which lead goes where does not matter. You should read an open, no measurement. If you read some ohms, the sensor is defective. You are testing the sensor. My manual shows the same test for the CPS. Check the connector and make sure it is clean. Trace the wiring and make sure all is good.
Unless Pep Boys is located far away, I would not call them. It is easy to say no on the phone. You might be better off going in person. Have them test the CPS. Just claim it was defective.
I can't think of anything else. Maybe checking the connectors at the PCM. Remove and reinstall them if not too difficult. Check the ground.
I think it is the CPS. If it is defective, the PCM will not read it and the ASD will shutdown ignition and fuel. These are the symptoms you are experiencing.
I disconnected the PCM and reconnected it..
Will pepboys be able to test the CPS.. I can take it to pepboys on saturday.. How can i test the PCM to check if its working and not FRIED?
10-29-2009, 07:43 PM
#29
Renix Super Guru
Join Date: Mar 2008
Location: In yourz postez fissin jurr spelinzs
Posts: 24,653
Likes: 0
Received 16 Likes
on
12 Posts
Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
Does not sound like you have done anything to fry the ECU. Unless o.you hook up the battery backwards putting 12v through the ground side or fry it by welding without disconnecting the battery then the ECU is pretty bulletproof.
Could you trace the CPS wiring to make sure nothing got pinched or broken. CPS requires a +/- 5v on the Renix ECU so it may be the same on the H.O.
Blue
Could you trace the CPS wiring to make sure nothing got pinched or broken. CPS requires a +/- 5v on the Renix ECU so it may be the same on the H.O.
Blue
10-29-2009, 10:05 PM
#30
Seasoned Member
Join Date: Sep 2009
Location: East Texas
Posts: 454
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1997
Model: Grand Cherokee
Engine: 4.0
That test was for the CPS sensor. You test B n C and if you get a low resistance reading (ohms) the sensor is bad. You do not need the key on for the sensor test.
On the wiring harness, jeep side, you do a voltage test. The manual that I have does not show that voltage test. I do have a Dodge manual with similar system that does show it. Your decision if you want to try it. The PCM feeds 8 volts to the CPS on both systems and all pin numbers are the same.
Pep boys testing the sensor is just a guess. You can wait til Saturday and see if Pep boys will exchange it. I will see if I can find the Jeep test. I found it for the Renix engine.
On the wiring harness, jeep side, you do a voltage test. The manual that I have does not show that voltage test. I do have a Dodge manual with similar system that does show it. Your decision if you want to try it. The PCM feeds 8 volts to the CPS on both systems and all pin numbers are the same.
Pep boys testing the sensor is just a guess. You can wait til Saturday and see if Pep boys will exchange it. I will see if I can find the Jeep test. I found it for the Renix engine.