Advice for locating bad wiring
#1
01-24-2018, 01:54 PM
Advice for locating bad wiring
The problem I’m having is that my 04 Disco keeps blowing fuse #2. Right before it does it will stall/lurch like it’s just put effort to push a clog out, then immediately the CEL pops and ultraguage shows many different codes.
My local mechanic ran the codes and linked it to a power issue that he first thought was a loose terminal connection at the battery. He tightened it (while he was checking my radiator for a leak), but I was no more than 1/2 mile down the road when the stall/lurch happened and CEL came on. Sure enough fuse was popped as well.
I’ve found the old thread https://landroverforums.com/forum/di...blowing-47500/ so I know to check air injection valve, purge valve and evap canister vent first.
My question is, how do I check these to see what the problem is? Can I use a multimeter?
Also, I noticed my driver side pre-cat O2 sensor wiring was loose. Thought it might be the culprit if it got too close to the manifold.
How can I test those to see if there’s an issue with O2 wiring?
It’s funny that I’ve replaced upper intake gaskets but the electrical system is what slows me down.
Thanks for replies in advance.
My local mechanic ran the codes and linked it to a power issue that he first thought was a loose terminal connection at the battery. He tightened it (while he was checking my radiator for a leak), but I was no more than 1/2 mile down the road when the stall/lurch happened and CEL came on. Sure enough fuse was popped as well.
I’ve found the old thread https://landroverforums.com/forum/di...blowing-47500/ so I know to check air injection valve, purge valve and evap canister vent first.
My question is, how do I check these to see what the problem is? Can I use a multimeter?
Also, I noticed my driver side pre-cat O2 sensor wiring was loose. Thought it might be the culprit if it got too close to the manifold.
How can I test those to see if there’s an issue with O2 wiring?
It’s funny that I’ve replaced upper intake gaskets but the electrical system is what slows me down.
Thanks for replies in advance.
#2
01-24-2018, 02:15 PM
Sounds like you probably have a short ground in the circuit which will cause the fuse to pop every time. Check the harnesses associated with fuse #2 (its listed in the link you posted) and check visually for any rubbed through harnesses that are making contact with the chassis or grounding out. Then if nothing obvious is found, you can use a multimeter to check each wire for continuity and go from there.
The thread you linked has all the info you need, just gotta be patient and find out what the issue is!
The thread you linked has all the info you need, just gotta be patient and find out what the issue is!
#3
01-24-2018, 02:51 PM
Okay, a couple of questions:
According to the link I should start with the Air injection valve, purge valve, and evap canister. Does it make sense to start looking for a bare spot at that end of the harness or the other end?
Also, how do I check for continuity on each of these items? I’ve never done that before.
Also, does it make sense to disconnect each item one at a time and drive around to see if it triggers the codes or blows fuse?
sorry for the dumb questions but I’m a complete novice when it comes to troubleshooting electrical problems.
According to the link I should start with the Air injection valve, purge valve, and evap canister. Does it make sense to start looking for a bare spot at that end of the harness or the other end?
Also, how do I check for continuity on each of these items? I’ve never done that before.
Also, does it make sense to disconnect each item one at a time and drive around to see if it triggers the codes or blows fuse?
sorry for the dumb questions but I’m a complete novice when it comes to troubleshooting electrical problems.
#4
01-24-2018, 03:05 PM
Honestly, I don't know which item you should check first but going with the thread you posted is probably a good place to start. Probably doesn't matter which side of the harness you start at, just as long as you check the whole thing for any damage.
Check the link below for how to check continuity @ 4:50ish.
You can probably disconnect items on at a time and see what triggers the fuse to blow but I would imagine you wouldn't have to drive around to do these tests. I'm not a pro so I'm sure one of the other seasoned forum members can chime in about doing those tests.
No such thing as a dumb question -- You'd be dumb for not asking them to learn/figure out how to fix your issues
Check the link below for how to check continuity @ 4:50ish.
You can probably disconnect items on at a time and see what triggers the fuse to blow but I would imagine you wouldn't have to drive around to do these tests. I'm not a pro so I'm sure one of the other seasoned forum members can chime in about doing those tests.
No such thing as a dumb question -- You'd be dumb for not asking them to learn/figure out how to fix your issues
#5
01-24-2018, 06:49 PM
So I pulled the plugs for both Purge Valve and Evap Canister (couldn’t find SAI Valve and google was no help) and drove around for 20 minutes with no original CEL codes popping (I did pull p0413 and p0444 but I expected those).
Given this less-than-definitive result I’m considering running a continuity test to isolate the problem.
The rub now is that while the video from the post above shows me the settings on the multimeter to use to test for continuity, it doesn’t explain WHERE I’m supposed to touch the wiring to perform the test.
Am I supposed to test the end that connects to the valve or check one side to the valve connector and the other end to other and of the wiring harness?
The way this harness is wrapped around the engine is not very clear so I don’t know that I would be able to follow it all the way around to find IF there was a stripped spot in the wire.
like I said, I am a complete novice when it comes to electrical wiring so I’m trying to figure this out like a first grader trying to figure out algebra.
Given this less-than-definitive result I’m considering running a continuity test to isolate the problem.
The rub now is that while the video from the post above shows me the settings on the multimeter to use to test for continuity, it doesn’t explain WHERE I’m supposed to touch the wiring to perform the test.
Am I supposed to test the end that connects to the valve or check one side to the valve connector and the other end to other and of the wiring harness?
The way this harness is wrapped around the engine is not very clear so I don’t know that I would be able to follow it all the way around to find IF there was a stripped spot in the wire.
like I said, I am a complete novice when it comes to electrical wiring so I’m trying to figure this out like a first grader trying to figure out algebra.
#6
01-24-2018, 11:05 PM
You got the right idea! Locate pin#1 for example on one side of a harness and then find where it ends in the other end of the wiring harness. Use the multimeter at that point to see if wire is either faulty or passes current just fine.
Its an annoying process but really the only way to figure out electrical issues with items.
Its an annoying process but really the only way to figure out electrical issues with items.
The rub now is that while the video from the post above shows me the settings on the multimeter to use to test for continuity, it doesn’t explain WHERE I’m supposed to touch the wiring to perform the test.
Am I supposed to test the end that connects to the valve or check one side to the valve connector and the other end to other and of the wiring harness?
The way this harness is wrapped around the engine is not very clear so I don’t know that I would be able to follow it all the way around to find IF there was a stripped spot in the wire.
like I said, I am a complete novice when it comes to electrical wiring so I’m trying to figure this out like a first grader trying to figure out algebra.
Am I supposed to test the end that connects to the valve or check one side to the valve connector and the other end to other and of the wiring harness?
The way this harness is wrapped around the engine is not very clear so I don’t know that I would be able to follow it all the way around to find IF there was a stripped spot in the wire.
like I said, I am a complete novice when it comes to electrical wiring so I’m trying to figure this out like a first grader trying to figure out algebra.
#7
01-25-2018, 12:26 PM
Which electrical diagram shows where those pins terminate? I've seen some of the diagrams, but they're more than I can make sense of. If I knew which one I needed to look at maybe I could figure it out.
I have all the manuals that Savannah Buzz had in his signature.
If I can't figure it out I may be dropping it off at my friendly local independent LR mechanic.
I have all the manuals that Savannah Buzz had in his signature.
If I can't figure it out I may be dropping it off at my friendly local independent LR mechanic.
#9
01-25-2018, 03:09 PM
Am I supposed to test the end that connects to the valve or check one side to the valve connector and the other end to other and of the wiring harness?
......
#10
01-25-2018, 03:35 PM
