Cranks no start

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
So I’m working on a 03 Disco. Cranks but won’t start. Not immobilized. I have a known good crank sensor in it and measured the output of the crank sensor right at the ECM connector. I have some faults for a missing or incorrect security code.
So I asked a few questions of the owner and found out that he took it to a shop after it stalled and wouldn’t restart. His key was all janky in the ign lock and somehow got fucked up beyond repair by someone before they ever got around to diagnosing the no start. They put a Disco 1 ign switch in it. Left a couple connectors just hanging in there cause the Disco1 doesn’t have them. Just screwed the original electrical switch to the new lock cylinder.

what I figured out is one of the connectors left hanging caused the passive coil to be open. The BCM uses the passive coil to monitor for a change of position in the ign lock cylinder. If the BCM sees no change in the lock cylinder position it won’t spit out the code. Cause someone is steeling the truck. How else could it be cranking with the key still off?
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
Are you sure it doesn’t just have a bad fuse box? Any D2 with a crank and no start is typically the crank sensor or fuse box.

I’m sure you know this, but common problems vary by region
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Are you sure it doesn’t just have a bad fuse box? Any D2 with a crank and no start is typically the crank sensor or fuse box.

I’m sure you know this, but common problems vary by region
I looked at that car a little today. i got rid of the code for the passive coil being open and it stilll wont start. I even started looking for a fuse box I know I have here somewhere. Whats strange is that while I have a good ac voltage signal from the crank sensor right at the ECM the T4 Handheld is saying no crank rpm.
If I had a working T4 I would have run mobilization on the thing already. Its got the P1673 code that says new module fitted. So either I have a fuse box issue or this thing is just really pissed off. I kind of remember one of those codes getting stored if you cranked them too long with no start.
Do you remember what's missing when the fuse box fails? I can't remember cause I used to just jam that good one in a car instead of actually diagnosing the thing.
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
You lose voltage to the coil packs when the fuse box is bad. You need to check with them plugged in because it will show voltage without a load. Easiest place to check is the connector by the expansion tank
 
  • Like
Reactions: discostew

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Thanks. Not sure that explains the crank speed not showing up but… I found my test fusebox.
 

Attachments

  • B89633DF-1C71-4785-BF1C-B08BF6033351.jpeg
    B89633DF-1C71-4785-BF1C-B08BF6033351.jpeg
    205.5 KB · Views: 15

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
You lose voltage to the coil packs when the fuse box is bad. You need to check with them plugged in because it will show voltage without a load. Easiest place to check is the connector by the expansion tank
So you say I have to use my meter the correct way? I’ve seen that mess up more young guys than I can count.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I typically use a powerprobe and if I can’t diagnose it with that then I use the Picoscope
I won’t use a power probe, be afraid.

I have the fuse box ready to go. I was talking to another old timer today who reminded me about a car we had back in the Sweeney days. There was a wire on the BCM that gets a ground signal from the fuse box. Pretty sure it’s the wire that gets grounded to bypass security.
I don’t know if other high end cars do it too. But in my experience they like to leave a lot of confusion about security systems. With time you figure it out but they’re less than clear with the info.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I typically use a powerprobe and if I can’t diagnose it with that then I use the Picoscope
I use a Fluke then a Picoscope. So I put that fuse box in and still no start. It was immobilized, I ran mobilization with this T4 Heritage thing I posted a pic of.
Now when I crank it a scanner sees crank rpm and I smell fuel. No more security fault. Still no spark.
Sneaking up on it.
 

Attachments

  • 321BCB86-CDDF-453C-936C-C698AA0570C2.jpeg
    321BCB86-CDDF-453C-936C-C698AA0570C2.jpeg
    197.8 KB · Views: 4
  • 403CFCA0-8A01-4511-B2F2-6ED127EA2BD1.jpeg
    403CFCA0-8A01-4511-B2F2-6ED127EA2BD1.jpeg
    298.3 KB · Views: 4

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I put the original fuse box back in and then it had spark. But it would start and stall. Like it’s got the wrong security code. But still no security faults.
So I’m reading in the SIDS document that one failure mode of a mass air flow sensor is starting and stalling right away. I unplugged the mass air flow sensor and it runs.
So I think that’s what was originally wrong with it. All the other stuff was caused by at least 2 other shops. But it hasn’t run for over a year the guy said.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
i finally got this thing sorted out. Several shops looked at it over the last year.
Crank sensor was fucked up when they replaced it with an aftermarket sensor.
Security was immobilized and probably because someone programmed the ECM.
Ign switch was causing a passive coil fault but that didn’t fix the no start. Fixed code/ still no start.
Once security was fixed still no start but could smell fuel now.
Swapped out the cabin fuse box but that didn’t fix anything. Switched it back.
Unplugged the mass air sensor and it started and ran. Replaced it with new Bosch sensor and vehicle ran.
Then it was running but not well. So during attempting to fix it someone put plug wires and coils on it and had crossed a couple plug wires on the coils.
My guess is it all started with the mass air sensor then they fucked up the crank sensor/ ign switch / security code/ and the plug wires.
 
  • Like
Reactions: latarheel and p m

boxster

Well-known member
Jun 1, 2009
443
88
Fallbrook Ca.
It’s hard to make the correct repair when someone else starts changing parts out and not finding the root cause. Success is a beautiful thing!
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
I love when people avoid the dealership to save money and end up with scenarios like this. It happens surprisingly often.

I actually had an LR3 come in last year that was at another local Land Rover shop. They replaced a bunch of parts, to the point the owner sold the car to Will Tillery for parts. Will had it towed to me and I had it running in less than 20 minutes. It had a broken can bus wire.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I love when people avoid the dealership to save money
This guy actually came into the dealership and was brought back to talk to me. First thing he said to me was he had it at a shop and pulled it out of that place then nobody would work on it. He told me I had to work on it cause this is a Land Rover dealership. I broke that down for him and helped him understand I don’t have to do shit to an 18 year old truck.
Next thing you know the guys working at the dealership as a porter running the car wash.
 

latarheel

Well-known member
Oct 10, 2011
183
4
AZ
At the risk of hijacking your now successfully closed thread, I would like the benefit of your thoughts on my thread thats been going on since May with a similar crank , no start issue on a '98 D1.