300 TDI Intermittent No Start

Dfunder90

Active member
Bypassed and manually triggered the starter and it works every time. Tried to take down the fuse box to get to back of the relays and it is quite a stretch with AC unit in place. The wiring diagram says there is an immobilizer in that circuit. The connections on the starter are clean and tight. The fuse box is dusty and I cleaned up with some electric connection cleaner.
 

Napalm00

Technical Excellence Contributor
Check the ignition switch and starter circut for continuity. You going to have to dig for an immobilizer
 

Dfunder90

Active member
If I end up digging back to the immobilizer, how do I know if the fault is there? I haven’t found a ton of specific information on the immobilizers though it seems mine has one based the red flashing light on the dash and the black box connected to the front corner of the box under the LH seat.
 

Napalm00

Technical Excellence Contributor
Bunch of stuff via Google. Long story short : run a new circuit from the ignition switch to the starter and the fuel solenoid if present.

Also sometimes the back of the ignition switch just falls apart
 

Dfunder90

Active member
I took a look behind the instrument cluster and sure enough there is a 10AS immobilizing system there as well as the spider underneath the LH seat in the black box. Someone has cut and removed the wire a position 4. I need to read more about if mine has been bypassed. I don't have a key fob, so it has to have been at least partially bypassed? I have 2 wires coming out of my underseat spider with a fuse. When the fuse is removed, the engine turns over but doesn't start which is different than my usual non starting issue where the engine won't even turn over and it sounds like the starter is not activated. I've switched out the starter relay for one that I know is a working one and it doesn't seem to make any difference with the intermittent starting. With the truck running it also bogs down and shuts off like it is starved for fuel. Not sure if these things are related, but it is not drivable now.
 

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Dfunder90

Active member
Would intermittent non starting and then starving for fuel and a dying motor with any load be a symptom of an immobilizer problem? Still trying to sort this out. My main ground is clean and tight, all connections on starter are clean and tight. I have a non functioning hazard switch and when replaced with functioning hazard switch the flasher come on as well as the lights for the glow plugs, oil and battery on the dash without the key in the ignition. It is like the key is in the ignition, but it's not.
 

Napalm00

Technical Excellence Contributor
Have you checked the back of the ignition switch and all of the circuits there? Sounds like you have an electrical issue
 

Dfunder90

Active member
Seems electrical to me. I’m also having the problem with the engine going dead under load. The electrical work is intimidating to me. I have the wiring diagrams like everyone suggest but don’t understand it well enough to figure out what is going on. Especially since the previous owner add a bunch of gauges and additional wiring. I had it towed to a shop. They are working on trying to figure out the issue now. I’ve taken it to another Land Rover shop before who said the blinking immobilizer light on the dash was draining the battery, despite the fact that the battery test good on charge and cranking power. They jumped it off a couple times and where able to get it to start. It is very random on non starting and doesn’t seem to relate to the amount of time the battery sits. I can’t drive it now to retest the battery as the engine bogs down under load and seems starved for fuel. Real problem when it goes dead on the road with a hazard light switch that doesn’t work and the ongoing staring issues.
 
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