I just got her going after doing both head gaskets. Started right up. I have an exhuast leak or something but I'll worry about that later... Anyways... My temp guage is sweeping when you turn the key on but stays on zero while the engine is running and the red light stays on. Completely cold engine. I did not have this problem before doing the job. I checked the sensor connection right between the alternator and a/c compressor on the front of the intake manifold. Seems to be ok. What am I missing here? I forgot to install the little wire on the back of the alternator that has a nut attached to it. Still haven't attached it as I just gave up for the night. Would that be a ground for the sensor or anything? I cut the engine off just because, checked connections, tried starting again and I had to spin it over forever and it sort of sputtered to life. The battery was dead and had to be jumped. The RAVE manuals says that without a ECT sensor reading it could cause difficult starts which all of a sudden I seem to have. I don't have a RAVE manual btw just something I read online. Anyone have a wiring diagram or know where the wires go for the temp sensor? Will air around the sensor set off the temp light if I didn't get the system full? Stupid disco. ugh.

 

The coolant temp sensor is either unplugged, defective, or the circuit is open. ECU monitors that and drives the guage, it puts gauge on zero and turns on the warning light for no signal. If it was just an air bubble the guage would read above zero. From the RAVE shop manual on instruments:

If the engine coolant temperature gauge receives no input or the input is out of range the

temperature gauge will read cold and the high coolant temperature warning lamp will be illuminated.

This would also show up on your OBDII scanner, as coolant temp being an illogical value. ECU will default to a back up plan, but as you saw that can be hard starting.

The little wire on the alternator is brown and yellow? If so, that is the "exciter" voltage from the "battery" light on the dash, and you are not charging the battery. Please hook it up first, what ever the color.

Don't have a copy of the RAVE? - below are two links for you to download this or access on line and it has wiring diagrams and pictures of component locatons in color. And I threw in some diagrams to show you what is inside the RAVE.

re: Stupid disco. ugh.

re: I don't have a RAVE manual btw just something I read online.

re: previous post - I am a shop foreman for a dealership... I can tell you right now

A Disco cares not which hand is on the wrench.

 

Appreciate it. I jumped the connector and the guage still sits low so I'm assuming some how I lost a wire in the head gasket process. Of course everything runs under the MASSIVE plenum so it's looking like I'm going to do an overlay to the main loom.

Savannah... I've been a diesel mechanic for the last 16 years. I eat, sleep and breath diesel. These screwy gas engines through me with their IAC, ECT dependant fuel maps, etc. lol I can teach class on a modern diesel but I'm just an average joe when it comes to EFI gas.

Anyways.. she's running smooth as glass. Really happy with the job. Got an exhuast leak some where on the driver side to fix and this wiring to do. Again, appreciate it.

 

Check your coolant temp sensor plug to make sure you didnt install it backwards.

 

The ECT is a variable resistor, so a jumper would also be bad. It is hard to make out on the resistor curve for the device, but somewhere about 1000 - 2200 ohms might be a fixed substitute you could use for testing. Note - if buying a new sensor please go OEM, the generics are all over the place and cause problems. I believe there is no header between the device and the ECU.

I certainly enjoy the diesel tractors, rough terrain forklifts, and a few trucks that I have at the office, and our rigid hull inflatable SOLAS boat with a diesel stern drive. Mucho simpler.

BTW that RAVE stuff will fit on a USB drive so you can have it in the glove box if needed at the office, etc.

 

I downloaded it all. Definitely appreciate it.

Anyways just a little update.. I left the rover sitting in the driveway after having looked at the ECM connectors and realizing that land rover was too cheap to number their wires full length... I ran out of time and had to go to work. Came home from work... hooked my scanner up to it that I brought home... had a bunch of codes.. cleared them.. most came back. Cleared again.. came back.... Then I started the engine and cleared them. None of them came back and my temp gauge just started magically working??? Everything is fine now. Ran the truck an hour all over the place. Good as gold except my exhuast leak. Only thing I can figure is the battery was still real low and most sensors were on their threshold and running the truck and having the alternator pump voltage into the system and THEN clearing them made the difference? HEll if I know. I do remember my wife calling me at work after the rover had sat in the driveway untouched for a month that the alarm started going off on it's own magically. I told her it was probably the voltage getting low and the CAN was dropping out causing other modules to loose communication. Anyways... she sounds great and runs smooth. My scanner showed 4 pending codes though.

P0300
P0305
P0150
P0130

Both #1 oxy sensors... I'm guessing they were causing the misfire codes? Going to order two oxy sensors. One has never been replaced with 101k on the clock. I replaced the other 13k ago but the engine ran so bad and had so many oil leaks I wouldn't be suprised if it is bad now too.