Outer Limits 4x4 Board

As you know, for RD2.8RT engine, Nissan has 2 types of glow plugs: 1 type for 1,2.3 cylinders and second for 4,5,6 ones.
When I turn on the key,- starts the 1,2and3 cylinder glow plugs. Is it normal?
The weather temperature is about 7C.
P.S. 1. I've measured the current between engine block and glow plug connection strip - when the key is ON- its about 10.5 and when it stops to heat its 0.
2. Each glow plug is tested on battery.
3. I've checked the connection strips- one comes on all 6 plugs, then the second only on 4,5and6 cylinder ones. When the key is ON, the current comes only to 1,2and3 ones.
(as I've noticed the ground for 1,2and3 cylinder plugs comes from the block for 4,5and6 cylinder plugs it should come form second connection strip, but it wont.)
WHAT IS THE PROBLEM.
Protempory, I've connected the 4,5and6 cylinder connection strip,to the engine block. CAUSE MY PATROL didnt start smoothly!!!
And it works!

On the RD2.8T there are 2 glow plug relays. One relay is a standard relay which supplies battery voltage to all the glow plugs, including those on cylinders 4,5&6 which are a different type of glow plug. The second relay is a 2 position type-when its not energised by the control unit, it supplies the earth return for the glow plugs on cylinder 4,5&6. If the no 2 relay is faulty, then there will be no earth path for the 4,5&6 glow plugs. If the 2 relays switch on at the same time (faulty glow plug control unit) then a short circuit will occur, blowing the Eng Control fuse. Disconnect the glow plug connection strip and leave only the lower strip on Cylinders 4,5&6. With a multimeter, measure between the center screw terminal on any of the 4,5&6 glow plugs and cylinder block and see if there is continuity... If its open circuit, check the 2nd relay is earthing properly and or faulty contacts......

Nick

What do you mean:
"The second relay is a 2 position type-when its not energised by the control unit, it supplies the earth return for the glow plugs on cylinder 4,5&6"
In what cases the second relay could not be energised by the control unit?

Where are these realys located?

"Disconnect the glow plug connection strip and leave only the lower strip on Cylinders 4,5&6"
Its the upper strip connects only the 4,5&6 cylinder glow plugs, you have in mind them? I dont wanna cut lower one to connect so

The 2 glowplug relays are located under the steel flap next to the battery. Glow plug relay 2 is closest to the front of the vehicle. Theere are 2 types of glowplugs fitted to the 2.8. The type fitted to cyl 1,2&3 are normal type glowplugs. These plugs earth via the thread which screws them into the cylinder head. To test these for continuity, measure between the top threaded section (where the strap screws on) and the thread that screws into the cyl head. The plugs fitted to cyl 4,5&6 go to earth via the 2nd strap and the 2nd glow plug relay NOT the mounting thread.

The second glowplug relay has 2 sets of contacts: 1 set of contacts connects to earth-the other contacts connect to the battery. These 2 relays are controlled by the glow plug controller. When starting a cold engine, relay 1 switches on, supplying battery voltage to all 6 plugs-1,2&3 earthing via the cylinder block-4,5&6 go to earth via a second strap and relay number 2 contacts which are connected to earth.

After the engine has started, if required in cold conditions the controller switches off relay 1 and switches on relay 2 engaging its second contacts which are connected to the battery as previously mentioned. Battery voltage now goes to plugs 4,5&6 and they NOW go to earth via plugs 1,2&3 which are earthed via the threads into the cylinder head.

The second relay only turns on if engine is cold.

Hope this makes sense...PM me if you need any more info.

Nick