2.8ltr guru's help

[Hally]

Hi Guys,

What are the usual symptoms of an earthing issue. I was talking with one of the guys from work about my problem with my 99 model 2.8ltr going in to limp mode. He mentioned an issue he had with his a couple of years ago, something about replacing the earth strap in a few places. He had issues with the engine stopping and dash lights coming on.

Early this year while I was driving home from camping, it has gone in to limp mode. I have manually checked the codes and cleared them, the codes were showing 1-3 (COOLANT TEMP SEN) and 2-8 (OVER HEAT). The gauge in the dash was reading as per normal and there was no loss of fluids.

I have since replaced the coolant temp sensor that feeds the ECU, but it has happened again.

Do you think this could be caused by a bad earth or should I be looking elsewhere.

I am really keen to fix this issue so any help or ideas would be much appreciated


Shane

[mudski]

Bad earth is a common issue on the Patrols.
Best to remove all the earth straps on the vehicle and give the area of contact a thorough clean. You should have atleast two on the vehicle. One from the crank battery to the motor, usually the intake manifold, and one from the battery to the chassis. If they look a bit ratty, replace them. It has been advised to also add an extra earth from the drive line to the body say from under the vehicle, trans to body.
Get some MAF sensor spray too and give the air flow meter a good hit with it. A dirty MAF can also bring on limp mode...

[Yendor]

It doesn't sound like an earth issue to me.

The coolant temp sensor you replaced, did it have one wire or two wires?. Did you check continuity in the wires between the ECU and temp sensor?

When it goes into limp mode what happens?, how did you get it out of limp mode?

[Hally]

When it goes into limp mode I either stop and check the code manually before clearing it or turn the car off and then back on until it is a safer place to look at it.
This morning is the first time it has done it in four days of driving to work and back (25km each way), I was starting it from cold and it was harder to start. The engine light stayed on, I checked the code and it was 2-8 (overheat), from a cold start. It just doesn't make sence.

[Hally]

It doesn't sound like an earth issue to me.

The coolant temp sensor you replaced, did it have one wire or two wires?. Did you check continuity in the wires between the ECU and temp sensor?

When it goes into limp mode what happens?, how did you get it out of limp mode?

The one with the two wires on the front of the intercooler.

[Kimbo63]

The one with the two wires on the front of the intercooler.
Hi Hally
That sensor is the air intake temp sensor you need to look at the sensor on the cylinder head or bottom R/H side of radiator
Cheers Kimbo

[Yendor]

The one with the two wires on the front of the intercooler.

The engine coolant temp sensor is mounted in the rear of head on the RHS of the engine, just under the intercooler.

With the engine running and air conditioning on does the electric cooling fan in the engine bay come on?

[Hally]

Hi Hally
That sensor is the air intake temp sensor you need to look at the sensor on the cylinder head or bottom R/H side of radiator
Cheers Kimbo

The sensor that I have replaced is the one that the nissan dealer (spare parts guy) told me was the coolant temp sensor. I thought that it was a bit weird it being on the intercooler.

[Hally]

The engine coolant temp sensor is mounted in the rear of head on the RHS of the engine, just under the intercooler.

With the engine running and air conditioning on does the electric cooling fan in the engine bay come on?

Will check that tomorrow.

[Hally]

Ok, checked that the electric cooling fan is on while engine and A/C are on.

[Yendor]

Ok you will need to check the connector and wiring harness at the coolant temp sensor. Look for signs of damage in the harness and corrosion in the connector.

[Hally]

Ok, Just an update on how things are going. I have replaced the correct sensor and checked the harness (looks like it has never been touched since new).

I have driven it to work for the last two days and all is good. only time will tell but seems it might be fixed.

Thanks for you help guy's

[Hally]

New update, I spoke too soon.
It did it on start up today in the morning while cold (had not been driven for a day).
I did notice that when I started it this afternoon it was making a faint ticking sound, similar to when the air con clutch kicks in and out. It was also idling funny for about 10 seconds and then it was fine.

Any idea's

[Kimbo63]

As Yendor said re check your connector an harness being some 17 years old and living right next to the engine tend to cook the wires making them brittle and hard causing the wires inside to break you could test by moving the harness and see if you can get it to fault also re terminate where it connects to the sensor and check the plug next to fuse box in front of brake booster
cheers Kim

[Hally]

After spending a week or so with the auto electrician, the problem has been found. One of the wires leading into the coolant temp sensor was snapped inside the insulation.
All fixed now and running well.

Thanks to everyone, you have been awesome help. Hopefully I can be of help back one day.