Then if you're asking me, it has been done a couple of years ago when I was chasing a stalling issue, but now it is irrelevant. I will try to clean it but since I have another one on a shelf in my dad's garage I'll simply try to swap it in, after cleaning it. If it doesn't change anything, then I'll try to check it with the multimeter.

 

Sorry gents, didn't mean to mislead no one here! Just me and my big mouth...
Personally, I haven't ran into any MAF related problems with my first ever owned Landy (the '95 I bought 3 yrs ago).
However, I've been involved with Volvo cars for the past 15 yrs or so (still keeping a couple of oldies around the house, just in case), which used primarily Bosch fi sys for many years (the Lucas found on my DD looks awfully close to an "L" sys by Bosch).
The first thing one supposed to check when confronted with a no start situation, was to start the car with the AMF sensor unplugged, which move will get the vehicle into the mentioned "limp mode", that will ultimately make for a very slooooow drive back home.
I should've also read the post more carefully, since was clearly mentioned that the truck starts when given gas pedal, AND tthe fi is GEMS in this case.
Hence my wrong statement! ( again!)
Too bad I can't buy beers all-around!

 

I had some time today to check the truck. Cleaned both MAF I had and none of them work! Well to be more precise, both of them give me a 0,06g/s @ idle. It rather unlikely that both of them are bad, even more unlikely that they are bad and give me the exact same reading. Which leads me to believe that the problem might be in the wire harness or in the ECM. I checked continuity in the wires but not resistance, which I think' might influence the reading the ECM gets from the MAF. I did not had time to dig this eventuality deeper, I had to put my dad's ATV back together.

However the MAF being bad, the truck starts if I give it some throttle. And it seems that after being driven a while it manages to idle correctly.

 

While fiddling under the truck, I saw a sensor which looks like a coolant temp sensor. It has a blue plug and it is located on the left underside of the engine. Right beside the block heater. Anybody has an idea what this sensor is?

 

Block Heater!!! HA Man am I glad to live in FLA for now.

That sensor is making me think... now I have to go and look.

 

I need one. This morning it was -20*C, and we got 70 cm (28 inches) of snow yesterday. Some days I wish I lived in a snow free place, but then I wouldn't be able to ride my snowmobile

 

I had a couple of hours yesterday to check a couple of things with my brother. We checked the voltage out of the MAF, going to the ECM and the signal is within specs. Therefore, it means I can rule out the wire harness and the MAF. Which also means whether my OBDII reader does not interpret well the data the ECM provides or the problem might be in the ECM.

We went to discuss the problem with another mechanic. He threw some new ideas around. Are the O2 sensor used on the Disco wideband sensors? Because Mitchell, and data provided by Cosmic say the reading of the front O2 should be between 0.2v and 4.98v. Given that all the aftermarket sensors are 0v - 1v, the reading is basically impossible to get. So I'd like to know if the genuine sensors are 0v-5v.

The other thing he thought about is that the P1193 code I have might be related even if it is in the rear O2. If it is not an open loop but a short within the O2, the computer can't tell if it is a short or an open loop, and therefore throws a code for an open loop in the circuit. And the short might be throwing the other O2s out of whack. We ran out of time to check this theory but it should be pretty easy to test. If I unplug the faulty sensor it will show if it is related to my problem.

Saturday I'm supposed to have access to a good testbook and I'll continue to check things around with my brother. I'll let you know what we find out.

 

Well a couple things... first the 02's aren't a part of the fuel mix / mapping equation untill a short period after the truck is started from cold. The ECM looks for a few indicators to tell it that the O2 is warmed up and ready to give accurate readings... ECT being one of them. IF the heater circuit is bad then they will certainly not get warm until the exhaust gasses themselves have heated the sensor up and you will, again, have a rich mix and bad idle. A bad heater circuit is simple to test... check continuity of the heater circuit wires at the sensor.

The OEM O2's for your model year are Titania based sensors (a Titanium sensor located in the Ceramic sensor tip). Many other manufacturers use Zirconia based sensors which "generate a voltage". Titanium O2's are supplied with a voltage from the ECM and alter the internal resistance based on Oxygen content of gasses in relation to ambient O2 levels. Titanium sensors are rerely used in cars so you average mech may not know about them or the difference.

Have you checked to make sure the connections for up and downstream sensors aren't crossed side to side(i.e. left on right and vice versa? If they are the signal sent to each bank will be backwards.... leanin or enrichening the wrong bank which will give you a horrible idle and misfires.

**edit** I forgot to add (answer your question) that the Titanium sensors are a type of narrow band sensor.

Also here is some good info on part numbers for o2's based on model year https://landroverforums.com/forum/sh...ad.php?t=34923

 

Knock sensor ....???

 

I already replaced my O2 sensors for NTK 25044 last spring but there is one that already crapped out. I already knew the right part number. I'm 99,9% sure that none of the connections are inverted because the truck ran fine from April to December. This confirms my thought that aftermarket sensors are just fine and are not a problem, unless they go bad.

On second thought, yes it is the knock sensor beside my block heater.