Jobs, Progress and Questions!

[Monsterlime]

Only the driver side is very awkward, which is why I checked it at the connection at the Plenum, but I did unplug it and test the actual socket.

On the passenger side, I checked it from the socket directly attached to the lambda, unplugged from the loom.

I have read the ACT doc and I guess the next bit is to take the car out and give it a good drive to and test the lambdas then, and check at the ECU (carefully).

Obviously I don’t know they are cheap knockoffs, so will see if I can get one genuine sensor to compare with.

[Penelope Stopit]

Guessing that you've now proven the heater element supplies and sensor returns are good

[Monsterlime]

Yes, other than the wires being different to the docs, everything on the lambda side itself seems as it should be. Will get it up to temp and see what it does then, and be very careful with checking the ECU.

Reading the 14CUX Lambda Fault Finding doc, it does reference incorrectly connected plug wires, and at least one of the old beru extenders was very loose and just came away without any effort, and another was so welded to the plug I had to unscrew it from the plug before I could remove it. While getting the car up to temp etc, I'll stick Rovergauge on again, clear the codes and see what it does.

[Monsterlime]

Ok, so took the car for a good run and got it nice and hot. With Rovergauge connected, I could see short term trim (visually) on the even bank was at +100%, but the odd bank never moved. Checked the log, and both show 255 (so 100%). I am wondering if I am having a software issue causing Rovergauge not to display properly, although everything else is showing up in it fine. When switching to Long Term, nothing came up at all.

Log example -


I am going to put Rovergauge on a Windows laptop I have sitting around and see what it does. I'll also try and record the screen on both laptops.

However, after reading various PDFs and the ACT thing again and again, because my brain is very slow, I do believe either both lambda's are faulty or there is wiring issue in the loom somewhere. I have ordered one lambda to test with a known good one.

Testing them again (with the engine hot and running), both were only showing 8.5 volts at the lambda end, and am pretty sure it is supposed to be 12 at the lambda as well as the relay, correct? Also, when checking the sensor return, they were sitting at 0.1v and pretty much never moved - https://www.youtube.com/watch?v=svIZUwtQkPo&fe... . I did rev the engine as well, to see if this made any difference, and held it at just over 1000rpm, but nothing (I couldn't video the multimeter while doing this!).

On the Lambda fault finding document, it suggests to pull a vaccum line off to see if things move, but which one? Does it matter? I also have some easy start on the way to see if that makes any difference when sprayed.

Also, I got a bit of smoking on the drivers side from the plugs/socks - https://www.youtube.com/watch?v=sdMUDCtou38&fe... This is slightly concerning, but might just be the socks themselves touching the block? Should I pull them back up a bit?

Finally, towards the end of the drive I started getting some whining from what I think was just to the left/behind me, which I suspect is the fuel pump and it stopped when I stopped and came back when revving etc. Since I am fairly certain the car is running rich with the above RG output, I assume the fuel pump is being worked hard but is this the point I need to consider replacing it?

[Penelope Stopit]

Yes the voltage at the sensors heater elements should be the same as the relay terminal 87 output that supplies them (give or take 0.something volts volt-drop)

With only having 8.5 volts at the heater elements, there is no point in testing any further until solving this fault

The volt-drop in the heater elements supply voltage circuit is intermittent (checked out ok earlier) and this is going to make tracing the fault a touch difficult

When 8.5 volts is present at the heater elements, first check that the earths to the heater elements are ok by connecting the volt meter between battery positive and those earths (battery positive being the best positive to use when checking negatives). If the earths are good, check what voltage is present at fuel pump relay terminal 87 that supplies them and should this be approximately 8.5 volts check what the input voltage at fuel pump terminal 30 is

There is a chance that the intermittent loss of voltage to the elements is being caused by bad earth points that are used by another or several other circuits, I'm wondering if the fault occurs when the temperature is up and the fans cut-in (fans using same earth point????)

[Belle427]

If you split the circuit in half so to speak and test at those connections you identified next to the plenum.
See what you have there voltage wise.

[Monsterlime]

Penelope Stopit said:

Yes the voltage at the sensors heater elements should be the same as the relay terminal 87 output that supplies them (give or take 0.something volts volt-drop)

With only having 8.5 volts at the heater elements, there is no point in testing any further until solving this fault

The volt-drop in the heater elements supply voltage circuit is intermittent (checked out ok earlier) and this is going to make tracing the fault a touch difficult

When 8.5 volts is present at the heater elements, first check that the earths to the heater elements are ok by connecting the volt meter between battery positive and those earths (battery positive being the best positive to use when checking negatives). If the earths are good, check what voltage is present at fuel pump relay terminal 87 that supplies them and should this be approximately 8.5 volts check what the input voltage at fuel pump terminal 30 is

There is a chance that the intermittent loss of voltage to the elements is being caused by bad earth points that are used by another or several other circuits, I'm wondering if the fault occurs when the temperature is up and the fans cut-in (fans using same earth point????)

Ok, thank you! I just need to confirm - I would connect positive to the battery positive and then negative to the ground wire for the Lambda and check resistance or voltage (am assuming resistance, but I want to be sure)? I will need to trace the wiring back into the cabin or under the dash to confirm exactly where they ground, correct? My probes aren't long enough to go that far into the engine bay from the battery..heh

I had actually checked the voltage at the relay, with the engine running (pin 87 white/orange for the lambdas and battery negative) and it was around 13.5 volts, but will double check. A previous check with just turning the ignition on but not starting the car, had it at 12 volts briely when it dropped away as expected. I will check pin 30 as well, with the car running, as I had previously checked with the ignition off and it had a constant 12v.

I'll check the different points along from the Plenum connections as well.

Re Rovergauge, I had a chance to try it shortly after posting on my other laptop, and both short term trims this time showed +100% but long term never moved (left it idling a while and made sure it was warm - I was expecting it to just hit 100%), so I am guessing that while there may be a display issue on the Linux version, it is still reading the data correctly.

[Belle427]

Marks pages here explain the lambda will stick at zero volts if the heater supply is missing.

http://www.g33.co.uk/pages/technical-fuel-injectio...

[Penelope Stopit]

Monsterlime said:

Penelope Stopit said:

Yes the voltage at the sensors heater elements should be the same as the relay terminal 87 output that supplies them (give or take 0.something volts volt-drop)

With only having 8.5 volts at the heater elements, there is no point in testing any further until solving this fault

The volt-drop in the heater elements supply voltage circuit is intermittent (checked out ok earlier) and this is going to make tracing the fault a touch difficult

When 8.5 volts is present at the heater elements, first check that the earths to the heater elements are ok by connecting the volt meter between battery positive and those earths (battery positive being the best positive to use when checking negatives). If the earths are good, check what voltage is present at fuel pump relay terminal 87 that supplies them and should this be approximately 8.5 volts check what the input voltage at fuel pump terminal 30 is

There is a chance that the intermittent loss of voltage to the elements is being caused by bad earth points that are used by another or several other circuits, I'm wondering if the fault occurs when the temperature is up and the fans cut-in (fans using same earth point????)

Ok, thank you! I just need to confirm - I would connect positive to the battery positive and then negative to the ground wire for the Lambda and check resistance or voltage (am assuming resistance, but I want to be sure)? I will need to trace the wiring back into the cabin or under the dash to confirm exactly where they ground, correct? My probes aren't long enough to go that far into the engine bay from the battery..heh

I had actually checked the voltage at the relay, with the engine running (pin 87 white/orange for the lambdas and battery negative) and it was around 13.5 volts, but will double check. A previous check with just turning the ignition on but not starting the car, had it at 12 volts briely when it dropped away as expected. I will check pin 30 as well, with the car running, as I had previously checked with the ignition off and it had a constant 12v.

I'll check the different points along from the Plenum connections as well.

Re Rovergauge, I had a chance to try it shortly after posting on my other laptop, and both short term trims this time showed +100% but long term never moved (left it idling a while and made sure it was warm - I was expecting it to just hit 100%), so I am guessing that while there may be a display issue on the Linux version, it is still reading the data correctly.

Check for voltage not resistance

With fault on vehicle (8.5 volts), need to know which side of circuit is failing, Positive or Negative

Sensors connected

Engine running

Negatives (Earths) at sensors need checking first

Checking negatives, extend voltmeter positive cable to reach battery positive post (known good positive), connect voltmeter negative to one sensor earth and then the other

[Penelope Stopit]

The fuel pump note could change if the supply voltage to it lowered, due to the same relay supplying Lambda Sensor Heaters and Fuel Pump there is a possibility that the relay or supply to it is failing intermittently

Do check the earths first when the voltage has dropped to 8.5 volts

[Monsterlime]

What number should I expect? I must have done this wrong as I managed to extend the positive to the battery and the negative to the white lambda wire (ground) and I got 233 volts.

Did I totally misunderstand?

I checked the Plenum area connection on the side leading to the loom and got 8.5 volts.

[Penelope Stopit]

Monsterlime said:

What number should I expect?

You should be reading a voltage the same as whatever the battery voltage is with the engine running (give or take 0.something volts volt-drop)

Monsterlime said:

I must have done this wrong as I managed to extend the positive to the battery and the negative to the white lambda wire (ground) and I got 233 volts.

Multimeter playing up or its battery going flat?

Monsterlime said:

Did I totally misunderstand?

Very doubtful as it's a simple negative return test with a voltmeter connected between battery positive and the Lambda Sensors negative return cables, checking one sensors return (earth) and then the other

[Monsterlime]

This is what I thought, but 230 volts was rather..alarming. It may have been how I had to extend the cable then, I've ordered some longer test leads that will just give a single run each side. On the positive side I had to use 2, one clamped to the battery terminal and then used a probe from the other to connect to the connector within the first.

I do have another multimeter I can test with, and also have a small probe camera coming which I am going to run round the back of the block to look at the wiring there, save me taking the whole lot apart if I don't need to!

The relay's themselves are pretty new, I have a receipt for them being replaced this year and are the correct Bosch items. Although what I failed to realise or remember before now is that the receipt also says they had to "Check all wiring and connections at fuseboard - repair loose connections as mess". I wonder if this is the source of my woe. I only noticed by using Rovergauge my Lambda's weren't doing anything so I guess they could easily have inadvertently knocked or damaged something in doing the work and not realised.

[Penelope Stopit]

Monsterlime said:

Belle427 said:

Here is the 14 cux diagram, as you can see lambdas are fed from fuel pump relay terminal 87a.

Got it, thank you.

To confirm, the advice given here - https://www.actproducts.co.uk/2011/lucas-14cux-fue... on how to test the sensors, is that correct? I've seen a couple of threads that disagree so want to make sure before I stick probes in the sensors!

ACT said:

With the ignition switched off, test for continuity between the White ground wire and the engine block. There should be no resistance (i.e. a short circuit). Now set the multimeter to read Voltage, and insert the negative probe into the White ground wire, and the positive probe into the Red heater wire.

Now start the engine and check the voltage. There should be 12-14 Volts present when the engine is running, which is the supply for the sensor heater. This comes from the same relay that feeds the fuel pump, and shares the same fuse. If this supply is absent then the sensors will never give the correct reading.

Next the sensor signal itself should be probed. Leave the negative ground probe in the White ground wire, and put the positive probe into the Black signal wire. The voltage here should oscillate up and down between 0.2 and 1.2 Volts approximately 2 to 3 times per second. If the signal is stuck at 0 Volts or over 3.5 Volts then the sensor MAY be defective.

Re the resistors, I've ordered the RimmerBros ones. They are definitely pricier than what I was expecting for a resistor, but would prefer to use the "right" part. I ordered 2, even though one seems fine, a spare is always handy.

I've now noticed that ACT also mentioned

" A simple electrical test is now necessary by probing the sensor at the connector whilst it is still connected"

ACT aren't suggesting the wires are to be probed but could have made that much clearer throughout the testing steps

I take back my earlier comment

Penelope Stopit said:

The above test that you have linked to is suggesting that wires are probed, which is comical

Test at terminals

[Penelope Stopit]

Monsterlime said:

The relay's themselves are pretty new, I have a receipt for them being replaced this year and are the correct Bosch items. Although what I failed to realise or remember before now is that the receipt also says they had to "Check all wiring and connections at fuseboard - repair loose connections as mess". I wonder if this is the source of my woe. I only noticed by using Rovergauge my Lambda's weren't doing anything so I guess they could easily have inadvertently knocked or damaged something in doing the work and not realised.

Once you know which side of the circuit is failing (earths or positives) you can then check that side through

Should it be that the positive supply is failing then there is a good possibility that the fault is inside the vehicle, you will be able to prove this by checking the supply in and out of the relay, obviously needs proving when the fault is present

Anything could have been disturbed including fuse-box and main safety fuse that supplies the fuse-box

[Monsterlime]

Once the leads arrive I will test again.

I can definitely understand why people move the battery to the boot now!

[Penelope Stopit]

Monsterlime said:

Once the leads arrive I will test again.

I can definitely understand why people move the battery to the boot now!

The modification is a very good one and also the moving of the fusebox to behind the seat, although there is something that the majority of people that have moved the fusebox seem to have overlooked (needs its own topic, I may create one)

[Monsterlime]

Longer test leads arrived yesterday and this morning I managed to get back out to retest. I am confused.

Red Positive Battery to Lambda White
Engine OFF - 12 volts (both multimeters)
Engine on - 1 multimeter - 233 volts, the other - 0.21

Red Positive Battery to Lambda Black
Engine off - 12V (both multimeters)
Engine on - 8.5v (both multimeters)

Both lambdas have the same results.

At the relay, pin 30 has 12V all the time. The fuel and lambda pins (87) have 12v when engine running.

Someone has wired in (can't follow it at the moment) extra cigarrette lighter sockets, a triple. They are always live. I did test to see if plugging in my phone would make anything drop on the lambda side any further, but no, so I am assuming they are wired in correctly for now.

But, I am still confused. I assume this means there is an issue with the positive earth somewhere but everything else on the car works fine, so it must be isolated to the lambda's?

[Penelope Stopit]

Monsterlime said:

Longer test leads arrived yesterday and this morning I managed to get back out to retest. I am confused.

Red Positive Battery to Lambda White
Engine OFF - 12 volts (both multimeters)
Engine on - 1 multimeter - 233 volts, the other - 0.21

Red Positive Battery to Lambda Black
Engine off - 12V (both multimeters)
Engine on - 8.5v (both multimeters)

Both lambdas have the same results.

At the relay, pin 30 has 12V all the time. The fuel and lambda pins (87) have 12v when engine running.

Someone has wired in (can't follow it at the moment) extra cigarrette lighter sockets, a triple. They are always live. I did test to see if plugging in my phone would make anything drop on the lambda side any further, but no, so I am assuming they are wired in correctly for now.

But, I am still confused. I assume this means there is an issue with the positive earth somewhere but everything else on the car works fine, so it must be isolated to the lambda's?

See below, I suggested you use a known good positive (battery positive terminal) to check that the Lambda sensors earths are good or not

Penelope Stopit said:

Yes the voltage at the sensors heater elements should be the same as the relay terminal 87 output that supplies them (give or take 0.something volts volt-drop)

With only having 8.5 volts at the heater elements, there is no point in testing any further until solving this fault

The volt-drop in the heater elements supply voltage circuit is intermittent (checked out ok earlier) and this is going to make tracing the fault a touch difficult

When 8.5 volts is present at the heater elements, first check that the earths to the heater elements are ok by connecting the volt meter between battery positive and those earths (battery positive being the best positive to use when checking negatives). If the earths are good, check what voltage is present at fuel pump relay terminal 87 that supplies them and should this be approximately 8.5 volts check what the input voltage at fuel pump terminal 30 is

There is a chance that the intermittent loss of voltage to the elements is being caused by bad earth points that are used by another or several other circuits, I'm wondering if the fault occurs when the temperature is up and the fans cut-in (fans using same earth point????)

You need to be using a known good negative/earth to check any other sensor wiring

Engine on - 1 multimeter - 233 volts, the other - 0.21

As you know, high voltage is dangerous, If both meters show 230 volts at the one cable there is a very good chance that the readings are correct

Have you a battery charger connected while checking the lambda sensors?

Is there an inverter wired inside the vehicle?

Are HID headlights fitted, they run on high voltages?

I suggest you contact an electrician who will be able to safely check where the high voltage is being generated

[Monsterlime]

Yes, I did use the positive battery terminal. Crocodile clip on to it, into the multimeter and then negative multimeter lead to the lambda (white and black, separate tests).

Only one meter showed 230v, the other was very low (0.21 volts). Which is annoying, since the newer meter was showing the high result.

Part of the reason I am confused, is when putting the multimeter negative lead to the white lambda wire (allegedly ground) and the red multimeter wire to the black lambda wire, I would get a negative reading (-8.5v), which is surely wrong? The leads were plugged into the correct multimeter inputs as well.

I do use a CTEK battery conditioner via the drivers door socket, but always make sure it is disconnected when doing any of these tests. As far as I know, there is no inverter and HIDs are not fitted.

The low voltage is constant, no matter if the car is warmed up or not.

Would the earth for lambda be the earth point at the radiator? Sure I read somewhere that the fans use that point, but they work fine. Everything else seems fine other than the lambdas.

I have already been considering taking this to someone to look at, as either I am an idiot (likely) or something is very wrong.