Help please! Attempting to troubleshoot 2001 Berlingo Multispace 1.9d starting issues

[moizeau]

Have a read of this Wheeler, I'm sure you know most of it
https://www.frenchcarforum.co.uk/forum/ ... hp?t=83615

[blythecooper]

Thank you for all of the replies, and apologies for the delay in thanks.

I've bought myself the test lamp linked and intend to (slowly) fully familiarise myself with the electrical workings under my bonnet. There's definitely some strange electrical stuff going on besides the starter.. the speakers had an absolute meltdown a couple of times last year and made a sound that I can only imagine is the sound you hear in hell. A screeching that was absolutely deafening, and scared the living daylights out of me. Less alarmingly, I regularly get a brief warning beep that my keys are still in the car when I open the drivers door (they're not), and there's something else that happens that I can't quite remember right now...

I confess I also bought a new starter motor (£56) and installed it. I have a tendency to get frustrated and procrastinate and give up, and this felt like the easier option to get me on the road again quickly. It felt like money well wasted. It's running fine, but I still intend to run through all of the diagnostics recommended above to make sure it wasn't just me playing with the connections that sorted everything out.

I really appreciate the discussion and detailed responses- I've learnt a lot from this! And I know changing out the starter motor is just a plug and play kind of job, but I'm still pretty chuffed with myself for doing it myself.

If only they'd offered to teach me this kind of thing at school instead of textiles and home economics...

[Rhothgar]

I'd say a bit of both, a bulb (not an LED) test lamp is great for a quick check. Simply just measuring the voltage at the terminal is also only really any good for a quick check to see if something is there. A high resistance can still show 12v but there is not enough current to power anything. Resistance checks on wiring are also pretty useless too, a single strand of copper wire can show a good resistance.
As said above volt drop checking is a great way to check wiring, the circuit really needs to be tested under load. its also worth noting that earth circuits can be tested in the same way, set to volts, put one of the voltmeter wires on the negative terminal & the other on the casing of the starter motor & attempt to crank.
As for readings, general rule on alternator & starter circuits up to 0.5v is acceptable, on all other circuits up to 0.3v is acceptable.

Good to hear from you on this matter. Not sure if you are a tech but you certainly come across as one in your posts.

A high resistance can still show 12v but there is not enough current to power anything.

Agreed assuming that the circuit is not powered and you hit a single strand in which good continuity exists.

Resistance checks on wiring are also pretty useless too, a single strand of copper wire can show a good resistance.

Essentially, the same as above. Unless it is loaded, it provides a rabbit hole to go down.

volt drop checking is a great way to check wiring, the circuit really needs to be tested under load.

I think we agree on everything. I just have a problem with perhaps over-complicating things where someone doesn't have any knowledge hence why I think a visual indicator is a quicker and infallible test providing it is down right. As you say the general rule is for a drop of between 0.3V - 0.5V but that surely depends on the length and gauge of cable, does it not?

I attach a voltage drop chart for Maxi Fuses for reference. These are surely definitive in terms of load and voltage drop. Are these charts not the Holy Grail of voltage drop testing? I'd be very interested to hear your further thoughts on this, Wheeler.

Perhaps these actually over-complicate things?

NOTE: I typed a slightly different reply and saved it out as a draft. Went it to drafts and half of my message was missing. I don't see any way to 'launch' a reply from the Manage Drafts!

[Rhothgar]

It's running fine, but I still intend to run through all of the diagnostics recommended above to make sure it wasn't just me playing with the connections that sorted everything out.

You'll never know if the starter could have been a connection issue because now it has been disturbed. Assuming that is what you are referring to?

Glad it's been a lesson for you. We're never too old to learn.

[wheeler]

Perhaps these actually over-complicate things?

I would say so yes.
I have always just worked to 0.3v-0.5v all my working life & has worked fine for me. Generally i find when there is a volt drop causing a problem on a starter or alternator circuit its usually at least 1.5v anyway.
As for test lamps, modern manufacturers fault finding processes usually tell you to never use a test lamp. However in the real world its sometimes needed. I would normally use a test lamp for initial basic checks for narrowing down then switch to a multi meter to go more in depth.
There was a common fault on mk2 Xsara HDi's (Bosch system), where the low pressure fuel pump wont run, if you stick a volt meter on the connector it will show 12v but if you stick a test lamp in it the bulb wont light. The issue is a poor connection at the multi connector behind the ECU.

[Rhothgar]

Perhaps these actually over-complicate things?

I would say so yes.
I have always just worked to 0.3v-0.5v all my working life & has worked fine for me. Generally i find when there is a volt drop causing a problem on a starter or alternator circuit its usually at least 1.5v anyway.
As for test lamps, modern manufacturers fault finding processes usually tell you to never use a test lamp. However in the real world its sometimes needed. I would normally use a test lamp for initial basic checks for narrowing down then switch to a multi meter to go more in depth.
There was a common fault on mk2 Xsara HDi's (Bosch system), where the low pressure fuel pump wont run, if you stick a volt meter on the connector it will show 12v but if you stick a test lamp in it the bulb wont light. The issue is a poor connection at the multi connector behind the ECU.

I'd be really interested to hear your thoughts on the ScannerDanner video I posted a link too and that shows the narrowing down of cause using test lamp only. At the end of the day, you still need wiring diagrams or be familiar with the circuit being tested.

[wheeler]

I'd be really interested to hear your thoughts on the ScannerDanner video I posted a link too and that shows the narrowing down of cause using test lamp only. At the end of the day, you still need wiring diagrams or be familiar with the circuit being tested.

Yeah, just watched it, Great video. For a starter circuit like this its not likely i would have needed to reach for a multi meter although i probably would have done just to see a number out of curiosity and see just how much of a drop there was.
In this case there was an obvious large drop & the bulb went completely out, however the drop may not have been that bad that the bulb never went completely out & only dimmed a bit but could have stopped enough current to operate the starter.
It's lower current circuits where a test lamp may be less helpful.
CAN lines, test lamp wont get you very far there.
ECU's that use 5v outputs, sticking a test lamp in there could potentially cause damage as it could pull too much current, i would imagine this is one of the reasons that manufacturers dont recommend the use of test lamps. Again though its all about knowing the circuit you are working on.

[Rhothgar]

Some very valid points.

I've not seen the particular video but Pine Hollow Auto has several different test lamps to emulate different loads.

You point about 5V lines is extremely valid. I guess one of those small electrical test lamps might be OK on such a circuit but how could one power it? PowerProbe is a great tool until it becomes a liability. Besides I think that only does 12V.

EDIT:

PowerProbe do manufacture a 5V adapter for use with their main unit.

I'll be the first to admit that I don't know enough about CAN and the like to go messing with modern cars. I guess some of those circuits carry even less power.

[wheeler]

I have an adapter for my power probe that converts it to 5v for checking ECU’s

https://www.ebay.co.uk/itm/166211920857 ... media=COPY

EDIT: Typed that before i saw your edit.

[Rhothgar]

I have an adapter for my power probe that converts it to 5v for checking ECU’s

I wish I had the confidence and experience to use a PowerProbe.

[wheeler]

I dont leave home without a power probe. Every vehicle i use has one in the boot.

Just like above with a power probe you need to understand the circuit you are working on.

[Rhothgar]

To my mind, there is a distinct difference between a passive test (with the exception of the point you make about getting anywhere near an ECU with a test lamp) and an active test where you apply 12V to a circuit.

I hope one day I will know enough to have that confidence.

I guess it's fine for actuators and other 12V circuits but steer clear of sensors and ECU with a 12V tester. Some CAN stuff is 1.25V (and probably lower than that maybe).

[wheeler]

CAN is 5v in total split over CAN H & CAN L.
Should in theory be 2.5v each but as long as both add up to 5v should be ok.

[Rhothgar]

@Wheeler

On the subject of starter issues, what is considered to be an acceptable cranking voltage whilst cranking please?

I had a mate's Bosch KTS590 plugged into one of my cars yesterday and, as you know, it displays the battery voltage (more likely OBD voltage) in the top right. On cranking, it naturally drops and I guess this is actually classsed as voltage drop, is it not?

I suspect the battery on the car isn't in the very best of condition and probably needs replacing as I left an ELM327 plugged in a few weeks ago and within a week it had drained the battery to a level that it needed charging.

I've not looked at the connections on the starter yet or the earth as I seem to have a lot on with cars at the moment. Never a dull moment...

[wheeler]

Thats not really the same thing as a volt drop test but yes there is an acceptable limit for this.
Firstly i wouldn’t use a voltage display on a diag tool, there is too much of a delay, use a proper voltmeter connected directly to the battery.
A good battery should not go below 9v on cranking.
An old way of testing a battery would be to disable the engine from starting (removing the fuel pump fuse for example) then crank the engine for 10 seconds. A good quality meter will have a max/min record function, set it to record minimum & it should not go below 9v with 10 seconds of cranking.