Trouble turning over

[jambono5]

Hi all

I have had an ongoing issue with my van struggling to turn over, this all started towards the end of last year when I went on holiday for 2 weeks. When I returned I started the van and although it started it struggled turning over, I didn't think a lot of it as the van had been stood, after charging the battery it seemed to be ok. A few days later exactly the same.

As the van was still under warranty (66 plate 150bhp model) I took it to VW commercial, they tested the battery (Varta), tested the van overnight for power drains and checked the alternator charge, all came back ok. They did say they had found some corrosion on a terminal which had been put right. A week later exactly the same! After backwards and forwards a few times with VW I gave up with them and took it to a local garage, they said there may be an issue with the battery but couldn't say for sure, I opted to have a new battery which seemed fine. A week later ARGHH the same again!!

The van does have a camper conversion with a CTEK 250 split charger and leisure battery but none of this was connected when the problems started.

The van doesn't get used day to day and does sit for fairly long periods, the strange thing is that when I have been out in the van and stop the engine such as going shopping it sometimes struggles more than when it first starts?? On occasions when the start/stop has kicked in the van has almost not started.

Has anyone had any experience of this or have any idea of what may be causing this? I have thought it may be an issue with the starter motor but don't want to just keep throwing money at new parts.

Thanks

 

[Spaghetti]

Worthchecking for parasitic electrical loads when the van is sitting, and double check the starter motor connections are clean and tight.

Worth also checking the battery voltage when left for a week or so and then when you turn the starter motor over.

This may start to eliminate some possibilities.

 

[Mooncat]

I'd be checking all the earth connections from the battery to the body and to the drivetrain. Get a jump lead and directly connect the battery earth to the engine to see if it makes a difference (connect it to something structural such as the block, gearbox, lifting point)

 

[jambono5]

Thanks for the advice

I've removed and cleaned the connections on the starter motor and the small connection between the block and chassis - still the same. I'l have a look for the main battery earth today and check the voltage, jump lead as suggested.

 

[Mooncat]

Have you been checking the coolant level? If the battery, starter, wiring is all good, the issue could be coolant leaking into the cylinders which will effectively increase the compression ratio until it has been pushed out of the exhaust during the first couple of engine revolutions on start up (too much water and you'll have a hydraulic lock). You have a water cooled EGR and a water cooled charge air cooler on your Euro 6 engine and a small leak on one of these could allow water to be ingested by the engine.

 

[$immo]

I may be way off, but are you getting in the van via the driver's door? When you open the driver's door you can hear a pre-start charge of fuel. I sometimes forget and go in via the sliding door after unlock and it always has trouble starting (turns over a couple of times before firing up).
Doesn't sound like your problem but may be contributing if you are always going in via the sliding door.

 

[jambono5]

OK, so as an update......

Yesterday I stripped down and cleaned the main battery earth connection, again the starter motor connection and the block to chassis connection plus two small ground cables that are behind the front bumper (not sure what they're for but just though while I was there!)

It struggled to turn over (but started), after leaving the engine running for around 10-15 minutes yesterday (just on the drive not out driving) I measured the voltage at just over 12.4v, I checked for parasitic drains and read nothing on the ameter. This morning I checked the voltage before trying to start it and got a reading of 12.05v (it is a lot colder this morning so was expecting some drop), again the van struggled to turn over but did start.

The battery had a full overnight charge about a week and a half ago and although it has not been driven it has been started and the engine run for short periods in between.

I have checked the coolant level which looks fine and has not been topped up since I bought the van last year.

 

[Mooncat]

If the engine had been idling for 10 - 15 mins I would have expected the voltage to have been 12.8v, possibly slightly higher immediately after you had turned the engine off....and slowly settle to where it had been before you started it.

To give you a comparison, my van has not moved or been started for over four weeks and last weekend I connected up a 50W solar charger for about four hours to keep the battery happy. I have just checked the voltage and it's showing 12.18v (I was expecting more!). Next to that is 1960s Landrover and that has not moved for about five weeks and the battery is showing 12.68v. The Landrover has absolutely zero parasitic load however the van does. Just to double check something, when you checked the parasitic load, you did disconnect one of the battery leads and put the multimeter in series between the battery lead and the battery as it should have measured something, even if it was only a fraction of an ampere.

 

[jambono5]

If the engine had been idling for 10 - 15 mins I would have expected the voltage to have been 12.8v, possibly slightly higher immediately after you had turned the engine off....and slowly settle to where it had been before you started it.

To give you a comparison, my van has not moved or been started for over four weeks and last weekend I connected up a 50W solar charger for about four hours to keep the battery happy. I have just checked the voltage and it's showing 12.18v (I was expecting more!). Next to that is 1960s Landrover and that has not moved for about five weeks and the battery is showing 12.68v. The Landrover has absolutely zero parasitic load however the van does. Just to double check something, when you checked the parasitic load, you did disconnect one of the battery leads and put the multimeter in series between the battery lead and the battery as it should have measured something, even if it was only a fraction of an ampere.

Hi

Yeah when testing I removed the negative terminal and tested in series between the battery and cable. The reading I got was 0.00 on the 10A scale (I didn't test any lower as read to expect a maximum of 0.02A) I'm not sure what the normal reading would be on a van? Also not sure if it would make a difference but I did the test after unlocking the van on the fob as to not set off the alarm?

Would you also expect that a drain of this type would cause the problem even after the vehicle has been running for some time? Before replacing the battery I drove to a show over an hour away, when we got there the start/stop kicked in when queuing to get in and did not restart. I had to manually restart the van and it only just started then, at the end of the day when I returned to the van it started first time.... It seems a really odd fault to me.

 

[mmi]

what the normal reading would be on a van?

Normally approx. 0.03 A. Should not exceed 0.05 A.

Also not sure if it would make a difference but I did the test after unlocking the van on the fob as to not set off the alarm?

Yes, it makes difference. Even having hood open prevents the van to fall "asleep". For the measurement the hood lock must be latched "closed".
Did you check your multimeter is still actually working? I'd expect to see quite a current rush if van is unlocked and the battery cable was disconnected and reconnected (instead of hooking up the meter across the "breaking point" and then disconnecting).

 

[jambono5]

Normally approx. 0.03 A. Should not exceed 0.05 A.

Yes, it makes difference. Even having hood open prevents the van to fall "asleep". For the measurement the hood lock must be latched "closed".
Did you check your multimeter is still actually working? I'd expect to see quite a current rush if van is unlocked and the battery cable was disconnected and reconnected (instead of hooking up the meter across the "breaking point" and then disconnecting).

I will test it again with the bonnet latch closed, the multimeter is brand new as bought it yesterday to carry out the test.

If the van is locked up can I disconnect the battery without setting off the alarm to test?

I did expect to see some current when testing but not knowing what expected reading I assumed this was ok.

 

[mmi]

If the van is locked up can I disconnect the battery without setting off the alarm to test?

I don't know - the alarm has a dedicated battery so... You should connect the meter beforehand across the "breaking point" - which is a bit tricky I have to say... especially if afraid of setting off the alarm

I'm thinking that possibly the meter's fuse was blown at reconnect, thus showing plain "0.00" - I have experienced this (more than once ) and probably will...

EDIT: One of the conditions to trigger the alarm is labelled as "Power on reset"

 

[jambono5]

I don't know - the alarm has a dedicated battery so... You should connect the meter beforehand across the "breaking point" - which is a bit tricky I have to say... especially if afraid of setting off the alarm

I'm thinking that possibly the meter's fuse was blown at reconnect, thus showing plain "0.00" - I have experienced this (more than once ) and probably will...

I know they can blow easy when carrying out this test (did it to my last meter within half an hour of buying it) I would have thought though that the caution I took should have prevented this, however I have just tested the fuse and it has blown!

The procedure I followed was simply - unlocked the van, disconnected the negative, with the meter on 10A setting tested between the terminal and removed cable, no reading so removed the meter then reconnected the battery cable. Is there anything I'm missing? All doors were shut except the bonnet and everything switched off?

 

[mmi]

The procedure I followed was simply - unlocked the van, disconnected the negative, with the meter on 10A setting tested between the terminal and removed cable, no reading so removed the meter then reconnected the battery cable. Is there anything I'm missing? All doors were shut except the bonnet and everything switched off?

I did duplicate the above except disconnecting the battery negative. Measured the current using a DC-clamp meter over battery negative cable (checked the zeroing of the meter quite a few times).
- Unlocked the van, opened driver's door, opened the hood, closed all the doors, radio and interior lights were switched off
- Fluctuating current flow of several Amps
- After approx. 40 seconds (of shutting driver's door) the current stabilizes down to 0.5 A.
- At 5 mins current drops down to 0.2 A
- At 15 mins - current 0.2 A

 

[Mooncat]

@mmi that confirms the schoolboy error I made when checking my voltage yesterday as it was immediately after unlocking the van, opening the driver's door and then opening the bonnet. I've just done the same this morning and indeed after a short time, the battery voltage starts to increase once the loads have been removed (e.g. the glow plugs pre heating when the driver's door is opened!!)

To the problem with @jambono5 what is most interesting is that the engine can be harder to crank over after it has been running for an hour. Perhaps the starter motor solenoid is not always making a good connection and not transferring the full current to the actual motor? On older vehicles I've stripped the solenoids and cleaned up the internal contact points as they do get lots of arcing marks on them due to how they actually work but this is very old vehicles. This is where you need a friend with a spare starter you can borrow for testing as like you said before, you don't want to keep throwing money at parts in the chance they fix it.

 

[jambono5]

@mmii do have a (Cheap) clamp on meter but it only reads to 0.1 amps, looking at your meter I'm taking that your reading showing is 0.2 amps or 200ma? I was expecting lower than this (from tutorials etc online) but these are shown on older car models so dont know how accurate they are? I will try the same test today.

@Mooncat my friend who is a truck mechanic said similar to me, he had said he would strip down and try cleaning the starter motor parts but said he would suggest this as a last resort as it could get damaged in the process.

 

[DaveD]

I'm no auto electrician by any stretch and there are clearly a lot of people here with a lot of knowledge, but I'm curious. You said that "the engine can be harder to crank over after it has been running for an hour."
I'm going to stick my neck out and say that parasitic battery drain might not be the problem here, as you already suspect. (from post 9)
After an hour of driving, assuming your alternator and charging system is effective, and with a warm / hot engine, any parasitic drain wouldn't have had time to drain the battery sufficiently to make the van harder to start, in my opinion.
You've had a new battery and got no improvement so I'd start to suspect the starter motor itself, as your truck mechanic does.

 

[jambono5]

I'm no auto electrician by any stretch and there are clearly a lot of people here with a lot of knowledge, but I'm curious. You said that "the engine can be harder to crank over after it has been running for an hour."
I'm going to stick my neck out and say that parasitic battery drain might not be the problem here, as you already suspect. (from post 9)
After an hour of driving, assuming your alternator and charging system is effective, and with a warm / hot engine, any parasitic drain wouldn't have had time to drain the battery sufficiently to make the van harder to start, in my opinion.
You've had a new battery and got no improvement so I'd start to suspect the starter motor itself, as your truck mechanic does.

Hi Dave, yes this was my initial thought also. I thought I'd post on here just to see if there where any other recommended checks before taking the plunge at further expense. My truck mechanic mate did say it would be worth checking for poor earth contacts etc first.

@mmi I've just carried out the same test using the clamp on meter, after 5 mins & 15 mins with the bonnet latch closed and after locking the van it drops and hovers around 0.1-0.2 amps, so similar readings to yours.

 

[mmi]

looking at your meter I'm taking that your reading showing is 0.2 amps or 200ma?

True - that's the current for an unlocked T6. Checked a bit more last night. When unlocked (but all the doors and the bonnet shut) it does not go any lower.

@mmi I've just carried out the same test using the clamp on meter, after 5 mins & 15 mins with the bonnet latch closed and after locking the van it drops and hovers around 0.1-0.2 amps, so similar readings to yours.

That's interesting - when van is locked with all the hatches shut it should drop below 50 mA (in a few minutes - VW spec). Mine is approx. 35 mA. The bonnet latch was "closed"? Certainly could be that the current is now at edge of the resolution of the meter (just the last digit "fluctuating").
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The DC clamp meter in the picture is a cheap one UNI-T UT210E. I used 20A range. It has also 2A range.

 

[jambono5]

True - that's the current for an unlocked T6. Checked a bit more last night. When unlocked (but all the doors and the bonnet shut) it does not go any lower.


That's interesting - when van is locked with all the hatches shut it should drop below 50 mA (in a few minutes - VW spec). Mine is approx. 35 mA. The bonnet latch was "closed"? Certainly could be that the current is now at edge of the resolution of the meter (just the last digit "fluctuating").
--------------

The DC clamp meter in the picture is a cheap one UNI-T UT210E. I used 20A range. It has also 2A range.

Yeah my meter only has a single (auto) amp measurement scale, I don't really think the unit is accurate enough to be taken as a true reading, it does flicker to 0.0 intermittently also. This was why I tried (unsuccessfully) using the multimeter, I've ordered some replacement fuses so will try again. Maybe disconnect battery, bridge with a jump lead, attach meter then remove jump lead. I think this should prevent any spike which would blow the fuse but also allow me to leave the van locked as the alarm shouldn't sound?