Technical Increased tick over

[andytw]

Mmmm thanks for that but not good news.

Just been out and started it up.
Revs good at 850 rpm then started to speed up. Went up to c. 1200 rpm
I checked the voltages for both batteries at the control panel, ...12 volts so not under charge.

I left it alone and did nothing. N.B. The ignition light definitely NOT on.

After a minute the revs started to drop so I, again, checked the control panel. Both batteries now showing 13.5 volts, so now charging.
Revs settled back at 850 rpm.

andytw

 

[rolopolo]

Have you had it read with a code reader IE. Multiecuscan?
I'm no tech genius, but could be a temp sensor or air flow meter, fuel pressure regulator or anything there's that many gizmos that could be out of action or bad earth in wiring from water ingress

 

[Thewad]

Mmmm thanks for that but not good news.

Just been out and started it up.
Revs good at 850 rpm then started to speed up. Went up to c. 1200 rpm
I checked the voltages for both batteries at the control panel, ...12 volts so not under charge.

I left it alone and did nothing. N.B. The ignition light definitely NOT on.

After a minute the revs started to drop so I, again, checked the control panel. Both batteries now showing 13.5 volts, so now charging.
Revs settled back at 850 rpm.

andytw

Thanks a shame this may happen to me yet, mine was ok after first test I will try again next week.

 

[andytw]

Some more to report and summary to date.

Startup Scenario 1
============
Battery voltage 12.5 volts.
Fit a a single jump lead between the engine and the chassis to rule out grounding issues.
Start engine, ignition/battery light goes out.
Engine revs slowly increase to 1200 rpm.
Battery voltage stays at 12.5 volts so it is not being charged.
After EXACTLY 2 minutes the ignition/battery light comes on.

OR

Startup Scenario 2
============
Battery voltage 12.5 volts.
Start engine, ignition/battery light goes out.
Briefly rev the engine with accelerator to 2000-3000 rpm.
Engine revs settle back to 850 rpm.
Battery voltage at 14.4 volts so it is being charged.

Actions taken
=========

1. Battery ground cable and engine ground strap cleaned and bolted up tight.

Problem persists.

2. Remove and clean all connections at jumpstart +ve connection. This is live, beware !
Remove and clean 12 volt connector going to fuse block.
Tighten large +ve cable on alternator. This is live but can be done when connectors have been seperated at the jumpstart connection.
Remove and refit (with squirt of WD40) the black D+ connector on the alternator.

Currently I am no longer seeing the problem.

Of interest, though, was seeing the ignition/battery light coming on EXACTLY 2 minutes after starting the engine. This indicates to me that it is under the control of "something" and not just wired to the alternator D+ connector as would have been traditionally expected.

andytw

 

[Techno100]

AFAIK The revs increase to 1200 because the ECU has seen the voltage drop below 12 then failure for the voltage to increase brings the battery indicator on.
Mine is doing the same . I noticed my engine battery had dropped to 12.2 but still managed to start but it takes less than a minute for the revs to increase and the voltage when fault is indicated is at 11.8.
I have accepted that my alternator has failed and sourced a brand new 150 amp replacement for my 110 amp Bosch.
I replaced my earth quite a while ago after difficult starting when engine hot

 

[Techno100]

If you want the best price with 24hrs delivery let me know. I only found out Wednesday evening and it arrived Thursday morning (XMAS EVE!)

Also the Elearn manual instructions basically outline the removal of the alternator pulley as a solid one BUT you are more likely to find it is a clutch pulley. I got a universal clutch pulley tool kit off ebay about £19

 

[dfk]

Started my van yesterday after 1 month idle ,within 1 minute revs rise to 1200 battery not charging.Was hoping it was a fuse maybe, haven't checked anything yet as been raining constant.Will watch to see if your new alternator fixes problem.
PS I hope you will be putting up a step by step guide to changing it.

 

[andytw]

Checked mine again today and it failed so it isn't fixed. Not surprised to be honest, I always keep an open mind. I have a multimeter across the jumpstart +ve point and chassis and as soon as I saw it was not charging I hit the gas and released. Voila sorted.
Inclined to believe it is the alternator but in my case I will progress this under the motorhome warranty. I have not raised it with them so far as it is easier to observe and clean up a few connections than to drive it to them, get a lift home etc.

andytw

 

[corcai]

With a motorhome its likely they've hung a relay, panel input or electroblock off the b+ terminal. Too much current drawn can stop excitation and knock the alternator off. I would disconnect that before writing off the alternator.

 

[Techno100]

Motorhome converters are not in the habit of overloading alternators.
If you are suggesting that disconnecting normal services is a solution I think you're barking up the wrong tree.

 

[corcai]

Motorhome converters are not in the habit of overloading alternators.
If you are suggesting that disconnecting normal services is a solution I think you're barking up the wrong tree.

Eletroblocks and panels are in the habit of failing, cabin to habitation wiring has a habit of fraying and corroding like any other wire I am suggesting disconnecting it as part of a systematic diagnosis rather than fling a new alternator at it and see if it sticks.

 

[Techno100]

I see what you are saying but the only wire used from the alternator is the D+ signal that feeds relay coils only. All other loads such as fridge and battery charging are fed through the relay contacts.
So the habitation cannot draw load unless the D+ signal is present first which requires a healthy alternator.
If any circuits apply more load than design due to a fault its fuse will blow
An early warning sign of mine failing was actually the battery parallel indicator dropping out occasionally until complete failure and the dash battery warning light on.

 

[dfk]

With a motorhome its likely they've hung a relay, panel input or electroblock off the b+ terminal. Too much current drawn can stop excitation and knock the alternator off. I would disconnect that before writing off the alternator.

Mine is a self build set up that the alternator charges the van battery as normal but throw a switch and it charges the leisure batteries thru a split charge relay so if it is "knocked off" how would you reset it.




























2

 

[Thewad]

Thanks a shame this may happen to me yet, mine was ok after first test I will try again next week.

Ok test number two today after leaving for a week or so,starts a lot better then before, left running for a while then loaded the battery by turning on all electrical items i could, voltage did drop a little (14.1) but maintained at 13.7v no increase in idle speed, but there was no set pattern to fault, so far so good need to give a longer run which i will this weekend coming.

 

[Thewad]

Quick update, on my increased idle speed, 80 mile around trip today no problems what so ever looks like a nice easy fix 'clean that earth strap people' not only does the engine turn faster on start idle has sorted it's self out but I did have EML come on at start up, no more all completely cleared up, thanks for all the advice

 

[andytw]

This might help others.

To recap my issue.
1. Start engine, do not touch the throttle.
2. Revs slowly speed up to 1250 rpm.
3. Exactly 2 minutes after starting, the battery warning light comes on.

If engine is revved up to c. 2000 r.p.m. when it is started then all is OK.

I replaced the ground strap with one professionally made up, no effect.

Motorhome dealer replaced the alternator under warranty, all has been fine since.

andytw

 

[pgh]

Some more to report and summary to date.

Startup Scenario 1
============
Battery voltage 12.5 volts.
Fit a a single jump lead between the engine and the chassis to rule out grounding issues.
Start engine, ignition/battery light goes out.
Engine revs slowly increase to 1200 rpm.
Battery voltage stays at 12.5 volts so it is not being charged.
After EXACTLY 2 minutes the ignition/battery light comes on.

OR

Startup Scenario 2
============
Battery voltage 12.5 volts.
Start engine, ignition/battery light goes out.
Briefly rev the engine with accelerator to 2000-3000 rpm.
Engine revs settle back to 850 rpm.
Battery voltage at 14.4 volts so it is being charged.

Actions taken
=========

1. Battery ground cable and engine ground strap cleaned and bolted up tight.

Problem persists.

2. Remove and clean all connections at jumpstart +ve connection. This is live, beware !
Remove and clean 12 volt connector going to fuse block.
Tighten large +ve cable on alternator. This is live but can be done when connectors have been seperated at the jumpstart connection.
Remove and refit (with squirt of WD40) the black D+ connector on the alternator.

Currently I am no longer seeing the problem.

Of interest, though, was seeing the ignition/battery light coming on EXACTLY 2 minutes after starting the engine. This indicates to me that it is under the control of "something" and not just wired to the alternator D+ connector as would have been traditionally expected.

andytw

In view of not having found any other thread dealing with the topic of jumpstarts and rollstarts (push-start, bump-start are other terms) are you able to tell me, please, whether or not it's okay to push-start a Ducato diesel van in the same manner as push-starting a petrol engine vehicle; i.e., turn the ignition to 'on', put the vehicle in, say, second gear and engage the clutch, roll it down a hill (or be pushed by numerous volunteers) and then 'drop' the clutch. Would that cause damage? Is it likely to be worth the effort?

 

[corcai]

For common rail pressure is proportional to rpm so youre better putting it 4th rather than 2nd. I suppose as pump is driven by timing belt dropping the clutch could be a large sudden load on the belt but as rail pressure starts at a couple of bar I would think the rail would buffer it.

 

[pgh]

For common rail pressure is proportional to rpm so youre better putting it 4th rather than 2nd. I suppose as pump is driven by timing belt dropping the clutch could be a large sudden load on the belt but as rail pressure starts at a couple of bar I would think the rail would buffer it.

Thanks for the advice, Corcai. I take it, then, that it's okay to 'roll-start', or at least to attempt to start that way if an inclined plane or group of fit and healthy folk prepared to put their collective shoulder to the wheel (rear of van) is available?