Volvo D130 Tacho pulses

[ducati996guy]

Hi All

I have come across this kit which I have recently built and attempted to add to my D130 saildrives.

K6220 - Silicon Chip Magazine Twin Boat Engine Speed Matching Kit - Altronics

It is not working as expected and it could be one of 2 things.

1. The number of pulses the tacho uses are are outside of the specs for the kit. Kit instructions say the pulses need to be between 2 and 4 pulses per revolution.

2. I am picking up from the wrong place. I am using the gray and gray/black wires off the back of the tacho.

Does anyone know how the volvo tacho works or how many pulses per engine? I found some wiring diagrams and it looks like the gray and gray/black wires are the right place. So that just leaves the pulses. I dont own an oscilloscope so I cant check.

I was hoping some expert here may be able to assist.

Many Thanks

David

[colemj]

I believe the number of poles on that alternator is 12, which would give 12 pulses/revolution. I don't know of any 2 or 4 pole alternators. Are you sure that those numbers aren't 12 and 14 pulses?

Mark

[ducati996guy]

Thanks Mark,

The number of pulses I am referring to is the pulses the kit will accept. It is a generic kit, not just for Volvo.

There is a way to change the kit to support a different number of pulses, but I need to know the number before I make the change.

If anyone knows the answer to this it would help greatly and save me going down a rat hole.

Best Wishes

David

[colemj]

Pretty sure its twelve.

Mark

[Wotname]

Hmm... sorry I can't help directly but I am wondering if the kit is designed more for petrol engines than diesels in so far as it is expecting pulses from the ignition system???

And if it is indeed suitable for diesel tachomters, then are we talking alternator pulses or pulses from a flywheel magnetic pickoff.

A D130 service service manual should at least tell you how the pulses are generated for the tacho and that would be a good starting point.

[Wotname]

OK, don't know if this will help but...

A quick read of a Volvo electrical manual for a D1-30 found on the Mantra Owners Website suggests the tacho receives information from the MDI on a CAN bus. The MDI registers the rpm by way of a single inductive pickup up from the flywheel. What remains unknown at this time is the number of magnets embedded in the flywheel assuming it uses magnets.

The wiring manual gives different arrangements for the D1-30A & the D1-30B/F but in all cases it shows the pickup as a grey wire and a grey/black wire.

[DougR]

As mentioned there are two different tach drive systems for the D1-30 engine depending on its vintage.

Earlier engines (D1-30 A) pulled the tach drive signal from the Mitsubishi 115 amp alternator and fed this signal to the tach on the grey & grey/blk. wires. The tach is a 12 pole unit, and then you need to take the crankshaft to alternator pulley step-up ratio into consideration as well. This will then give you the pulses per crankshaft revolution.

Later generation engines (D1-30 B thru F) didn't use the alternator to drive the tach. A magnetic pickup mounted on the flywheel housing counts notches machined into the flywheel and feeds this info into the MDI box. The MDI box calculates the RPM from these pulses and places the info on the CAN bus harness which is seen and displayed by the tach. There are no grey & grey/blk. wires on these models.

In any event, there will be way more than 2 or 4 pulses per crankshaft revolution.

DougR

[BruceS]

Suggest you get in touch with Collyn Rivers (Google) as he was the owner/editor of that magazine.
I recently put a tach on my diesel and had an auto elec open up and solder an extra lead from one pole that I used to pulse the tacho.
Looking at that kit I'd suggest it doesn't matter how many pulses you get from either alternator. Even if they are different makes/models.
You'll need a rev counter to initially do the calibration by altering the trim pots. (blue square with screw adjuster on them)
The kit simply shows difference between the two ........ not as in a tacho.
The rev counters are not that dear and I can assist with that if needed.?
http://www.ebay.com.au/itm/Digital-L...item339fc4ed0a

[Wotname]

Originally Posted by DougR

As mentioned there are two different tach drive systems for the D1-30 engine depending on its vintage.

Earlier engines (D1-30 A) pulled the tach drive signal from the Mitsubishi 115 amp alternator and fed this signal to the tach on the grey & grey/blk. wires. The tach is a 12 pole unit, and then you need to take the crankshaft to alternator pulley step-up ratio into consideration as well. This will then give you the pulses per crankshaft revolution.

Later generation engines (D1-30 B thru F) didn't use the alternator to drive the tach. A magnetic pickup mounted on the flywheel housing counts notches machined into the flywheel and feeds this info into the MDI box. The MDI box calculates the RPM from these pulses and places the info on the CAN bus harness which is seen and displayed by the tach. There are no grey & grey/blk. wires on these models.

In any event, there will be way more than 2 or 4 pulses per crankshaft revolution.

DougR

DougR, it is not my intention to contradict this information - especially as I have no experience with this engine - but it doesn't exactly agree with the Volvo manual (47704383 06-2013) I found on-line.
Here http://mantaowners.org/wp-content/up...ELECTRICAL.pdf

The wiring variations as shown on page 38 (D1-30A) and page 44 (D1-30B/F) suggest the pickup is flywheel activated in both engines and the wiring remains grey and tray/black in all cases. The early engine does not use an MDI or CAN bus data as far as I can work out.

However I have read enough service manuals to know they contain errors and that real field experience trumps them every time so you information may well be correct.

EDIT: Is there an earlier model than the D1-30A??? (perhaps a D1-30)???

[DougR]

Watname, I stand corrected! All versions of the D1-30 obtain tach signal information from the mag pickup on the flywheel housing. What happens to the signal thereafter is different between the A version and the later versions.

As you state, the A version doesn't use a CAN bus, and feeds the info directly to the tach on the grey and grey/black wires. The later versions send the pulse info to the Mechanical Diesel Interface (MDI) which converts the info to CAN protocol.

So, if Ducatiguy removes the tach sensor from the flywheel housing and carefully counts the notches machined into the flywheel he will know the number of pulses per revolution.

DougR

[ducati996guy]

HI All

Firstly thanks for all the great information. I have been travelling for a few days and have not been online.

All of the above makes a great deal of sense. Not so sure about removing the flywheel cover, that sounds like a lot of work. Having coffee here my knowledgeable sensible friend, who recommends a call to a Volvo tech may be a little simpler. I did a quick bit of googling and cant find anything obvious.

The kit has instructions for changing the value of one capacitor to cater for different pulse counts and the appropriate formula to determine a new value.

Once I have an answer I will post back here for future reference.

Many Thanks

David
On Y Va
Lavezzi 40

[DougR]

Not necessary to remove the flywheel cover, just remove the tach sender from the top of the flywheel housing and look in the hole where the sender was sitting. Count the notches and you have your answer.

DougR