Volvo-Penta D3 160A-A - technical

[ruaridhmaccallum]

Hi all,

Bit of a long shot but I don't suppose anyone has a workshop manual for a D3-160A-A (5 cyl)?
Specifically I'm trying to find out what the resistance should be on the flywheel sensor.
I have an infuriating intermittent problem where sometimes the engine cuts out as soon as the throttle position sensor starts to move. Have replaced TPS with a new one - no different. At the end of the summer the problem was happening 9 / 10 times the throttle was moved, so thought it would be relatively straightforward to home in on it.
Of course what do you know, with the boat (RIB) on a trailer in the shed, the bl**dy problem stubbornly refuses to show itself. I opened and checked every connection I can find, have tried running it with all sorts of bits disconnected to no avail, problem still won't show itself.
I thought next port of call was the flywheel sensor, maybe going out of range? I ordered a new one but stupidly thought I knew which one it was and of course was wrong, the one I got was the new-style D4 one which won't fit in the flywheel housing. However interestingly it measures a very different resistance to the existing one.
It's a real hassle to get the sensor in and out involving removing turbo pipe etc., so before I put it back in or blow another £70 on a new one I'd really like to get an idea of what the resistance should be.
I've been able to download older VP manuals in the past but have drawn a blank with this one - can only find dodgy sites that want CC details and you can't even tell if it's the exact right manual.
I think it has to be the 160A-A specifically because looking at the parts diagram on the Marine Parts Europe site there's a difference in the sensor for the 160A-B.
I'm reluctant to spend a lot of money on a manual for this one tiny bit of information that probably isn't the root of the problem anyway....if you've been here you'll understand!
Thanks in advance.

 

[spannerman]

I have the VP manual which covers the 110, 130, 160 A-A engines and it should have a resistance of 124 ohms @ 20C.
Its strange that it runs on the trailer without any apparent load, do you have manual or electronic shift? as the electronic shift will stop the engine if there is a problem with the microswitch in the shift lever, it means the engine doesn't know if its in neutral so plays safe by cutting the motor when you try to select a gear. Don't know if this relates to the problem you have.

 

[ruaridhmaccallum]

Many thanks for that.
No it doesn't have electronic shift. When the problem was apparent it would do it even when moving the TPS lever with the throttle cable disconnected, i.e. not even touching the main shift lever. I don't think there's a neutral switch in there but I'll have a look, I suppose there could be one somewhere down on the engine as well.
I don't think the problem has anything to do with load, I think it's just sheer bad luck that's it's disappeared now that we're looking for it properly. When in the water it would cut just the same when giving it throttle-in-neutral using the centre button on the lever.
A friend has suggested there's a screen or filter in the HP fuel pump which can get blocked with diesel bug, I suppose if this happened it might be reading low fuel pressure at the rail and cut the engine as soon as it was asked for any throttle? Seems unlikely though, normally these things go into some kind of limp mode for safety rather than cutting the engine altogether which is potentially dangerous.
Thanks very much again for the resistance figure, it's a big help to be able to eliminate one more thing.

 

[spannerman]

On a manual shift there is a neutral switch in the throttle lever and is only to prevent a start in gear, have you recently changed the fuel filter on the engine, as these have to be tightened with a filter strap as they have a sealing ring in the centre which stands proud and will prevent the outer sealing ring from contacting its mating face properly allowing air to sneak in, the engine will idle but under acceleration will stumble due to air being pulled in.

 

[volvopaul]

On a manual shift there is a neutral switch in the throttle lever and is only to prevent a start in gear, have you recently changed the fuel filter on the engine, as these have to be tightened with a filter strap as they have a sealing ring in the centre which stands proud and will prevent the outer sealing ring from contacting its mating face properly allowing air to sneak in, the engine will idle but under acceleration will stumble due to air being pulled in.

Sure been the victim of that!!! Stupid filter design.