Faulty Tachometer??

[SirenaDK]

Hi all

I have a strange problem. My tachometer in on my standard VP panel, with a VP 2003T needs to be kicked in gear.
When I switch on the panel, I get an alarm and only the lamp for oil pressure lights up. Then I start up without problems. Now, the tachometer still don't work, but if I quickly press start button, the tachometer kicks in and works fine. And if I shut the engine down, all lights lights up, with no alarm..

Does anyone have a clue about what's going on?

[JoeRobertJr]

My first guess would be weak/dirty connections. So, my first step would be to clean the connections on the back of the panel, the oil pressure switch on the engine, and the tach sender at the engine, whether that is your alternator or a separate engine RPM sender.

P.S. Welcome to the forum!

[deblen]

Some VP 2000 series Instrument panel info:Penta 2003 Instrument Panel.pdf Views: 34 Size: 352.0 KB ">Volvo-IRJDSUNE9932123321222xxeww-Penta-IRJDSUNE9932123321222xxeww-2003-IRJDSUNE9932123321222xxeww-Instrument-IRJDSUNE9932123321222xxeww-Panel.pdf

Penta Alarm Module - Simpler fix.pdf Views: 41 Size: 260.9 KB ">Volvo-IRJDSUNE9932123321222xxeww-Penta-IRJDSUNE9932123321222xxeww-Alarm-IRJDSUNE9932123321222xxeww-Module-IRJDSUNE9932123321222xxeww---IRJDSUNE9932123321222xxeww-Simpler-IRJDSUNE9932123321222xxeww-fix.pdf

VP 2000 Dash Manual.pdf

[HeywoodJ]

IIRC the tach pickup on those engines is the alternator. Coupled with the rest of the symptoms the alternator could be not getting the juice is needs to magnetize during startup, but does when the engine is running and the start button is pushed. Which leads to either alternator or voltage drop during cranking. Which gets you back to checking all the connections first (including the negative connection to the engine block) but then I'd also start looking at the alternator (seems a long way from the problem, but it has a lot to do with the instrument panel, and the tach is symptom if I am remembering right about the tach pickup).

[SirenaDK]

Originally Posted by JoeRobertJr

My first guess would be weak/dirty connections. So, my first step would be to clean the connections on the back of the panel, the oil pressure switch on the engine, and the tach sender at the engine, whether that is your alternator or a separate engine RPM sender.

P.S. Welcome to the forum!

Thank You for the welcome and for answer!

I've already cleaned all the connections and found a bad connections, but sadly it didn't make a difference.

[SirenaDK]

Thank You for that manual! I've been looking for it.

[SirenaDK]

Originally Posted by HeywoodJ

IIRC the tach pickup on those engines is the alternator. Coupled with the rest of the symptoms the alternator could be not getting the juice is needs to magnetize during startup, but does when the engine is running and the start button is pushed. Which leads to either alternator or voltage drop during cranking. Which gets you back to checking all the connections first (including the negative connection to the engine block) but then I'd also start looking at the alternator (seems a long way from the problem, but it has a lot to do with the instrument panel, and the tach is symptom if I am remembering right about the tach pickup).

Thank You for reply!
I've had the alternator out and had a close look at all the connections.
Somebody suggersted it could the instrument it self?

[SirenaDK]

Originally Posted by deblen

Some VP 2000 series Instrument panel info:Attachment 274423

Attachment 274424

Attachment 274425

Attachment 274426

Oh now I see your description of the problem in the pdf file a the possible solution. Thank you so much for that! 😊

[deblen]

Some VP 2000 series have a tachometer sender mounted on camshaft cover- front of engine.
https://forums.ybw.com/threads/volvo...sensor.452332/


https://forums.ybw.com/threads/volvo...w-revs.440520/