RPM Gauge - Erratic at Low RPM

[mcbridek]

2000 Four Winns / Volvo SX / 8 cyclinder
The Gauge cluster on on four winns was just changed from the original digital VDO to analog Faria Gauges (New Four Winns dash). The RPM gauge at low RPM's (idle) is jumping around wildly, needle will be at 700, then jump to 5000, drop back to 700 then jump to 3000...., when the RPM's increase displays normal.
Any ideas ?

 

[Bondo]

Re: RPM Gauge - Erratic at Low RPM

Ayuh,.....

Check the Ground path for the Dash panel.....

 

[rodbolt]

Re: RPM Gauge - Erratic at Low RPM

yep, check all connections. then you will find why I wont use faria products
cheaper than VDO or OEM and for a reason

 

[BAYLINER185]

Re: RPM Gauge - Erratic at Low RPM

Why go from digital to analog? Im courious

Just for new model year look? or was the digitals going bad and/or hard to see during the day? I was just woundering if they made digital displays for boats and though it would be cool looking.

Sure its true analong are problably fool proof and will always be reliable!

 

[mcbridek]

Re: RPM Gauge - Erratic at Low RPM

The Original intergrated dig. VDO cluster was a nightmare. Entire panel has to be sent in when a gauge went a single guage goes bad - $250 flat rate repair cost. My last problem gauge the temp gauge - yes - $250 to repair a temp guage ! I will never buy another boat with integrated digital guages. And if someone is a VDO fan - it's not me !

 

[Coors]

Re: RPM Gauge - Erratic at Low RPM

Do you have a wiring diagram?
for the dash?

 

[newport dave]

Re: RPM Gauge - Erratic at Low RPM

You could have a high voltage leak (spark) coming out from under the coil wire boot and arcing to the negitive side of the coil. Check for a tight fit of the boot on the coil tower and seal it with dieletric grease.

 

[pensacola]

Re: RPM Gauge - Erratic at Low RPM

I am sort of having this problem with my 99 mercruiser 5.0
At idle its saying 2000 rpm's even though I know its around 650-700. Then when I am running about 25-30 its maxed out at 6000 rpm when its running nice and easy and I know its not running at 6000 rpm.

 

[rodbolt]

Re: RPM Gauge - Erratic at Low RPM

double check your tach settings, you can also use a multimeter,analog preferably, to check the ac voltage on the tach signal wire to see if its steady or is it fluctuating, if its steady its not a signal problem.
digital meter may not react quick enough to detect the variations.