DP Tachometer

[zzjea]

My 2001 Marlin DP with 300hp Turbo diesel and Allison transmission has a tachometer that stays @ 20k rpm no matter what. At startup it will bounce around like the other guages do and then it goes to 20k and stays there. Is this NORMAL?

[Jim_HiTek]

Do you mean 2,000 RPM (2K)? Don't know of any tachs that go to 20,000 RPM (20K).

But to answer your question, NO that's not normal. The fact that it bounces around when you turn on the key and then start it would indicate that the meter itself is OK but the device that feeds it is wacky.

Newer RVs have a signal system that links to the meters from a computer. These devices commonly have problems with poor connections so chase the wiring and clean any contacts in connectors you can find. That's a start, anyway.

[doc]

That would be one HIGH REVVING engine!

[firedoc]

Must be a motorcycle!

[rvjimmy]

Might just be the RPM sensor on the engine. Jim

[Papa_Jim]

I'm not familiar with your coach, so consider that when you read my thoughts.

On my coach, the alternator provides the signal for the tach. When the tach begins to operate erratically, it is an indicator that the alternator is getting ready to fail.

[zzjea]

Not being used to diesel, I misread the tach. I am used to x1000 on a car tach and it was x100. So it idles at 2000rpm and hardly moves no matter what speed.

I am planning to go to a diesel shop this week to have them look at the air pressure loss overnight and do a thorough check out of belts, hoses, etc. They should be able to tell what is wrong with the tach too.

Thanks,

John

[zzjea]

I just received my Scangauge D and hooked it up. The RPMS at idle are 750 and I will try all the other gauges out next trip. Just got back from one and the gauge had arrived.

Thanks

John