Dash tachometer quit

Topic: Dash tachometer quit (Read 3237 times) previous topic - next topic

Re: Dash tachometer quit

Reply #50 – January 01, 2021, 10:58:27 pm

So your tach quit when you unplugged a connector on the ECM (and obviously plugged it back in)?
Thx

Re: Dash tachometer quit

Reply #51 – January 01, 2021, 11:24:59 pm

It didn't work after I put the Jake brake in. I don't know if that had anything to do with it or not. I didn't start the engine for a few
weeks when and after I put the Jake Brake in.

Re: Dash tachometer quit

Reply #52 – April 19, 2021, 09:57:31 am

Still looking for a fix to tach not working.
Anybody?

Re: Dash tachometer quit

Reply #53 – April 19, 2021, 01:30:25 pm

I'm with you, still looking.

Re: Dash tachometer quit

Reply #54 – April 19, 2021, 11:39:44 pm

Last resort, have you "broken tach" guys considered replacing the stock instrument with a aftermarket product? Couple ideas below (I know nothing about either of them):

Electric Tachometers for Diesel Engine | 15,000 Satisfied Customers | Diesel...

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Re: Dash tachometer quit

Reply #55 – April 22, 2021, 05:37:47 pm

Could some computerized Cummins Foretravels still use a magnetic tach pickup located on engine bell housing like non-computerized engines use. The bell housing pickup wire connection can come loose.

Re: Dash tachometer quit

Reply #56 – April 23, 2021, 09:00:31 am

Just a thought reinforcing Barry's suggestion. When we installed the Rostra aftermarket cruise control (on the death of my King unit) the tech discovered the signal from the top of the Allison was very weak. He pulled the magnet and found it to be worn paper thin. Replaced the magnet and greatly improved the tach signal. Might be some value in this.

Re: Dash tachometer quit

Reply #57 – July 12, 2022, 11:02:09 am

Anybody have any update on a tach fix? Replaced tach, no joy. Certified wire from tach to ecu. Still thinking it could be the ECU

Re: Dash tachometer quit

Reply #58 – July 12, 2022, 11:20:35 am

If the magnet or wiring is not the problem, send it in to a speedo shop. They do fast turnaround, repairing any speedo, tach or auto clock. VDO gauges are sure a lot better looking than SW stuff. I sent all my Grey Market speedos down to North Hollywood Speedometer Repair - NH Speedometer where they put the U.S. face and ODO gears in them. Fast and reasonable. Call them first and explain the problem.

Pierce.

Re: Dash tachometer quit

Reply #59 – July 12, 2022, 12:09:11 pm

Barry,
I don't suppose you have a picture of specifically where on the bell housing PU wire attaches? I have looked and looked but there are a lot of wires in that area on top of the bell housing.
Don

Quote from: Barry & Cindy – April 22, 2021, 05:37:47 pm

Could some computerized Cummins Foretravels still use a magnetic tach pickup located on engine bell housing like non-computerized engines use. The bell housing pickup wire connection can come loose.

Re: Dash tachometer quit

Reply #60 – July 12, 2022, 03:45:15 pm

Ldillow already stated that they replaced the tach, so advice to send the tach in for repair probably not useful.

If the tach is new, and the wire from tach to ECU checks out good, then that just leaves whatever generates the signal that goes to the ECU. If you can identify and locate the source of the RPM signal as mentioned by Barry and Alan (above), try replacing it and see what happens?

New signal generator will certainly be cheaper than getting into repairing or replacing the ECU.

Re: Dash tachometer quit

Reply #61 – July 12, 2022, 05:38:28 pm

There is a few of us with the tach not working. As I have a Silverleaf and the tach works
with Silverleaf it isn't a priority with me as I don't look at the dash much anymore. I have
wonder if the connection on the ECU is bad as mine quit after I had the ECU connection
off when I need to add the connection for the Jake Brake when I put it in. If it was easier to
get at I would have checked it out. Maybe some day.

Re: Dash tachometer quit

Reply #62 – July 12, 2022, 09:38:16 pm

Don,

No photo, but the C8.3 without a computer had a single long sensor with a single wire that was bolted to near top of bell housing which could be observed by looking down at rear of engine with bed up. Bell housing is between engine and tranny. Don't think there are any other wires in this area.

Barry

Re: Dash tachometer quit

Reply #63 – July 15, 2022, 12:50:12 pm

Not the same, but my book shows the tach grounding through the oil pressure switch . Bad switch and the hr meter and tack dont work .

Re: Dash tachometer quit

Reply #64 – July 16, 2022, 12:30:43 pm

I had the wire integrity checked by cummins. From connector B pin 17 to tach, they said it was good and the proper signal is being offered to tach. They said bad tach, it is the second tach so not sure that is true. The saga continues

Re: Dash tachometer quit

Reply #65 – September 24, 2022, 08:51:15 am

Fixed my tach after 2 years of trying and roughly 400 in troubleshooting costs. FT took the tach back so that helped.

There is a diagnostic button under dash cover. If it is pushed, the tach does not work.

Just that simple

Re: Dash tachometer quit

Reply #66 – September 24, 2022, 10:53:11 am

Is that the button beside the button that raises and lowers the RPM, key on, engine on?

Re: Dash tachometer quit

Reply #67 – September 24, 2022, 10:57:11 am

Surely it can't be that simple. Several of us here have had this issue and like you spent years and hundreds of dollars trying to resolve it. I will check my system out in the next few days and hopefully have a tach again. Thanks.

Richard

Re: Dash tachometer quit

Reply #68 – September 24, 2022, 11:00:53 am

When in doubt, add a ground wire. As I said above, Mine grounds through the oil pressure switch . Grounds corrode on these old things .

Re: Dash tachometer quit

Reply #69 – September 28, 2022, 06:55:56 pm

I tried the button nest to the tach adjustment and nothing, the tach still not working.

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