• Steel Soldiers now has a few new forums, read more about it at: New Munitions Forums!

  • Microsoft MSN, Live, Hotmail, Outlook email users may not be receiving emails. We are working to resolve this issue. Please add support@steelsoldiers.com to your trusted contacts.

 

hmmwv tachometer installation

ryanruck

Active member
427
43
28
Location
Cincinnati, OH
Bought one of TNriverjet's tachs. He got it to me very quick! Thanks again!

Just got around to installing it today after wrapping up some exhaust repairs. Instructions he included were simple, easy to follow, and worked great.

https://www.youtube.com/embed/q16x7-QMVdE

(The pyrometer on the right isn't hooked up yet.)

I used some 14/4 wire and split the red and black under the dash for power, blue and yellow for tach pulse continued to under the hood. To keep wiring contained to the 14/4 I just wired the light into the power feed on the gauge.

I ended up getting an Auto Meter 5204 to mount it but the fit isn't perfect.

The diameter is fine but the cup itself is a hair shallow. Not enough to matter to me though and the mount works perfectly otherwise.

IMG_1882.jpg

And that was after I trimmed the original mounting posts and the terminal block:

IMG_1883.jpg

Also went ahead and replaced the incandescent light with a green 24v LED to match the rest of the LED dash lights I've installed:

IMG_1889.jpg

Definitely a nice accessory to have!
 

juanprado

Well-known member
Steel Soldiers Supporter
5,482
2,656
113
Location
Metairie/La (N'awlins)
My mounting solution was to use a tach mounting cup from Autometer part number 5204 and hang it on bottom of the top radio shelf. I had to cut the studs off the back of the tach as the cup does not have the depth for the rear bracket OE stud set up. The tach is slightly longer so I painted the outer part of the gold case black so it is not noticeable.

I did wire the ground to the ground stud by the top left of the doghouse as I thought that was better than at a gauge. I already had a hole with the rubber grommet and steel cup on the passenger side by the tunnel. I removed the cut remains of the old cabling from the radio and used this to run all the wires for the tach into a loom and under the radio tray. I drilled a small hole in the firewall behind the gauges to run the wires out and down the main harness to the tach drive and to the hole already there.

I bought a 5 wire Gm style weather tight male/female pigtail from China vendor on ebay very cheap as a quick disconnect at the tach incase I need to pull the radio shelves to get into the doghouse.
 

Attachments

Last edited:

NormB

Well-known member
1,221
77
48
Location
Cloverly,MD
Well...

Got everything plugged in today, wiring harness connected, splices done, switched power on, needle jumped a bit, started truck and... nothing.

Will poke around again tomorrow maybe, check again for power/ground, but I'm wondering if the wires coming off the tachometer mechanical pulse (6680011488875) generator/sender (nomenclature's a problem, I had a hard enough time finding the NSN, then the part, can't find a test for it anywhere in "the manuals") might not have a good connection to the leads off the sender but I did disconnect it (at the two-prong connector to the truck wiring harness) and hook up a VOM to it. Don't know if it's magnetic sending a pulse or an energized coil with a rotating magnet or who knows what kind of circuit inside, but I got zip, nada in ohms OR millivolts.

Two thoughts:

1 - wire gage is more like 16-18 than 14-16 so there's some plastic insulating the splice connection, or

2 - sender's bad.

Would help if I could find its function and testing somewhere in "the manuals," but that was the 45 minutes before I posted this.

Thanks in advance.
 
Last edited:

NormB

Well-known member
1,221
77
48
Location
Cloverly,MD
Correction. Measured the sender (tachometer, mechanical) resistance and it varies 0.1-0.3 Ohms engine off. Like I said, engine on, nothing. Wiring's good, good continuity everywhere.

Definitely getting voltage to the tach with switch on, 25+ engine off, 27.+ running/charging - needle bounces, engine starts, no reading, either on dial or hour meter (I ran it for about an hour to charge batteries, annoy the neighbors).

Anyone have an idea where to proceed? But another tach? These things go DOA sometimes?

Norm
 

TNriverjet

Active member
Steel Soldiers Supporter
1,170
22
38
Location
Nashville, TN
Anyone have an idea where to proceed? But another tach? These things go DOA sometimes?
Norm
I've not had any I've sold returned as DOA. I'd advise checking grounds and signal wire connections. Are you also sure you have "keyed" power hooked up right?

Either way, I've got a replacement unit headed your way. I wanted to make sure you've got a good one in hands when you dive back into troubleshooting. I'd be interested to know if that first one ends up being dead. Let us know how this works out.
 
As I have a r/h drive truck It`s never just a simple bolt on for me. I have to make reverse brackets for everything I want to mount and the tacho was no exception. I just made a frame to pack out the windshield frame so that I could fit the emergency pop out windshields. I took the opportunity to reverse the tacho and wiper motor at the same time.
20160731_143323.jpg20160706_133220.jpg
 

NormB

Well-known member
1,221
77
48
Location
Cloverly,MD
Kudos to TNriverjet, who went above and beyond the call of duty fiduciary or fraternally and sent me another tachometer.

[I WILL get one back to you soon's as I figure this out].

I could use some help troubleshooting this, folks. Anyone with some direct experience/knowledge please chime in.


I'd like to say swapping the tachometer worked, it didn't.

Again, I have power to the tach from the fuel gauge splice - I even ran a jumper from a charging port I installed with anderson power poles - to the old AND the new tach. No function.

I have checked continuity from tach to sender, it's the sender I'm thinking is broken.

Stranger things have happened.

From what I can tell on circuit diagrams in "the TMs" the tach/sender doesn't wire into anything except the 2" diagnostic port just forward of the shifter/TC selector which no one seems to have the computer/reader for. Thinking it MIGHT be tied into the EESS PCB I tried running with and without the 2-connector plug from the sender to the wiring harness engaged.

No joy.

I wasted about an hour - literally - between appointments yesterday to look into this thing the manual calls "Tachometer, mechanical" and my search took me to NSN land (NSN now I couldn't reach from the company network) Oshkosh, Caterpillar and beyond, but NOWHERE can I find any useful data on it like resistance/impedence, output signal and how to read it.

I'd tried measuring resistance on it and got really weird readings of about 100 to 300 ohms and, while running the engine, not a bit of output current or resistance change.

I have no idea if it's broken, but I'm about the blow $20 and change for another one - my time's worth more than that.

Unless any of you have other suggestions.

OR, and this is a stretch, if the standard wiring is to connect to the alternator, how and where do I tap into a standard 60A alternator? Or do I wait until I install the 200A alternator in a few weeks (when it's warmer out) and use IT as the tachometer installation schematic/diagram shows?

Has anyone actually gotten this to work off their alternator?

In for a penny, in for a pound.

Thanks in advance.

Norm
 

juanprado

Well-known member
Steel Soldiers Supporter
5,482
2,656
113
Location
Metairie/La (N'awlins)
I would gamble $20 on a new ste tach sending unit.

I do not believe that is sends a signal or has anything to do with the KDS/ESS or ___box no matter which flavor it is.

The tach that runs off the alt for the ambulance has a different cannon plug and requires its own pricey harness and rare.

Go for the sending unit and maybe just for giggles tap the existing one in a different location.
 

NormB

Well-known member
1,221
77
48
Location
Cloverly,MD
AAAAAND, it worked.

replaced tachometer sender. MAN, what a chore, nut was frozen on the drive block, took considerable time for Kroil to soak in and judicious use of a rubber mallet to loosen things up. Ceaned threads, started engine to make sure the "drive" was working, then I installed the sender, connected some jumper leads, started truck...
nothing but a little "twitch" of the hour meter. ???
Well, as someone else suggested, try another power source, maybe connection to fuel gauge (+) is faulty, not enough current reaching the tach.

Shut down truck.
Pull instrument cluster forward and, D'oh!

I'd disconnected the leads last time I messed with this before buttoning up the instrument cluster, you know, "just in case."
Reconnected leads, started truck, and an angelic chorus sang "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH!"

Or maybe that was just my ears ringing from engine noise.
https://vimeo.com/208868891

(not sure how to do video link embedding, link should work) but this is what I saw:

View attachment 671436

Buttoned everything up and ran truck for about an hour to charge batteries (then hooked up the battery tender which tells me they're charged already).

Interesting, the old sender didn't give same signals/readings as the new one. The new I could hook up to a VOM and watch resistance change as I twisted the spindle by hand.

Also, so far as I can tell, the little tab on the side of the spindle had corroded/worn off and wasn't even engaging the drive. When I reassembled everything I put a few drops of rust-inhibitor spray in the hub, some grease, and antiseize on the 1" nut that holds the thing down. Should work for a few years, I'd think.

Thanks again to TNriverjet and Juanprado. Problem solved - for a little time, effort, and $23 on fleabay.

NB
 

llong66

New member
453
2
0
Location
kokomo, In
I know this is an older post but I have 2 questions, are there any left for sale, and did anyone get one to work with the W term on a CUCV alt? I don't normaly have trouble with schematics and drawings but the one posted a few pages back is giving me a headache! lol

Thanks,
Greg
 

TNriverjet

Active member
Steel Soldiers Supporter
1,170
22
38
Location
Nashville, TN
One guy bought a tach from me early on and was going to try an install on a CUCV. I never heard back from him, so I don't know if he got it to work. The challenge is to find a clean RPM signal somewhere. The schematics seem to indicate a feed available on the alternator. But again, I'm not clear if anyone has got this to work.

I do have more available. See link to classified section in my signature below.
 

Sharecropper

Well-known member
Steel Soldiers Supporter
1,814
942
113
Location
Paris KY
One guy bought a tach from me early on and was going to try an install on a CUCV. I never heard back from him, so I don't know if he got it to work.

Yeah that was me. I still have not got around to hooking the tach up in my CUCV however I intend on getting the signal from a HMMWV oil pump / tach sender which I will install in place of my 6.2 vacuum pump. I am installing a 700R4 transmission and will not need to vacuum pump anymore. I will photo-document this if I can ever find the time....................
 

TNriverjet

Active member
Steel Soldiers Supporter
1,170
22
38
Location
Nashville, TN
I had a pretty good lot of NOS tachs about 18 months ago (149 to be exact). It took me a year, but they are all sold. You may have success finding one on the big “e” auction site that rhymes with “pay”
 

mdes0

Member
42
2
8
Location
Brookline NH
Ran into the same issue with my 6.2 . Replaced the sender with a new one but no luck. The old sender was yellow and the new one I got is black, is there a difference? The black one was the only one on e bay.
 
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!

I've Disabled AdBlock
No Thanks