Recommendations for a Tach on a '92 M998 with a 6.2 and a generator

[FlameRed]

Hi Folks - another newbie seeking more wisdom

I did a search and found lots of information on how people installed a tach on later Humvees with the 6.5 and alternators. But mine is a 6.2 and has a generator.

I will probably mount mine high like shown here:

I see that most of the threads seem to use the later tach shown here and pictured above.

My question is, does the 6.2 have a sensor already on the engine for the above tach to use? If not, how do you get the above to work on a 6.2? I guess if the above tach will work, how does it exactly get connected to the engine? The threads I found don't cover that part.

I know there are other tachs that have a sensor meant to strap on an alternator but no mention about using those on the generator I have. I also found generic desiel tachs that possibly can mount the sensor on the fuel pump.

I know one of you fine folks have done this on my platform and I would appreciate how you paved the way

Thank you in advance!

 

[springer1981]

That tach will work, it is what I have on mine. It is not the exact same as the one pictured. The mount in the one pictured is harder to find and costs a lot if you do. You can buy that kit on epay for over $500. I used the same tach you linked and bought an aftermarket mount that doesn't quite fit but made it work. You have the sensor on the engine already so you just need to connect it to the sensor and run the wires to where ever you plan to put the tach. I've seen them for less than $100. If you do not plan to buy the tach kit for $500++ then just get the tach first and go from there.

Here's a picture of my mount..

 

[TOBASH]

The tachometers are roughly $100. You can take a piece of flat steel and bend it as shown in the picture that you provided, or I took an old soup can and painted it army green and it looks like something out of a World War II vehicle. Unless you are going for a 100% realistic military look, there are 1000 ways you can do this.

The thing that you splice into is a piece on top of an oil gauge sensor/sender IIRC with two wires coming out of it. There are plenty of posts regarding how to install and the search function will give you more details.

 

[TOBASH]

Here's a picture of my mount..

Springer, you’re still running a three speed? Or is that an old picture?

 

[springer1981]

Springer, you’re still running a three speed? Or is that an old picture?

Old picture from when I installed the tach. The 4 speed was upgraded after but the tach mount is the same.

 

[86humv]

The tach with round threaded connector wont work with the 60 amp system.
You would need a 100 or 200 amp dual volt system.
You can use a tach with buss bar on back, and use the tach drive you have on back of motor.
The tach should go up to 3500 rpm...the 3000 rpm one won't read right.

 

[FlameRed]

...bought an aftermarket mount that doesn't quite fit but made it work.

Can anyone point me to an aftermarket housing or mount that is close? My fabrication skills are not that great.

 

[juanprado]

look on my thread post 34

Juan's M998 HMMWV

There is a rubber collar to mesh the pipe to it and it is all the way down. It is actually shorter than another style I passed on. Part of the reason they are taller is that there is a fan blade inside that spins to force more air flow down the pipe.

www.steelsoldiers.com

 

[springer1981]

Can anyone point me to an aftermarket housing or mount that is close? My fabrication skills are not that great.

I think I used this one https://www.amazon.com/Auto-Meter-5204-Solutions-Pedestal/dp/B0002M701S and it looks the same as the one juanprado mentioned above.

I had to cut the back off it so it only covers the side and front of the gauge.

look on my thread post 34

Juan's M998 HMMWV

There is a rubber collar to mesh the pipe to it and it is all the way down. It is actually shorter than another style I passed on. Part of the reason they are taller is that there is a fan blade inside that spins to force more air flow down the pipe.

www.steelsoldiers.com

 

[papakb]

Check with Greg at 86HUMV. He makes exellant repro brackets.

 

[FlameRed]

Thank you for all the info folks. So I picked up a 3500 RPM black tach for just a bit over $100. I think I will try to make my own mount and if it looks like crap I can always buy something else later.

I wanted to find that sensor on the engine so I opened the hood and I believe I saw it way on the back of the engine. Tough to get to from the hood.

So reading some of the threads, you get easy access to this sensor by removing the dog house. Well, a prior owner mounted an AC unit under the radio tray and I could not easily get the dog house open any appreciable amount to see anything. I did not want to force anything as I did not want to break any AC pipes he installed. The AC blow ice cold and we need it in the Florida Inferno!

So I thought I might look at the electrical schematics to see where these leads go and get access to them some ohter place easier to access.

What is this sensor officially called so I might find it on the electrical schematics?

 

[springer1981]

There's nothing to look for. There is a connector on the tach sensor and all it does is connects to the ICE plug for troubleshooting. Unplug that sensor and plug in a twisted pair of wires and run it to your tack. Here is a picture... mine is black, yours is yellow but they are the same. The arrow points to the plug. Unplug it and plug in the the tach. That simple.



Here is my install. Tach mount was less than $50 and I modified it with a hack saw.

 

[FlameRed]

All good with the advice on this forum.

No way to get at it without taking off the dog house. Was not to bad with the AC underneth the radio shelf, I just had to remove the four bolts for the radio shelf, and then I was able to crack open the Dog House several inches without disturbing the AC lines and then I could get to the sensor.

Works like a champ!

So what is the max recommended RPMs for cruising for the stock 6.2 Diesel?