First gen tach

I'm thinking about putting a knee knocker in my truck since I've been doing a few more performance mods to it. How do I do this? Also what tachs have u guys used and are u happy with them

x2 i've wondered this also

"A knee knocker"...I am unfamiliar with that term....????

As for a Tach. The 89/90/91 trucks did not have any factory provision for a tach, unlike the 92/93 trucks. So you will need to decided on what type of tach signal generator that you want to use. There are kits that work off the injection pulse of the fuel delivery system, or use a signal from the alternator. and the last one, which I like and have used, uses two magnets glued to your harmonic balancer and a magnetic pick up.

I had the magnetic pick up style on my 89 motor, with an Isspro tach. Worked great with never an issue. You can find this style of tach system on teh Geno's website.

thrashingcows said:

"A knee knocker"...I am unfamiliar with that term....????

As for a Tach. The 89/90/91 trucks did not have any factory provision for a tach, unlike the 92/93 trucks. So you will need to decided on what type of tach signal generator that you want to use. There are kits that work off the injection pulse of the fuel delivery system, or use a signal from the alternator. and the last one, which I like and have used, uses two magnets glued to your harmonic balancer and a magnetic pick up.

I had the magnetic pick up style on my 89 motor, with an Isspro tach. Worked great with never an issue. You can find this style of tach system on teh Geno's website.

Click to expand...

Sorry I grew up around the old hot rod guys and they always used terms like "pizza cutters" for skinny tires and so on. Knee knocker is reffering to putting it on the steering column with a clamp.
Now the magnetic type your talking about is that how the second gens are too because if I remember right I think I saw something like that on my dads 95. I attached a pic of it it's right underneath the belt.

Ahh I see about the tach on the column with a clamp...I thought maybe that was what you were making reference too...or tach mounted under the dash somewhere.

As for your Dads 95...that is a CPS (Crank Position Sensor) and yes the ECM uses that signal to convert to a tach signal. The 92/93 1st Gen's have the same basic system...CPS that generates a signal that the ECM can use to send a signal for the tach.

The Magnets have to be glued on 180* apart on the harmonic balancer, then you have to mount the magnetic pick up so that it can read those magnets as they spin by. Very simple, and dead nuts reliable system.

Here you can see the magnet mounted on the original balancer...I was converting to a fluidampr at this time...



Then I had to change the mount for the magnetic pick up, since the fluidampr was a bit bigger in diameter...but you can see where I mounted the pick up, and how I ran the 2 wires.

1989-1991 did in fact have a factory harness provision for the tach under the dash.
It's located in a similar place to the '92-'93 style.
The '89-'91 tachs incorporated a 2-wire crank sensor into the tachometer package.
The 1992-'93 crank sensors have a 3rd wire for a 5 volt reference signal that the ECM reads.

I have one of the early tachs put away, I can get it out and take some pics on the sensor and plugs for you.

Mark.

Mark Nixon said:

1989-1991 did in fact have a factory harness provision for the tach under the dash.
It's located in a similar place to the '92-'93 style.
The '89-'91 tachs incorporated a 2-wire crank sensor into the tachometer package.
The 1992-'93 crank sensors have a 3rd wire for a 5 volt reference signal that the ECM reads.

I have one of the early tachs put away, I can get it out and take some pics on the sensor and plugs for you.

Mark.

Click to expand...

Hey Mark,

I was under the impression that those early system were a separate, stand alone, dealer add on item, and was not incorporated into the factory wiring?

Okay.
Pic 1 depicts the actual sub-harness that the tachometer and crank sensor plugs into.
The lower 3 round pin plug is the crank sensor plug.
The middle, smaller, rectangular plug, with the clipped-off harness connector, is the power supply plug.
The upper, larger, rectangular plug is where the tachometer plugs into.
This particular setup was designed such that the harness does not eliminate the accessory plug under the dash, which indicates that Dodge intended it for this purpose.

Pics 2 & 3 depict the crank sensor and tachometer, showing both plug ends.

In pic 1 there ARE 4 connectors pictured, the one with the masking tape is the replacement for the power supply plug that this apparatus takes up, so there is still an accessory plug in available.

Mark.

thrashingcows said:

Ahh I see about the tach on the column with a clamp...I thought maybe that was what you were making reference too...or tach mounted under the dash somewhere.

As for your Dads 95...that is a CPS (Crank Position Sensor) and yes the ECM uses that signal to convert to a tach signal. The 92/93 1st Gen's have the same basic system...CPS that generates a signal that the ECM can use to send a signal for the tach.

The Magnets have to be glued on 180* apart on the harmonic balancer, then you have to mount the magnetic pick up so that it can read those magnets as they spin by. Very simple, and dead nuts reliable system.

Here you can see the magnet mounted on the original balancer...I was converting to a fluidampr at this time...

Then I had to change the mount for the magnetic pick up, since the fluidampr was a bit bigger in diameter...but you can see where I mounted the pick up, and how I ran the 2 wires.

Click to expand...

That's interesting I found it on genos I think that's what I'll do. Will any old tach work or are there certain ones?

There's not much of a selection of tachs for diesels. isopro seems to be the easiest to install with the magnets. I've been looking and I can't find much information on mounting these. From the looks of the issopros they may slide into a pod? What kinda mounting hardware do these come with? If anybody has pics that would be great autometer makes pretty nice ones and there a little bigger which is what I'm looking for but they operate off the alternator I think. If someone could clear this up and show me my options it would be very appreciated

Autometer 2888 is what I run. Very easy to install on the alternater and works great.

fatty said:

Autometer 2888 is what I run. Very easy to install on the alternater and works great.

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Did you need to calibrate it or was it ready to use?

It needed calibrated with an optical tach.

89cumminstd said:

There's not much of a selection of tachs for diesels. isopro seems to be the easiest to install with the magnets. I've been looking and I can't find much information on mounting these. From the looks of the issopros they may slide into a pod? What kinda mounting hardware do these come with? If anybody has pics that would be great autometer makes pretty nice ones and there a little bigger which is what I'm looking for but they operate off the alternator I think. If someone could clear this up and show me my options it would be very appreciated

Click to expand...

Check out this Gauges thread over on the DTR...

http://www.dieseltruckresource.com/forums/1st-gen-ram-all-topics-93/lets-see-your-gauges-picture-thread-266761/