Engine/Transmission (1994 - 1998) Speedo

[proskeeterman]

Ok, I know this will sound dumb to some, so I'll admit it up front. I am not the most engine literate person around. Can you tell me what the first 3 marks on the speedo translate to in rpm's? For example is it 250, 500 and 750? I'm trying to reset my idle and would like to know how thats suppose to look on the speedo. My sincere thanks to those that reply.

 

[fest3er]

First, I assume you mean the tachometer... .

My '98 12V has 4 tics from 0 to 500 (5 if you include 0 RPM). That corresponds to:

500/4, or 125 RPM per tic

Thus, the tics are 0, 125, 250, 375 and 500 RPM. Or, where you will be working, 500, 625, 750, 875 and 1000 RPM.

I *hope* you aren't setting your engine idle speed via vehicle speed!

Also, I don't know how different the '95 tach is from the '98; it *could* be marked completely differntly, in which case the above won't apply atall.

Fest3er

 

[illflem]

No 500 on mine

My '95s have two marks between 0 and 1000, that means each one is 333. 333 rpms. In-between 1k and 2k, and 2k and 3k there are three marks = 250 rpm each. Then in the area you need it the most , in the red between 3 and 4k there are 7 marks=125 each. I set my idle about halfway between 666. 666 and 1000, in D with the A/C on. Goofy setup, DC must have saved a lot of money not making the extra marks. Cheap-asses even left out the I in diesel



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photo courtesy of gitchesum

 

[fest3er]

Now that I've seen a pic of Gitch's dash, I would expect the tics to be 0, 500 and 750, as that would match the rest of the tach (being x000, x250, x500 and x750).

I would guess DC did it this way because the engine will probably never idle at less than 500 RPM. Also, it is easier (cheaper) to 'rotate' the dial and lose 0-250 RPM than it would be to make the gauge have two different scales.

Fest3er

 

[P-38]

You got ripped off!!



I wonder how much that "I" is worth. . I think I would call my congress man.



John

 

[proskeeterman]

Many thnx to all that replied, illflem, your answer is exactly what I needed to hear. As usual I was wrong, stating 3 tics instead of two. I see now that I have some adjusting to do. Again thank you all very much.

 

[Missouri Mule]

I would have to agree with fest3er that the marks before 1000 represent 500 and 750.

I think I'll look thru owner's/service manual and see if it sheds a light on the rpm marks. I also thought they discussed this in the TDR.

 

[illflem]

Bill, it makes ¢ents in a DC kind of way