TACH ON DIESEL MODEL TRUCK

[CORVAIRWILD]

Tach is rare, gas or diesel. I've only seen a couple in all the years, prolly not in a diesel, but seen so few... I wonder what the date code is on the back??? And the fuel gauge ends up hidden where the next to invisible clock was.

 

[CORVAIRWILD]

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[Eriknor]

Hi, if your engine have the vacuumpump with ESS sensor on top? you can use this for a rpm-signal with a diy circiut. One circuit is with a transistor and one with Lm393 IC.

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[CORVAIRWILD]

Vacuum pump on the 6.2? Pix?

 

[Eriknor]

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[Eriknor]

Top picure is of a standard vacuumpump for 6.2 in trucks, Van,s and 6.5 had it mount in front of the engine, belt driven. next picure is of the Ess sensor.

 

[CORVAIRWILD]

Hmmmmmm... I don't recall ever seeing the sensor. Nor did I know to look. So this would have come on a 6.2 w a tach? And the 90's non turbo or turbo?

 

[Eriknor]

I got on form a 91 suburban,You can use the setup from Van,s with 4l80e trans, but you have to use the vacuum pump for the Van then.

 

[CORVAIRWILD]

So the Sub had a tach??? Wow, rare

 

[Eriknor]

No, the 91 suburbans with 4l80e trans have Ess sensor, the 4l80e ned a rpm-signal to work.

 

[highdesertrange]

yes but the 6.2 didn't get put in until 1982 and the OP said it was a 1979 which would be a 5.7. there are several ways to have a tach on a 6.2 but I don't believe the factory put them in, at least that's what I have been told. highdesertranger

 

[hatzie]

well if it is a 1979 and it was a diesel that would be the 5.7 liter diesel. I was told the square body diesels never came with a tach. interesting. highdesertranger

They did come with a tach as an option even on the 350 Olds Diesel. The diesel tachs drive off pre-diode AC from the alternator. If it's a diesel tach it wont have the right calibration for V8 or I6.
I've seen more medium duty squares with tachs on various diesels than light duty trucks.

The filter amp driving off the ESS vacuum pump on the 6.2L RV series with a 4L80E is an old trick from the Clevite Kid on thedieselpage. Google Lee Swanger tach driver.

 

[Rusty Nail]

Green.

lol?

 

[CORVAIRWILD]

Interesting...

 

[HotRodPC]

Top picure is of a standard vacuumpump for 6.2 in trucks, Van,s and 6.5 had it mount in front of the engine, belt driven. next picure is of the Ess sensor.

Thanks for the input all the way from Norway. I guess you'd know since you have a 6.2 in yours. I wasn't sure how the diesel got the signal myself.

The gas HEI tach lead just counts coil fires and divides by 8.