G30 Tach install questions

Hello all!!! This is my first post here on the forum and its great to be here. First of all my vehicle doesn’t fit into any category here so if someone will post me in the right direction I would be grateful.

I have a 1995 Chevy G30 1-ton air force radio van (For grins ill post a pic of the military nomenclature). It has a 6.5 diesel Y vin, no emissions no computer and no turbo so it is closer to a 6.2 than a 6.5, transmission is a 4l80e. The engine does has an engine speed sensor/ oil pump drive which sends a signal to a transmission controller (computer).

So, I have read that diesels take a tach signal from the alternator. I am wondering if I should attempt to read the tach from the ESS or the alternator? Will an old off the wall tach work? Its driving me crazy driving 70mph and not knowing the RPM, Thanks in advance!

No, you cannot use a standard "off the shelf" gas engine tach. You have a few options. One, you can use a Dakota Digital tach interface (either using alt or a fiywheel sensor, both listed here http://www.dakotadigital.com/index.cfm/page/ptype=results/category_id=694/mode=cat/cat694.htm ).

Second would be getting a diesel specific aftermarket tach. VDO, Speedhut, Autometer, ISSPRO and others. These are designed to specifically hook to the alt directly without any interface unit. I custom ordered a full set of Speedhut gauges with their diesel tach. Waiting for these to come in.

Third, use a Tiny Tach that has a sender that clamps onto one of the fuel rail lines. It detects the injector pulse in the line. I used one of these on my first M1010 and it works great and is fairly cheap when looking at all of the other options. https://www.tinytach.com/diesel-tinytach

There could be other ways but those are what I know of.

Chevymike thanks a ton!! lots to look at there! I have been eyeing the autometer diesel tach....my concern however is calibrating it which would require getting one of those laser tachs which are cool but im concerned about their accuracy when setting the tach up.

Tinytach is a very interesting! I have never heard of taking the injector pulses for a tach thats a pretty **** good idea and is like you say a cheaper alternative! By the way I love your avatar photo, is that a rear AC up there? Thanks again for your input!

Yeah, the Tiny Tach is a great unit. Worked really well and if I wasn't doing a full gauge upgrade, I would have bought another one.

Yes that is an A/C unit for the rear box. Doesn't work and I'll be removing it anyways. Don't need it for my camper build that I am doing.

chevymike said:

Yeah, the Tiny Tach is a great unit. Worked really well and if I wasn't doing a full gauge upgrade, I would have bought another one.

Yes that is an A/C unit for the rear box. Doesn't work and I'll be removing it anyways. Don't need it for my camper build that I am doing.

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I am in the process of converting mine into a covert camper also. Mine had a rear AC that didnt work, first thing I did was pull it and got an 8k btu portable AC, even runs on the generator. I will probably be buying one of those tinytachs in the very near future. With the 4.10 rear end I am just afraid its maxing out the engine at 70-75. One thing is certain, best milage at 65mph! Does yours have a funky rear heater?

rkub13 said:

I am in the process of converting mine into a covert camper also. Mine had a rear AC that didnt work, first thing I did was pull it and got an 8k btu portable AC, even runs on the generator. I will probably be buying one of those tinytachs in the very near future. With the 4.10 rear end I am just afraid its maxing out the engine at 70-75. One thing is certain, best milage at 65mph! Does yours have a funky rear heater?

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Cool. Yep, has the heater in the back but that is coming out too. Will likely use a Propex Heat Source unit. Thought about a diesel powered camp heater but they are a little finicky and require more maintenance than a propane unit. Still planning out everything.

I would like to see a few pictures of the cutaway van. I work at an up fitter and in 1995 we up fitted several hundred blue Air Force and white Navy Chevrolet G30 Chevrolet cutaways. They were expediter trucks for use on the flight line. They had a heater in the rear and if I remember correctly they had doors on back and both sides of the rear body with seats. Pictures would be cool. I bought one in 2005 at a local scrap auction with 1,300 miles on it. It was crushed on the top side and the engine ran perfect. Sold it to a local salvage yard. They needed an engine and paid more for the engine than I paid for the truck. Easy answer. Sold them the entire unit.