Cruise Control RPM pickup on LD28 maxi's for tach?

#31

Can this go a step further and a stand alone system be made via a proto board? I need a tach, but don't have the maxima controller to do the mod nor the brain power to develop one on my own.

#32

Well . . . there is an EGR Rev Sensor already on the engine, if it came from a Maxima, but its output is very low (I think). Amplification will be necessary, possibly some signal conditioning as well, beyond what the existing mod does. Maybe Chris has some input on this.

You might want to look at the Diesel Tachometer thread where I show how to make a mod to the alternator to provide a stator tap that many diesel-specific tachs (that can be had fairly cheap on eBay) can use. Works for my $50 Beede diesel tach (new, eBay).

Also discussed is the Tiny-Tach, same thread. Uses a piezo pickup on an injector line. Is cheap but limited.

And there's a link to an article to build an optical-pickup tach in this thread.

#33

Tiny-Tach is most cost effective to date. I was examining the possibility of using an engine knock-sensor for a diesel tachometer. A wide-band GM knock sensor ($30.00) would work.
A special bracket is needed to attach the sensor to an injection line. A knock-sensor amplifier needs to be build to convert the sensor signal to a pulse-train that can trigger the tach. A special 1-cylinder engine-tach is needed. These are not common but Equus makes them.
http://www.iequus.com/
It's price is around $70.00 The amplifier would be the least expensive, maybe $10.00 Machining the bracket would be another $30-40 if not more. Adding all the cost of the hardware and labor, it would add up to more than $150.00

#34

I just had hopes of using the factory tach that was in the 280z.

#35

How about picking up a Maxima EGR controller, adding the dieseldorf board, and using that to drive the stock 280Z tach?

See the '81-82 EGR wiring diagram in this post. You will only need four wires to the EGR Controller: 12v+ switched, Ground, and the two wires to the EGR Rev Sensor up behind the front of the IP.

The output of the dieseldorf board should drive the OEM 280Z tach OK.

Chopping up the full EGR control system, you'd be left with something like this (click on image for larger):

#36

There was a misunderstanding. I thought that cab does not have the LD28 engine with the speed-sensor. Of course the simplest solution is to use the EGR module with the buffer amp. It will drive any engine-tach that can be switched to 6 cylinder 4-stroke engine, e.g. 280Z engine. Down the road, if there is enough demand, I could build a stand alone module that would connect to the speed-sensor directly. EGR module would be not needed.

#37

The engine he shows in this post shows an EGR valve, so I think it's from a Maxima and should have the EGR Rev Sensor, unless someone took it off, or more likely cut the wires too short to graft to.

#38

The Maxima motor was allready pulled when I bought the engine. It does have the sensor intact. I would really be interested in a stand alone module but I guess I'll be looking for a controller until a module can be developed.

#39

I'd be quick to buy a stand-alone module, or a simplified module, for my Z tach - which I miss so dearly.

#40

I hooked up the tach output from the mod'd EGR controller to my spare tach from a 90 300zx but it didn't work...

I know the tach output works and pretty sure that I had good +12v and ground connections. Do I need an universal tach to work with the mod'd EGR? What brand/model tachometer are preferable?

#41

I've been using a couple of different aftermarket tachs for testing. One (my better one) is a Beede. But since you're installing in a 24xZ, you'll want to use a tach that looks good in your dash.

Paul, if you send to me both the EGR Controller and your tach, I'll spend some time checking it out (free, of course). AFAIK, there should not be any reason why the OEM gasser tach shouldn't work with the modded EGR Controller.

#42

asavage wrote:AFAIK, there should not be any reason why the OEM gasser tach shouldn't work with the modded EGR Controller.

Unless the EGR Rev Sensor is bad, like mine is in the '82 Wagon. Should be ~1300 ohms between the blue & green bullet connectors.

#43

dieseldorf wrote:There was a misunderstanding. I thought that cab does not have the LD28 engine with the speed-sensor. Of course the simplest solution is to use the EGR module with the buffer amp. It will drive any engine-tach that can be switched to 6 cylinder 4-stroke engine, e.g. 280Z engine. Down the road, if there is enough demand, I could build a stand alone module that would connect to the speed-sensor directly. EGR module would be not needed.

Hi Dieseldorf,

I too run an LD28 without an EGR controller and would be interested in a 'stand-alone' module. Has there been any further interest to inspire the design and construction of any?

EDIT: Just been out and checked ohms of the sensor; 1372 ohms so that is good to go... right?

Cheers,

Phil

#44

Most users converted their EGR controllers to drive a tach, I think.
There is no demand (yet) to justify developing a PCB for it. Sorry.

#45

dieseldorf wrote:Most users converted their EGR controllers to drive a tach, I think.
There is no demand (yet) to justify developing a PCB for it. Sorry.

Thanks for the reply Dieseldorf. I'll reconsider the many options again.

Cheers,

Phil

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Cruise Control RPM pickup on LD28 maxi's for tach?

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