engine and drivetrain Tach Not Working How To Diagnose

[FunkyLaneO]

yup, that is smog equipment as well, if you desmog that will go away too.  Do a search on desmog, I know there used to be quite a few posts with pictures of what needed to be removed. but yes the entire blue bundle and all the relays and timers and vacuum switches that are attached to it go away. These cars were designed for the european market and smog was added to cars being shipped to the US so it was kind of an afterthought and it all comes off pretty easily.

[paulram]

I was checking last night and that seems to be a valve for the vaccuum advance on the distributor. All posts I read seem to lead that I should keep the vaccuum advance unless I buy a mechanical distributor (from IE) which is not a cure all but opening the door to other issues that unless I know what I am doing could be more of a problem.  I've been reading the desmog threads.  Evidently the silver box full of wires is all smog related.  I cringe to remove any wires yet until I know they haven't been re purposed for something else.  

 

On a side note, The electrical inside the cabin looks super tight like it came out of the factory.  Am I missing something about the connection to the tach?  I can't see jack.  Do I need to remove the gauge cluster to see the wiring?  Seems like that might be a pain. I'm leaning to connection in the engine compartment?

 

On the bright side I removed the air pump and all of the other junk which gives me a bunch more room to work.  With sausage fingers like mine it all helps.

 

37 years of grime is hard to clean...

[FunkyLaneO]

Yeah, if you eliminate the smog stuff you run a single vacuum hose from the distributer to the base of the carb, if you keep the fuel pressure regulator (most people don't) then you would have a vacuum hose from there to the manifold as well.

 

You will need to take the cluster out to access the back of the tach, it is pretty easy, you just need to reach behind it and find the two knobs and unscrew them, then unscrew the coupler on the speedo cable then just pull the cluster out.  you may have to reach behind it and guide the bundle of wires through so it doesn't hang up.  once you have it out you can just pull the big round plug off and on the other side of the cluster there should be a single black wire plugged into a spade, that is your tach signal wire.  if it is not plugged it then find it and plug it in (it really only will fit one place) then plug the round plug back in and start the car, if the tach works then put it all back together, if not then it is time to do some trouneshooting.

 

I am ataching a picture of the cluster for clarification, the other two pictures are what I promised, on teh coil you can see the white plug, that is the tach connection, in the other you can see where it used to plug into the points (I replaced my points with a Crane system), that is the double wire that leads to teh tach, it is bundled with the windshield washer wires.

[paulram]

Thanks.  Everything is now based on my replacement powervalve.  Hopefully is comes in today.  Have a long string of things to do based on it coming in.  I'm tempted to just put the old one on so I can move forward.  I'll check the cluster in the meantime.

 

This also assumes my disassembly and reassembly were done correctly and the car runs....

 

For now I just wait and spend my time cleaning filth out of the engine bay.  I have a new found respect for a clean engine compartment.

[paulram]

never mind just got the powervalve...USPS Priority mail rules.

[dswan]

@paulram I recently bought a 1973 2002 and have the exact same issue. No tach, no defrost, no fans. Did you solve yours and do you have any advice?

[TobyB]

You most likely have 3 unrelated problems...

 

...all pretty common to 2002's.

 

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