donq88

Hello,

Background: I bought my 1984 300ZX Turbo (IMG 01-03) end of 2011 with 39K original miles on it. Kept the car in a garage since then and now I知 back in town and able to work on it. The issue I知 having is that most of the meters and gauges work fine except for the Oil, Water Temp and Volt, (IMG 04). I致e been reading about the issues wit the Power Unit (corroded contacts, cracked and loosened solder joints). I obtained the FSM and read about the test procedures and trouble shooting section. I知 a beginner on car痴 electronic but went and removed the Power Unit (IMG 5) to see for any obvious defects but couldn稚 identify any.

I tried to perform the voltage and continuity tests as explained in the FSM but I obtained no reads on the multimeter. Because I tried different contacts, not only #23 describe on the FSM as the one related to the Oil, Water Temp and Volt, and since most of the meters and gauges are working, I believe that the multimeter痴 test leads used were not making contact (not sure what I was doing wrong). The multimter is brand new and I tested the same before using it so I知 positive the multimiter is ok. I tried the alligators test clips but nothing as well. It is a bit tricky as the cables in the harness plug are quite tight to each other and getting the test leads in is not easy as illustrated by the FSM. I also performed to several contacts, in specific #23, a continuity test and I got a beep (not sure if this test makes sense but I thought that if a connector is broken, corroded etc. it may not allow current to travel from one end to the other end).

I知 guessing is difficult to provide advise using images but I took a few shots to see if someone can provide some comments on those. IMGs #6 to #8 shows the contacts from the bottom view of the motherboard of the power unit (assuming upper part is where the harnesses attached to the power unit). On IMG #9, I identified #23 that seems to be in the same shape as the other ones. Do the contacts and solder joints look ok? Any thoughts on what could be causing the issue I知 facing? Is there a fuse(s) in the digital dash that I should verify?

In advance greatly appreciated for your time and feedback.

Cheers

Gerbil

I'm just posting to say, that car is AWESOME! So clean...

Unfortunately, I only have the analog dash, so I don't know the specifics on that system. That car looks so well kept, that it probably is something with that unit causing the problem.

In my experience with electronics, capacitors are a common thing to go in old electronics. You should be able to remove the board from the unit and check for bulging capacitors.

**dude, I am in awe of how nice that car is! Nice find.

Donn144

My AE when I got it 12 years ago had the same problem. I have driven very few miles in the intervening years but the dash has now gone dead! I tried 2-3 new Power supplies hoping that would fix it but it did not. I hate to thnk I am going to have rip the damn car apart, but so it seems to get at the dash.

beautiful car!

rogerz

dash removal isn't that hard. look at az bum site he has instructions for dummies there. hard to tell from the pics but the screws are sure corroded. buy a pencil solder iron and just touch each wire until the solder melts. get some electronic duty flux to help. both sides of board. don't use a gun too much heat you fry the board. always touch your leads together with the range on the 1 ohm scale to be sure they are good. I have had to redo leads a couple times that were faulty. if you are depending on the beep forget it. get a reading. when checking continuity always be on the lowest ohms scale. put the meter on highest ohm setting and grab a lead with each hand you will get a reading. is it analog or digital. if you have no experience with these devices the digital ones can lead a tyro astray. i use a Harbor Freight cheapo analog when checking for 12 volts and continuity. you can see the needle move and you know something is there. I have a fluke that I use for more precise measurements like checking a maf. Also MSEE and worked in the industry so know some about that which I speak. download the fsm. take the schematics to Kinkos on a thumb drive and blow them up to 11x17. much more readable plus you can tape them together to see the entire schematic and trace wires check connectors for looseness and corrosion. don't discount the possibility that the sensors are faulty. you can ground them out and see if you get a reading unless they are completely dark. use the leads with the pointy end not the alligator clip type.

donq88

Thank you all for your comments. I'll try my best to fix it and will let you know how all ended.

PredatorZ

Have you looked at EL-47 to EL-51 in your fsm ? Looks like you have either a bad display section, or the power unit is bad. I am also assuming you have done the display check test procedure using the trip meter A reset and ignition ?

reddzx

XenonZcar.com Z31 Digital Dash Repairs

Donn144

Question for RogerZ: When you refer to checking continuity, what are you referring to?
Are we checking after the dash has been pulled? Are we checking the PS?
I replaced my PS with 2 different units and that did not help.

Please just clarify if I am checking the dask itself and if I can test prior to pulling it.

thx

rogerz

continuity means when you put your vom on it you should get zero ohms or close to it from a wire that goes from point a to point b. don't need voltage the battery in the vom provides that. if you managed to buy one of those fancy digital meters without really knowing how to use a vom you just bought yourself a headache for the newbie.

Donn144

RogerZ: I got that ..not a newbie to using meters and no offense taken
Just what is it that will be \should be showing continuity? One side of the board to the other or the connectors on the board to the soldering points?

rogerz

your second choice. that board was made before multilayer boards were made. but it is a double sided board.

Donn144

RogerZ: I'll ask you for your opinion and of course not hold your feet to the fire:

These are the symptoms with my dash: For a long time I would periodically get a wink out..with a bang or tap in the right place I could get the dash back. Finally, it just gave up and went batty on me. This means I get funky readings on the tach lines and the speedometer flashes all over the place. In other words; NOT all lights are out.

Having said this: When I got the car many years ago, the batter, oil and temp gauges never worked. They were total lights out!

As I have written, I tried 2 separate PS's and they did not do the trick..

Does it sound like bad connections on the dash or is the dash fried?

Looking forward to your opinion

Donn144

I got the dash out of the car not easy!..NOW, how the hell do I get the dash out of the console to work on it?

Please advise!

Donn144

OK I got it out and somewhat taken apart...a lot of times with PC's just taking boards apart and re-seating them helped clear problems. But, to test this dash I am going to have to bring the whole damn thing back to the car and test it just to see if it works.
Is there a way just to plug the dash in w\o the entire front piece?

Donn144

I reseated the boards and tried the dash out. i plugged in all the connections..single handed..not easy! But I got nothing from the dash..which is worse than before when I at least got squiggles. So, I am ordering a dash from Ebay and hope I have better luck. Guy says it worked.

There are not real short cuts with pulling a dash..since the cluster fits in from the back, one must pull the entire console out. Would have been nice if it came out from the front.