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77 280z Restoration


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So after driving a couple hundred miles with success I discovered my brakes aren’t up to snuff.   I have stock rear drums and Wilwood calipers and rotors on the front and a stock 7/8” master cylinder.  There was a lot of brake pedal force required to stop the car and I couldn’t lock up the brakes when I tried.  The booster was under suspicion.   I pulled the line off the intake that goes the brake booster and put a vac pump on it.   Nothing….couldn’t  get the needle to move on the pump.   I double checked for hose leaks and couldn’t find one.   To confirm my findings, I plugged up the nipple on intake line that the brake booster hose normally goes on and drove the car.   Brakes were exactly the same with the booster not attached.  I also had to adjust my engine idle screw after warm up to get the idle right which make me think the intake was seeing a vacuum leak with the booster connected.   So I pulled the booster and sent it off to Power Brake Exchange.  Should be back next week.  $120 plus $40 to powder coat it.   I considered just buying a new one but these guys warranty the booster for life and the crap you get at the local auto stores like duralast (duratrash) and cardone don’t inspire me.   Car is off the road for a week.  I knew I’d be working out kinks these coming week and slowly expanding the car’s operating sand box.  
Also seeing a intermittently low oil pressure readings.  After teases him I realize I have a Oil Pressure Sending unit from the wrong year.  Mine should have a single bullet connector and the sensor on my block has 2 spade connectors in a “T” shape.  I had to modify my wire to attach it  when I put it on.  I’m wondering if this is my problem,   I just ordered the proper one and will see how that works.  If it shows similar readings, I’ll have to dig further.  
Side bar question.  Does anyone know where you can get the replacement rubber boots that go on the brake cable right where the cable connects to the rear wheels (one per side).  Mine are dust. Thanks 

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Re the oil pressure, my thought is that the wrong sender would give a consistently bad reading.  I’d suggest more likely the sender is intermittently bad (which will be cured by the replacement) or there’s an electrical connection somewhere that’s not the best.  If the problem persists with a new sender, consider hooking up, temporarily, a direct reading pressure gauge, the kind with the little oil line.   This would be for piece of mind just to make sure you don’t have an actual oil pressure problem like the oil pressure relief valve occasionally hanging up.  

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  • 4 weeks later...

In a previous post I mentioned I was concerned with low oil pressure.  Even after buying a new sender it was still reading low.   I took advice from a few of you and installed a gauge off the block to check my readings.   First, the gauge and the adaptor recommended worked perfect.   On start up the block gauge show 50 psi (cold engine, cold oil).  At operating temp it was stable at 30 psi.  Revving it goes up linearly with RPM.   Saw as high at 65-70 psi.  
I’ve been working like a dog recently, operation baby formula has eating up plane cargo capacity so they’re not letting people drop trips.   Once crisis after another.  

I haven’t been able to work on the car for a couple weeks now.   Soon it’s going to hot and humid as hell out and without my AC up and running it’s going to make engine break in driving a little sweaty and not fun.  Texas AC (windows down) doesn’t work enough and make the interior more prone to exhaust fumes too..    

 

29CD3B9A-1805-4D0D-B757-C78EA749E8F3.jpeg

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  • 1 month later...

Okay, I’ve been out of pocket for a few weeks.  With a combination of work and getting COVID I’ve been MIA on the forum. 
Covid was a 10 day ordeal, had it last year as well.  Was worse this time but was just a really bad cold.   The worst part was my wife putting me in double quarantine in my own house. 
So, I’ve been working a bit on the Z but it’s been minimal.   I had been working on a turn signal problem that I’ve mostly resolved.  I had 3 problems I found when troubleshooting . 1. Corded contacts inside the combo switch.  2. Bad Flasher. 3.  Two front turn bulbs that had burned out filament.  So now the turn signals work normally but there are still some problems.  One is I cannot hear an clicking when I select a turn in either direction and neither bulbs in the tach work.  The bulbs are good, contacts are clean on the receptacles.   I had been told that the hazard switch and it’s circuit effects the turn signals.   So the Hazards didn’t work either.  I discovered I had a bad switch and replaced it with another one I had in my parts bin.  Now the Hazard lights only work on the passenger side of the car .  I can also hear them clicking but the arrows in the tach gauge do not illuminate So I still don’t know what’ the problem could be.  Bulbs are all replaced, including tach bulbs My next plan is to get a new hazard flasher and see if this helps.  
Does anyone have any idea how I should proceed?  
Thanks 

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LED or incandescent bulbs?

Electronic or mechanical flasher relays?

I hope someone else can help you with the circuits. I'm busy this week, so I don't have as much time to devote to reading the wiring diagrams.

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I have a mixed bag of bulbs.   Front turn signals are incandescent, backs are LED.   The hazard flasher is OEM.  Turn single was on zcardepot for $6.99.   Bulbs in tach for turn signal lights are incandescent.  

Was considering buying an EF-32RL flasher for hazards and for turn signals.   No sure is I need you can use the same one in both locations? 
 

BTW, here is a pic of the inside of my hazard switch that didn’t work a bit crusty.
 

06924FF0-2444-4786-979B-286D1B955285.jpeg

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7 hours ago, Av8ferg said:

Okay, I’ve been out of pocket for a few weeks.  With a combination of work and getting COVID I’ve been MIA on the forum. 
Covid was a 10 day ordeal, had it last year as well.  Was worse this time but was just a really bad cold.   The worst part was my wife putting me in double quarantine in my own house. 
So, I’ve been working a bit on the Z but it’s been minimal.   I had been working on a turn signal problem that I’ve mostly resolved.  I had 3 problems I found when troubleshooting . 1. Corded contacts inside the combo switch.  2. Bad Flasher. 3.  Two front turn bulbs that had burned out filament.  So now the turn signals work normally but there are still some problems.  One is I cannot hear an clicking when I select a turn in either direction and neither bulbs in the tach work.  The bulbs are good, contacts are clean on the receptacles.   I had been told that the hazard switch and it’s circuit effects the turn signals.   So the Hazards didn’t work either.  I discovered I had a bad switch and replaced it with another one I had in my parts bin.  Now the Hazard lights only work on the passenger side of the car .  I can also hear them clicking but the arrows in the tach gauge do not illuminate So I still don’t know what’ the problem could be.  Bulbs are all replaced, including tach bulbs My next plan is to get a new hazard flasher and see if this helps.  
Does anyone have any idea how I should proceed?  
Thanks 

The clicking should come from the flasher unit. With the mix of incandescent and LED, it may not be drawing enough power to click in the flasher though it can still blink when using the turn signals. (Speculation and no proof to back up my speculation)

For the bulbs in the gauge, there is a common ground wire. It also grounds the tachometer circuit. The color diagram is missing the dot that shows the junction. That's the common point for both of those bulbs.

image.png

When the hazards are on, G/L wire should be connected to the G/R wire (left turn signal bulbs) and G/B wire (right turn signal bulbs). That indicates a problem with the hazard switch. It might be letting some current flow, but not enough to light up the bulbs.

4 hours ago, Av8ferg said:

I have a mixed bag of bulbs.   Front turn signals are incandescent, backs are LED.   The hazard flasher is OEM.  Turn single was on zcardepot for $6.99.   Bulbs in tach for turn signal lights are incandescent.  

Was considering buying an EF-32RL flasher for hazards and for turn signals.   No sure is I need you can use the same one in both locations? 
 

BTW, here is a pic of the inside of my hazard switch that didn’t work a bit crusty.

This is the flasher I have for the turn signals in both my cars. I like that it's adjustable. https://www.amazon.com/gp/product/B0811GTVH2

You can use the same unit for the hazard lights. You would need to run a ground wire. The EF-32RL has the ground wire attached already, but it may be too short to run to a convenient ground.

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Thanks Steve, I’ll get in there and check on that common ground for these tach bulbs.  I did try and put my multi-meter on the neg and pos sides of the bulb sockets and got nothing,  I even tried put the neg lead on the chassis to get a solid ground.  Did this with the flashers on.  I got zero voltage.  I’ll keep poking around.  Hoping it’s a simple fix.  
That Amazon link you sent is for a three prong flasher, is that what you intended?  
Thanks again

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14 minutes ago, Av8ferg said:

Thanks Steve, I’ll get in there and check on that common ground for these tach bulbs.  I did try and put my multi-meter on the neg and pos sides of the bulb sockets and got nothing,  I even tried put the neg lead on the chassis to get a solid ground.  Did this with the flashers on.  I got zero voltage.  I’ll keep poking around.  Hoping it’s a simple fix.  
That Amazon link you sent is for a three prong flasher, is that what you intended?  
Thanks again

Yes, terminals B & L go into the stock plug, and you run a ground to the E terminal. It's not that much different in that respect to the EF-32RL. It's just that the EF-32RL has the ground wire coming out of the top.

image.png

The downside of having it pre-wired like that is that you need to have the grounding point nearby. If you're running your own ground wire to the adjustable flasher, you can route it to whatever ground point suits your fancy.

Make sure the connector for the tach wiring harness is clean on both the gauge and dash harness sides. The turn signal bulbs are wired to that connector. You might even want to take out the tach and test for voltage at that connector. Back from there it would be the C5 (white) connector.

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So I got a chance to look at the wiring diagram, and here are my thoughts.

First, the indicator lamps in the tach are simply in parallel with the corner lamps. The implication of that is... If all four corners blink with the turn signals, your non-functioning indicators in the tach have nothing to do with either of the flasher modules. It also has nothing to do with the hazard switch.

Steve's thought about the ground for those two bulbs being broken is a good one, but I'm thinking if there was a problem with that ground, the tach wouldn't work either. Depends on where it's broken (if it's broken at all).

So I have a C.O. question... What is the possibility you swapped the turn signal indicators with the tach illumination bulbs? Maybe you have the bulb sockets swapped? I remember you said that you don't care about the illumination circuit because you don't drive at night... I'm thinking maybe when you put a turn signal on, one of your illumination lamps is blinking and you just can't see it in a bright garage? Just tossing out theories.  LOL

And for the hazard issue where only the left side blinks... I'm thinking that since all four corners work fine with the turn signals, then that problem must be inside the hazard switch. I took a refresher look and they do have separate circuits coming out of that switch for left and right sides. So it's completely conceivable that one dirty or deformed pair of contacts could knock out one side of the car's hazard lights.

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I found a pic of the back of the tach installed. It looks to me like they are grounding the turn signal indicators through the tach body and not through the harness? I don't have a tach here loose to verify, but it looks like that to me. That opens up the possibility for some other ideas.

You can also see that they changed a bunch the wire colors on the little stub harness on the back of the tach. So you have to be careful about referencing wire colors since some of them changed at the tach connector:
P1100238.JPG

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Okay, good ideas here.   I think you’re correct about be hazard switch contact issue.  I will pull that apart and inspect it and clean the contacts with some Deoxit D5.  I’ll also test the continuity with the switch selected before plugging it back into the dash harness.

I don’t think I have the bulbs  in the wrong position behind the tach.  My tach illumination bulbs work fine.  They’re LED and I see them turn on when I turn on the headlights.  Sidebar, you have to swap two wires in the harness receptacle to get those LED bulbs to work in the tac.  Found that out doing some research.   BTW, I have standard bulbs in the turn signal receptacle.   Here the link to getting LEDs to work as back lights. 

https://forums.hybridz.org/topic/129101-tachometer-illumination-issue-solved/

I think you are both right.  It has to be a ground connection.   I’ll check it out when I get home.  


 

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Posted (edited)

Well,  cleaned the other hazard switch I had and replaced the flasher and no change.  Both switches and both flashers cause the exact same problem.  Only the passenger side lights work.   Highly Unlikely both switches have the same issue.  Those turn lights on the driver’s work fine when I use the turn signals, so I know the circuit and bulbs are good.  Haven’t got a chance to test the grounds on the bulbs in the tach.  


 

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Hazards fixed.   I pulled all the connectors C8 and C7 and cleaned all the terminals with Deoxit D5, there was some green residue in some of those terminals.   I put the harness back in and now the Hazards are working.  

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Glad you got the hazards working! And what you found makes perfect sense. I was thinking it had to be inside the switch itself, but that's not true. It had to be either inside the switch, or the downstream wiring until it joined with the firewall harness. Good work!

That corrosion is from your heater core leaking 20 years ago. Most 260's and 280's have some green fuzz growing in those connectors.

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Looking for some advice,  Been working on the Z this week with success.  Hazards, Radio installed, lights all working so I was pretty happy until yesterday.   I hadn’t driven the car in a couple weeks as I was working on fixing the above items and general interior work.   I decide to take to car for a short drive.  Total distance was about 3-4 miles but never far from home.   The car was driving great, the best I’ve noticed since I had got the timing perfect and the idle mixture set right,  I got a timing light with RPM and advance capability.   Did this over a month ago but haven’t really driven it any real long distance .  
So, I was driving and all of a sudden the engine began to shutter, it felt like it was cutting out I was at about 3800 rpm when I notice the power loss.   A few moment later the engine total died.   Pulled off into the grass in shame.  Tired to start it and got nothing,   Cranking just produced a fuel light cloud of vapor out the tailpipe. Sometimes it would hint of starting but nothing, would just crank.   I pushed the car to the next neighborhood (sweating my arse off) along the 2 lane road by myself with a 35 mph speed limit and left the car there.   Came back 45 mins later and tried starting the car and it started but ran really bad, very rough as it were misfiring.  Exhaust was still very rich smelling.  I went back home got a new ECU and my tools.  By the time I got there (had kids to shuttle around first) it had been sitting about 90 mins.   I put the replacement ECU in and it started right up.   Began to drive it home, 2 mins into the drive it began to slight misfire again.  Temp was not at the center position on the gauge yet.  By the time I was in my driveway it was running really bad again and at operating temp.  Barely made it into the garage..   

I know the fuel pressure is good. Gauge in engine bay is stable around 35 psi.   Car has a new coil, which I replaced 6 weeks ago and it’s run fine with that one previously. Took it at least 50 miles with that coil.  
 

So what could be the cause,?  Obviously not the ECU because the problem came right back once the engine got hot.  I checked the temp sensor on the head between cylinder 5 & 6 (yes ZX setup with P79 head), it was secure.   I know this popping of will give you a rough runner. 
 

I’m leaning toward a problem with the ignition module.  The E12 type on the side of the ZX distributor.   It sits very close to the coolant hose and was very hot to the touch yesterday.  Hasn’t been a problem in the past but it’s where my thoughts are focused.  Cold the engine fires right up.  I’ve read that there have been problems with these modules at time when they get hot.  
 

Anyone with any good ideas to begin my troubleshooting? 

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Put a can of dusting air in the car. If the car acts up, open the hood, hold the can upside down, and spray the ignition module with the liquid. That should cool it off quickly. If your car runs fine after that, you found your problem.

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I agree the ignition is the likely problem and the test proposed for the module is a good one.  Other possibility is the magnetic pickup in the distributor, but I think that’s less likely.  

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15 hours ago, SteveJ said:

Put a can of dusting air in the car. If the car acts up, open the hood, hold the can upside down, and spray the ignition module with the liquid. That should cool it off quickly. If your car runs fine after that, you found your problem.

This is the standard test for the E12 module failures, from what I've read over the years.

You can wire in a GM HEI module using the red and green trigger wires from the distributor if you find that that's the problem.  People have even mounted them on the sides of the ZX distributor.  It's the same type of module, just a different shape.

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Could also be a bad connection.. somewhere.. I would start to clean every cable connection in the car as they are over 40 years old.. use some de-oxid in your connections and some special grease to keep the connections perfect.

This is a few hours of work i think but keeps you from A LOT of trouble that bad connections can cause.

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Thanks for all the advice guys.  I will get a can of that stuff for the future.   
so I had a couple back up E12 modules so I just swapped one out.  Cleaned the connections with contact cleaner and triple checked the connections.   I also tested the temp sensors resistance to make sure it was in tolerance.   300 ohms at the sensor and 307 at the plug to the ECU when engine was hot.   Thanks S30driver for that advice.   Car is running now, let it heat up and took it for a spin.  Stayed less than 1/2 mile from gloss at all times and put my kids electric skate board in the back incase I needed to get back.   
So far so, it’s shaken my confidence so it will be awhile before I hit the real roads.   
I like the idea of the GM HEI as a back up.   Would be nice to mount that near the coil and have the wire coiled up and ready to go.  ZedHead, what’s requited for that mod where I currently sit? 
 

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Curious, are your E12 modules Nissan brand or aftermarket?  I think that that is one of the issues a person has to consider.  The E12 aftermarket does not have much competition so the product quality is sketchy.  Look at the price difference on the only two available on Rockauto and then look at the pictures.  Who knows what's going on...

https://www.rockauto.com/en/catalog/nissan,1981,280zx,2.8l+l6,1209338,ignition,ignition+control+module+(icm),7172

Anyway, you can get get lost down a rabbit hole when you start modifying things, as you've already found out.  Here is a write-up about the HEI module from EuroDat.  In short, there are five connections that you need to worry about.  Get those five correct and you can put the module wherever you want to.  I have seen people put it in place of the E12 module on the side of the distributor. 

The five points are the two trigger wires, red and green to G and W on the module, the B for battery, the C for coil negative, and the ground contact through the mounting hole.

There is another writeup in the downloads area showing how to jumper the board in the E12 module but it seems overly complex to me.  Just extend the green and red wire from inside the distributor.

You have to put your electronics nerd hat on to get in to it.  

 

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