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1983 Datsun 280ZX Base 5-speed Coupe
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Hello,

I recently acquired a 1983 Datsun 280ZX, and after driving it periodically over the past few weeks, I've discovered a few issues. Some of these I have a general idea of how to fix and just need to make sure I'm not missing anything, and some of them have me stumped even after reading the entire service manual.

1. Clutch: The clutch slips pretty badly. I'm not too worried about this one, from what I've heard the clutch replacement is pretty easy. I'm looking at an OEM spec one because the performance ones are overkill and too expensive.

2. Power Steering: The power steering system is completely non-operational, which isn't a big issue right now because I'm young and strong and have no issues cranking the wheel when I'm not really moving, but it could be a problem in the future. I know for sure that there is a leak somewhere in the power steering system and I also believe that the pump is non-operational, but I don't really know how to diagnose that. I haven't really been able to find any guides on the power steering system or anywhere that sells the parts I might need so I would like some advice on that.

3. Assorted Vacuum Lines: This is one of the ones that has me the most confused. When I was poking around my engine bay trying to find where all the power steering fluid all over my garage floor was coming from, I found two vacuum lines that weren't doing what they were supposed to do. One of them has one end plugged into the intake manifold and the other end isn't plugged into anything, and when the engine is running it sucks in air through that end. I currently have an orange sensor warning light on my dash and I think that once I figure out where this hose needs to be plugged in that will go away. The other hose I found had BOTH ends not plugged into anything and has me very confused. I don't have any pictures of where I found that one but I can get some.
108916

Here is the hose that I believe is some kind of air sensor for the intake.
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Here is my whole engine bay. I've read a few threads on how to clean this up, but I couldn't really find a consensus on what could and couldn't be removed.

4. Down on power: This issue is the most severe, the one I am most concerned about, and the most confusing. Much more often than not, my car is so down on power that she cannot get above 55 mph and struggles to climb the smallest of hills. When she is at full power, the exhaust note sounds very throaty, she accelerates quickly and smoothly, and I've gotten her up to around 70 mph and the engine has full rev range. When she is down on power, I can barely hear any exhaust note, but instead, I hear a hissing noise that I believe is coming from somewhere either in front of me or below me when I'm in the driver's seat, and she refuses to rev above 2k or 2.5k RPMs. I think there is probably a very severe exhaust leak somewhere that is leading to the lack of torque, the lack of exhaust note, and the weird hissing noise I'm hearing. I haven't yet conducted a soapy water test to try to see if there is a leak, and I haven't investigated other common reasons for losing power like something wrong with the fuel system. I'm mostly wondering if anyone has experienced this before and if there's a way to fix it without buying new headers and a new exhaust system (which I'm going to do eventually anyway but I don't have the funds to do right now.) I can get some video of me driving it to show what the tach looks like and what it sounds like when I try to go up a hill or accelerate. I can also see if I can get some video of when she's up on power for comparison, but it happens very rarely.

Thank you for any replies!
Quinn
 

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vacuum boost to the power brake. I would be amazed it runs at all with that disconnected, it would be a HUGE vacuum leak.
 

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generally speaking besides hooking that power brake hose back to the booster, you should replace ALL vacuum lines, just buy some bulk vacuum lines from your local auto supply store, you will need a couple different sizes, and carefully replace on line at a time. Recheck the car performance after each replacement is done, that way if you really screw the pooch you can focus on the last thing done.
 

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It's not the brake booster. That is the big line to the right of it. I have an 81 Turbo but looks similar. Until you figure out where it goes, plug it and any other hissing lines or ports. It appears to have headers? If so make sure they are tight and have a good gasket. I looked to see if I have a good engine bay pic and can't find it. I can take a fresh one later. On the clutch, don't go super cheap. Its OK to stay with OEM but get a decent brand. I like Exedy. I just converted my automatic to a stick and went with exedy and it is very easy to push in and out and does not catch abruptly when starting out. Power steering: I need to rebuild mine as well but in order to do so the motor has to be lifted so the crossmember below it can be removed. Try doing a flush and fresh fluid until you get ambitious (or rich enough) to get it out and rebuilt. As for cleaning up the engine clutter. I plan to replace the fuel rail with an aftermarket setup and get rid of some of the clutter. But that will also include bigger injectors and a mega-squirt system. Always something...

Good luck and I will try and post a pic of where my lines go.

Keith
 

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geez sorry Keith is right, my eyes fooled me on that, it looked like it due to the close up and I followed it down to where it seemed to be the booster line.
 

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I'm just going to leave this here as it sounds like you may need it.

There's a diagram of the vacuum hoses in here somewhere... or should be IIRC.

 

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Yeah, I read that after I posted.

Did you get your issues resolved?
 

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#1 For a clutch go with Exedy, they are good for stock replacement, and they are good enough to go with many mild performance upgrades and harder driving without any problems. I sell the clutch kits for 168.00 to zcar.com users and I usually have them in stock.
#2 As far as your PS leak, it's usually the internal seals for the rack that have blown. Look closely at the accordion boots that are on the rack and see if they're wet. If they are that's usually a dead give away that the rack seal or seals are blown out. If your pump has been run while it's dry that usually ruins the pump. I do sell rebuilt racks and have cores in stock so I wouldn't need your rack until I sent you my rebuilt one. That way after you do the job then you can send me your core.
#3 That mysterious vacuum hose goes to the vacuum servo that is hooked up to the cruise control vacuum pod. That unit is right in front of the battery and on the engine side of the control pod is a pair of vacuum servos. Someone has slipped the larger hose over the smaller hose and it's not supposed to be that way, remove the larger hose and replace the smaller hose with one that is long enough. The smaller hose which I refer to as the HVAC hose is supposed to run from the intake manifold, over the top of the valve cover and then down to the vacuum pod using the smaller hose all the way. I sell that hose by the foot and it's about a buck a foot to zcar.com users. I'd recommend replacing all of it under the hood which is about 30 feet worth. As far as the other vacuum hose goes, not enough info or pics on that one. As far as your sensor light goes that means absolutely nothing. It's just a useless light. Above the passengers right knee there is are 2 wires coming out of the secondary wire harness for the radio console and they are a pair of short yellow wires with green tracers. They plug into each other and that triggers the sensor light at 30K miles. Unplug the wires and the light will go out once the engine is started. I usually snip the wires off so that someone down the road won't plug them back into each other again. Trust me, I'm not the kind of technician that usually snips off stock wires, this is one of my very few exceptions.
From the pics you posted it looks like the PCV hose heat shield is missing and the intake manifold heat shield that attaches to the underside of the intake is also missing. Whoever installed your header probably did that major mistake. Those shields are very necessary and need to be put back on if they're actually missing. When the pcv shield is removed that will cause the exhaust heat to burn right through the pcv hose creating a major vacuum leak. I've got the heat shields in stock. Check it out. Also check and see if the tube for the EGR valve is hooked up to the header. If it isn't you may as well pull the vacuum hose going to the EGR to keep it from opening. If it opens without the tube down below hooked up it will cause a major vacuum leak also.
If you need any parts new or used, I handle just about everything for the cars from 70-83 and carry a lot of items in stock. Z man of Washington
 
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