Dead cylinder #3! Ignition or Fuel?

[240260280z]

cold battery at 12.0V is flat

cold battery at 12.8V is fully charged

Voltage from alternator-regulator to charge battery when iding and running is typically 13.5 to 14.5V range

A hot battery with the car just shut off will show the Vreg voltage then slowly decrease from this to its cold state (over hours). You can watch it drop with a volt meter.

[Jennys280Z]

Feels like 30 horsepower! The moment I touched the gas pedal after backing out of the driveway it was immediately obvious.

I tapped on the #3 injector about a few hundred times with the plastic end of a screwdriver, and even more uselessly, tapped on the fuel pressure regulator a few dozen times as well. In a really old video from "Big Phil" from HybridZ (turbo280Z on Youtube) he mentioned that a Z mechanic told him he could raise the fuel pressure in the fuel rails temporarily by tapping on the regulator. I'm sure it's a useless idea to make your car faster, but having some extra psi in the fuel rails couldn't hurt when I'm trying to unstick or upvolt an injector. The 2 & 3 wires are still swapped; I suppose I'll swap them back to their proper injectors again. I'll be left having to wonder: Was it physical or electrical or a combination of the two? I question that maybe it was a combination of the two. I brushed the female connectors like a mouth full of cavities in between several soakings with Caigs. Jenn said she cleaned the injectors but they all still looked pretty corroded to me. Looking at the spark plugs again, cylinders 2, 4 and 6 all show lean running conditions so I cleaned #4 and 6 before the test drive. #2 was already cleaned as the test cylinder, and #3 was of course dead which got cleaned first. I've got the battery unplugged for now and I might as well clean #1 and 5 too, which looked like the healthiest of my spark plugs by far.

Time for the clutch hydraulics. I might be pining for more help in that forum in the next week or so. I'll know more for sure after the clutch work is done whether the transmission has seen its better days. I'm interested in a remanufactured 5-speed from a '77 or '78 280 that has the same ratios as the one I've got now and is plug and play with my stock motor. Thanks again for the pro advice you guys. I wouldn't have been able to do it without you guys. Special thanks to Blue; your wisdom was golden.

[Jennys280Z]

For posterity, I actually did have to tighten up the idle adjuster quite a bit. I had an idle of over 1100 warmed up. I settled it down to about 850 and the screw actually feels 'tight' now.

The vacuum was already healthy on five cylinders. It must be super healthy now.

I must have been enjoying the ride too because I caught myself going 65mph in a 35 zone. Actually an oncoming car was flashing his brights at me so I must have looked like I was going really fast. And only then did I check the Speedo. That slowed me down too, since the bro-code for cops is flashing your brights, after all.

Edited August 14, 2014 by Jennys280Z

[240260280z]

I'm happy for you.

[madkaw]

So am I reading this correct and between the battery change and tapping the injector fixed the issue?

You do know that an injector is basically a small selonoid(I always question this spelling). They can stick just like they do on your starter. They can also not want to engage-just like your starter from insufficient batter voltage.It's funny how many cars I have got started with a hammer-

The voltage your alternator is putting out helps maintain your battery which is the main source for your electronics.

Like I said-you will really enjoy 6 cylinders;)

[Jennys280Z]

Well I kept the same old battery but I charged it till it hit 12.65V then installed it quickly and started the motor right away. Maybe it wasn't electrical and the injector was physically stuck. It's hard to think that a voltage issue would have affected one injector completely when some of the other connectors looked just as bad or worse. I didn't put any of the metal clips back on and I suppose this is okay? I do want to pull the connectors in about three months and inspect them...maybe when they get this old the corrosion becomes more of an issue faster and have to apply some regular TLC not to have problems.

The motor felt so strong now that the clutch feels like it's having more issues...vibration or just noise coming from below the center console. When the car was garaged and not running for nine years or so, all the brake cylinders were toast but the clutch cylinders are still hanging in there. I changed the fluid but it turned black almost immediately so there's a lot of corroded rubber probably coming from the master cylinder. The slave cylinder and hose were replaced in '89 but I think the master is the original from '76. So now that the motor's done (never done really, ready to install a new oil sending switch but I'm reluctant that it might be seized in the block) I'll move to the clutch and I'd like to change the transmission fluid too...planning on jacking up the front to drain it, jack up the back to fill it. Lower the back to drain excess fluid out, then jack up the back again to tighten the fill plug. If all this doesn't make the car happy I'll have to start saving for the transmission fund.

It was actually Blue's comments about the current producing a magnet moving a slug allowing the injector to spray gave me the tapping idea. The alternator is original...still hanging in there. Jennie thinks there's a broken bolt in the front of it, we'll need a pro to do that since we don't have any kits to extract bolts (or experience).

Happy that the engine runs so smooth now.

[EuroDat]

Have you changed the transmission fluid since it came out of storage? If its been standing for 9 years it might be a good place to start.

Clutches don't start vibrating because the engine runs better and has more power. Slipping is a different story though, you will notice that when you engage the clucth and it takes a lot longer to grab when your driving harder or in your case the engines has more power.

Poor quality oil in the transmission will create more noise and can increase vibrations.

To change the oil, get the transmission warm and drain it over night. I use a cooper 90degree water pope elbow, a hose to and funnel to fill it from the engine bay.

Redline MT-90 and Royal Purple Max gear are recommended by many Zed owners, but there are lots of other good brands out there. It should be a GL-4 or a GL-5 suitable for yellow metal (synchros).

Chas

[Jennys280Z]

Thanks Chas I'll go with one of those two brands. Just read other classiczcar threads on doing this job...looks like all my questions are answered at this point. But the diff oil prob ought to be changed too. Looks like my labor just doubled

[Zed Head]

This car was running last year right? The 9 years is previous. Isn't this somebody else on Jenny's account? Still Jenny's car though. Kind of confusing on what's going on here.

Anyway, on your noise/vibration from the console area - that's about where the propeller shaft u-joint is, along with the slip-yoke to the transmission. You might check the yoke for play when you're under there, grab it and shake, and the u-joint also. You'll need to pry that one around with a screwdriver to see if it's loose. Look for signs of rust and dryness.

And when draining the fluid, level puts the drain plug at the bottom I believe. And puts the fill plug at the right spot. No real need to tilt the front or back independently. And the fluid will expand a lot when hot or warm, so don't be surprised if a bunch comes out if you remove the fill plug first. Which is always a good idea, just to be sure that you'll be able to refill it, before you drain the fluid.

[Jennys280Z]

Zed Head, sorry about the confusion. Yep I hijacked her account. At first, I did create a new account name "1976280Z" at first to avoid confusion but never got the verification email. Nothing in spam folder. Then we couldn't remember the username/password until I got back to her place last Sunday and her password was still in the browser cache on her old desktop. She's out of state in grad school atm and gave up on the car before that because she didn't have the time or money to put into it. She was considering selling it for a time but when we couldn't agree on what "fun" car to eventually own, and then the car started to grow on me over time. I think it still has a lot of potential to be a great car but it's not even close yet imo. I used to own a 442 and worked on that myself but the Datsun has been more interesting to work on after all the stories she's had to tell about it. So it's the same car and still hers, I've hijacked the car too in the meantime. She's consulting from afar and referred me here. She mentioned you specifically too Zed Head and a few other ppl I forget and that you guys have saved her hundreds if not thousands in labor cost.

Your ID on the slip yoke is probably dead on because it does have the "clunk" when accelerating in gear from a standing start especially. J said this was an issue years before the car went into hibernation. A local Z shop specialist at the time acted like he didn't know what making the noise exactly, remarked about the U-joints but she can't remember what he said exactly. Either she couldn't afford the repair, or the guy didn't want to do it or couldn't do it, or ...

[EuroDat]

That clunk sound "smells" like diff related to me.

Along with the uni-joints you can also check things like the front diff mount, rear diff cover bolts, rear transmission mount or if could be just play (backlash) in the pinion/crownwheel. These diffs are known to be a little whinny. New oil can quieten in down, but won't do much to reduce backlash. Most of us use extra insulation in the rear to reduce the noise.

Note: a little of topic but if you are considering replacing suspension bushes in the future, consider the effects of PU (Poly Urethene) as well. Other than reducing flex they also tranfser road and drive train noise a lot more efficiently. Some people regret the move to PU because of this reason.

The rubber diff and rear transmission mounts can sage over the years, although they look good the metal in the rubber mount can tap each other causing clunk sounds and transfer vibrations to the body. My old ones had dropped about 10mm IIRC compared to the new ones I installed and the old ones didn't look half bad. I think Blue has a how to on AtlanticZ that shows the difference between old and new. http://atlanticz.ca/zclub/techtips/suspension/rearend/index.html

The two bolts on the diff cover (mustache bar) becoming loose over time is another source. Tighten them to FSM spec.

Chas

Edited August 18, 2014 by EuroDat
Link to AtlanticZ

[Jennys280Z]

Thank you Eurodat we got a new carpet with extra insulation in the hatch for noise reasons last year which doesn't help now that I'm trying to hear noise again, dont think I want to hear it through polyurethane though.

A 2nd quick test drive and a vacuum test is showing 19 inches. There's a vault of information on here about every problem. I'll get under the car when the weather cools down a bit (95-100 lately). J's really looking forward to driving the car next month.

Don't want to take the thread off-topic too badly so I will let this dead cylinder thread close with a successful result. You guys are the best thanks again

Sean