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So I broke down... again. This time I was able to fix it on the roadside with highway traffic flying by a few feet from my head. Electrical issues are still rampant I guess, as with other tweaks that need getting done. The exhaust almost popped off the headers again, so I stopped at the next Advance Auto store on the way to my gf's house and installed some better clamps (on BOTH pipes this time). That charcoal canister vacuum line is still only hanging on by some duct tape, which won't stay on forever. I'm wondering though if its the cause of my issues. The symptoms when its broken down are that the gas pedal just stops responding altogether, then the RPMs slowly drop to zero. The slow drop is because its been in gear both times, my memory is fuzzy, but I think once I hit the clutch pedal or put it in neutral the engine stopped spinning. I still have electrical power though, the engine just cranks and won't turn over. My guess is that fuel just cuts off, not spark, but there is no sputtering beforehand, its sudden. And its all very random too. The car performs like a champ otherwise.

So I'm going to be messing with relays again soon, its probably a bad ground (again) somewhere. I really need to put in some dynamat too, because its godaweful loud in the cabin (even if it does sound awesome) and the radio is impossible to hear. The seafoam's time is almost up in my oil too, so I'll be completing the treatment within the next hundred miles and dropping the oil pan/changing the oil/adjusting valve clearances. And I still need to buff out the paint! Ugh!!

This nice weather has gotten me a bit frisky too... I keep looking at the L28ET sitting there and thinking about how soon I should start the rebuild. Need MOAR power!!

Yeah sounds like a bad ground or bad connection. Could be a bad pump though, does it do it when it's warm or been driving a while, or will it do it when cold or run a few minutes only? Fuel pumps will cut out after certain amount of time running, or when it get hot outside (high ambient temps), or when worked hard for prolonged periods. The original pump in my GLHS would work fine while driving around normally, but put 5-10 mins on it in a mountain run, and it would crap out. Put in a Walbro 255, never had any more problem with it.

So far its only been when the engine is warm. True, it could be the fuel pump, but my seatbelt warning buzzer also seems to cut out at the same time. Now, this would seem unrelated, until you see where the seatbelt warning timer relay is; bolted to the same bracket as the ignition relay. What I found when I took apart the stock ignition relay to troubleshoot is that it grounds itself through its metal casing, which is also directly in contact with the bracket, which is bolted to the chassis. So, if that's the case there must be some corrosion on the bracket or in between the relays causing a bad ground. I'm guessing that vibes while driving may be inducing a bad connection once in a while. But I need to get a new fuel pump ANYWAY when I swap in the turbo motor so I guess I'll find out in the long run!

Im sorry to hear about the issues, I just hope its something as simple as a bad ground. With electrical issues, you never know just what it is. It may take some time, but follow the entire circuit around with a test light and see what you come up with!

Good luck!

Been there, done that, over 9000 times. The Z has her share of gremlins.

That is why I've replaced half the car all together

Under the knife again, but not because she's broke. Thankfully its my choosing.


I put enough miles on the seafoam treated oil so now its time to change it. While I'm at it, I'm removing the sump to de-rust and paint, replace the gasket, install a new valve cover gasket, and adjust the valve clearances (if needed).


As you can see in the background of the second pic the VHT didn't hold up too well on my headers. I'm thinking I just didn't prep the surface correctly, I don't think I'm running hot and lean.

The white pasty filth on the sump isn't because I had way too much fun removing it, that's just engine degreaser. Now here's your chance; I'm having a hard time deciding what color ceramic paint I'm going to use on the sump, so I'm holding a little social experiment so anyone with interest can "vote". Choices are either blue, orange, or I could put WAY too much effort into painting something no one will ever see and make it orange/black to match my valve cover. Straight black is just too boring.

Unfortunately I also found some presents in the sump when I cleaned it out;

Now, if this were a helicopter, you better believe that the engine would be written off as compromised, but I'm hoping the standards for a 30 year old car are somewhat less strict. Not shown are a couple sort, hair sized slivers of metal. The largest piece you see there is interesting. Its about the size of a dime and is stamped "3M". I don't think there's any sort of space age duct tape wedged in there, but I'm completely dumbfounded as to what 3M product could have possibly been in my engine.
Everything seemed to be pretty non-magnetic, but metallic. I'll be checking for play while I'm down there, but hopefully I don't need new bearings. I'd like to put as little money as possible into this engine from now on, as I'm focusing on the turbo motor.

the smaller pieces wouldn't concern me much, because those are just excess casting imperfections. But the big piece would . Is that big piece just part of the pan gasket?

Well you know now that no one has ever touched the engine internals

This post has been edited by AK-Z on May 4 2009, 10:34 PM

I had a friend who's S30 would shut down at random times when it was warm. His issue was the ECU harness, happened to be a little loose. Some dielectric grease and re-attaching it seemed to work. BUT it is old school bosch fuel injection, so that could be an issue right there.

I'd say check electrical connections everywhere. 30 years doesnt do good things to wiring.

that big piece says 3M on it, so it might be part of a cutting disc, or a peice of circular sand paper

This post has been edited by TexasDemonZ on May 4 2009, 11:10 PM

Agreed on the connections bit. Have you had a go at the EFI Bible yet? It's the most detailed piece of material there is when it comes to diagnosing issues with the EFI system in the L-series motors. Definitely give it a look if you haven't already.

http://www.sendspace.com/file/ntmwzd

Lol, DEFINITELY! I think if you added up the amount of time I've spent on that and a printed out '78 FSM you'd have time measured in days, not hours. The combination of those two manuals are probably what finally got me to track down my original problem to the ignition relay (the car wouldn't start for the longest time at the project's beginning). The only other relay on that bracket that hasn't acted up at one point or another is the wiper relay. The horn miraculously started working the other day (its been broken since 5 years ago), although it sounds terrible. I didn't touch any part of its circuit, just the ign relay which is on the same bracket. The defroster is also broken and the seatbelt warning sound cuts in and out. Relays for all these systems are on the same bracket.




[ Post merged on May 5 2009, 08:43 AM ]

I've never doubted that, lol. I think I'm the only person who's ever shown this car any love.


[ Post merged on May 5 2009, 08:46 AM ]

Its possible, however it would certainly make for a very small disc (which I think I have seen in stores before). The side with the 3M label is smooth, but the other side has a cross hatch pattern imprinted on it, leaving me to believe that it used to be stuck to some sort of fabric at one point.


[ Post merged on May 5 2009, 08:49 AM ]

I should try plugging in the original computer again. I bought a spare one off ebay for $20 which is running the car right now, but now I'm curious as to see if my old computer was really kaput. I replaced it and the ignition relay and the distributor at the same time, so I really caused a little mystery for myself.


[ Post merged on May 5 2009, 12:53 PM ]
"Polls" for the oil sump color close tonight at 11pm EST when the rust treatment is complete, in case anyone cares.

This post has been edited by Oddmanout84 on May 5 2009, 12:54 PM

don't care on color lol .

fuel pump should be easy to mess with, 280z had an external pump in front of the diff, if you haven't looked too much down there

if the ECU is just getting a bad sensor reading (due to bad sensor(s), or bad connections), then it would just run the engine in limp mode (running rich )

Did you check for spark, could bad plugs, worn cap, or failing coil.

Just trying to narrow it down for ya, when you get it back together

This post has been edited by AK-Z on May 6 2009, 12:54 AM

As AK-Z said, check the entire ignition system. The coil, distributor and car and wires could be worn/bad.

I would also check the ECU ground(s) for corrosion.

That gaint '3M' piece isnt pretty either, I vote black >.<

Or pink...

Too late! I arbitrarily decided last night that my differential was getting lonely being the only orange part under the car and thus so is the oil sump!

LOL, your differential case is orange? Tangy.

Its a pumpkin, get it?


[ Post merged on May 7 2009, 05:01 PM ]

You're right. Looks like I found the problem. I unplugged my ECU so I could use a push button to position the engine for valve clearances. After all was said and done the Z would not start again. GRRR! Looking at the harness end that plugs into the ECU, a few pin holes have bent connectors. Holding the harness at an angle made the car start again. Tilted it slightly and the car sputtered and died. Don't know how the f*ck I'm going to fix those little pins in there, dielectric grease will just screw it up by limiting conductivity even more.


[ Post merged on May 7 2009, 05:38 PM ]
Fixed. Turned out I had a pick just small enough to bend the few wayward tabs back into place. Then I took the Z for a spin. A little hesitation in the lower RPMs is gone, and strangely all my valve clearances seemed to be within limits...

holy block casting bat man



that block looks stout, i need to get my hand on a L28 to play around with which block has the thickest and strongest cast? the n42?

bwahahahaha, score another one for the Z Demon.

Good to hear you managed to get her moving again.

would of been easy enough to just use needle nose pliers for the pins

Both are more than strong enough stock, but if you want to over bore you might as well get the N42.


And on a semi related Z note: it's amazing what a set of fresh plugs can do for your engine. I'll post some pics tomorrow of the bad ones (in a diff thread)...

Never ventured much into the Automotive thread as my knowledge is so lacking in comparison to you all here.

But oddmanout84, i just want to say that this Z is an inspiration to all young Z lovers (like me) out there

And i must say i thought i would never like a Z in orange but you have proven me wrong =)

She is indeed a pretty car.

It's amazing how nice and how aggressive you can make an S30 look without having to do a whole lot to it.



I greatly miss having the 'ol DemonZ all together, she was pretty too

Dude, don't worry about that, only way to learn is to ask right? While we have our occasional..errm...heated debates no one here is opposed to helping someone learn more about cars.

lol, no doubt there

like the debate of stuffing a ls1 in a 280z lol =)