ey guys!

I have a 1977 280z which used to have the California specific emissions tech. I recently "refreshed" the engine after I got it. I completely redid the fuel tank and fuel system from the tank back going as far as to replace all the hoses for the vapor tank as well. 

I am just going to list off new things.

• rebuilt fuel injectos
• new fuel pressure regulator
• new fuel damper
• fuel lines
• fuel pump
• rebuilt fuel rail
• rebuilt head and new headgasket
• all new seals around the engine
• spark plugs
• rotor
• distributor cap
• plug wires
• oil pressure sender
• water temp sendor
• water pump/ radiator / fan clutch / thermostat etc
• cold air intake
• intake hoses at AFM
• vacuum lines
• new fuseable links
• new fuses inside the car under the passenger dash area
• several cleaned up grounds throughout the car

 

I also modified the EGR system by removing it, along with the BPT system. I just did this to simplify things. I also have a 6 to 1 header from MSA going back to a 2.5 in exhaust. This deleted the catalytic converter it had.  Other major change is I removed the AC. Might still be some things left over like the vacuum canister, but they aren't hooked up.

Anyways, I am positive the mechanical timing on the engine is solid. I also set the ignition timing as the sticker on the hood. I think it recommended 10degrees BTDC, could have been after tho. The car starts beautifully like a top. However, cold or warm it cannot rev the car. If I hold the gas pedal down it will slowly rise, but then it sounds terrible and won't go further. My assumption could be it is misfiring. In addition as the car heats up it will begin to stumble, buck, and eventually die.  Quite sad to watch. I would also like to mention it idles right around 850rpm. Even when cold.

So I went to troubleshooting. If I unplug the water temp sensor the car will die pretty much immediately, so I know that it is at least getting connection. I tried adjusting the idle speed and it pretty much has zero affect until i close it, and then it will choke out and die. I also tried to test vacuum. People recommended removing the oil cap and see if the engine runs worse. I did, and it made zero affect to how the engine ran. Which made me think a vacuum leak, although I can't find one for the life of me. Except that maybe I did not plug the EGR right.

Next came the AFM. I noticed that as the car warmed up I could watch the counter balance thing on the AFM begin to bobble (representing the vane itself inside bobbling). As the car got to operating temp the AFM bobbles more and more until I can see it making extreme movements to stay alive. Then the car dies. So I thought, lets help the little bugger out. So I had a friend slightly hold the AFM open so it would run a little richer. The engine immediately ran SOOO much smoother. I tested further and had him open it slightly more as I followed with my foot on the gas pedal. And the engine would rev up with it. I actually could get it to rev all the way to 6k rpm. Sometimes it took a while to get there, other times it would rev there super quick. Never would reach redline though, most likely because the mixture was still way off.  So to me this rules out that spark as an issue. But I just have no idea what it could be. I really don't know where to start. I never got to see the car start before I redid it, because it was so crusty and likely had a blown head gasket.

I actually drove the car about a quarter mile, by running the AFM about 3 cog teeth richer. Although I had what felt like 50hp. Can't say it was a great idea, but I needed a pick me up.

I will provide some photos and let me know if you see anything immediately wrong with how I hooked things up. This is my first z car and I am on that initial steep learning curve. 

I also am based in Phoenix, Arizona. If you or anyone you know would want to help I'd be happy to host. 

 

Edited March 29, 20213 yr by ckurtz2

Another update. Re fired it up, really struggled this time. Back to sounding like its cammed with chop chop chop. In addition, the volts on the dash read now about 2, but at the battery i get about 12.6. Dash used to be accurate before.  I am hoping that is a problem I can ignore for now.

I will start going through the distributor. I haven't gone through the internals yet so it should be good to go through.

Yip, I believe it. Car has to put you through hell before it starts to give anything in return. I still think I am going to do that potentiometer trick though. Can't hurt.

 

Edited May 19, 20213 yr by ckurtz2

Kind of like a girlfriend, no? Take you down then slowly bring you back to good. 

I won't get a haircut until she makes me.

 

1 hour ago, ckurtz2 said:

Yip, I believe it. Car has to put you through hell before it starts to give anything in return. 

 

1 hour ago, siteunseen said:

Kind of like a girlfriend, no? Take you down then slowly bring you back to good. 

I won't get a haircut until she makes me.

 

Exactly, haha. Resist the haircut by all means🙃.

Yah this car is an evil girlfriend, she keeps digging all the money out of my wallet with a smile, then coughs and sputters it right back at me. Thank God she hasn't got ahold of a credit card🤣

Like I tell everyone who asks about my car. She has an attitude problem and nothing I do pleases her, but in time she will turn round. Or cough a piston through the hood.

Does anyone know who makes good remanufactured distributors for these cars? I am going to go through the process of testing it, but I would like to have a backup plan if it fails

I can get one from partsgeek or rockauto. I am just worried those will be lousy rebuilds.

What do you think of this company? http://advanceddistributors.com/wordpress1/ 

 

20 hours ago, ckurtz2 said:

I can get one from partsgeek or rockauto. I am just worried those will be lousy rebuilds.

What do you think of this company? http://advanceddistributors.com/wordpress1/ 

 

You will almost certainly get a better product from an independent distributor specialist than you will from rockauto , of course it will cost more. You could also have a go at it yourself, those dizzys are not very complicated, pretty basic to teardown, clean and reassemble.

Edited May 20, 20213 yr by grannyknot

49 minutes ago, grannyknot said:

those dizzys are very complicated,

Am sure he meant.. NOT very complicated..   And.. take pictures before you take it apart and during it!!  you always know what it was like before..

Come on guys... let's watch this, if the single spring comes up again!!  😉 

Edited May 20, 20213 yr by dutchzcarguy

10 hours ago, dutchzcarguy said:

Am sure he meant.. NOT very complicated.. 

Thanks, slipped right by me.

Ok, took a breather for most of the day, but went back at it this afternoon. I was still iffy of my timing light being correct saying 40deg advanced cause I stepped on it yesterday😬. I borrowed another to make sure. Turns out is was right, and I backed it down back to about 18deg BTDC. Now the timing light is much more stable and not bouncing everywhere, so I don't think I need that rebuild. Though I will probably get it done anyways in the future.

The chop chop chop is gone, and it hasn't spit out the intake since. The gentleman who let me borrow his timing light also let me borrow the vac gauge, because mine was broken. The results were unsettling. It seems I have like 3Hg of vacuum when idling. A good thing to note is I hooked it up at the T fitting coming off the throttle body, I just disconnected the dizzy advance and hooked it up. Not sure if this is an ok port to use. 

Now, what could cause such low vac? Could it still be a low fuel issue due to the control unit drifting in resistance. Overtightened valves maybe? I'm not sure where to go from here. I am thinking maybe of smoke testing the engine. Which speaking of that, what is a good way to go about that on these cars. I know lots of questions.

Anyways to bring everyone more face to face with the problem I have I made another video so you can see what I am seeing. 

 

 

15 minutes ago, ckurtz2 said:

A good thing to note is I hooked it up at the T fitting coming off the throttle body, I just disconnected the dizzy advance and hooked it up. Not sure if this is an ok port to use. 

Not okay.  The ports at the throttle body are "ported".  They don't get manifold vacuum until the throttle blade is opened.

A good one is the tiny one that feeds the AC bottle, or the larger one that goes over to the charcoal canister.  Both sitting right on top of the intake manifold and enter it directly.  That's where you want to measure.  Intake manifold vacuum.

Copy. I will go figure out a way to hook up the vac to that and update you. The AC fitting was too small for it and the brake booster was too large