Hey all, wanted to start a thread to track the restoration of a 1978 280Z I got in April. This is my first personal restoration/project car I've undertaken so much of this is learning as I go and just fumbling through it. Photos of the car/progress will be kept up-to-date within a Google Photos Album (will likely cull stuff periodically to save space). Current focus is getting it mechanically sound enough that I can just take it out and drive it. At that point I'll start on the rust repairs.

April 4th

According to the previous owner (Brian) and verified by documentation provided to me during purchase the car was originally an Arizona car. I'm unaware if that was the first owner but may track that down at some point. Story given to me was that the Brian had bought the car during High school in 2014 as a project but largely sat unused.

At time of purchase the odometer read 44,286 miles. According to Brian this is the original miles and it had not rolled over. Previous title odometer reading indicated 40,000mi. As such I'm skeptical as to whether or not that's true. That being said one of the first things I did after getting the car home was to run a compression test on all 6 cylinders. Given they all tested in at 170-175 does give some minor credence to the possibility.

Furthermore the car ran at time of purchase, albeit not well. I was additionally informed that the brakes were also largely non-functional.

When running the car appears to be giving off a blueish smoke, indicative of it burning oil; upon revving producing black smoke, indicative of running rich. See video of exhaust

Today

To spare all of you a wall of text I'll condense what I've done thus far since the above. Many of the injector connectors were replaced with push-to-release connectors but not all, additionally the previous work involved a really shoddy soldering job. I've since replaced all injector connectors, as well as the AAR. I also chose to solder but this was done using a lasso method. Even if the others weren't problematic, knowing how bad they were I wouldn't be able to let it go. Only connector not yet replaced is the Cold Start Injector. Approximately 80% of the vacuum lines have been replaced in addition to all fuel hoes from the feed to the return hard lines with the exception of the injector hoses. I've lashed valves to ensure they're within spec according to the FSM, ensured all grounds (7 of them) in the engine bay are nice and clean, and replaced all 6 spark plugs.

Once the above was done I took a vacuum reading while the motor was running and seem to be getting a fluctuating reading between 11-15 in Hg. From my research it should be closer to 18-20 in Hg I believe so this indicative of something still being off. Additionally checked plugs, all are fouled (unsurprising due to rich/oil conditions). Recently got a borescope so I've also scoped all cylinders. #5 is the one I've suspected the most thus far based on the plugs. Upon scoping there's a small puddle of oil within the dish of the piston. #6 also appears to have some level of oil on the piston, but not near as much. Otherwise all the cylinders per my eyes look to be in healthy shape. See scope results, and video of vacuum reading here.

At this point I'm a little unsure where to focus my energy. Compression test was good but that doesn't paint a complete picture. Considering attempting to do a leak down test and potentially replace valve stem seals. Although that won't do much for helping to fix the richness issue which I believe to be the bigger priority. Will try to periodically update this.

Edited yesterday at 06:22 AM1 day by shadow1872
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Welcome to the forum!

The interior is where I check to see if the speedo has turned over. Seat, carpet, and especially pedal cover wear are good indicators.

Here's a similar thread with good advice in it, linked below.

Download the EFI Book from 1980 and run the electrical tests. Get actual resistance measurements at the ECU. Write them down and let us know what they are. Don't do the continuity tests and don't report any measurements as "good". If you want to save time.

Check the vacuum hose to the fuel pressure regulator for fuel. It should be dry.

Welcome to the 280Z EFI problem club. Good luck.

https://www.classiczcars.com/files/category/4-manuals/

6 hours ago, Zed Head said:

Here's a similar thread with good advice in it, linked below.

Download the EFI Book from 1980 and run the electrical tests. Get actual resistance measurements at the ECU. Write them down and let us know what they are. Don't do the continuity tests and don't report any measurements as "good". If you want to save time.

Check the vacuum hose to the fuel pressure regulator for fuel. It should be dry.

Welcome to the 280Z EFI problem club. Good luck.

https://www.classiczcars.com/files/category/4-manuals/

Thanks for the link. I started to go through some of the ECU tests (Test #1) although was attempting to do continuity as a first pass. Of which only 3 passed continuity to ground but they also failed when throttle was open which was unexpected. It does appear that I'm missing pins 11, 19, and 26 though.

Will review the manuals provided above as they may be different then the ones I've pulled from alanticzcar. Either way I'm trying to keep a really detailed list of diagnostics/procedures I run through w/ step by step instructions to give back to the community. Time will tell if I manage to do it sufficiently.

Might be a bit before I can get out to the garage and work through it. Got a friend's wedding this weekend.

6 hours ago, Zed Head said:

Check the vacuum hose to the fuel pressure regulator for fuel. It should be dry.

I have done this and I've additionally tested the regulator and confirmed it holds vacuum as expected so it should be fine. Lastly I have installed a fuel pressure gauge in-line after the filter and it sits roughly around 36 PSI which I believe to proper.

It should be 36psi with the car not running! It should drop at idle based on manifold vacuum

15 hours ago, Zed Head said:

Here's a similar thread with good advice in it, linked below.

Thanks for the mention! I just updated the thread as I’m diving head first into the AFM rabbit hole.

Some tips I picked up on my journey:

-            Clean all the electrical connectors to the sensors (also the bullet connectors in the harness).

-            Measure the resistance to the AFM air temperature sensor and the coolant temperature sensor to make sure there within spec (coolant sensor is one of the most important sensors in the EFI system!).

-            Buy or borrow a timing gun and make sure the timing is set correctly.

-            Verify you are getting enough spark (right type and gap spark plugs, distributer contacts in good condition, ignition coil resistance within spec (0,8 to 1 Ohm)).

-            Install a wideband O2 sensor with gauge (cheap Chinese one is good enough for now) or if you don’t have a bung in you exhaust buy an exhaust sniffer so you can measure you AFR (Air Fuel Ratio). Idle should be around 14,7 and wide open throttle 12,5 I believe.

-            Try and see (while monitoring the AFR) if only you idle or the entire rpm range is out of spec. If it’s only idle maybe try and play with the idle air screw on the AFM to get the idle AFR back into spec.

And If nothing work only then take the AFM off the car and start testing the resistance values. The number 7 pin is hard to measure the resistance so you must hook it up to a battery (9 or 12V) to test the output voltage on the number 7 pin. If you determine that that is your issue then welcome to my world! As you are based in the US maybe an AFM rebuilt offered by jdm-car-parts or Z-store is an option for you. Unfortunately I am not so it would cost an fortune to do so for me in postage and import tariffs.