chaseincats

My car and my friends' 78 work like that and our oil pump switches are plugged in 🤷‍♂️

It depends if you have the 5 or 7 pin AFR connector. The later 280z AFRs had the fuel pump hardware removed from the AFR's jurisdiction which is how the pump can be primed in the "on" position. The problem isn't (for the moment) that the pressure isn't holding in the rail overnight, it's that I'm not getting 36psi to the rail until a fair bit of cranking. Good point with the hoses.

Hi guys, So I'm having a strange issue here. I recently changed my fuel injectors and fuel filter (for the first time in 4 years) and the car started up on the first crank but gradually started taking longer and longer to start with each drive. When I unhooked my old fuel filter to change it, the gas coming out of the bottom was black for some reason (the gas coming out of the filter was clear though, so the filter was working). I went to my local parts store and rented a fuel pressure gauge then spliced it in between the fuel filter & fuel rail. When I primed the pump by turning the key to "on", the gauge read 10psi. I cleared the gauge and primed the pump with the key again, this time it read 5psi. I cranked the car, and after a bit, the gauge hit 36 psi and the car started immediately. I checked the pressure a couple years ago when I had a different issue and I remember the gauge reading 36 immediately with the key set to "on." Note: the later 280s prime the pump with the key in the "on" position, not just when the car is cranking like the earlier cars. I would have thought it was the fuel pump, but the car doesn't stumble when revved high or on inclines and once it gets to 36PSI, it stays there. The tank looks clean when I look in the inspection hole (the sending unit is accessible via the hatch on a '78). Could the seals in the pump be coming apart (do pumps have these)? The black gas that came out of the bottom of the filter was liquid and didn't have any goop or chunks in it indicating a clogged rail. The only strange thing that comes to mind is the pump used to hum for a good 5-10 seconds when I put the key in "on" but it no longer does that - it clicks on then off immediately when putting the key in "on." Not sure if that helps diagnose this but it's something I noticed. Any ideas? -chase

Just keep us in the loop when you eventually get to it since I don't think many people have seen how this is hooked up or even knew this feature existed (I sure didn't). Will you need to make a harness for it, or is it already in the loom just disconnected in the non-JDM models?

please document this 🙂

Oh wow, I'd love to see how/if this works.

Wow, you certainly did. I've never heard of parking lights until now I guess - thanks!

Does anybody know what went on the center console that this panel covers up? My car came with the original panel cover and was always curious. This is the panel: https://zcardepot.com/products/console-switch-delete-plate-cover-plug-240z-260z-280z

And here is the end of the post-credits scene for this feature-length thread: after 3 separate mismatched injector shipments from rockauto, I finally got 6 matching ones and sent the rest back. Took the car out today for the first time and interestingly enough, with the new reman injectors, I needed to richen the car a bit to get it to our numbers. I expected the old injectors to have had a diminished fuel output due to age but who knows.

Update: The issue was old/tired/maybe dirty injectors. Bought new injectors/fuel filter and it starts on the first crank when stone cold.

Hi, I tested my EGR by connecting the BPT valve and later the EGR valve directly to intake vacuum (my thermal vacuum valve isn't working) and the engine almost immediately died and the EGR valve made this strange whistling noise. Any idea why this happens? The engine was at operating temp in the video: https://www.youtube.com/watch?v=hTZni7rL87k

Good point about them matching regardless of flow rate. I just took a look at the bottoms to compare what was on there (left) and the Bosch ones I bought (right) and they look way different. Are the ones that were on there for the turbo or just some weird reproduction maybe?

I was sent 5 tan and 1 green injector from Rock Auto. Besides being annoying, since it seems that the tan is the earlier year's 280 color and the green being later they should all be the same spec right and would be ok to mix/match (http://www.atlanticz.ca/zclub/techtips/injectors/index.html)? The injector hole on the bottom of both are the same size so that should indicate the same flow rate, right?

Well this is interesting, I bought replacement injectors since I'm sure they've never been changed and Rock Auto sent me brown-top 280zx turbo injectors. Since those flow more I'm guessing I'll need to retune the car right?

So I noticed today, one of my injectors is leaking now. Could the increased head due to running leaner have been the final straw on the seal/hose (not sure which yet) causing it to give?

In the post-credits scene of this thread here are my 'a couple days later' thoughts/observations: - I pulled a couple of my spark plugs just to see how they looked and they were QUITE grey indicating the car was running very lean. Now, I don't know if they got like that when we were running off the charts lean earlier and if they will return to how they looked before this or not, but the car seems to be running well and the gauge numbers check out so I guess I'll ignore them? Could my valve seats suffer if my plugs got toasted like that? - My car has a delayed start which as previously noted got worse when we unplugged the TPS but will start immediately when I jury rigged the CSV to fire on every start (https://www.classiczcars.com/forums/topic/64824-very-strange-cold-start-valve-issue/) which I'd have though was indicative of running lean. That said, I have a "Jacobs Electrical" coil/box setup (part number 380672) and the guy in the below video says if you have the wrong coil resistance (this one is correct) or if it is hooked up backwards you'll have weaker spark but the car will still run. Since the PO rewired this part of the car for the ignition box, could I flip the wires attached to the coil posts or would I risk frying the box? All the stock wire colors are of course wrong since all wiring comes from the box: Video will start at the appropriate time stamp: https://youtu.be/TlxiZXK06lI?t=647

The problem is that the main carb canister chamber connected to the large vacuum hose (the one that goes directly to the manifold) does not hold vacuum so there's a permanent vacuum leak there and then a slight one via the ported chamber so I just took it out of the picture. Both chambers are supposed to be vacuum tight it seems - I tested this by spraying carb cleaner on the canister at idle and the rpms rose. I can confirm later today if the mixture changes with it plugged in though.

No, I completely took the carb canister out of the picture. It is still in the car/connected to the tank vent line but its vacuum hoses are disconnected. Yeah, there is indeed a change when the wot pin connects it feels kind of like when turbo boost comes in on a turbo car.

Absolutely agree and here are the final numbers: Idle - 14.2 Cruise: 14.7-15.2 (depending on load) WOT: 12.3 In the end, I moved to the lean side by 2 teeth from where the PO had it set. I originally moved it 15 teeth back but that was undone once we discovered the TPS's WOT pin was to blame.

And so my friends, we shut the book on this project. I drove the car about 60 miles today and settled on around 14.9-15.1's tooth for cruising and man, I'm floored at this engine. My other car is electric and I've never driven a gas powered car that runs as smoothly at speed as this does now. Adjusting the TPS was the key but I was also running it too lean earlier today, as I felt I needed to rely on the WOT pin to get any sort of power out of it. Richening the cruise out from 15.5 to 14.9ish really was the key to smell, responsiveness, smoothness and power (even before the WOT pin connects). For reference, that was richening by 1 gear tooth this also changed WOT numbers from 13.3 to 12.2. I can't thank you all enough - I hope this thread helps others in the future if they decide to tune with one of these gauges. Some other observations due to leanness I believe: - the car comes to operating temperature faster than before (but does not overheat) - the car is harder to start now if the TPS is disconnected

It seems to be holding the position I bent it at originally but in terms of bending it back up so WOT comes on earlier it doesn't seem to want to stay in that position...

Right, stock felt like MAYBE 1/4 or so, right? Do you think I bent it too far? I tried to bend it back in a bit but it wasn't holding that position and I didn't want to keep messing with it for fear of it breaking...

Interesting idea - we may go that route depending on how the bending goes. One final question, am I bending the thin copper arm (noted as "1" in the below picture) or the thicker grey metal arm (noted as "2" in the below picture)? UPDATE: I bent #2 and using a multimeter to test the wot pin I'm now getting WOT continuity at 3/4 pedal pressure instead of 1/4 lol. I tried to bend it back to get WOT at 2/3 but it doesn't really want to go back in place. Either way, I'm happy with this and will report back on the driving dynamics/numbers tomorrow night.

Ok gang we are at the finish line here - I followed @240260280 's method. We're sitting at a 15.5 highway cruise with the TPS unplugged, so I cranked the bolt down, put some paint on the current gear tooth for future reference, and shut the cover. I then plugged the TPS in and set the idle to 14.2 while running at 800rpm. Now to bend the WOT arm which I will do when it's light out haha.

@240260280 Good plan, very methodical - I'll do that probably tomorrow evening. Regarding the tape, I'm guessing you mean just electrical tape wrapped around the WOT contact, right? @Captain Obvious Interesting idea, I might take that up down the road after everything is setup properly @madkaw Good to know on the max leanness number for WOT thx