chaseincats

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

Thanks @Captain Obvious & @siteunseen I definitely think I'll need to keep the TPS switch plugged in in some form as the car drives like a wet shoe without it lol

Ok gang, I have some pretty big findings. Our issue is very much the TPS. I was driving and getting in the high 13s after leaning it way out. Frustrated, I pulled over and unplugged the TPS and immediately cruise changed from the 13s to the 17s. The next plan (probably tomorrow) will be to configure the car to get low 15s (good target?) on cruise with the TPS unplugged, then fiddle with the TPS pins until I am able to get the proper cruise with it plugged in. The problem very much is a lack of space between the cruise and WOT pin as I was barely able to hold it in the 14s with some really finite pedal work when it was plugged in.

Why not just bend it back delaying when the center pin touches it?

That's odd but I don't see how it would change anything. I thought he bent the main support pin of WOT back.

Sounds great, thanks!

Wow ya that is a huge difference compared to the pic I put up last night. I'll get some numbers/rpms for you near the end of the week and then I'll do some bending. Any idea what RPM you have to hit before it connects to the WOT tab? I set mine using a multimeter on the bottom two pins and twisted the sensor so that when it got above 1400 the contacts would lose continuity.

Can you pop the cover off and take a picture of the arm spacing? That would be awesome

Gotcha - I originally set mine using the 1400rpm method and haven't fiddled with it yet - but now I know not to! Ya I was thinking about just bending the lil WOT contact arm a bit but I should have new numbers for you Thursday or Friday night before I fiddle wit it. My reasoning for wanting to bend the WOT enrichment pin would be that it seems to think freeway driving (3500 rpm) counts as WOT which seems a bit silly to me, no? The adventure continues haha.

Awesome, I'll respond in there, thanks! Brief update - I didn't drive the car at all this past weekend as I left my gauge powered up when I scampered up the stairs to write the previous numbers post which subsequently drained my battery when I went to start it a few days later lol. I got the car going in the driveway today and noticed that with the car set as lean as it is, my idle speed dropped to around 450, so I brought that back up to 800 and the idle is sitting at around 14.7. The idle air bypass screw is indeed turned all the way in and the only way to lean out the idle further is to retard the black gear. I think at this point, that is just how it will have to sit. When playing with the throttle, I noticed in cruise mode it will sit in the mid 15s and pushing the linkage to when the WOT pin connects on the TPS, brings the gauge to the mid 12s which all look really good (although when the car is under load I'm expecting the numbers to change a bit). That lead me to the TPS configuration question because it seems that the cruise mode leanness only lasts a short amount of pedal travel - maybe only an inch or so. I can check tomorrow at what rpm the WOT pin connects in the TPS if that information would be of some help? I attached a picture of my TPS but its in a different orientation because of the weber throttlebody. The bottom pin in the WOT pin - should I bend it down somewhat?

Gotcha so it looks like my TPS is set properly then. Out of curiosity, why isn't TPS set like some folks above noted where the pins separate once you touch the pedal? That would seem like the way to get better mpg and not throw extra gas in there if the car is already moving, no?

Right, but what I mean is AtlanticZ says that throttle movement up to 1400rpm should be counted as "idle" which sounds strange.

When adjusting the throttle position sensor (TPS) I'm seeing two schools of thought. One says the idle enrichment arm should be connected to the middle contact until 1400rpm (atlanticZ) and a bunch of other folks saying the idle enrichment contact should disconnect once you hit the pedal which makes more sense to me. Any ideas? I found this thread which discusses it: https://www.classiczcars.com/forums/topic/25240-tps-adjustment/