chaseincats

I wanted to avoid that stuff but if you think that's the only way then I'll go grab some. You need to wait 24h before starting the car, right? As a sidenote, could it be that since my gasket doesnt have the other side of the screw holes, the screws are bowing it out, creating the leak? EDIT: Do you think its possible to fix my carbon canister's leaky vacuum valve? Are these even serviceable?

@madkaw It's strange because I used some light sandpaper and sanded both the intake and and cold start valve side a well as the gasket and it still didn't work. @Captain Obvious The CSV definitely is used in the winter since I think it is triggered when the coolant is below just 50 degrees (even got a new one when mine died) lateron I wired it so that it triggers during each start regardless of outside temp because the car just starts so quick with it - very satisfying haha. I later figured out though that if you are starting it before the engine has time to cool it basically floods the mixture and you will be stranded until the engine cools down (ask me how I know) so I undid that. What do you mean by silicone sealer - do you mean RTV gasket marker? I was going to head to autozone to grab some gasket paper and cut a new one, but you think a new dry gasket won't do much?

I actually have the perfect solution for you guys. This is what I did and it is a very happy medium between a zippier car but without the issues of driving a super light flywheel: https://www.californiadatsun.com/flywheel/lightened-resurfaced-balanced-steel-non-turbo-225mm-flywheel.html The car definitely is quicker but not a pain to drive at all. I paired that with the 2+2's 240mm clutch kit for extra grip (the owner of that site can find you a 240mm flywheel if you call and ask). It was professionally lightened/balanced from a 23/24lb flywheel (the 2+2's is heavier of course) to around I think 17-18lb (I don't remember).

Looks like there's definitely egg on my face - I will be eating crow for dinner. @madkaw @Captain Obvious There was indeed a non-trivial vacuum leak coming from the cold start valve's gasket. Regarding the valve on the carbon canister, are those supposed to hold vacuum or are they a pass through because mine seems to bleed vacuum on this vacuum hand pump I got. After covering the cold start valve inlet hole, the gauge's idle went from 17 to 13 immediately - I think we're onto something. The cold start valve gasket had some bumps and unevenness to it which I sanded down and it still leaked after I screwed the bolts in with vigor, so it looks like I need a new one of those. I don't understand how it was leaking though as there are no rips...

Ok, so update for you guys: I went to autozone and grabbed a handheld vacuum pressure tester and discovered that my carbon canister valve didn't hold vacuum and was creating a vacuum leak when the pedal was pressed (this is supposed to hold vacuum, right?). So I disconnected the T-connector to the throttlebody and capped the hose port on the intake manifold and now I'm able to get to the 14s with a WAY leaner setting but the idle was still pretty lean up there. I tried what @Captain Obvious was saying and started it then watched the gauge as I unplugged the TPS connector at idle and it did lean out, so that should be working. I checked my altitude switch and that is set at off currently. I've smoke tested the engine a few times so it shouldn't have any leaks in the AFM boot etc though. The engine is warm now, so I'll wait until it cools off tomorrow to spray it with flammable chemicals lol. It did occur to me that maybe the idle speed screw seal is worn down or something inside, is that a thing? I have no idea how that looks internally. EDIT: my impatience got the best of me so I grabbed a fire extinguisher and got spraying. There MAY be a vacuum leak in the cold start injector inlet (I was messing with this recently). Going to grab a pack of cigarettes and a pump BBL.

I'd prefer not to mess with the distributor it is right bang on factory spec along with all the other sensors/contacts/valves etc (I went through the engine tuneup chapter of the FSM).

I'm pretty sure it's working - the vacuum bladder holds air and the plate is movable but I've never tested it with a vacuum pump. That shouldn't affect idle richness though I'd think.

WOT gets to low 13s Timing is at factory which if I remember is 10 degrees btdc Premium 93 octane Off cruise that lean felt pretty anemic There are absolutely no vacuum leaks in that engine at all - I've smoke tested it a few times and found a big one originally but it is perfect now The engine runs well enough at idle that you can put a glass of water on the valve cover and you won't get ripples so it isn't anything internal that's the issue

So I just spent a lot of time playing with the AFM to get it to cruise at 14.6 but I cannot get the idle to sit at less than 16.5 which is way too high with that setting on the black gear (brought the idle screw all the way in). Should I re-richen the black gear a bit and call it a day or leave it like that? I hear tiny little pops in the exhaust when holding it at 3k in my driveway (I did the testing under load though, that was just an observation as I didn't hear pops while driving). I have tested my coolant temp sensor and it is within spec of the FSM and set my TPS before installing the gauge by following the atlanticZ page so my system is setup correctly.

@jonbill Freeway speed sits between 12.3 and as low as 11.9 - I think it's safe to say I need to play with that gear a bit. Am I going to me really turning this wheel or will just a couple of teeth do it?

Stock L28 with original bosch injection. I was reading that with today's ethanol fuel levels, running that lean isn't good for our engines. Or is that a wives tale?

Good to know. I'll take it on the highway tonight and let you know what it says. I just changed the idle to 14.7 now, thx.

What rpm would you say is 'cruise' so I can have the pedal held when tuning it?

So you're thinking I should lean out the drive gear and re-richen the idle a bit? I thought the idle was supposed to be leaner than cruise, no? I did notice after leaning the idle out that the car off the line is a lot zippier. I almost smacked my garage door when turning away from my house the first time I drove it post-tune lol.

Ok gang, here come the numbers on my stock EFI system as-is: Idle: 13.4 2500 rpm shift points: ~13.2 WOT: 12.4 Highway cruise: TBD (will update tonight) NOTE: This is without the high altitude switch on (when enabled it seems to lean the mixture out 1 full point) Changes made: leaned idle to low 15s, will adjust big drive mix gear at a later time. @AK260 Is that chart (except for the ones labeled WOT) for idle, or highway cruise (4k-4500rpm)?

So I just finished wiring the gauge and will be taking it in tomorrow morning to have the o2 sensor bung welded in then I'll drive back and give you guys some numbers. Stock l28 with EFI. I pretty much followed this guys video (even got the same gauge): https://www.youtube.com/watch?v=XS_f2ciKVqo&t=9s

https://en.wikipedia.org/wiki/Air–fuel_ratio_meter#Wide-band_sensors

Again, this is not measured in the intake manifold, there is an o2 sensor welded into the exhaust headers.

It measures oxygen in your headers/exhaust manifold's back piping (not your intake manifold as that's just air not air/fuel). Jonbill also made some good points.

It has an oxygen sensor ("o2 sensor") that is welded into your exhaust. All modern cars have this.

Hi guys, I just purchased an air/fuel mixture gauge (https://www.amazon.com/gp/product/B00N3VGPYS/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1) and was wondering where to find the number the car should read when driving/idle. Has anyone done this before? The FSM shows fuel percentages but that isn't readable on these gauges it seems. -chase

If you're talking about finding a replacement for the accordion-style spare that came with the '77/78 (and maybe ZX?) then I don't believe you can get those anywhere. Tires for the standard wheels can be bought off amazon for like $60 each so I'm not sure what he's talking about...

I actually was thinking about that, because that happened a year and a half ago and I ended up changing the alternator which solved it. The difference is this time my volt meter is reading a normal charge rate compared to before which I think was around 15v. I'll keep that in mind though next time it happens.

Well this is a new one... I was driving this evening (about 40 degrees out) and my temp gauge passed the half mark which I have never seen it do outside of 100+ degree heat with the AC on. I noticed that when I turned off my cabin heater fan, the temp gauge would drop down to where it normally sits almost immediately (a little below the half-way mark) but rose back up past the half mark when I turned the heater on again. I had a long drive so I had a chance to try this over and over again and that is oddly exactly what's going on here. I played with the temperature slider to see if max hot would change the degree of movement on the coolant temp gauge but it literally is an on/off issue. How is that possible?

It might have not been in all the way - who knows. Not sure if the dist caps were the same brand as the first one came on the car when I got it years ago.