Babalouie

Yes I want one...but no, I can't afford one

http://atlanticz.ca/zclub/techtips/distributor/index.html If your distributor looks like this, then it's the common E12-80 upgrade from a 280ZX. The link above has a wiring guide. I'd say if it works on some of the cylinders but not others, it might be a dizzy cap/lead issue. Are the 2 "cold" cylinders on the same carb?

If you're going to do another round of tinkering, remember that the ideal carb settings are only "findable" when the car is warmed up and running cleanly. So the "get the damn thing started" settings will prolly have to be revisited and finetuned (eg the ilde mixture screws) when you do finally solve the issue.

^good tip!

So it's starting and running, but the current status is that it's a bit rough and maybe missing on 1 pot? Does it idle by itself, or does it need revving to stay alive? Pull all the plugs and compare colour, just to eliminate any issues that might be only affecting one cylinder. Check if they are all the same colour, or if one is blacker, or if one carb's plugs are blacker. That'll narrow it down a bit more, if it's say a problem from just one carb, then we can take off the top plate and start looking checking float levels. Pull all the main jets out again, and this time pull the jet off the end of the emulsion tube and look to see if there's garbage blocking some of them. Ditto the idle jets. If they're second hand carbs and an unknown quantity, you never know, it might be as simple as garbage stuck inside the carbs. Distributor sounds like the usual E12-80 electronic upgrade from the 280ZX too.

Well you got nothing to lose by trying 15-36-24 as a firing order (with #1 being the closest to the radiator) Hang in there, you'll get it working soon I'm sure! Here's some motivation (my car and it's got the same carbs as you got):

If the motor hasn't been run for a few years, it could be a heaps of things at play here. Checked the ignition timing yet? As for gaskets, I found that the Weber UK distributor is pretty sharp on pricing, (especially now that the pound is in the toilet). I'm not sure if these are cheaper than USA prices tho: http://stores.shop.ebay.com.au/FAST-ROAD-CARS-LIMITED_Weber-Service-Kits-Gaskets_W0QQ_fsubZ3QQ_sidZ21855701QQ_trksidZp4634Q2ec0Q2em322 My mnemonic for remembering the plug wire order is "too young....too old...just right": 15 - 36 - 24

I had problems with my ignition too, and the more I "improved" it with upgraded parts the worse it got. In the end it turned out a few of the connections on the keybarrel were dodgy. Just to be sure, now I run a relay with the coil +ve getting a direct feed of juice from the battery. Do Zs run a relay?

Well as luck would have it, this weekend I found myself swapping out chokes in a Weber carb So here's what it looks like: When you get the carb out and onto your bench, you'll see these "inserts" in the throats of the carbs. They're the aux venturis. The aux venturis just slide in, and have a spring clip that clicks into place, so you just wiggle them out with your fingers. Once out, you can see the choke tube sitting underneath. The chokes are a similarly loose fit and will just slide out...and here's what they look like. Factory chokes will have the size cast into the front edge, in this case they're 32s. On a 45DCOE there's a bolt underneath that holds in the chokes, but on a 40DCOE it just slides out. ...a better view of the choke and the aux venturi.. What I was doing was installing bigger 36mm chokes for more top end power. The new ones aren't cast, but are machined aluminium and are 36mm (which is the biggest you can fit into a 40DCOE) As I've said before, the chokes and the jets should be seen as matched, so when the chokes are upsized, the main jets should be too. In this case, we're going from 125 to 140 mains, to stick with the rule of thumb that the jets should be 4 times the choke diameter. Here I've fitted one of the 36mm chokes on the right. You can see that it's noticeably bigger than the 32mm one on the left. There's no trick to it, just make sure the chokes are seated all the way home, and when you refit the aux venturi, you should feel it click into position. Just to be sure, have a look from the other end of the carb just to check that the chokes are seated. Button it all back together and you're good to go

There are decades-old charts that Weber and Dell put out that give you the starting point for your jetting, but years ago, a helpful Alfa Romeo enthusiast put it all into a spreadsheet, so all you have to do is plug in your values and it'll recommend settings. I've attached it, and it's easy to use...just remember that it's set up for 4cyl Alfa Romeo engines and so you have to convert your Zed L28 to a theoretical 4cyl config. So a 2750cc stock L28 would convert into a 1833cc four. Ok, well those jet sizes sound ok for a 30-32mm choke size (which would also work just fine on your stock L28). Open up that attachment (I think you have to save it to desktop before unzipping) and plug in 1833cc and a power peak figure of 5500rpm (probably about right for a stock L28) and tune for Flexibility and you'll find it'll recommend exactly the jetting you got, plus a choke size of 31mm. Your carbs look like the old ones like mine...there should be a serial number on the top plate somewhere, something along the lines of "40DCOE18K" What's it say? But assuming they are older carbs, it already sounds like your idle screw settings might be too rich. Try setting them at 1 turn from bottom, clean your plugs, and see if it'll fire up clean. If that works, then to fine-tune the idle screws, here's what you do. With the engine idling and warm, start richening all the screws (turn anticlockwise) 1/4 turn. Give it 5-10secs for the idle to settle, and see if the idle speed goes up and smooths out or not compared to before. If it seems to get a bit rougher, then go back 1/4 turn clockwise back to the original setting of 1 turn. Now try leaning all the screws 1/4 turn (clockwise). Give it 5-10secs and see if the idle gets slightly faster and smoother. And basically you keep doing that until you find a happy medium. As a guide, Weber says that if your idle jets are correctly sized (and yours are) then the ideal setting will be between three quarters of a turn, to one and a quarter turn from closed. (So straight out, your initial settings of one and a half and two and a half sounds too rich). Give that a try for starters...if there is nothing else wrong, you should find that tweaking the idle screws 1/4 turn should make a noticeable difference. The idle won't jump 200rpm or anything dramatic like that but it will get noticeably smoother. If 1/4 turn on the screws makes no discernible difference, then that's a sign that there's another problem we got to look at (maybe ignition, etc or maybe another carb setting like idle speed). If this does the trick, then the next step will be to synchronise all 3 carbs to the same idle speed/throttle position. jetting.zip

Well the car I have right now is the first one I've had with multiple Webers, I'd never tuned carbs before and like Willy, I had to learn. There is actually a lot of info on the 'net but even so it does seem quite daunting. But in the end it's not actually that difficult at all to understand IMHO....it's maybe hard to visualise at first, that's all. But you're right about the ignition, in the sense that if you have a problem with the ignition, you will drive yourself crazy trying to diagnose the issues from the carb-side. We went NUTS playing with the carbs, even going to the extent of swapping out a borrowed set of carbs, only to discover that a fault with the ignition wiring was not giving the coil a full serve of juice Once we fixed a couple of loose connections the engine fired up like a champ But...for the time being let's see what we got with Willy's carbs. For all we know, he's got early DCOEs, but a well-meaning previous owner read on the 'net that the ideal idle setting is two and a half turns out on the idle screws (not realising that only works on later carbs) and hence it's way too rich and he's just a few turns of a screwdriver away from a decent tune Oh and no I'm not on ausZcar...because I don't have a Z My Nissan product starts with an "S"

This first step is just to see what Willy's got to work with. If the jetting is wrong, then there is no point trying to tune around it until we address it. But sure, once we we ensure that the jetting/hardware is all in the ballpark, then we'll look at the tuning. Yup. You see those two smaller brass screws next to the main/correctors (under the round cover)? Those are the idle jets, and you can just unscrew them to have a looksee. They seem to be quite forgiving though, so anything from 45 to 55 seems to work just fine. Try this check for now: see those big screws with the spring? That's the idle mixture screw and there's six of 'em in total. Now the way it works is that from idle to 3000rpm the idle circuit is doing all the heavy lifting. So the fuel is coming thru the idle jet and the mixture is set by the idle screw. Between about 2500rpm and 3000rpm the idle circuit fades out and the main circuit (that's the main jet) blends in. At the top end, the main jet is still providing the fuel, but left to its own devices it will be too rich, so the corrector compensates by allowing some air to bleed in at the top end to balance things out. So above 3000rpm the mixture is purely set by the jet/choke sizing. Below 3000rpm, the fuelling is set by the size of the idle jet, however, you also have that idle screw mechanism to fine tune it. From what you described, you're fouling the plugs at low rpm so it probably isn't your main jet/corrector/choke that's at fault (just the same...you really should pull one carb out to see what you got). Anyway...back to the idle screw...get a screwdriver and very gently with fingertip pressure, turn it clockwise and count how many turns before the screw bottoms. The more turns (out) it is, the richer the idle setting. Take a pic of one of the carbs if you could, but if yours is an early carb (made in Italy, it will say Bologna Weber Brevitatta), then a rule of thumb is that one turn from bottom is about right. For a later carb two turns is more like it. A quarter turn too rich and it will blacken the plugs a little, a half turn too rich and they'll be quite black. So see what you got, pull the idle jet and read the size, then count the number of turns the idle screws are currently at. If your idle jet is too big, then you might find that the ideal setting is less turns out than the rule of thumb and vice versa. But let's see what idle jets you got, and how many turns the screws are at. If the idle screw is out by miles then we can cover how that is adjusted. BTW it could be an ignition fault we're dealing with too...if the spark is weak the plugs will foul. But we should at least eliminate the carbs as a cause.

40DCOEs will be just fine, that's what I run on my L28. First step is to see what you have got. Remove the round covers on top of the carbs, and unscrew the main jet and emulsion tube. The main jet is at the bottom... ...and the corrector is at the top. The choke size is a little tricker to find....it'll be cast into the front of the choke tube, which is behind the "pillar" in this pic...this is looking right down the throat of the carb from the air filter side. Easy to see if you have the carb out and sitting on your bench, not so easy to find if you're just leaving the carb on the motor and messing around with flashlights and mirrors The jet/corrector sizes are a matched set with the choke size, so you won't know if your jetting is in the ballpark until you obtain the choke size you currently have. As a rough rule of thumb, most ppl say that the main jet should be 4x the choke size, and the corrector should be 40-50 bigger than that. In my case, the chokes were 32mm and 125mains and 175 correctors (I swapped out the 220s in the pic above) and turned out to be optimum after some dyno tuning, so the rules of thumb are pretty much on the money IMHO. At the end of the day your jetting could be perfectly correct, but the carbs are just out of tune. But verifying your current hardware is a good place to start.

If it's only one plug that looks lean, I'd be more tempted to suspect an air leak in the manifold. Give your manifold to head bolts a quick visual check? One of my friends had this same issue and when he looked, one of the nuts was finger tight ...and at the carb to manifold join, what are you using? Are they are those big o-ring type gaskets?

Maybe float levels are out in the 3rd carb? I had that prob too, one carb was leaner than the rest, and in the end the float level in that carb was 3mm out. Once it was fixed the plug colours evened out. I'm sure the process of checking Dell floats would be similar to Webers: http://www.webcon.co.uk/Downloads/DCOE%20float%20height%20setting.pdf