Decided to tune my 85GSL, for the first time, since it idles way too low and it failed a couple smog readings for the first time ever, so, armed with Sterlings excellent guide I tried to find the idle screw and was confronted by a thick maze of parts, among which I could find neither screw.

I'm attaching pix.

Meanwhile, I'm gonna examine the 83, which is much simpler, and find where the screws are on THAT Nikki, so I have a hint.

Can anyone tell me where I should be looking more closely in these pix? I started with the naive assumption that by poking around I would find a slotted head adjustment screw pretty easily, but it is not so.

 

They aren't plainly visible in your pictures, but they are there. You've got to dig a little deeper into the pile of emissions crap. Both screws are on the driver's side of the carb.

The mixture screw is the easier of the two to find. It is all the way down on the base of the carburetor, dead center underneath the fuel lines. It angles up towards you at a 45 degree angle as you look at it. Since you're in California, I'd guess that your mixture screw has a black plastic cap on it. For some reason the CA cars came with those to keep people from tampering with the mixture. At least that's what my Haynes manual says. Seeing as I'm in Indiana, I've never had to deal with that. But it may be a possibility. You may have to cut that black cap off if it is on there.

Second is the idle speed screw. It is tucked back in there a little farther and is tricky to find sometimes. It is on the back driver's side of the carburetor and runs PARALLEL to the ground. It is not angled at all, and you'll only be able to see it's little phillips headed face shining out at you, if anything. The easiest thing sometimes is to stick your screwdriver in and start feeling around. She's definitely in there though.

I attached a picture showing the general area for each. I can post pictures of my stripped down Nikki if need be.

Jamie

 

On this side:

https://www.rx7club.com/attachment.p...4&d=1220638092

http://foxed.ca/rx7manual/manuals/19...ssions_12A.pdf
Page 63.

 

More pictures...http://intertron.com/ron/carb.html

 

Thanks guys!

Looks like they're each reached from the drivers side, shooting the screwdriver in over the engine and thru the tangle.

Also, looks like they're each a small (#1?) phillips head screwdriver on a long (6", 9"?) shaft.

I'll try it when I get back to the house.

 

Both take a flat blade. #2 if I remember my sizes correctly.

 

Armed with marked up pictures I went under the hood again and tried to spot the screwheads. I Think I found he mixture screw, covered by a silver cap with a peculiar shape, which jiggles slightly. I think it's the factory cover, and when I dig out my strong-long needlenose pliers I'll try getting a grip on it, maybe loosen or break it. That cap appears to mount horizontally and I expected it to be slanted up somewhat.

I think for the idle screw, which is unseeable from anyplace, I'll have to pass in a long shaft (14"?) screwdriver horizontally over the row of solenoids and thru the tangle. I thiink I aim just above the seam of the shutter valve, which is just visible. Then, I guess, it's a matter of blind fishing.

 

The cap on the mix screw has to be cut off. Measure down 10mm from the top of the cap and cut it off. Instructions are in the factory carb manual. To get to the idle screw, remove the air cleaner, plug the large vacuum hose, then you'll be able to see it better.

Since you failed CARB emissions, it's probably going to take more than a little screw turning to pass. Post up your emission numbers, doc and a couple of others can narrow down your real problem.

 

Here's the actual smog report. This car has always passed easily and I put in a Bonerz cat about 5 years ago. But last year I replaced the intake manifold orings, or rather, my inept mechanic did. Since then it will only hold an idle when warm, and at 400rpm, so I have to do something.

I'd rather have someone else do it, but that means digging up Ivan (wherever he is) or taking it down to that rotary specialist in Campbell (In the Camden, Winchester, 17 maze).

I appreciate any light anyone can shed on this.

I want to sell this car, but vehicle prices have gone thru the floor around here because of gas prices and general economic misery.

 

in my experience over time the idle mixture screw needs adjusting, our fuel is different than it was in 1983, and the catylitic converters sometimes smog better with a richer mixture.

but the idle speed screw does not need to be touched. if it idles low, theres a vacuum leak or something

 

he lives right around the corner from me, if you need his contact info, i've got it

 

Yes, please. You can PM me if you want to not broadcast it.

All the vacuum hoses seem flexible, almost like new. This car has always been treated well, covered or garaged.

 

it wont hurt to check for a leak, i don't think you have one but you never know, as far as the mixture, as far as i know all you'd have to mess with is the air mixture, and not the speed screw...try raising the idle to 750 which is where its supposed to idle at, and see how it does.

 

The smog report looks odd to me. HC and CO very high, but CO2 and O2 and NO very low. Sure looks like a mixture problem.