wow thats a pretty crappy problem mate you have seem to have coverd most of the area's

i have had the same symptoms before and that was a combo of not blocking the secondary's vaccum ports and a screw had stripped by the the fuel bowel which caused a major vaccum leak

also im currently rebuilding a stripped nikki for the 12a in my repu :)

Thanks Mr. Bad, I've already got the block off plate on this one but haven't removed the shutter valve because that's a one way trip for the intake manifold. But that gives me an idea, I do have two extra manifolds sitting out in the back yard. Maybe I'll do one of those up.

But like I said earlier and because of Trochoid's warnings about the shutter valve, I took a real close look at this and when I couldn't remove the shutter valve easily, I just wired it so it stays in the open position. Shouldn't that take care of the problem?

When you say disconnect every vacuum line leading to the base plate, does that include the plumbing for the crank case vent? I tried to follow the instructions on that but never fully understood what it was all about. So that's another good idea, I'll unhook it and plug the ports and see if it helps.

Thanks Mr. Bad.

"Just for shits and giggles, try spraying a little carb cleaner around the back of the carb, around the float window and throttle/choke shafts and see if your rpms change if you haven't already sprayed there."

Yup already sprayed there, no difference, but thanks for the suggestion.

Yes, everything. This is the only way to make sure that you do not have something plumbed wrong. With everything disconnected, then you can rule out any error on your work. Then you can try checking for leaks around yor carb and intake. The backfiring and not being able to idle is coming from a lean condition. Hense everyones diagnosis of a vacuum leak. I run a blowthrough Nikki on my FB without any problems. This mod your doing is a simple upgrade.

Got it, the sun's going down but I think I'll go hook up a lamp.

Ray

might help!
 

ok i have done tons of these you could pretty much plug all of them. i think your problem is that you have a vacumn line poen which i think is the one right where the vacumn line goes to the brake booster, sometime it hides because of the stock spacer in between the carb and the intake manifold. if you look closely at the top part of the exhast manifold and right where the intake manifold is at on your left when staanding over the carb. there is three tubes that come out of the intake manifold one has a bolt that holds it in place and another one goes to the exhuast(long pipe that comes in the side of the side of the exhuast flange) then there is a small tube thats about the size of a finger nail, take a good look. reason why i tell you is because i just did one about two weeks ago and had the same problem would idle high and i could not get it lower than 2000 rpm. and also back firing. take a good look. if you remove the spacer inbetween the carb(which is that long black plastic thing) i will try to take a pic on one that i have around here, good luck:icon_tup:

I hope this helps you find your problem. When you are ready to commit to mechanical secondaries, you will need to brase to linkages together to prevent any stretch on your wiring job. This will also insure the secondaries fully open at wide open throttle.

help 2!
 

the one that my finger is pointing to! Is this one plugged?check the pic

Thanks jm, if that's the one up on the air horn that the crankcase vent hooks up to, I thing I got it plugged (see the red cap). Also I removed all the vacuum lines from the base plate, capped the tubes and plugged in the shut off valves too there sockets.

And yeh Mr. Bad, I'll brace the secondaries if I like it, which means the friggin thing needs to idle.

Here're some photos of the current situation:

http://memimage.cardomain.net/member...7_241_full.jpg

http://memimage.cardomain.net/member...7_242_full.jpg

Still no change, the idle still sucks, but the good news it there is getting to be less and less to mess with.

I've also sprayed it down pretty good on several occaisions with starter fluid, looking for vacuum leaks, no results. That plus a lot of attention during the rebuild rules out vacuum leaks, I think.

Why won't this sucker run?

are you talking about the red cap by the fuel lines at the carb? because the pic is o fthe intake manifold below that black spacer plate!

I know you sprayed it down pretty good from the sound of it , but did you do around your ACV block off plate?
Also, I'm not sure right now, but I think the separate chambers under the block off plate can be a leak if they are not sealed from each other and the tube that bolts on toward the back of the manifold is not sealed.

Mr. Foxx,

So you mean this one?

http://memimage.cardomain.net/member...7_243_full.jpg

OK, so I plugged it:

http://memimage.cardomain.net/member...7_244_full.jpg

Here's a movie of the White One idling at 400 rpm, which I don't think she's done before:

http://youtube.com/watch?v=MhbD59XSlIg

Thank you Mr. Foxx, you know your rotaries.

Ray

you got it!!!!!!!!!!!
 

thats happen to me before. the spacer blocks the view,what i would normally do is crack the excess of the spacer which would allow me to view that pipe,but when i would leave it stock that would happen, but anyways good luck!!! glad i could help!!!!

How's she running now Ray? Pretty good? Just curious to see if this fixed your problem...

hay have you got a close up on how you tired youy mec secondarys im trying to find a better way than using wire

also you can get rid of two linkages ones for the cruise controll and the other's for subzero start..
https://www.rx7club.com/attachment.p...1&d=1181663226
https://www.rx7club.com/attachment.p...1&d=1181663226

Well let's start with the good news. I used stainless steel mirror hanging wire for the secondaries, they have held up without stretching for the entire week that I have been working on the car:

http://memimage.cardomain.net/member...7_245_full.jpg

Now the bad news, when I put this cap on that port coming out of the intake manifold:

http://memimage.cardomain.net/member...7_244_full.jpg

the car will idle smoothly all the way down to 300-400 rpms and it revs quickly and smoothly when sitting in the driveway. But when you go out on the street, it runs like crap, really really bad. At first I thought something had happened to the ignition but everything looked good there.

So I removed the plugs, which turned out to be fouled black, obviously a very rich mixture with that cap on the manifold port, great for idle but no power.

So I took the cap back off and I was back to where I started, rough idle that's hard to keep going in the driveway, but get it out on the street and it runs like a rocket, including some nice explosive backfires here and there. Much better, at least, than with the cap on.

That capped port on the intake manifold connects to a tube that runs to the #2 anti afterburner valve, which was removed during the stripping. Makes me wonder what is going on with the intake that isn't right.

I don't think the problem is with a leaking block off plate, I used silicone gasket sealer to make a seal by coating the plate before I put it on. But could the gasket sealer be causing some kind of problem in those ports it covers up if it gets down in them? I'm redoing the plate, but just putting the sealer on the contact points at the sealing surface of the intake manifold, but frankly, it's just more grasping at straws.

More clues, but the problem is still the same. Why is it running so rich that it needs an additional air intake to run OK? (float levels have the gas halfway up the carb windows, so I don't think it's flooding).

So I'm about ready to put the stock Nikki back on and go from there unless somebody has another suggestion.

Thanks
Ray

Don't give up Ray! You've already found a couple of oversights here and there, so you're bound to find the one that's causing the problem pretty soon. This might be a dumb suggestion, but you did adjust your mixture screw after putting the carb back on, right?

ok so did you readjust mixture screw if so go 2 to 2and a half turns so you could rule that out, second and the pic with the carb you have a long hose going towards the distributor are you using that? third the vacumn lines from the distributor you could have them open, so un plug them, forth that shutter valve thats in the intake manifold did you mess with that if so make sure the shutter valve stays open since you have the vacumn closed it might be closing on you! let me know,one thing that i always happen is it will run perfect,but when drive the car around and let it sit it will take a few seconds to turn on, but never had the problem you are saying.

Thanks Mr. Foxx and Mr. Ham, you guys have as much patience as I do.

1. Yes I did readjust the mixture screw after every change that I made by turning it out three turns, then back in until the engine slowed a bit, then back out half a turn. This always turned out to be around 2-3 turns from all the way in.

2. I have the hoses set up according to Carl's tutorial, here's the pictures showing how they are attached:

http://memimage.cardomain.net/member...7_225_full.jpg

http://memimage.cardomain.net/member...7_226_full.jpg

3. When testing for vacuum leaks I did have the vacuum lines from the distributor plugged both at the distributor lead tube, with a bolt, and at the carb plate (hole #2 from the left in the spacer plate) with a rubber cap.

4. I did take a close look at the shutter valve when it was disabled and the flap pretty much wanted to stay in open on its own, but just to be sure I wired the shaft so it had to stay open.

So I'm plumb out of ideas. Last night I decided to switch in my stock Nikki, which has everything on it except the #2 anti afterburner valve, leaving the rest of the set up exactly as I had it for the stripped Nikki (in other words, according to Carl's tutorial).

Wow. The car runs great, better than ever, I'm happy and back to normal. But building that stripped Nikki was fun and educational, the engine bay is cleaner than ever and the car is fast. I hope the photos and discussion were of some use to those considering this mod. It might be a good one, but I would suggest having someone with experience with stripped Nikki's nearby when you do it.

Also thanks to Doc and aws, who suggested early on that they didn't think this was a good idea. With a little more experience, I now tend to agree with them!

Now, what to do with that stripped Nikki?

swap the nipple your vac advance is on. put it on the nipple farthest to the front/left.

Yeh aws you said that before, but why would it make a difference?

I've got the stock carb back in and the car is running great, blazing in fact. I'm having to get used to driving it all over again. But there is still a high idle, I can't get it below 1000, which really isn't that bad, just annoying.

So if I swap that tube it'll idle down? I'll go out and see.

OK I went out and swapped the vacuum advance tube to the front port and capped the second. But there's no difference at all in the idle or driveway revs. Runs great, just idles a bit high.

Anyway, anybody interested in doing some experiments on that stripped Nikki? I'd like to see somebody make it run right.

Ray,

I might be willing to do some experimentation with it. I was going to strip down my Nikki per the specs of the thread that I put together with all of the diagrams. However, if I had your carb already stripped then I could troubleshoot it and hopefully get it running right.

After that is done I can use my stock carburetor to do a complete writeup with actual pictures on stripping down the Nikki. I think the experience from tuning a stripped Nikki would make my own adventure much easier. It would also be a nice addition to the archives.

Jamie

Just another thought Ray, did you ever check the tension on your throttle cable? There is a chance that you had it too tight, which would obviously keep the car from being able to idle down properly since it would always be at partial throttle. I know that I myself have made this very same oversight on a couple of different occasions...

I think you'd be a good one for the experiment, I'm confident this thing would run great if it were hooked up right. I was very careful with the rebuild and it's my second Nikki, along with several other carbs over the years. And my first Nikki rebuild (that one stock a few months ago) is in the car and running fine, although I still haven't figured how to get the idle down to 750 (it's currently at 100 rpms, which is OK). I'll pm you with what it would be worth for me to put it in a box and send it out.

And yes the throttle cable has enought slack at idle, that's not the problem with my slightly high idle, although I'm thinking I might not have somethinq quite right with the throttle linkage and adjustments, so I'll be looking at that this evening.

Ray

The idle problem turned out to be this do-dad. Loosen the phillip screw, move it out a bit and then go back and forth between the carb idle and this gadjet. I'm getting a smooth 750 rpms on the stock Nikki and the throttle is very responsive. I'll have to go look it up in the FSM and see what it does, might have helped the stripped Nikki, I don't know.

http://memimage.cardomain.net/member...7_246_full.jpg