Hey all,
Recently got my Nikki rebuilt in preparation for my engine swap. Got everything all hooked up and when I fully pull out the choke to get the car going when it’s cold it revs to an obscene amount. It used to hold the idle at about 2.5k RPM with the choke fully pulled out but now is at about 4k. How can I go about adjusting this so I don’t grenade my engine off a cold start. Thanks

 

Your choke only stays out at full engagement? Mine always has stayed out at any point in its travel. I can choose what RPM to adjust it to for warmup. Usually 1,500 - 2000 RPM which is probably 3/8 to 1/2 of the way out. Could be the magnetic part of the choke cable is malfunctioning?

 

No it’ll stay out at any point and go in automatically like it always used to so I don’t think it’s the magnet. It’s just that with the choke fully out it holds the RPM at a hilarious amount in comparison to what it used to. Fully engaged before the rebuild it was about 2.5K RPM and now with the choke fully engaged it hold at nearly 4.5K RPM. I was curious if maybe the choke cable got tightened or loosened and is causing the choke plate to open up differently than before.

 

I'm pretty sure my stock 12A would idle at +/- 4,500 RPM when it was fully engaged.

As Banzai suggested, once the engine has started you can reduce the RPM by gradually pushing the choke **** in.

So maybe your choke is working properly now .. and it wasn't fully engaging prior to the rebuild?

 

The choke is magnetic. Once the engine is at temp, via the sensor on the back of the water pump, it signals the magnet to release. Like others have mentioned. when it is working correctly, you can adjust it the the desired RPM for warmup. Full out mine is between 2-2.5K RPM but I normally adjust it to say 1.5K for warmup.

 

Speaking of the choke, anyone know where to buy a replacement choke sensor. I would imagine this is a common issue as the same thing happened to my uncle and I. When we replaced the water pump on our cars (12a 1983 & 1985), the wires were so brittle and corroded near the sensor that they broke off during the installation.

 

These are NLA, No Longer Available. If you have the old one, they can be repaired by removing the red epoxy coating and soldering back together.

I have several used ones stashed away.

 

I agree, I will most likely pull one out of my uncles parts cars to try and solder it.

 

I see, full out for my choke is now about 4.5K RPM and I wish it would be at 2.5K RPM full out like yours.

 

Even the carb manual says to adjust to pullout choke to 2K. Look at page 76. I don't think the choke is calibrated to a certain RPM full out. You might be able to adjust it at the carb. Might also look at the Choke Delay Valve (page 77).

https://foxed.ca/rx7manual/manuals/m...01979-1985.pdf

 

It's been a while since I have been able to use my choke where it keeps the rpm held since the wires broke off. I now have to pull and hold it manually until the engine warms enough to idle without dying. My question to you is - aren't you able to step on the gas pedal and hold the rpm at the desired rpm? Not sure if I am remembering correctly but I do recall stepping on the gas pedal and holding the rpms between 1500-2000rpm when I pulled the choke all they way out.

 

I never thought of the choke being necessary to hit a certain RPM, rather I've always used it to get the car started and to run at an RPM high enough to keep going and to run smoothly but not maxed out.

As the car warms up I generally release the choke incrementally

While you can use the gas pedal to increase the RPM while the choke is pulled, in my car it creates a floor value RPM until the magnet releases.

 

ok, that makes sense. I have always used it to warm up my car quickly. When it was still operational and on my previous rx7 - I would press the gas peddle and rev the rpm's to about 2-2,500rpm and hold the rev by pulling the choke out. Once the car warmed up, it would go back to regular idle which would advise me the car was ready for me to hop in and take off as i heard it from inside the house.

 

It's adjustable, it's just fast idle. There's another throttle looking cable going to your carb that has a nut on it. Just spin that in or out to adjust max choked idle speed. You gotta take off your air filter to access it but it should be near the top of the carb on the firewall side.