Chasing cold start warm up issue
 

Hi there, just got my first rotary recently which is a 85 GSL, there has been a small issue, when the car is warming up and chock knob is pulled, the idle is kinda rough. And if I use the throttle with the chock pushed in the idle is smooth during warm up.

Looked at both the chock linkage and diaphragm they seem working fine, also checked the chock delay valve and it's in good shape. So the question is, could it be related to other solenoid/valve when chock is used during warm up? I noticed the chock knob assembly sends a signal into the emission control unit but there's little infor out there regards what the ECU actually controls when the chock is used.

Any help would be appreciated. :nod:

The choke is electromagnet controlled via the temp sensor on the back of the water pump.

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

Its a manual choke, you need to adjust the choke right after start to get a smooth idle. The temp sensor on the back of the water pump will then let it pull in once it warms up. The other issues is the farther you pull the choke the higher the idle gets. If you are not seeing an idle increase then I would look at the fast idle linkage in the carb and make sire all is hooked up correctly. You don't mention if the idle increases or not.

So looks like it is a choke plate issue, checked the idle while play around with the chock plate, seems like it does not open enough once the engine is started.

Everything else in the choke system works as it should, fast idle cam, magnetic hold all works.


Checking the No.1 choke diaphragm, function as it should, inner vacuum tube has vacuum. However the outer vacuum tube (red circle in the first pic) does not have any vacuum when the engine is running, is it suppose to be like this?

https://cimg0.ibsrv.net/gimg/www.rx7...4765316a82.jpg

Looking at the vacuum diagram it looks like this hose is routed before the throttle plate(pic 2), so I assume there's no vacuum applied to this port?

https://cimg5.ibsrv.net/gimg/www.rx7...30c5205a17.jpg