MadDuck

PLEASE HELP:



Car Description:

83 12A



Car sat for about 1 year while I took my time putting a LSD rear in.



I also did following mods:

o 2nd gen DF

o 2nd gen fuse block

o 80 AMP 2nd gen alternator

o new clean spark plug wires

o I have a new red Optima battery.



I don't think there was a lot of gas in the tank while it sat. Then I filled it up with some premium gas.

The spark plugs are likely pretty fouled due to sitting and flooding many times.



I have only had the car on the road about 3 times since it sat.





Problem:

Frequently when I first start the car it starts up and idles high with the choke on.

BUT the idle is VERY rough. I can't explain it, but is very bad. It's like it is

stumbling or "missing". If I put the car in gear with this idle it will barely drive.

THEN if I let it warm up a few minutes with the rough idle and THEN rev the car

up to about 4.5 - 5 G RPM it will suddenly even out and idle/drive absolutely perfect.



I have not checked the timing because I need to locate the timing marks on the main pulley.



I think this used to happen to a lesser degree before any of my ignition mods.



NOTE: Once the car gets over that rough idle it is absolutely perfect.



What is happening?



Any advise will be greatly appreciated!!

j9fd3s

it olny does this with the choke on?

MadDuck

Well, its always a at-start-up condition, hence choke is on. I never tried disengaging the choke and checking. But generally I can get it to smooth out before the choke shuts itself off.



Hope this helps...



Jon

j9fd3s

couple things to check.



1. theres a little green delay valve on the passenger side of the carburettor, it goes to the choke plate, i dont remember why but when this goes bad it runs rough with the choke on, n201-13-980a is the part number, but i think you can just bypass it.



2. start checking the choke pull off diaphrams, if you've got a bad one, maybe the choke plate doesnt open enough, or doesnt close enough.

Rx7carl

Yea that sounds reasonable. Probably the choke isint opening in response to the fast idle speed. As a test you can hold or wire the choke to stay open when its warming up. See if that smooths it out, then youll know for sure its in that choke system.

MadDuck

Hey:



yeah, definately seems to be choke related. When I took to the car back to work at lunch yesterday I had the choke on and it had the usual gnarley idle problem. But when I left work at the end of the day I started and ran the car with no choke at all, I just feathered the gas to keep it at good R. When I didn't use the choke at all I did NOT have the rough idle problem. It ran perfect. Then I drove the car into work again this morning and again I didn't use the choke at all and NO IDLE PROBLEM.



SO: What do I look at? I am not familiar at all with how the choke hooks up to the carb.



Any help/explanation into the details of what to diagnose here would be GREATLY appreciated.



But I am really happy I have narrowed it down to the choke and it isn't a problem with the carb or the ignition or compression in the motor.



Thanx for all your feedback.



Jon

Rx7carl

Get the FSM or even a Haynes manual. Theres detailed instructions on testing the components.

j9fd3s

basically there are a couple of vacuum diaphrams on top of the carb, find the choke and basically these things are attached in some fashion.



and on the right side of the carb is a green valve, its the delay valve, its inline with a vacuum hose

MadDuck

sounds great guys, thanx.



I have the Haynes and the FSM PDFs. So I'll check those out.



I didn't even look at the car over the week-end, started to shift my attention to my over-neglected black-on-black 91 JSpec 13BT car... UGH!...



may the projects never end...