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-   -   High cold idle (https://www.rx7club.com/new-member-rx-7-technical-256/high-cold-idle-940095/)

dludden 01-31-11 01:04 AM

High cold idle
 
I took my 1985 GSL-SE RX7 in for wavering idle between 900-1200 but wasn't fixed. Instead when I started it next morning the cold idle skied to 3000+. First, how does the cold idle work on this and how do I bring it down to more normal 2000 or so. Then after this is fixed how to fix the wavering idle? I know enough to bring down the air adjust screw all the way down to give a 800 idle. Thanks
I have instructions for idle problems but nothing on cold idle. Are dealer struts better than after market?

gracer7-rx7 01-31-11 10:05 PM

Normally cold start will rev the motor to 3000.

You may want to refer to the 1st gen FAQ while you wait for others to comment.

dludden 02-01-11 01:46 AM

Thanks, but it normally it revs to around 2000 give or take a few hundred. I've had this car since 2004 and when I got it back from a mechanic the next day it started reving up to 3000 at a cold start and the drove itself since the rev was so high. That said do you know how to bring down the cold idle? FAQ doesn't answer this. I have no idea how the cold idle works on this. I think the mechanic messed with something. Too much gas or air going in?
It does however go back down to normal running temp when warm. I can't stand this high cold idle, though.

wjk0817 02-01-11 02:58 AM

I have an 2nd gen. And my normal warm up will be 3k rev. If not it will be werid. And from 3k it will drop down in about 30sec, and after a minute, a regular drive :)

gracer7-rx7 02-01-11 09:45 AM

Have you checked the throttle cable? Perhaps he shortened it a bit when he reattached it.

dludden 02-01-11 01:50 PM

cold idle
 
I also have a GS and I pull the choke out so that it revs at 2000 from cold start which is what my GSL-SE used to do. I don't know why you think 3000 is OK because that high I can't even control it with the gas pedal. And it takes a couple of minutes for it to start to come down. Does this car have a throttle cable
that controls the idle like the GS. Could the throttle plate be stuck open a little letting too much air in. It seem also to have lost a little power.

RotaryRocket88 02-01-11 02:41 PM

The engine in a GSL-SE is going to be roughly what you'd find in an S4 NA (2nd gen). It's a fuel injected 13B, so there will be considerable differences between it and a carbed 12A. Take a look in the 2nd gen FAQ for suggestions.

A bad TPS can cause symptoms like this, or a sticking throttle cable/plates. You've also got the thermowax on the throttle body, which is there to raise idle speed when the coolant is warm. Under normal conditions, this should only be about 1.5k RPM. The BAC and air supply valve (ASV) should deliver additional air on cold starts, which will boost idle speed up to about 3k RPM. But it should go down after ~17 seconds (or at least it does on an FC).

dludden 02-02-11 02:21 AM

cold high idle
 
Thanks, maybe the mechanic did something to the TPS, throttleplates,cable.
It wouldn't go from good for several years and then all of sudden after the mechanic looks at it the idle go way up to 3000 and stay there for a minute or two. before gradually coming down. I checked 2nd gen FAQ and there was something on the TPS but the site was down for maintenance.

RotaryRocket88 02-02-11 12:43 PM

Fixed the FAQ. That dead teamFC3S.org link was in there twice, and it's now replaced with a thread within the forum: https://www.rx7club.com/showthread.p...hreadid=235007.


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