Idles low when in drive?

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Fiat88

Idles low when in drive?

Post by Fiat88 »

Trying to figure out why my spider idles low when I come to stops like at a stop sign or red light. In Park she idles good like 800-1000 rpms but when put in "D" gear she idles lower like 200 rpms but she never stalls. I've tried to adjust the carb using the idle scew, one by the linkage. Should I try adjusting the fast idle. Will that help maybe? Anything else could be my problem? Thanks for any suggestions.

32/36 DFEV 1800 intake- Auto trans
So Cal Mark

Re: Idles low when in drive?

Post by So Cal Mark »

the load of the auto trans is what drops the idle speed. The fast idle speed is only working when the choke is on.
Fiat88

Re: Idles low when in drive?

Post by Fiat88 »

So Cal Mark wrote:the load of the auto trans is what drops the idle speed. The fast idle speed is only working when the choke is on.
In drive shouldn't the idle speed be about 800 rpm Mark?
So Cal Mark

Re: Idles low when in drive?

Post by So Cal Mark »

I'd say something in the 800rpm range in D would be adequate. Set the idle speed with the lights on and the fan running so you know it won't stall with a load on the charging system
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: Idles low when in drive?

Post by bradartigue »

I believe the idle speed for the auto cars in P is 950 RPM; the expected drop should be 100-150 RPM. You're dropping 600 RPM or so it sounds. Didn't automatic cars have an electrovalve for when the car is in drive, to increase idle speed? Check your shop manual...automatics are a kind of mysterious thing to me.
Fiat88

Re: Idles low when in drive?

Post by Fiat88 »

So Cal Mark wrote:I'd say something in the 800rpm range in D would be adequate. Set the idle speed with the lights on and the fan running so you know it won't stall with a load on the charging system
Didn't think of that, will try it.
bradartigue wrote:I believe the idle speed for the auto cars in P is 950 RPM; the expected drop should be 100-150 RPM. You're dropping 600 RPM or so it sounds. Didn't automatic cars have an electrovalve for when the car is in drive, to increase idle speed? Check your shop manual...automatics are a kind of mysterious thing to me.
I only have the brookland book manual,not sure if I saw anything about an electrovalve. Anyone have a better book they can look in for me to see? Would appreciate it!
Fiat88

Re: Idles low when in drive?

Post by Fiat88 »

Maybe when I removed the emission stuff I took something else out I needed for the auto trans. Anyone know about that electrovalve?
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