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Dashpot Delete on 1990 NA6

Old 10-16-2018, 01:38 PM
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Default Dashpot Delete on 1990 NA6

I just got my hands on a 1990 NA6 Miata and was planning on going turbo by next summer. I am going to be running the MegaSquirt DIYPNP and had a question about the dashpot on the throttle body. From my understanding it is there to prevent the throttle plate from closing to quickly and prevent idle-dip. I'm curious if it is possible to delete the entire dashpot since I would be able to use a "virtual" dashpot using the dashpot adder option on Megasquirt? I just want to keep the throttle body as simple as possible.

If there is anyone that has done this before please let me know what settings you used. I am new to this forum and using MegaSquirt so any help would be appreciated, thanks!
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Old 10-17-2018, 11:23 AM
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I mean, you can? But it works super well so I would just leave it.

Try it and report back.
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Old 10-17-2018, 12:54 PM
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I'd have to agree with x_25 on this.

Can you remove it? Sure.

Should you remove it? Not in my opinion. You'd be replacing a very simple, extremely reliable system which pretty much works perfectly without having to think about it with a complicated software solution that you'll have to tune. As a broad generalization, idle control, which seems like it should be simple, can be one of the more frustrating elements of any MS install.
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Old 10-20-2018, 03:55 AM
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Thanks for the advice, I guess you're right about not deleting it.

The real issue that I am having with idle right now is on cold mornings it starts to hang around 1200-1500 when I let off the gas, even when the coolant temp. is in the middle of the gauge.
It goes back to idling normally after I drive around for about 15 min or so, but I don't remember it doing this before I cleaned the throttle body.

I am thinking that the dashpot is just sticky when it's cold and that is causing the high idle? I'm not sure, I am new to these cars so any input would be appreciated.
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Old 10-20-2018, 09:58 AM
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At the current age of any NA, yeah, it's probably sticking. Your IAC is also probably failing, and the car probably has ED.

Just a little 1.6 idle background; it actually has three components. There's the standard electric IAC, the mechanical dashpot, and also the coolant controlled IAC. That's the thing sitting on the side of the manifold with coolant lines going to it. Because of these other independently controlled devices, the electronic IAC functions in a very narrow range compared to an NB. Depending on the condition of yours, you may find it struggles to operate outside of this range when you remove either of the other two, or simply just try to program a different idle than factory.
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