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Discussion Starter · #1 ·
as the title suggests, i have an idle swine...of a problem. anyway, mi mate brought his 6 over today, to try sort out a high idle problem. Following Johns advice, we ground + ten, and adjusted the idle control screw, which i may add was already all the way down (??). So I got him to switch off, totally unsrew the valcve and re grnd+ten, still same issue. We could only get it to idle at 750....anything else we can check? He says its due a service, and will do the Ht leads at the same time, but it strikes me that there is something else causing his high idle. The car drives fine otherwise he says, with only a small amount of power loss (service due tho). We didnt reset the ecu, OR check the timing, because it struck me that the timing MUST be fine, as the engines purrs nicely, and otherwise runs fine...

??
 

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Sounds like a stuck bac/aic valve buddy .. unplug the white connector to the black cylinder at the bottom of the throttle body and see if there is any change.. if not .. pretty much the culprit.

As for the bleed screw. fully in .. 3 back.

Paul.
 

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Discussion Starter · #3 ·
interesting, will get him to do that, thanks a lot Paul!
 

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yea sounds like that, ive got a spare if u need it, or is the throttle stop set wrong holding the revs on, it wants to be set so it does not rev the engine but does not let the throttle flap shut so far it sticks. takes 5 seconds to set it right.
 

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either that, or a loose or disconnected pipe/airleak..

John
 

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Sounds like a stuck bac/aic valve buddy .. unplug the white connector to the black cylinder at the bottom of the throttle body and see if there is any change.. if not .. pretty much the culprit.

As for the bleed screw. fully in .. 3 back.

Paul.
Should that be done when the engine is at normal operating temperature yes?

Elmer
 

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Yes...

The BAC (bypass air circuit) is like the choke. it works via coolant flowing through the valve body... once warm, it shuts off the valve..

The ISC (idle speed control) is used to control the idle........ but to be more exact, it's really an "Idle up" device... when a load is put on the engine, such as power steering, A/C or high current electrical devices.. the ISC valve opens to raise the idle speed slightly so it doesn't stall the engine.

The Idle speed itself is set primarily with the air screw, and then maintained by the ECU.

In your case, if the ISC valve is stuck open, the revs will be slightly higher..

Luckily it can be cleaned........ watch out for the spring and valve inside... :)


John
 

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Discussion Starter · #8 ·
ok, I will warn him john...springs...valves.....this spells danger and awkwardness!
 

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Yes...

The BAC (bypass air circuit) is like the choke. it works via coolant flowing through the valve body... once warm, it shuts off the valve..

The ISC (idle speed control) is used to control the idle........ but to be more exact, it's really an "Idle up" device... when a load is put on the engine, such as power steering, A/C or high current electrical devices.. the ISC valve opens to raise the idle speed slightly so it doesn't stall the engine.

The Idle speed itself is set primarily with the air screw, and then maintained by the ECU.

In your case, if the ISC valve is stuck open, the revs will be slightly higher..

Luckily it can be cleaned........ watch out for the spring and valve inside... :)


John
Thx john

>>Noob question<<
Do you have any pics of where the BAC and ISC is?

Mark
 

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They are together in one unit.. Item 9 in first pic...

The ISC is the round bit sticking out in front..






John
 

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Discussion Starter · #11 ·
ok, so we checked what john suggested, all aprt from removing something to clean it, because we were not sure what part we were to remove. The black cylinder type thing seemed pretty stuck fast, removing the plug resulted in no change to the revs - idling at 1000rpm...any other ideas??
 

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Discussion Starter · #12 ·
ok, it would seem it was a screw, on the accelerator cable clamp thingy-no idea what its called but the bit yuou push inside the engine bay to make it rev...mi mate says tne AA found the screw had come adjusted, and stuck, so it was sticking. NOT 100% sure which screw, but he sorted it by putting on a new screw...!
 

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yea sounds like that, ive got a spare if u need it, or is the throttle stop set wrong holding the revs on, it wants to be set so it does not rev the engine but does not let the throttle flap shut so far it sticks. takes 5 seconds to set it right.
Looks like mazdamatt got this one :tup:

Paul.
 

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Discussion Starter · #14 ·
certainly does Paul, thanks Mazda Matt!

latest news is-all running sweet, just needs and ECU reset then hes sorted! another MX6 saved!
 
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