Re: Fast/erratic idle and engine run-on 1.8 8v Carb

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timmaaah
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Re: Fast/erratic idle and engine run-on 1.8 8v Carb

Post by timmaaah » Sat Aug 25, 2018 9:16 am

Hey - the missus's 92 GT2 will sometimes idle at high revs - 1200 sometimes 1500 sometimes 2000rpm. A few blips of the throttle will usually make it settle down. It's had a Weber conversion at some point in it's life.

Also very occasionally the engine will keep running for a few seconds after the ignition is turned off (running on?)

Aside from these two issues, the engine is fine, pulls as it should, is not using any more fuel than normal. It may "smell" a bit more, but that is subjective I guess (by smell, I mean like cars used to smell before catalytic converters!!). What should we be looking at/for?

Cheers :-)



mark1gls
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Re: Re: Fast/erratic idle and engine run-on 1.8 8v Carb

Post by mark1gls » Sat Aug 25, 2018 9:27 am

2 things I would be looking at, timing may be a little off, vacuum leak could cause this?
Fuel mixture may be a little high, check colour of the spark plugs.


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james butler
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Re: Re: Fast/erratic idle and engine run-on 1.8 8v Carb

Post by james butler » Sat Aug 25, 2018 7:38 pm

no one suspect is air leak.
get some brake cleaner or wd40 and spray liberally over the carb joints, carb flange, manifold joints and the vac pipe to the brake servo.
weber carbs also suffer from chronic spindle wear and suffer from air leaks which manifest problems at idle but not when on throttle.
when you spray flammable liquids where theres an air leak the engine will change note indicating where the air leak is.


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chopperoli
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Re: Re: Fast/erratic idle and engine run-on 1.8 8v Carb

Post by chopperoli » Tue Aug 28, 2018 2:37 pm

there as a fuel shut-off solenoid available for the DMTL, to stop run-on