High idle

Author
Discussion

daqinggregg

Original Poster:

3,095 posts

136 months

Tuesday 28th February 2023
quotequote all
Idle running high, 1,050 RPM. I like cars, but I’m not very knowledgeable on mechanics of modern cars.

Last year Mrs DG was driving her car, when the engine started to rev erratically, car put on a flatbed and recovered to a garage, I was at work at the time. Initially I thought a MAF sensor. Car 2008 1.8 Hyundai Moinca (Sonata in a tarts frock).

This was the part they replaced, problem solved.





But since, RPM has remained high. Being old school I’d just adjust the throttle cable, but it seems things have moved on since I liked to tinker.

When we take it to the garage, they plug in a simple diagnostic (what looks like a lap top) machine, near the fuse box on the drivers side, but seem unable to lower the RPM.

Any ideas

GreenV8S

30,486 posts

291 months

Tuesday 28th February 2023
quotequote all
daqinggregg said:
problem solved.

But since, RPM has remained high.
In other words, problem NOT solved.

That looks like an idle air control valve. A fault there could cause idle speed problems, but we've no idea whether it was faulty or whether there were any other faults conrtibuting to the problem.

E-bmw

9,976 posts

159 months

Tuesday 28th February 2023
quotequote all
GreenV8S said:
daqinggregg said:
problem solved.

But since, RPM has remained high.
In other words, problem NOT solved.

That looks like an idle air control valve. A fault there could cause idle speed problems, but we've no idea whether it was faulty or whether there were any other faults conrtibuting to the problem.
As above, the problem was NOT solved & you should have taken it straight back, which is what you now need to do.

daqinggregg

Original Poster:

3,095 posts

136 months

Wednesday 1st March 2023
quotequote all
Thank you for the replies.

When the fault occurred, Mrs DG reported that once the car was up to temperature, the engine speed would become very erratic, the car running rough. She said in you depress the clutch of put the car in neutral, the RPM would rise and fall very erratically. New part fitted, the revs are no longer erratic, now stable, just a bit higher at idle.

Now for a bit of context, here we have a very extreme climate, -35 in winter +35 in summer, add to this, the car was doing a lot of short journeys.

We live in the arse end of nowhere; most garages have limited diagnostic equipment, probably just use generic software. The lads we use are very helpful and try their best, but seem unable to get the idle lower.

I’m probably not very good at explaining this, as my knowledge of modern engine management system is zero; I just know the engine idle speed should be lower.

Belle427

9,744 posts

240 months

Wednesday 1st March 2023
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Maybe check the throttle body see if its clean.

Rich1973

1,214 posts

184 months

Wednesday 1st March 2023
quotequote all
An air leak on the inlet side of the engine somewhere would give you a higher idle.