High engine idling

C_Breeze

Hey just thought i'd post this here to see if anyone here has any insightfull knowledge...


The battery in my car kept on dying for the past while so I brought it to an auto electrician and it was determined that the alternator has had its day.

Left it there for a few days and to get it sorted .

Went to collect it and paid E250.00 for parts and labour. .. He was explaining what was wrong with the alternator and that he fixed ("reconditioned")it but said something is definitely not right with my engine and i should go see a mechanic as it's not running right.... :eek:


I got in to drive it home and noticed that it certainly wasnt running well ... the car was is idling randomly and inexpicabbly anywhere between 2,500 - 3,200 rpm (engine warm) - this was not a sympton that was present when I initially left my car in for the alternator job.

They could have broken something or screwed something up when working on the alternator or it could have been a genuine coincidence that this happened while the car was in their hands

Anyone any ideas suggestion as im baffled

Whats could cause an engine to idle so highly and so irregularly.


Thanks

JHMEG

Is this your MX3?

Engine idle problems require a lot of pr1cking around to diagnose. And different manufacturers have different ways of doing things (eg Toyota use an electronic intake air bypass valve, aka choke, whereas Honda's is a wax filled mechanical valve), so someone might be very familiar with one manufacturer, but Mazda might do things differently.

Maybe Mazdas are prone to something going wrong with the idle, and someone might spot your post. Otherwise you'll have to bring it to someone who knows cars or a garage.

Not to rub salt in, but the alternator job would have taken less than an hour, and cost €10 in parts. At least it did the last time I 'reconditioned' one.

mike65

Idle control valve proberbly wonkey.

Mike.

Earth Worm Jim

C_Breeze wrote: »

Hey just thought i'd post this here to see if anyone here has any insightfull knowledge...


The battery in my car kept on dying for the past while so I brought it to an auto electrician and it was determined that the alternator has had its day.

Left it there for a few days and to get it sorted .

Went to collect it and paid E250.00 for parts and labour. .. He was explaining what was wrong with the alternator and that he fixed ("reconditioned")it but said something is definitely not right with my engine and i should go see a mechanic as it's not running right.... :eek:


I got in to drive it home and noticed that it certainly wasnt running well ... the car was is idling randomly and inexpicabbly anywhere between 2,500 - 3,200 rpm (engine warm) - this was not a sympton that was present when I initially left my car in for the alternator job.

They could have broken something or screwed something up when working on the alternator or it could have been a genuine coincidence that this happened while the car was in their hands

Anyone any ideas suggestion as im baffled

Whats could cause an engine to idle so highly and so irregularly.


Thanks

Could be the air mass meter - this causes symptoms like what you said - around 100 -200 euro to buy -

JHMEG

mike65 wrote: »

Idle control valve proberbly wonkey.

Mike.

Or possibly an electronic valve, ECU controlled, and some sensor is bad/disconnected and the ECU thinks the engine is freezing/stalling/not running and opening the valve to the max.

mike65

Bring back carbs!

Mike.

C_Breeze

Cheers for the replies

Yeah its my MX-3.

F***k I knew i got screwed on this one, I was told by somebody to expect a bill of up to 100 (i thought alternators cost in the region of 30 - 50 euro) - took me by surpise whe he asked for 250(parts & labour) but I paid it anyway as i had just gotten paid :rolleyes:

.. to add further insult to injury , before i suspected any issue with the alternator i bought a brand new battery for 105.00 and threw out the old battery which I thought was knakered but was probably still perfectly good.

I really dont want to put any more 100's into it and still not be able to resolve the problem or get any further - as i heard is the case with a lot of car idling problems, is this true?

So when a car is not idling properly its considered a fairly big engine issue yeah?

JHMEG

C_Breeze wrote: »

So when a car is not idling properly its considered a fairly big engine issue yeah?

From my own experience it can be an absolute b*stard to find the problem, but a cheap enough fix.

For staters: do you know is your intake air bypass valve, aka idle control valve, mechanical or electronically controlled?

mickdw

If running perfect before hand I would check if they disturbed something. Dont know the system in these cars however, check all wiring connectors anywhere near where they were working. make sure all pushed home. Also check air intake piping for tightness or cracks. Was the airbox removed for the job? Check everything. possibly air flow meter too. 95% chance that its down to something they did and I would have taken it straight back to them.
Its not an engine issue really but tricky enough problem at times.
The alternator job was not neccessarily a rip off. Sometimes the repairs are required to the internal wire windings or metal contact area due to wear etc and really its a exchange part then needing a factory rebuild and you would be looking at 150 for a recon one.

C_Breeze

Im not 100% sure if the idle control valve is mechanical or electronic .. but I would assume is electronic.

Mickdw, thanks for your input.

I checked everything around the engine and nothing seems out of place. Air filter is opposite side of engine bay to alternator so it does not seem to have been disturbed.


Anyway, had a chat with a local mechanic, he said its a b*tch of a problem as its hard to identify and you could end up spending money on replacing various parts and problem could still be persistent.

Is there any way to find out definitively what the issue is as opposed to guessing and spending money needlessly - maybe hook it up to a diagnostics machine or something along those lines?..

first time ive ever experienced this of engine issue so i'm a bit lost

C_Breeze

Just an update on this.

The problem has been sorted and engine is running like clockwork again...

The culprit ... a small split in the air pipe (the one running from the air filter box to the throttle body) which caused an air vaccum cuasing the engine to idle high!

after the car being parked up for a week and me thinkin it was fooked, i sorted it myself in literally 1 minute by wrapping some isolating tape around it!!




If anyone else ever has idling problems ..... look there first!!!! :rolleyes:

mickdw wrote: »

check air intake piping for tightness or cracks.

Spot on Mickdw!

Seth Brundle

C_Breeze wrote: »

...i bought a brand new battery for 105.00 and threw out the old battery which I thought was knakered but was probably still perfectly good.

What exactly did you do with the old battery?

chris85

kbannon wrote: »

What exactly did you do with the old battery?

He must have disposed of it bearing in mind the regulations of disposal of hazardous materials, which includes batteries! :rolleyes:

Seth Brundle

chris85 wrote: »

He must have disposed of it bearing in mind the regulations of disposal of hazardous materials, which includes batteries! :rolleyes:

Thats ok then - I misunderstood his original wording!

C_Breeze

I chucked it into the bleedin Liffey :rolleyes:

javaboy

C_Breeze wrote: »

I chucked it into the bleedin Liffey :rolleyes:

Did you have a WEEE in the Liffey while you were at it? :o