Car driven with no air intake...

Car driven with no air intake...

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Discussion

mx5tom

Original Poster:

573 posts

173 months

Wednesday 31st October 2012
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I noticed my car was idling quite rough driving home yesterday. It was idling a bit higher than normal, then drop to nearly stalling and then shoot back up again, etc.

Anyway, I pulled over, opened the bonnet and found the air intake had become loose and was completely disconnected. It was still in the engine bay, just disconnected from the throttle body.

I don't know how long it's been like this. I topped up my washer fluid last week and didn't notice it then, but in theory it could well have been like this a while. On the other hand, it was really obvious when driving it that something wasn't right, so if it had been disconnected for a while, surely I would have noticed sooner?

Anyways, that's beside the point. The air intake is reconnected and the idle settled back down immediately. The car seems fine now.

Obviously, I'm concerned that I may have in some way damaged the engine from running it without an air filter for an unknown amount of time. What the best thing to do at this point?

A quick google suggests mixing injector cleaner in with the fuel, oil change, etc. Anything else?

HustleRussell

24,637 posts

160 months

Wednesday 31st October 2012
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I wouldn't bother- it'll be fine.

TheEnd

15,370 posts

188 months

Wednesday 31st October 2012
quotequote all
You'd got filters to take care of that.
There's unlikely to be any damage, and nothing particularly important to do as a matter of urgency.

Killboy

7,252 posts

202 months

Wednesday 31st October 2012
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I wouldnt worry about it too much, not much you can do. Not sure on the engine, but its likely that the idle issue is because the airflow meter was not measuring airflow as it was disconnected. Its likely only been loose since the car started running odd.

This could be complete BS too. :P

kambites

67,543 posts

221 months

Wednesday 31st October 2012
quotequote all
Unless you've been driving through sand-storms, it'll probably be OK.

I can't imagine what you could do about it anyway - if anything big enough to cause damage has got into the cylinders and scored the bores, the damage is already done. I'd have thought it's highly unlikely that anything is lodged in the cylinder but hasn't yet caused any damage.

mx5tom

Original Poster:

573 posts

173 months

Wednesday 31st October 2012
quotequote all
TheEnd said:
You'd got filters to take care of that.
There's unlikely to be any damage, and nothing particularly important to do as a matter of urgency.
Just to be clear, there was no filter connected. Well, sort of. There was nothing connected to the throttle body, it was completely open.

The air intake (and filter) was still otherwise in place, just not connected to the throttle body. So I suppose the air 'was' getting filtered, but just not going directly where it was supposed to.

The rest of the engine bay is so dusty though it's just a bit worrying.

E30M3SE

8,467 posts

196 months

Wednesday 31st October 2012
quotequote all
mx5tom said:
A quick google suggests mixing injector cleaner in with the fuel, oil change, etc. Anything else?
I wouldn't do a thing if all is now normal.

Probably hadn't been like that for long.

Greg_D

6,542 posts

246 months

Wednesday 31st October 2012
quotequote all
Killboy said:
I wouldnt worry about it too much, not much you can do. Not sure on the engine, but its likely that the idle issue is because the airflow meter was not measuring airflow as it was disconnected. Its likely only been loose since the car started running odd.

This could be complete BS too. :P
sounds the most likely explanation to me as well

Chill winston, it'll be fine...

Mr MXT

7,691 posts

283 months

Wednesday 31st October 2012
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It'll be fine.

It it makes you feel better loads of the big power turbo cars on Youtube run without an air filter.

mx5tom

Original Poster:

573 posts

173 months

Wednesday 31st October 2012
quotequote all
Fair enough smile

Thanks.

TheEnd

15,370 posts

188 months

Wednesday 31st October 2012
quotequote all
mx5tom said:
Just to be clear, there was no filter connected. Well, sort of. There was nothing connected to the throttle body, it was completely open.

The air intake (and filter) was still otherwise in place, just not connected to the throttle body. So I suppose the air 'was' getting filtered, but just not going directly where it was supposed to.

The rest of the engine bay is so dusty though it's just a bit worrying.
Yep, but things like injector cleaner - the fuel system shouldn't be affected, and it'll cycle through the fuel filter anyway. Fine dust and particulates might have gone into the engine, and they should be screened by the oil filter, so it'll be self healing in a way if there is any dust about.

jimxms

1,633 posts

160 months

Wednesday 31st October 2012
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Unmetered air entering directly around your throttle body would have caused lean situation (too much air, too little fuel) resulting in much higher combustion temps and potential engine damage.


Naaaa.....you'll be fine.

sparkyhx

4,146 posts

204 months

Wednesday 31st October 2012
quotequote all
mx5tom said:
Just to be clear, there was no filter connected. Well, sort of. There was nothing connected to the throttle body, it was completely open.

The air intake (and filter) was still otherwise in place, just not connected to the throttle body. So I suppose the air 'was' getting filtered, but just not going directly where it was supposed to.

The rest of the engine bay is so dusty though it's just a bit worrying.
the key is whether its before or after the AFM, if its before then its probably ok you are just risking dust/water.

If its after the AFM then unmetered air will have gone into the engine aand the ECU will throw in fuel only for what the AFM has measured - i.e. very little and therefore it could have run very lean with potential DET and piston/engine damage.

beaten to it .......I shouldn't have taken that phone call



RobCrezz

7,892 posts

208 months

Wednesday 31st October 2012
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It probably hasn't been like it for long as you would notice if it was taking in unmetered air (which I assume was why you noticed it was running poorly).

Probably done no damage, but its not that expensive to change the oil and oil filter if you want to be careful.

sparkyhx

4,146 posts

204 months

Wednesday 31st October 2012
quotequote all
RobCrezz said:
It probably hasn't been like it for long as you would notice if it was taking in unmetered air (which I assume was why you noticed it was running poorly).

Probably done no damage, but its not that expensive to change the oil and oil filter if you want to be careful.
I would suggest the chance of lean running would be considerably higher than the chance of a foreign body.

Still if you caught it early enough and were only pootling you will probably be ok. A motorway blast on the otherhand..............

mx5tom

Original Poster:

573 posts

173 months

Wednesday 31st October 2012
quotequote all
Having thought about it, I was a bit wrong. It hadn't disconnected at the throttle body, but the air filter unit (it's a cone filter) had disconnected from the tubing with the AF..M. (Air flow meter?). So the AFM was still reading the air going into the throttle body, albeit unfiltered air.

So seems like it's the better of the two situations.

I [i]hope/i] it only happened recently. I only noticed yesterday when I was stuck in traffic, and the rough idle was very apparent. Once up to speed it was less (if at all) noticeable. I don't usually drive in heavy traffic so don't really spend much time stopped, so may not have noticed.

Ah well. It's due a service around the end of December, so might just push it up to a bit sooner.

nosittap

381 posts

145 months

Wednesday 31st October 2012
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Me and a friend bought a Hyundai Accent for a road trip, he used it as his daily for around 3 months and covered 2000 miles. Before the trip we gave it a service and found it had no air filter, replaced it and off we went, lack of air filer had no effect, it went over 8000 all the way to Mongolia without missing a beat.


sparkyhx

4,146 posts

204 months

Wednesday 31st October 2012
quotequote all
mx5tom said:
Having thought about it, I was a bit wrong. It hadn't disconnected at the throttle body, but the air filter unit (it's a cone filter) had disconnected from the tubing with the AF..M. (Air flow meter?). So the AFM was still reading the air going into the throttle body, albeit unfiltered air.

So seems like it's the better of the two situations.

I [i]hope/i] it only happened recently. I only noticed yesterday when I was stuck in traffic, and the rough idle was very apparent. Once up to speed it was less (if at all) noticeable. I don't usually drive in heavy traffic so don't really spend much time stopped, so may not have noticed.

Ah well. It's due a service around the end of December, so might just push it up to a bit sooner.
stop worrying you will more than likely be fine

Rickyy

6,618 posts

219 months

Wednesday 31st October 2012
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You will have scored the inside of the bores which will have increased cylinder capacity, which in turn will have increased performance.........


Seriously, I'm sure it will be fine.

g3org3y

20,627 posts

191 months

Wednesday 31st October 2012
quotequote all
sparkyhx said:
stop worrying you will more than likely be fine
Exactly. There's not much you can do now to change things regardless.

Put it to the back of your mind imo.