Rough idle on 2007 Aygo

[DavyBoy888]

I'm new to the forum,  and to Toyota ownership.  I have a question/problem I hope someone will be able to help with.

My recently purchased 2007 Aygo has quite a rough idle.  It clears up fine when the engine's revved a bit but it idles really badly to the point where the steering wheel and seats are shaking.  Today I removed the air filter housing as well as the throttle body and MAP sensor... and cleaned them all out with Wurth air intake cleaner.  The weren't all that dirty to be fair but in any event it hasn't made any difference.  Anyone any suggestions on what I could look at next ?

Huge thanks in advance for all your help.

[haelewyn]

Rough idling : my first idea would be ignition.

 

Spark plugs, coil...

But then it would shake hard, if a coil is gone,as only 2 out of 3 cilinders would be working.

Read out from the obd and see if there is an ignition problem, maybe misfiring.

 

I would think Map sensor first too cause you say it gets better when revving a bit.

However... Can't see , hear or feel it from here.

If a coil is gone, I guess you know some tricks to detect.

See on the obd computer if you have misfiring. Change the coil to an other cilinder and see if the coil follows.

Buy decent coils as a replacement. Not cheap Alibaba rubbish.

[DavyBoy888]

Thanks so much for the reply Ivan.

I've had coil packs go on other cars and they generally misfire all the way through the rev range and as you say,  they shake very hard.  This is just a rough,  make that very rough, idle.  It appears fine when revved.  Furthermore I've got Torque Pro and did a fault code scan before pulling the intake system apart and it's completely clear of faults.

I'm going to do a live data interrogation with Torque today to see what the MAP sensor's reading at idle... that would give an indication of air leaks in the manifold I guess.  Any idea what that should be at idle on a 1KR-FE ?

 

Again,  massive thanks for all your help here.

 

[haelewyn]

Did you check the spark plugs and wires ?

Vacuum leak and injector problem are next on the list of likely causes, I guess.

 

Is your car jerking while driving ? I remember that is one of the signs too when map sensor fails.

[DavyBoy888]

Haven't checked the plugs or their gaps yet,  nor the HT wires... gonna do that today... but when I have had electrical issues,  they generally tend to be more than just at idle.

Sorry missed the second part there... the car doesn't exhibit jerking when driving.

Ya vacuum leak is what I'm trying to rule out now.  I'll listen to the injectors with a stethoscope today as well... but I know that alone's not fool proof unfortunately.  I've got some STP that I'll run through the system as well when I start to drive it later this month... but I suppose it's best test/measure one thing at a time to diagnose the fault.

Hopefully if I can get to the bottom of it,  the thread will be helpful to somebody else in the future.

Thanks so much.  

[haelewyn]

I understand your thinking.

I would always try to rule out ignition first just cause it's more simple and cheap to do.

Recently bought 2007 Aygo ... I would think if you are lucky you take out one nasty ugly spark plug and you're done solving the riddle. 😄

 

Sometimes these faults are in a far away and dark corner but more often they are closeby, simple and overlooked.

Good luck !

 

Edit :  some general information on map readings >> see google.

 

[DavyBoy888]

Ya it's a good point... it would be great if it was a shot plug wouldn't it 🙂

Will report back on how I get on today.

Thanks for all your help here.

[DavyBoy888]

OK... the report back :

 

o  Manifold Absolute Pressure was around 300-320 Pascals at idle.  I think that's around about where it should be.  The MAP sensor read atmospheric pressure when ignition was on but engine not started.  When the engine was started and given time to settle down it got to around 300 Pascals.  It's worth noting that the temperature was quite cold outside today - around about 4C

o  I removed the PCV valve... it was a little dirty but not that much.  Nevertheless I cleaned with air intake cleaner and blew through it - to ensure it allowed air to pass through - and sucked on it - to ensure nothing was able to go the other way.

o  I removed all three plugs and you can see what they look like below.  The plug gaps appeared to be all around the same... and quite large... looked to be around 2mm.  Let me know what you think of those plugs [I can get higher res images if you need them] as everyone has their own opinion on plug reading 🙂

 

 

[flash22]

New plugs required you can drive a bus through that gap, they look like the engine is running very rich or just very old plugs

I'm surprised that hasn't thrown a MIL

off the top of my head, the gap should be 0.8 - 1.1mm

[DavyBoy888]

5 minutes ago, flash22 said:

New plugs required you can drive a bus through that gap, they look like the engine is running very rich or just very old plugs

 

Ha ha ha... I think it's the largest gap I've ever seen on a set of plugs !  I thought I'd check with you guys in case that's an Aygo thing or something but it looked very odd to me.  I'm ordering a set of Denso Iridiums and we'll see how we get on with those.

[flash22]

They have been changed as they are NGK LFR6C-11 plugs, Oem is Denso and these engines tend to run better on them, Denso K16HR-U11 are the standard plug

£3.58 each delivered

https://www.ebay.co.uk/itm/161450180432?

The platinum are £10 a plug (SC16HR11)

[haelewyn]

I would advise to replace them too.😁😇

Too black, big gap... Too much of dark stuff on it.

What's the mileage on your car ? Does it consume oil ? I would check that in future... Probably too soon to say now.

Be aware the oil content in total is less than 3 liters.

Cars that use 1 liter per 600 miles don't go on long.

I couldn't imagine these plugs are in use for 40.000 km / 26000 miles or so.

😇Let us know what's the difference in driving after spark plug change.

[DavyBoy888]

I'm not sure whether it consumes oil or not as I've not driven it yet... we'll soon find out though 😧

The mileage is 69K... so not massive.

Will of course.  Gonna bang in an order to Opie for oil,  filter,  plugs etc... probably tomorrow.

Huge thanks guys for your help.

[haelewyn]

 

Always happy to discuss this... And here's a little extra cause you said thanks already so often 

https://www.championautoparts.com/Parts-Matter/automotive-repair-and-maintenance/how-to-read-spark-plugs.html

My first idea was that the black comes from oil or it looks like a plug from a drowned engine. Touch or smell them. Is it oily or dry ? 

I heard a guy once who told me he bought second hand spark plugs for his car. It seems like the previous owner did the same, a long time ago !

[DavyBoy888]

They're dry.  It looks more like carbon deposits rather than oil to be honest... or possibly 'oil fouled'.  If the spark's not strong enough or intermittent at low revs,  maybe the charge isn't being burnt properly ?  I'm probably over speculating now.

You could well be right about the plugs... people do all sorts of crazy things don't they 🙃

Thanks for the Champion guide though,  that's really useful.

[flash22]

Just old and carbon fouled, black usually means rich, short journeys and the engine that doesn't quite get up to temp and/or supermarket fuel, 30-40k  miles on a set of standard plugs is about right for a 1KR

It should gain a bit of power with new plugs and an oil change

[DavyBoy888]

Thanks Bob... hopefully it should.  I'm gonna fit Iridium plugs to the car anyway.

[haelewyn]

Air filter still ok ?

Do they get dirty easy on Aygo ? Different cars, different habits.

 

 

 

 

 

 

 

[DavyBoy888]

Ya the air filter's fine,  but I'm gonna replace it anyways.

Ordered all the bits up today from Opie - my go to place for this stuff 🙂  So hopefully they'll arrive before Christmas.

[Puglet]

Good idea, worth giving it a full service so you know what's what, what I do when service history is questionable. I fitted Denso KH16TT to our similar 107 few years ago, I usually fitted NGKs to our cars for years, but stuck with Denso's for our Toyota engine, and it runs great. It was running ok on the originals but when our low mileage car hit 10 years old, decided refresh. Went TT ones cos they supposidly better start and economy, but they were also cheaper than the bog standard ones. 

 

[DavyBoy888]

I've always found Iridium plugs better than the standard ones - the IHK16TT's are a little pricier now though,  possibly due to the rise in the cost of precious metals.  They should probably outlast the car... in theory anyway 🙂

[Puglet]

Funny you should mention that, on other sites heard they were bit OTT for these ickle engines, so I was unsure which way to go, but think my 107 manual said originals were good for 40K, know what you mean about them being long lasting, but our 107 doesn't do mega miles so stuck with the nickel ones. Think the later first gen cars had iridiums as standard, so Toyota must know something. Either way, I'm of an age where I used to religiously change spark plugs every year so long service life on plugs today helps the pocket! 

[haelewyn]

And you only need three of them. That's nice too.

[DavyBoy888]

So I replaced the plugs,  I also changed the oil,  oil filter and air filter.  As above,  I cleaned the MAP [measured the manifold pressure which is normal] and also the PCV.  Idle seems to be a little better,  but we're not there yet.

When I rev the engine,  it vibrates and misfires from shortly after idle through to about 1500rpm or so.  I need to put the scanner back on in live data mode to get the exact rpm when it's missing [as the car doesn't have a tachometer] but it feels in/about that range.  It also struggles under load when pulling away from roundabouts traffic lights etc...  From 1500rpm upwards it's completely fine - revs and drives normally.  This happens whether driving or stationary,  so it's not transmission related.

Again,  there's no check engine light on and no error codes being reported.  

[flash22]

Have a look at the misfire counters, coil packs do fail, failing injectors can be another issue