Engine vibration@2k RPM, I want to pick your brains guys...

[Yiannis197]

ok bear with me with this one please....

I was driving the other day and while i was stopped at a traffic light the revs went up to 3k and stayed there for a couple of seconds. Before I think wtf etc the car went into limp mode, the stop and spanner indications went on and an error message read ''Injector Failed''.

I knew enough not to start panicking so I pulled over, I switched the engine off and then back on again BOOM no problems. As if nothing happened, the car was as it used to etc. No problems with that. Here I would like to mention that sometimes when the engine is cold and I blip on the throttle the revs go up to 2-3k and stay there so I have to engage a gear and lift the clutch slightly so as to drop them. This last about 10-15secs and then the car behaves normally which makes me think that the TB is on his way out? Just a guess but it's happening more and more often...

Anyhow, today I decided to take the car to my local mate/mechanic and plug the diagnostics pc in. The error that came up was ''Pedal Sensor Circuit Incoherence''. Again, I wasn't bothered because I thought that this had to do with the Sprintbooster.

However, and this is where the true problem lies, when my mate was messing about with the throttle and the revs etc we realised that at about over 2k rpm the car has a vibration. A quite noticeable one I might add. I've never noticed it and I really don't know when this started occurring because obviously I don't take the revs up to 2k and hold them there. I can not feel anything when driving, it only occurs when the car is stopped and the revs and 2k.

Moreover the guy told me (after listening to the engine with a thing similar to what doctors have, don't know the name of it) that the engine does not operate as smoothly as it gets and that every now and then it kind of kicks/knocks. Now this is difficult to explain but what I did was to place a glass of water on it when the engine is on. Here is a video.

https://www.youtube.com/watch?v=-uCOcedMZ7U

You can see that the pattern of the glass/water movement is not the same. (@5th second is quite clear and towards the end).

Now my question is what could cause this vibration? Would a bad cam timing do such a thing? Engine mounts? The top stabiliser has been replaced as well as the lower mount. Are these two things (or three if you include the error fault) connected somehow?

Sorry for the essay, any help greatly appreciated.

 

[Foxspeed]

mine always had a bit of a rough patch around the 2000-2500rpm and this also corresponds to the lambda test revs...

could be a few items and might be worth checking the plugs and wiring to injectors and throttle body also get your mate to check the o2
sensor voltages to see if they are changing quickly..

checked the throttle body to see if its clean?

 

[Stephen]

Could be you need to clean your TB, Chris with the AG 200 just had something similar so cleaned his and it was pretty bunged up.

 

[Yiannis197]

Thanks for your responses.

I cleaned my TB about 6 months ago, it was filthy indeed at the time but I can't see it being dirty in such a short time unless of course the Ktec filter is not doing its job properly...I'll have a look nevertheless.

Plugs have been changed at the last service and the old ones were not in a bad state anyway. I'll have them changed again at the next service just in case. No misfiring reported by the way so if I had any issues with any of the coil packs wouldn't that show in the diagnostics software?

I'll also have the O2 sensor checked as well just in case.

Foxy when you say that yours had a rough patch would it vibrate as well? Was the idle as rough as it is mine?

Also, can a slightly off cam timing cause something like that?

 

[lemonnobby]

Cam timing can cause that check your top engine mount is not sagging as this can cause problems.
The throttle thing sounds like the pedal or sprint booster is playing up.

 

[Foxspeed]

Thanks for your responses.

I cleaned my TB about 6 months ago, it was filthy indeed at the time but I can't see it being dirty in such a short time unless of course the Ktec filter is not doing its job properly...I'll have a look nevertheless.

Plugs have been changed at the last service and the old ones were not in a bad state anyway. I'll have them changed again at the next service just in case. No misfiring reported by the way so if I had any issues with any of the coil packs wouldn't that show in the diagnostics software?

I'll also have the O2 sensor checked as well just in case.

Foxy when you say that yours had a rough patch would it vibrate as well? Was the idle as rough as it is mine?

Also, can a slightly off cam timing cause something like that?

it had an underlying vibration - yes - but idle was smooth and consistent

as for off timing it would also be down on power

best off checking all the easy stuff first - the throttle body gets dirty from the pcv venting in to from the crankcase and not really the air filter being faulty

if the 02 sensor is going off or starting to slow it can effect idle/mixture control and is easy to check if you have the obd2/diagnostic equipment

 

[Yiannis197]

Great replies here thanks guys.
[MENTION=1006]lemonnobby[/MENTION] have there been cases of the pedal going tits up? Is it something that fails?
[MENTION=29]foxspeed[/MENTION] the pcv is blanked mate as I collect the fumes in a catch tank which is vented in the atmosphere. O2 sensor to be checked next time I go to my mechanic. Does it have to be removed from the manifold? The problem is that it's glued with silicon (in my attempt to fix the cold start issue as per X82)

 

[Foxspeed]

Great replies here thanks guys.
[MENTION=1006]lemonnobby[/MENTION] have there been cases of the pedal going tits up? Is it something that fails?
[MENTION=29]foxspeed[/MENTION] the pcv is blanked mate as I collect the fumes in a catch tank which is vented in the atmosphere. O2 sensor to be checked next time I go to my mechanic. Does it have to be removed from the manifold? The problem is that it's glued with silicon (in my attempt to fix the cold start issue as per X82)

o2 = lambda sensor theres 2 in the exhaust - first one monitors and adjusts mixture for the cat the second one sort of monitors the first and if its out
or poor conversion will throw a warning light on

o2 check is basically a voltage check to see that its swinging back and forth quickly

 

[lemonnobby]

Best doing live data on the O2 sensor. As it can pin point anything at any one time. It will be the up stream one most likely.
The engine mount sags and does give a vibration and wears the lower mount out.
Never heard of pedal problems but there is always a first.

 

[Yiannis197]

Ah ok I'm with you now foxy. When you said O2 I thought (for some reason) you meant the MAP sensor lol. ok I'll have them checked and report back thanks

Lemonnobby I'll check the engine mount cheers. As I said it's the only one I haven't replaced so far but I would have thought that if it was the engine mount it'd cause a vibration on idle and excessive engine movement on acceleration, lift off, gear change etc. Not when the car is still and revved up to 2+k rpm. But I'll check it regardless just to eliminate this possibility.

 

[lemonnobby]

I'm sure it's probably as foxspeed said.
But check it anyway. It might mean you just notice it more that's all. Megane is causes all starts of problems but clioS it doesn't.