Vibration under acceleration

[Philthy]

Probably an easy question here, but I have a slight vibration between about 2000-2500rpm when accelerating. More noticable when I'm taking off a bit quicker through 1st.
V6 auto, checking plugs and leads tomorrow, but if theres anything else I should look at let me know.
As I understand it, coil packs are a possibility as well. Is there a way to check it is working fine?

And while I'm here, I assume bad fuel can cause pinging? I put 93ron in for the first time in a year or so (premium was out of order), and have had a bit of pinging in higher revs. Its got a Greenfoam tune, but it used to be fine with regular fuel

[hako]

Commodores usually have a bit of vibration when accelerating hard but I'd guess you are aware of that and have ruled that out....re the pinging - if the knock sensors are working and the rest of the ignition electronics are OK then (in theory) it should never ping so maybe it's to do with tune. Sorry I cannot be of more help.

[grnvs]

My old vs v6 with an aftermaket tune used to ping on regular fuel but only under acceleration when cold, but only for a really short period of time and then the knock sensors took over and fixed up everything. Also with your vibration check out the engine mounts. They have a tendancy to sag with age and can cause vibration. Have a look and see if the rubber is starting to perish, and if the pin that goes through the middle of the engine mount is touching the k-frame then its time to get new ones!

[RX25SE]

Center bearing mount in the tail shaft?

[Philthy]

Commodores usually have a bit of vibration when accelerating hard but I'd guess you are aware of that and have ruled that out....re the pinging - if the knock sensors are working and the rest of the ignition electronics are OK then (in theory) it should never ping so maybe it's to do with tune. Sorry I cannot be of more help.

I have a MACE memcal on the way as well, so I'll throw that in when it arrives and see if it helps with the pinging.

My old vs v6 with an aftermaket tune used to ping on regular fuel but only under acceleration when cold, but only for a really short period of time and then the knock sensors took over and fixed up everything. Also with your vibration check out the engine mounts. They have a tendancy to sag with age and can cause vibration. Have a look and see if the rubber is starting to perish, and if the pin that goes through the middle of the engine mount is touching the k-frame then its time to get new ones!

I'll have a look at the engine mounts as well. I think the pinging is more when cold as well.

Center bearing mount in the tail shaft?

How do I check that? I was thinking more an ignition because it seems to hesitate/not pull as hard through those revs as well

[Philthy]

Ha, well that was easy. Pulled out a couple spark plugs and the gaps looked a bit all over the place. Not real worn or anything, just not gapped right. Threw in a set of new genuines and it felt alright on a quick squirt around the block.

On the subject, how does everyone check their gaps? The biggest feeler gauges I've seen only go to 1mm or less. I just used a drill bit and the genuines were at least consistant, but I don't know how accurate it is

[seq4x4]

Buy a filler gauge kit, then pull out the ones you need to add up to the total of the gap you want, easy as.

[Philthy]

Buy a filler gauge kit, then pull out the ones you need to add up to the total of the gap you want, easy as.

Ah, too easy! Shoulda thought of that myself

[seq4x4]

Always handy to have, i think i got a metric set and imperial set. Havnt used them in years, but that day will come soon, lol

[greenacc]

Grab a set of those wire feeler gauges. They go up to 1.5mm that you need and bigger. Adding 2 thinner gauges together sounds rather less than ideal.

[Brett_jjj]

Adding 2 thinner gauges together sounds rather less than ideal.

Usually most feeler gauge sets are made so they can be added together to make up larger gap sizes.Ive used them in this way for years now.

[wortus]

Your better off buying a spark plug gauge checking/adjusting tool. they have a series of loops made from round steel of various thickness and all you do is set the plugs so the size under the proper gap goes through and the one above doesn't. Feeler gauges are not the proper tools to use on spark plugs incase you slide the gauges in slightly off being perpendicular to the centre electrode the gap will be wrong.
Also knock sensors stop the engine pinging all together they don't let it ping and then "take over".

[wortus]

Your better off buying a spark plug gauge checking/adjusting tool. they have a series of loops made from round steel of various thickness and all you do is set the plugs so the size under the proper gap goes through and the one above doesn't. Flat type feeler gauges that you can "add" the blades together are not the proper tools to use on spark plugs incase you slide the gauges in slightly off being perpendicular to the centre electrode the gap will be wrong. There are also wire type feeler gauges available that will do the job.
Also knock sensors stop the engine pinging all together they don't let it ping and then "take over".

YouTube - Spark Plug Gap - NGK Spark Plugs - Tech Video

http://en.wikipedia.org/wiki/Feeler_gauge

[Brett_jjj]

Also knock sensors stop the engine pinging all together they don't let it ping and then "take over".

Thats not quite right.The pinging has to be happening first for the knock sensors to detect it,once its detected,the ECU retards the ignition timing until the pinging stops being detected.
This knock sensor signal repeats thousands of times a second while the engine is running,this is why you dont notice it.It all happens so quickly.I have a Tech 1 scantool, and it can show you when the knock sensors are detecting knock(Knock counts),(Ive found knock usually occurs from half to full throttle when running on 91 octane fuel,) ,the tech 1 also shows how much in degrees the ECU has wound back or retarded the ignition timing to stop the pinging from occuring.Ive played around with the timing maps before with tunerpro, and have wound up the timing values,and if you go too far,you can hear the engine pinging from inside the car,so the knock sensors definitely dont stop it from happening in the first place.They just detect it for the ECU and it then does its thing to try to stop it.

[delcowizzid]

yes they will pull timing well before the human ear can hear detonation unless its too far advanced in the tune and cant pull enough timing out to stop itself pinging then thats when you hear it

[wortus]

[QUOTE=Brett_jjj;1657146]Thats not quite right.The pinging has to be happening first for the knock sensors to detect it,once its detected,the ECU retards the ignition timing until the pinging stops being detected.

Exactly however the pinging will never be heard by a human ear if the electronic system and other things like EGR valve etc are working properly on a standard engine with a standard tune.
If the ECU is retarding the timing more often on 91 octane fuel than when using premium there may be something wrong with say the EGR valve reason being if the timing is being retarded more you'd expect the fuel consumption to increase a fair bit, my car uses the same on 91 as it does on 95 and uses about 10% more E10 than unleaded.

[Brett_jjj]

It really depends on how you drive your car.If you just cruise about all the time,you wont notice any real benefit from using 98 octane fuel. Its when you run at half to full throttle a lot (like me, he he).Thats when it makes all the difference.Theres hardly any knock detected from either of these fuels at light/medium throttle.But theres a big difference between the two once the throttle is opened up wide. .Mine uses 91 fuel like anything when driven like this,and the ECU just retards the timing anyway as soon as it detects knock.Whereas its still gets reasonable fuel economy,goes a lot better, and gets heaps less knock counts when driven like this with 98 fuel in it.I like to hold my car flat to the floor through the gears when overtaklng,taking off etc etc.

[wortus]

My car would rarely go above 2500/3000 rpm. Out of interest have you logged the knock sensor (knock counts) with E10 fuel given the octane rating is usually higher, (I read about 94)?

[Brett_jjj]

Ive used E10 a few times,never with the tech 1 connected though.Mine seemed to run ok on it,Ive used some normal 91 brands that didnt run as good as the E10, I didnt know it had a higher octane than the normal 91 stuff,I thought it was the same as it.You learn something new every day.Next time the servo is out of 98,and I have to get cheaper stuff,i will get the E10 and check it out on the tech 1.

[wortus]

Ive used E10 a few times,never with the tech 1 connected though.Mine seemed to run ok on it,Ive used some normal 91 brands that didnt run as good as the E10, I didnt know it had a higher octane than the normal 91 stuff,I thought it was the same as it.You learn something new every day.Next time the servo is out of 98,and I have to get cheaper stuff,i will get the E10 and check it out on the tech 1.

One of the servo's around here, I think it is Liberty their E10 comes in either 95 or 98 octane.

[Brett_jjj]

A lot of the independent brand servo's couldnt compete up here in the bush and got closed down.Only BP, shell or caltex here now.They used to be a lot cheaper too.Its wrong how a few companies can monopolise the oil industry in this country,especially in country areas..We pay a lot more for fuel than city folk in the first place,but we have the shittiest roads to drive on( you can barely call them roads!!more like bush tracks),we very rarely see any of the fuel tax thats paid from here, spent up here.Its wrong.I could run this country better than these idiots.We should have 10 lane wide (each way), freeways crossing aussie and joining melbourne,sydney and brisbane and right up the Qld coast.They should have open speed limits on the inside lanes.This country has no idea.The yanks offerend to build australia some freeways after world war 2,and the good old aussie government, god bless em,said no,shes right mate.It would have cost something like a couple a million pounds.Today it would cost millions,if not billions of dollars.Idiots,and they still havent changed any..I could go on for hours about the stuff they just plain dont get,or get totally wrong.Id better stop here.

[VS 5.0]

A lot of the independent brand servo's couldnt compete up here in the bush and got closed down.Only BP, shell or caltex here now.They used to be a lot cheaper too.Its wrong how a few companies can monopolise the oil industry in this country,especially in country areas..We pay a lot more for fuel than city folk in the first place,but we have the shittiest roads to drive on( you can barely call them roads!!more like bush tracks),we very rarely see any of the fuel tax thats paid from here, spent up here.Its wrong.I could run this country better than these idiots.We should have 10 lane wide (each way), freeways crossing aussie and joining melbourne,sydney and brisbane and right up the Qld coast.They should have open speed limits on the inside lanes.This country has no idea.The yanks offerend to build australia some freeways after world war 2,and the good old aussie government, god bless em,said no,shes right mate.It would have cost something like a couple a million pounds.Today it would cost millions,if not billions of dollars.Idiots,and they still havent changed any..I could go on for hours about the stuff they just plain dont get,or get totally wrong.Id better stop here.

There will be a federal election in no more than three years. Given the current state of affairs you might want to get your campaign started now just in case it is called a bit earlier. Look at the power the boys from the bush have wielded this time. That could be you next time.