Vibration under load at low rpm?

[Clarkj93]

So just took car for a drive and noticed that on high boost between 2000-2500rpm there is a bit of a judder or vibration that I can feel via the wheel and seat, quite minor but noticeable. Doesn't do it past 2500rpm and doesn't do it at all when I switch the map to low boost.

Rocker cover gasket does need changing and I've noticed the air seep out at 3500rpm which is when torque is at its peak. This seems different though and is not happening at max torque at least I can't feel it.

Not had time to run any logs yet. Checked the fuel trims while idling just now and they look healthy.

Opinions?

[pudding]

If you have VCDS, maybe log the ignition retard channels and enable the misfire counter, along with lambda requested and actual, and both the LPFP and HPFP requests.

If nothing unusual there, it could be a mechanical vibration in the drivetrain somewhere.

[GreigC]

I have the exact same issue. It’s an injector. You most likely have intermittent cold start issues also.

[Clarkj93]

I have the exact same issue. It’s an injector. You most likely have intermittent cold start issues also.

Don't say that they've just been cleaned by RTech less than 3 months ago cold start is fine though.

Yeah will have to run some logging then on weekend!

[pudding]

A potential issue from stripping/cleaning injectors is it removes the factory tolerances, which can then cause nozzle dribbling......something middle aged men suffer from.  It's been seen numerous times over the years with both DI and port injectors.

But if your the engine consistently starts up immediately and smoothly, hot and cold, they haven't reached that stage yet.  If it fires up a little sluggish and lumpy, the stored fuel pressure post shut down has bled off into the cylinder(s) because of dribbling.

Dribbling might not be evident on the test bench on the day, but it can happen after some miles/heat cycles.

For some context, a normal startup goes something like this when cranking......Wuh wuh, vrooooooom.  A sh1tty start is more like.....wuh,wuh,wuh,wuh,phut,phut,phut, vrooooom 

Anyway, get the logging done and let's see what the score is.

I know where Greig is coming from though, a partially failed injector causes poor cylinder contribution, which can definitely cause a wobbling sensation from the engine at medium revs under load.

[Clarkj93]

Yeah hoping it's not frankly although seems OK on low boost so can always turn it down for a bit until I get new injectors, don't fancy paying all that money for shiny new ones without going ko4 or hybrid ko3 and not sure I fancy the risk of sticking other old ones in and praying again.

One thing to note is car was recently seriously low on fuel, it was already well into red and drove it to Tesco for momentum which is a 10 min drive but they were empty so had to carefully get it back with what looked like 10 miles or so left in the tank. Ended up using Mrs car to fill a jerry can in the end to fill it up as it wouldn't make it back to Tesco as it was. Wondering if going that low sucked up some old yukky 95 sat at the bottom?

In the 3.5 years and 25k I've done in it its always alternated between starting great and starting chappy haha.

Ordered new sparkplugs from awesomegti anyway, my euro car parts best ones needed upgrading anyway. You never know!

[pudding]

I know, the injectors are silly money now.  You could be onto something with the spark plugs actually, if reducing the boost smooths it out again.  Get the trusty old BK7REIX as these engines seem to love them, even in standard trim.

How low did you run the tank?  Lowest I've ever got mine down to was needing 54.3 litres at the pump to refill it.  Given it's a 55 litre tank, that was a frickin close call 

The LPFP sits right at the bottom of the tank anyway mate, so is always picking up crud regardless     Probs worth swapping out the fuel filter if you suspect that could be an issue though.  There's also a filter on the pump itself, if you can be bothered to get the pump out of there for inspection.

Yeah I hear you on the inconsistency of these engines. Mine's been pretty up and down for 8 years.  Ballistic missile 1 week, and then a 1.2 Corsa the following week     Mine has always started on the button though.  It's had 1 set of injectors and 1 walnut blast over 166K miles. Not sure if that's the reason, but doesn't hurt!

[Clarkj93]

My guess was about half a gallon left in it! Wow 0.7 litres... barely enough to mow the lawn

Yeah I was wondering if it would be at the bottom or not. Fuel filter is 6 months or so old but who knows maybe it had a hard time recently. Think il change plugs, then sump and pickup pipe is getting cleaned out along with cambet waterpump and rocker cover gasket. If it's still happening after that then give the fuel filter a go, otherwise yeah new injector set I think so I can forget about them for a good long while haha. Il report back if the logs show up anything weird.

Yeah very much that inconsistent living breathing thing depends what day of the week it is sort of motoring

[pudding]

Thankfully the petrol station was on a flat road.  If it was up a hill, I'd have been in some bother   

Try not to run the tank too low, too often. HPFPs hate heat more than anything else, and they run pretty hot when there's very little fuel in the tank!

I reckon it's the plugs mate if they're an ECP brand, but let's see     

Yup, my car defo has a time of the month 

[Clarkj93]

Plugs changed, not made any difference it seems and logs show nothing weird. Think it could be an injector as cylinder 2 is misfiring on idle, only recently been cleaned, bloody things!

[rich83]

Plugs changed, not made any difference it seems and logs show nothing weird. Think it could be an injector as cylinder 2 is misfiring on idle, only recently been cleaned, bloody things!

Have you tried swapping the coil packs around?

[Clarkj93]

Plugs changed, not made any difference it seems and logs show nothing weird. Think it could be an injector as cylinder 2 is misfiring on idle, only recently been cleaned, bloody things!

Have you tried swapping the coil packs around?

Yeah swapped them just in case. Still misfires on Cylinder 2 and no change.

[pudding]

Plugs changed, not made any difference it seems and logs show nothing weird. Think it could be an injector as cylinder 2 is misfiring on idle, only recently been cleaned, bloody things!

Bugger, defo the injectors then. You always hope it's not them as the K04 ones at least, are 200 damn quid each 

[Clarkj93]

Plugs changed, not made any difference it seems and logs show nothing weird. Think it could be an injector as cylinder 2 is misfiring on idle, only recently been cleaned, bloody things!

Bugger, defo the injectors then. You always hope it's not them as the K04 ones at least, are 200 damn quid each 

VW just quoted me 215 each for ko3 injectors! Blimey was not expecting that price tag for the ko3 ones. Ko4 injectors from the likes of AKS or Awesome GTI are cheaper even...

[pudding]

Seriously??!  Holy Fork   

You could try ringing AKS.  They don't list the K03 ones on their site but might sell them.  I can't see why they're more than K04 ones, doesn't make sense!  Unless it's a supply and demand thing?  Less K04 engines out there vs K03?