A few niggly niggles!

J

Johnnyz4coupe

Member
 Swindon
Hi all

My coupe might have a cold and i was hoping someone could try and point me in the right direction.

1. The ABS light come on and off intermittently which is annoying. I got the other half to take it into work last week (She works at Audi) and one of the techs read the codes and it said it was the ABS pump. So i've found somewhere that recons these for about £200 so that's sorted!

2. Lumpy idle!!
This is only after the car has warmed up and started back up. So if i go for a drive and start it back up again anytime within 3-4 hrs, it searches for about 10 seconds before settling.
It also happens after its warm and i turn it off and then back on again almost straight away.
Ive changed the spark plugs. Two of the plugs in the car were different makes to the rest. Not sure if that is something sinister but all six are now NGK Iridiums.
Also replaced the solenoid things at the front of the engine.
New oil and filter.
Cleaned the IACV and MAF sensor.

3. Flat spots
This happens under gentle acceleration and is worse under load.
Its hard to explain the acceleration thing. Its almost lie it hits a power band which happens at different revs.
The other day, the ECL came on and a day or so later, it went off. When the woman that controls my life took the car into work for this and the above issues, the only code that did come up was for the ABS pump!!
When i did some hard acceleration onto the dual carriageway after a day later, it was horrible. A massive flat spot that caused the engine tone to change, the growl noise. It spooked me a little so i came off the power straight away. The CEL wasn't on prior to this and hasn't come on since.
The car is always run on V-power and has the eco-boost additive run with it too.
I've checked the plugs and all are tight and not loose (with a torque wrench).
I've take all the coils off and cleaned them. When i put the back on, i rotated them.
I then ran the car up to temp and then unplugged each coil in turn. Unlocking each one resulted in the cylinder shutting down as predicted.

So now i'm stumped guys. No codes are thrown up. The CEL light comes on and off.

Please help me!!
 
Hi, I know the eccentric shaft sensor can give a lumpy idle & a loss of power-try disconnecting at idle to see if the idle smooths out?
It’s expensive but can be got cheaper via German eBay I think :?
Rob
 
Smartbear said:
Hi, I know the eccentric shaft sensor can give a lumpy idle & a loss of power-try disconnecting at idle to see if the idle smooths out?
It’s expensive but can be got cheaper via German eBay I think :?
Rob
Click to expand...

Thanks rob.
Where is the sensor?

JJ
 
Found the sensor!

So i got the car up to temp, removed the sensor and it almost stalled but settled back down almost straight away.
It looked all clean and dry in there. I sprayed some contact cleaner in there and on the plug and put it back on and there didnt seem to be any difference.
 
Johnnyz4coupe said:
Found the sensor!

So i got the car up to temp, removed the sensor and it almost stalled but settled back down almost straight away.
It looked all clean and dry in there. I sprayed some contact cleaner in there and on the plug and put it back on and there didnt seem to be any difference.
Click to expand...

I’d rule that sensor out then :?
Rob
 
I had something similar when a coil pack started to die. I did get an occasional misfire, but no engine warning light/fault code, only happened under load. Was intermittent for about a month and then engine warning light and five cylinders......six new coil packs and plugs, and problem solved.

I don't know enough to say this is definitely your problem, but just thought I would share my experience as it could be the same. I got a full set of coil packs (genuine Bosch) for about £125.
 
Thanks mate

I’m thinking that’s the next thing to try as it’s throwing up no codes to point me in the right direction.

Would that also account for the crap idle?
 
Changing coils won't harm but lumpy idle and flat spot would get me thinking about VANOS. You say you have changed the vanos solenoids but there could be something internal leaking oil presure. Ducklakeview on here has a lot of experience on VANOS so could certainly give you some advice.

Other possible thing is a blocked crankcase ventilation valve which is reasonable common on the silver topped 3.0Si - they changed the design in 2007 to integrate the CCV into the cam cover. On yours it is separate so more serviceable. There is also a pipe that runs from it down to the sump that can collapse. I'm not convinced this would only cause your problem when stopping and re-starting straight away / within a few hours though.

Given the very noticeable flat spot and growly sound, vanos is more likely.

There are 2 off DISA valves on the 3.0Si. They don't fail that commonly like on the M54 cars but one is relatively easy to get to and it would be worthwhile removing it to see if there is a lot of oil in your intake. If there is then the CCV is defo stuffed. The 2nd DISA valve requires the removal of the inlet manifold to inspect. If they fail, it can give issues similar to vanos (i.e. poor idling and flat spots).
 
Mister T said:
Worth checking for splits in the hose between the MAF sensor and the inlet
Click to expand...

The si engine doesn’t have the bifurcated section that commonly splits on the m54 engines, of course the hose can still split though :thumbsup:
Rob
 
ph001 said:
Given the very noticeable flat spot and growly sound, vanos is more likely.

There are 2 off DISA valves on the 3.0Si. They don't fail that commonly like on the M54 cars but one is relatively easy to get to and it would be worthwhile removing it to see if there is a lot of oil in your intake. If there is then the CCV is defo stuffed. The 2nd DISA valve requires the removal of the inlet manifold to inspect. If they fail, it can give issues similar to vanos (i.e. poor idling and flat spots).
Click to expand...


When I took the IACV thing off the other month, I did notice oil in the manifold area. My car does seem to smoke a little all the time. Nothing horrendous but I have noticed it.

Also my oil consumption seemed to increase before I topped it back up, but I do very few miles in the car now.
 
Johnnyz4coupe said:
When I took the IACV thing off the other month, I did notice oil in the manifold area. My car does seem to smoke a little all the time. Nothing horrendous but I have noticed it.

Also my oil consumption seemed to increase before I topped it back up, but I do very few miles in the car now.
Click to expand...

I think the crank case ventilation should be high on your priority list in that case. If you do very few miles in the car, they can be susceptible to moisture buildup in the oil which makes it go sludgy and bungs everything up. It would probably benefit to a good hour long B road blast to try to get the oil temp as high as possible and evaporate all the moisture out.
 
A blocked CCV system won't account for your performance issues, but if you've got a significant amount of oil in your inlet and high oil consumption then it definitely sounds like it needs changing. I've changed CCVs on both my car and another forum member, we both have the lumpy idle issue but a new CCV system did not cure it. You can test your CCV by blowing through the pipe exiting the rear of the rocker cover into the CCV, if you hear gurgling oil it's clear, if not then it's blocked and you'll be blowing air/oil straight into the intake.

Not too sure on what determines the fitment of new/old CCV systems, but like PH001 mentioned if you have a silver engine cover it's likely yours will be external and can be replaced. Mine is a 2008 coupe and I have the external CCV, I've seen 2006 models that had the CCV integral to the cam cover.... of course mine may be an earlier build and registered late or had a replacement engine at some point in it's life!?

I've had a lumpy idle since buying my coupe, only appears when warm and usually when I'm using light throttle such as car parks or in traffic... blipping the throttle levels it out, does this sound similar to yours? My flat spot sounds exactly the same as yours but was a more recent thing and led to me changing coils, DISA and MAF

Vanos Solenoids - Had an error code and EML, no improvement on lumpy idle but helped with power delivery.
CCV system - reduced oil consumption, lumpy idle still exist.
New Coils - slight improvement in throttle response but nothing else. Mine were original at 95k so no harm in changing them i thought!
Large DISA valve - I did eventually get an error code for this but mine was clearly broken, if it can be moved by hand then it's shagged so quite easy to check, at £250 from a dealer you'd want to be sure this is the issue before changing! This removed flat spots at low RPM only but not the lumpy idle.
MAF sensor - after cleaning mine several times and getting slight improvements I eventually bit the bullet and bought a new one, I have not had the lumpy idle since, flat spots are pretty much non existent now and performance dramatically improved.

I tested my MAF by doing the same journey with it plugged in then unplugged the next day to see if i could feel any difference, the flat spots improved when unplugged so decided to change it. You will get an EML by driving with the MAF unplugged but the car drives fine but fuel economy will be horrendous, you'd need to be able to clear the codes after that sort of test though!

This is only my experience so cannot guarantee it will resolve your issues but wanted to share with you before you go throwing too many parts at it. I'd be happy to put my MAF into yours to test if it resolves your problems before you go buying a new one but i'm based in Rugby so would be a bit of a journey for you!? I managed to get a genuine part from eBay for £150 which is far cheaper than I can get from a dealer even with my discount!
 
Thank you

It’s all brilliant advice. I just don’t know where to start.

I’ve ordered six brand new Bosch coils that should turn up tomorrow.

Once I’ve fitted them, I will take it out and see. Then the next thing I guess is the ccv.

All I can do is take it all apart on the weekend and show some pics of what I’m seeing so you guys can advise.

I’ve cleaned the maf a few times now. But like you guys have said, try it with it disconnected.
 
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