Slight misfire, random hose, oily breather hoses and sensor query

[Therusterman 59]

Hello all, recently picked up a vr and have found a few bits that need attention.

The first is a slight misfire and flat spot that i can feel from around 1200-1800rpm. I took a look at the coil/plugs and leads and didn't notice anything unusual. I have read the coils can crack causing running problems, but couldn't see any problems with mine:

Is this worth replacing despite no external signs of wear? Also who is the manufacturer of this part, iirc the name is printed on the coil pack, but can't remember who it is!

Whilst i was having a nose under the bonnet, i also found this stray pipe:

It runs along the scuttle panel, and plugs into a sensor of some sought with another vacuum type pipe, any ideas what it is, and what the other end should be connected to?

Next i had a look at the intake pipe, and noticed around what looks like the oil cpv/breather there was a lot of oil on the outside of the hose, is this normal? Do the cpv's fail?

And finally, the sensor shown in the above picture, what is it for? Looking at the sensor itself, i didn't see any wire terminals in there for the plug to attach onto, could anyone shed any further light on this for me?

Many thanks in advance

[thesurgeon 51]

The last 2 answers are ; Yes and the ford part number is f7364573

and the sensor is for US emissions and not used over here.

Someone else will be along to answer the first 2 .

[wardycatt 7]

The coil pack is a bit of a liability (IMO) - I've read a few threads on here where people have had problems. On mine, you could see the electricity arcing / sparking to one of the bolts used to mount the coil pack. Never a good sign.

You can repair this yourself quite easily. I used some 2-part epoxy glue (<£5 from any B&Q / Halfrauds / eBay etc.). Take the coil pack apart and liberally apply epoxy around any gaps. Basically pour it in there, as much as you can get in - totally seal it up. Then, I used tape (like electrician's tape, only made of rubber) on any external gaps in the coilpack case.

This has done the trick, but I suspect it's only a temporary solution. I don't like the idea that the electricity is leaking out in the first place. A new coil pack can be obtained for about £80-90 from eBay.

The CPV / PCV (whatever it's called) is another very common fault. It happens from quite an early mileage apparently (supposedly people were having then replaced under warranty... 15 years ago). So if you've got a typical 100,000 mile car, it's pretty much certainly going to be leaking. Even if it had been replaced, it would probably still have failed again.

I don't THINK there's any (performance-related) issue with this valve venting to atmosphere, but letting oil leak out your car isn't good practice generally I suppose. However, this leaky valve could be related to your misfire. I've read on here that the oil can (apparently) drip down from the leaky valve into the recess of one of the spark plugs (number 6?) and cause a misfire.

If you're looking to replace the valve component, they are becoming harder to obtain. Supposedly you are cheaper going to Ford and asking them for one for the Ford Sharan - Ford borrowed the VR6 engine for that model. For the exact same part, VW dealers charge more. Used parts will probably have failed / will be about to fail, so that's a false economy IMO - unless you can visually inspect the part prior to purcahsing and it's much better than what you have at the moment.

However, I reckon that taking the valve off and repairing it yourself will do the trick, and will cost pennies in comparison to buying a new part (which may cost between £50 and £100). Some plain old sealant should stop the leak. That's more in keeping with the spirit of VR6 ownership! My car is officially 3% epoxy resin, 7% silicone sealant and 22% rust :-)

No doubt the experts will be along soon to correct me or expand upon all this.

p.s. - I wondered about that connector (shown in the last photo) on my car. I'd assumed that when it was remapped (many moons ago) that something was disconnected to 'trick' the ECU - that's my best guess. We need a boffin to clear this up.

[Therusterman 59]

Thanks for the extensive reply! To be honest, i'll probably replace the coil anyway just to be on the safe side and peace of mind, i like my cars with everything just-so!

I had a similar problem with the icv/pcv valve on my previous BMW, and replacing it made no difference, but its on the engine for a reason so i'll add sorting this to the list of jobs. Thing is with the valve, is that its not obviously failed anywhere, it looks like the breather hoses were almost sweating oil?!

Re the connector in the last picture, the first reply on this thread mentioned it was to do with U.S emmissions regulations, and the said sensor is not used on european applications.