8v lumpy idle when cold

[KIPVW 0]

Hi All,

 

Have a bit of an issue with my 8v Daily in that when it's cold it runs as if it's on 3 cylinders and usually goes after 20 seconds or so on it's own without having to blip the throtle.

 

Spark plugs were new last year as was air filter etc and all seem like they are secure.

 

Could it be injectors OR is there an Idle Stabilization Valve that can go on them?

 

Also tried some injector cleaner and it definitely pulls better but hasn't cured this issue.

 

Any help much appreciated.

 

Thanks

[Jim 2]

Have you checked out the HT leads Kip? I used to get something similar on my G60 that progressively got worse - running on three cylinders for 10 minutes or so when cold - pulled the leads off and one just fell apart with a load of copper corrosion pouring out. No idea how it ever worked!

[KIPVW 0]

One did feel a bit iffy Jim so may be worth getting a set or robbing Jude's to try lol!

[Jim 2]

Definitely mate :)

[Dox 23]

My MK2 8 valve did that when the head gasket went, if you remove the plugs and use a torch to pear into the cylinders if you have one piston steam cleaned you need a block test to confirm it. Mine was number one cylinder

[KIPVW 0]

Hope not Dox. That's a faff :(

[Harrier 1]

If it is as Dox says you would also expect to be loosing a bit of coolant , and excess pressure in cooling system .

[KIPVW 0]

I'm actually loosing some coolant too but it's trickling into the passenger footwell so I have all the carpets out too as I'm thinking it's the heater matrix :(

[Dox 23]

And HGF over pressurising the matrix could well of finished it off.

 

I'd randomly pull off the plug leads to find which one made no or little difference to idle when its miss-firing then concentrate on that cylinder

[Harrier 1]

I'm actually loosing some coolant too but it's trickling into the passenger footwell so I have all the carpets out too as I'm thinking it's the heater matrix :(

 

:( you could bypass the matrix for the time being (not such a big deal now the warmer weather is here) and see how it goes ?

[KIPVW 0]

Yeah was going to do that and see if the coolant stops leaking.

[Jim 2]

Coolant into the footwell is pretty much dead cert the heater matrix. Pull off the shelf under the glove box and have a feel around the underside of the heater box - if you get some coolant on your fingers, it's bad news.

 

Have you had bits of foam blasting at you from the heater when you switch it on lately...?

[KIPVW 0]

It has been chucking foam out Jim yes, is that moisture in the vents causing it to fall off the air duct flaps?

[Jon_vr6 1]

This the 1st time doing a matrix Paul?

[KIPVW 0]

It will be Jon yes. Pretty sure what to expect though and think I'm taking dash out to look at everything else too.

[Jon_vr6 1]

It will be Jon yes. Pretty sure what to expect though and think I'm taking dash out to look at everything else too.

Quite suprised at that mate the number of corrados youve had. Just take your time and try not to break any interior plastics. Good luck

Edited April 6, 2016 by Jon_vr6

[KIPVW 0]

Yes i thought so too.

[Jim 2]

It has been chucking foam out Jim yes, is that moisture in the vents causing it to fall off the air duct flaps?

 

Yep. Seems to be. Mine was doing exactly the same for a few days before I began to notice what had happened and began to smell coolant in the cabin. You're going to need to consider getting the heater box out of the car too for a refurb as the foam on the flaps is going to be toast now.

[g0ldf1ng3r 15]

Kip - I have a full guide with lots of pictures if you want me to email it to you BUT I am only around for another 10 mins before I leave work to go to Amsterdam to celebrate my 40th

 

or I did send Jim a copy if you see this post after i have gone ;)

[KIPVW 0]

No worries Enjoy Amsterdam 👍

Yeah expecting as much Jim lol.

Swapped Judiths Ignition Leads and Dizzy Cap over this morning and still lumpy.

Judiths runs fine on my leads though so that's one thing eliminated.

Now thinking Head Gasket, Injectors OR isv if there is one as not sure on the 2E Engine.

[Jim 2]

Worth picking up a compression tester I guess so you can confirm whether it may be the HG. Hopefully it's not, and the problem just lies elsewhere.

 

I do also have the guide that g0ldf1ng3r is referring to - I'll forward it to you over email now mate.

[Dox 23]

Compression test will show up a poorly seated valve or piston rings / bore wear, its unlikely to pick up a slightly weeping HGF at this stage.

 

When you switch off after a drive the coolant stays pressurised until cooled, without compression in the cylinder a small amount of coolant seeps into the cylinder and extinguishes the spark preventing combustion, the leak is tiny and seals itself once the engine is running / hot.

 

Piston crowns get steam cleaned if this is the case (you can see this with a torch with the plugs removed), 3 black crowns and a dull metal one means it needs a block test or a sniff test to confirm.

 

You need to pinpoint which cylinder is causing the problem and work from there - pulling off the plug leads in turn is the best way to find this, if you pull one and the idle is unaffected that's the cylinder with the issue (a good cylinder will become even more lumpy at idle because the engine is now running on 2 cylinders

[KIPVW 0]

Thanks Dox. Very comprehensive and I'll try this when i get the time.

Trouble is it goes very quickly so may have to try one a day and see if this is the case.

Cheers.

[Dox 23]

Thanks Dox. Very comprehensive and I'll try this when i get the time.

Trouble is it goes very quickly so may have to try one a day and see if this is the case.

Cheers.

 

You could depressurise the coolant by removing the cap when hot (put the cap on a plastic bag on the drivers seat while the engine cools so you don't forget to refit it) being careful not to scald yourself!

 

Refit the cap before restarting when cold and it should start up on 4 cylinders if the gasket is breached (pressure hasn't pushed coolant into the cylinder).

 

Don't scald yourself if you try this method

[davidwort 0]

I actually did the head gasket on this car kip about 4 years ago now, while I was at it I lapped in all the valves, the head faces were good iirc but the old gasket had rotted and water was escaping. The plugs should tell you a lot, what do they look like?