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[geoffr70]

Hello, my 3.0 v6 won't idle properly.

In the last 2 months or so, I've done all filters, fluids and plugs, oil, cam cover gaskets (correctly torqued up), new HBV, and cleaned out the throttle bodies, plenum, breathers, and ICV. The engine was running smoothly.

Then I replaced my drivers side exhaust manifold, and I used copper pipe to bridge the 3 inch gap between the SAI pipes just before it terminates into drivers side exhaust manifold (instead of rubber). I also discovered that the plug on SAI had been snapped from the socket looking thing, and the terminals had been bridged with thin copper wire. I removed copper wire and refitted plug into socket and checked all vacuum pipes.

Now, the manifold isn't blowing, but the car will just not idle properly, and is hunting. This is more noticeable when stationary, I pop it into drive and if the revs surge a little, the car surges forward, or if the revs dip the car dips a bit. It's not noticeable when moving.

I have just driven 20 miles urban, and 80 miles on a run, at a steady 56 mph, all I got back was 28.4 mpg total. Does that sound a little low and does anyone think it is related?

Thanks

[Jinglemaster2]

Air leak somewhere. Check all the vacuum piping.

[geoffr70]

Thanks for that advice, I'll check it all again! 

[beemerdevil]

Hello, my 3.0 v6 won't idle properly.

In the last 2 months or so, I've done all filters, fluids and plugs, oil, cam cover gaskets (correctly torqued up), new HBV, and cleaned out the throttle bodies, plenum, breathers, and ICV. The engine was running smoothly.

Then I replaced my drivers side exhaust manifold, and I used copper pipe to bridge the 3 inch gap between the SAI pipes just before it terminates into drivers side exhaust manifold (instead of rubber). I also discovered that the plug on SAI had been snapped from the socket looking thing, and the terminals had been bridged with thin copper wire. I removed copper wire and refitted plug into socket and checked all vacuum pipes.

Now, the manifold isn't blowing, but the car will just not idle properly, and is hunting. This is more noticeable when stationary, I pop it into drive and if the revs surge a little, the car surges forward, or if the revs dip the car dips a bit. It's not noticeable when moving.

I have just driven 20 miles urban, and 80 miles on a run, at a steady 56 mph, all I got back was 28.4 mpg total. Does that sound a little low and does anyone think it is related?

Thanks

sounds like its drawing in air somewhere - check all vacuum pipes are on/not split

[geoffr70]

Thanks both, I'll check them all now! If I find a split (I have a place in mind - the small offshoot from the ICV hose, that goes to rear of plenum) is there an effective temporary or permanent repair? Like a hose bandage or something? Thanks!

[Welung666]

2 of the favourites are the eco-tec strip isn't pushed fully home or the IACV isn't pushed home properly.

[geoffr70]

Thanks Welung666. I just assumed the eco-tec strip was cosmetic but I'll make a point of checking it. The ICV is always a pain to get in, I find it easiest to insert grommet then insert ICV with grommet in place but I'll check it again! Thanks.

[Welung666]

It's the breather chamber beneath the eco-tec strip I meant. I'm assuming you had that off and cleaned it along with the rest of the breathers??

[geoffr70]

Oh yeah sorry I'm just being thick! It did look as if it was protruding a little. i did put it back when i was tired, fed up, and in a rush though! I'll check that! thank you!

[Gaffers]

or the ICV is just completely fubared  :-/

[geoffr70]

I don't treally know how ICV operates. When i cleaned it i could manage to get a flap inside to rotate a bit so i could galoush it with carb cleaner, it's been ok since. Would it go immediately or would it be gradual? Thanks!