Hot/cold idle issue

[lightyears]

Hi guys,

I have a B230E engine with the K-Jetronic constant fuel injection system, ive noticed that on cold mornings the car starts but is quite burbly for a few moments, once warm the car idles way to high, some times up to 1500rpm. I have a fiddle around and seemed to have found the Auxiliary idle valve on the back on the cam cover, removing the top pipe it is neither shut or completely open at any point. Ive taken it off and given it a clean which appears to have made it open all the time, making the warm idle much worse. Is this something that can be repaired? I can't seem to find one anyway online, would it be worth blocking it off for the time being or reducing the flow with a basic valve?

[Laird Scooby]

Originally Posted by lightyears

Hi guys,

I have a B230E engine with the K-Jetronic constant fuel injection system, ive noticed that on cold mornings the car starts but is quite burbly for a few moments, once warm the car idles way to high, some times up to 1500rpm. I have a fiddle around and seemed to have found the Auxiliary idle valve on the back on the cam cover, removing the top pipe it is neither shut or completely open at any point. Ive taken it off and given it a clean which appears to have made it open all the time, making the warm idle much worse. Is this something that can be repaired? I can't seem to find one anyway online, would it be worth blocking it off for the time being or reducing the flow with a basic valve?

Get some carb and air intake cleaner in a spray can, spray it into the AAV (you don't have an AIV on the K-Jet) and use a screwdriver to gently lever it open more. Then try levering it the other way and spraying it again.

You can test it by first removing it and putting it in your freezer overnight, it should be fully open the next morning.
Make sure you have an ignition switched +12V feed on the plug that goes to it and a good earth on the other terminal in the plug. Once it starts moving, regular use and repeated cleaning with carb cleaner will help to increase its range of movement and make it do what it should. It's nothing more than a valve that opens and closes in relation to whether it's cold or hot and is heated to ensure it closes when hot. Usual cause of failure is that it's dirty.

[lightyears]

I’ve tried this overnight and it still appears to be stuck even with a good soak of the good stuff. The car started better but probably as a result of carb cleaner

[Laird Scooby]

Originally Posted by lightyears

I’ve tried this overnight and it still appears to be stuck even with a good soak of the good stuff. The car started better but probably as a result of carb cleaner

How long did you run the engine for?

[lightyears]

10 miles to work, thermostat was open and the car at full temperature by that point. By the looks of it, when I arrived at work it was completely open and see through which I understand is not supposed to happen at warm.

[Laird Scooby]

Originally Posted by lightyears

10 miles to work, thermostat was open and the car at full temperature by that point. By the looks of it, when I arrived at work it was completely open and see through which I understand is not supposed to happen at warm.

No, definitely not. Should be closed by then. Have you checked you have a switched ignition feed of +12V to the plug that connects to it? If so, it sounds as if it has jammed permanently so you'll need a replacement which must be from a K-Jet. Find the Bosch number on it, should be 10 digits and starting "0 280" then search online/ebay for that number.

[lightyears]

I’ve put the volt meter to it and it does appear to be alive, I’m of the mind that at 190k and never been cleaned that it’s dead. If I cap it off will it affect it other than being hard to start until I find a replacement. 0 280 140 114 is the number but I can’t for the life of me find either a new or used one, I found one from a V6 740 with a similar number but am not sure of the swap ability of these. If anyone has one laying about that they know work I would happily pay.

[Laird Scooby]

Originally Posted by lightyears

I’ve put the volt meter to it and it does appear to be alive, I’m of the mind that at 190k and never been cleaned that it’s dead. If I cap it off will it affect it other than being hard to start until I find a replacement. 0 280 140 114 is the number but I can’t for the life of me find either a new or used one, I found one from a V6 740 with a similar number but am not sure of the swap ability of these. If anyone has one laying about that they know work I would happily pay.

You could blank it off and gently tickle the accelerator pedal for cold starts until you find a replacement.

If that 760 V6 is the K-Jetronic (very early version) then as long as the number is very similar you should get away with it but i think the 760 uses a larger bore pipe in/out of the valve.

That said the De L'Orean DMC-12 used the K-Jet V6 lump and also uses the same AAV :

https://www.ebay.co.uk/itm/384665580027

It's in the USA though so delivery won't be quick and if HMRC get involved, could cost more on Import Duty (usually 20%) plus an £8 fee from Royal Mail for delivering the card telling you how much extra you need to pay and collecting said fee.

If you can find one with the same number in the UK you should be ok, assuming it works.

Having extensively trawled ebay, i found this :

https://www.ebay.co.uk/itm/153863854488

If the car in the pic is in fact the one being broken, you're in with a good chance as it appears to be an 87/88 GLE with the B230E engine so should be K-Jet. Worth sending a message at least!

[lightyears]

Thanks a lot, have messaged the eBay in the uk person to see. If anyone happens to breeze past this post as has one let me know 😁

[AllHailKingVolvo]

Just a thought-having been through this very issue with my wife’s 740 with B200E, have you checked that the microswitch that sits above the throttle butterfly lever is activated when off throttle?

Ours would idle horribly when cold, lumpy and uneven, then when hot would idle at 1400rpm. If I set the hot idle correctly, it wouldn’t run without throttle when cold.

I did some sleuthing and found that the little cap head bolts that hold the microswitch in place were loose, and it had worked it’s way into a position where the throttle lever wasn’t activating the switch. I refitted it correctly, which brought the hot idle down to around 500rpm when activated. I adjusted that up to 900rpm hot, and it now starts and runs very well whether hot or cold.