Hi all,
My '81 B23E after sitting for a week or so ( I don't use it all that much ) has taken to only running on 3 cylinders. Generally speaking it is use once a week, but sometimes might sit for a couple of weeks. However, when needed it needs to run right.

Prior to this condition, when starting from cold, the engine runs ( in park or neutral ) at only approx. 700rpm. This is in an Aussie temperate climate average of 50 defrees f.

Being a B23E it is fitted with the K Jetronic fuel system. It's a low mileage ( 112,000 kilometres or 70,000 miles ) car.

Running on 3 cylinders, it's a pig for sure, won't go up hills etc.
( once in the past, with this same symptom, cleaning one of the injectors fixed this condition, but not the slow idle on start up).

Tried cleaning out the injectors and testing fro leaks at the injector, but no go.

Can anyone please suggest a modus operandi for curing both these ills ?
Haynes manual is next to useless in this circumstance. I'm unable to afford to take the car to a dealer who charges some $85 per hour.
Thanks in advance.

If it is running on three cylinders it will have a rythmic miss. If the misfire is random, then it is running roughly, and that is a different diagnostic approach.
So if the miss is rythmic, remove the spark plugs leads one at a time and replace with the engine running. The one that makes no difference is then the affected cylinder. You have to identify the specific cylinder.
You can move items, one step at a time, from that cylinder to another to identify the cause. So change the spark plug with another cylinder and see if the miss moves too. Change an igntion wire (they have been know to be faulty brand new), and then an injector. Do a compression test on that cylinder. If bad, check the valve clearances on that cylinder.
If the ignition and compression check out fine, then check for a pulled intake manifold gasket - spray propane or acetylene around the runner at the head and see if the cylinder picks up.
Until the misfire is cured, there is no worrying about the cold low idle.

Okay, the misfire is cured, found No2 injector seals were suspect. Replaced both seals on all four injectors.Cleaned the areas where the seals are meant to do their job. There were deposits to be removed. Probably a buildup over the years.

The low cold idle problem.

This is on the B23E with the k-Jetronic CIS system.
Essentially, when starting cold, the idle is approx. 650 -700 rpm. When up to operating temp. the idle sits just under 1000rpm.

Living in a colder area ( compared to the rest of Australia ), it's essential for a good cold start.

The engine starts easily enough when cold, a couple of turns of the crank and it's away, but the low idle speed is accrentuated when selecting drive or reverse, dropping to approx. 500rpm. This can't be right !

Any suggestions on where to start would be appreciated. Thanks.
cheers
richo

So the low idle is one of two things. Lean mixture, which would indicate the warm up regulator. To test for that, blip the throttle vigorously after the cold start. If the engine accelerates above idle quickly and without backfiring, the mixture strength is good. Second is the auxiliary air valve, which may not be opening enough to allow air in to compensate for the cold engine. You can look inside it with a small light - there should he a substantial "half moon" opening with the engine at overnight cold. If there isn't, then the valve is not opening enough.
So lean mixture, or low air flow.

Thanks Rhys.
When the engine is cold and you give it some throttle whilst in park, revs increase without complaint.
Must be that auxilliary air valve.
I posted a new question ( auxilliary air valve - questions ) about that valve and it's functioning range, have been doing some experimenting !!
I think I'm near a solution or cure, depends on the condition of the bi-metal strip and its ability to move through the range to give me increased cold idle as well as being shut when the engine is at operating temperature.
Have now played with the adjusting nut on the side of the unit, will know tomorrow morning, or late tonigh if I've been successful.
cheers
richo

Hmm, the fiddling doesn't seem to have made any difference, still the same low idle when starting up this morning.
checked a couple of junkyard cars and the disc appeared to be in a similar position to mine.
Wondering if there can be anything else which might be causing the low idle when cold ??
cheers
richo

Sitting for long periods can cause problems with the fuel such as water accumulation in the fuel tank. The first thing that I would try is adding a good quality gas treatment to the tank. Have you changed the fuel filter lately?
steve

Take a look at your plugs, and check that they are all the same color at the burn tip. Check points, timing (with a timing light), I'd also check plug and coil wires to ensure that they all have continuity, and no cracked rubber sheathing. If you suspect cracked wires: check under the hood, at night where there is little if any light pollution, and see if you see any blue archs jumping from your wires to a bit of metal. You may be amazed at the light show going on under the hood.

Also check for air leaks at all hoses, and injector seals. Had read where one can test by having the car idle, and slowly pass an unlit propane torch (just the gas turne on low) over the hoses and injector seals, If there is an increase in idle...leak !! I've never tried this, sounds as though it should be effective. At any rate be real carefull not to allow a build up of propane gas in your engine compartment. I'd also highly suggest this be done outside, and not in a garage, or other sheltered area.

How often do you replace your air, and fuel filters ? If they are way over due, they become suspect.

Then you can get into valve adjustment, ECU, AMM, issues, and all the other little buggers, (fuel presure regulator, fuel relays, consistant fuel pressure, etc.) that can have one chasing all over the engine bay .

Good luck, and let us now what you found as the culprit. Begin with the simple, and work your way.

Enjoy.

Thanks for the suggestions......
Plug leads are near new, all plugs running an even tan colour.
Air and fuel filters replaced less than 2000 kilometres ago.

Will run the air leak test in a days time when I can get to the car in daylight ( as a mr. mum there's plenty of things to do ! ) Prefer to do the test with water in a squirt bottle, similar result without the possibility of kaboom.

Last time the 3 cylinder thing happened ( only a few weeks ago ) it turned out to be an injector requiring cleaning.

None of these things ( imho ) really point to the low idle speed at cold start. This was happening prior to the 3 cylinder scenario.