Discussion
Hi Robert can be a bit tricky on the K Jetronic to diagnose that kind of fault. However the first thing to be absolutely sure is that there is NO air leak downstream of the air flow meter. I have a bit of pipe about 1" bore I put to one ear and go round all the possible points listening for a 'hiss'. Found one under one corner of the plenum once where a gasket had broken.
A frequent problem, particularly if you have had the long air duct off, is a split underneath the air meter cover (big black rubbery thing!). I am afraid it is a very frequent problem. If it is original I would be amazed if it isn't cracked. They are very hard to find but a very good silicone car body adhesive should fix it.
DONT change the mixture setting on the fuel metering head. Changing the mixture before you have found the reason for it going out is merely adding problems and you will be 'chasing your own tail'. Leave that allen screw well alone until everything else is perfect! (While I am at it NEVER run the car with an allen key in there, the weight of the key is enough to throw the settings out)
While you are at it, take the air filter out and look at the metal plate behind it. That plate should be held on with either three or four 'pop' rivets. They corrode and drop out, or rather go into the airflow and damage the airflow meter. Plus if they are leaking air it will suck dust up very effectively and the slightest amount of dust stuck into the airflow meter will upset it.
Try that first and see if you get anywhere.
A frequent problem, particularly if you have had the long air duct off, is a split underneath the air meter cover (big black rubbery thing!). I am afraid it is a very frequent problem. If it is original I would be amazed if it isn't cracked. They are very hard to find but a very good silicone car body adhesive should fix it.
DONT change the mixture setting on the fuel metering head. Changing the mixture before you have found the reason for it going out is merely adding problems and you will be 'chasing your own tail'. Leave that allen screw well alone until everything else is perfect! (While I am at it NEVER run the car with an allen key in there, the weight of the key is enough to throw the settings out)
While you are at it, take the air filter out and look at the metal plate behind it. That plate should be held on with either three or four 'pop' rivets. They corrode and drop out, or rather go into the airflow and damage the airflow meter. Plus if they are leaking air it will suck dust up very effectively and the slightest amount of dust stuck into the airflow meter will upset it.
Try that first and see if you get anywhere.
I had the problem after moving the air filter housing and hose assembly to one side to remove the radiator and fit a new water pump when everything was refitted I had high Tickover, tried altering the Tickover screw without much success I then found a split in the old air hose.
I have now replaced it with a new hose but still have the same problem, I have only altered the Tickover screw so will remove the hose again and refit and try your trick and listen for air intake at the joints.
Thanks
Rob
I have now replaced it with a new hose but still have the same problem, I have only altered the Tickover screw so will remove the hose again and refit and try your trick and listen for air intake at the joints.
Thanks
Rob
s1robert said:
I had the problem after moving the air filter housing and hose assembly to one side ......
Check the rubber cap on the fuel injection unit around the area circled in the picture...
This join is particularly prone to cracking and splitting. If that has happened then it might explain your problem.
Edited by v8s4me on Tuesday 27th February 23:14
To be honest, any openings in the intake bellows normally results in a lack of tickover, not a tickover that's too fast. It's because any additional air that seeps in isn't metered, so there isn't enough fuel to burn with it.
It's possible that your tickover had been set up to counter a very small leak in the intake circuit, which then became a big leak when you carried out the other work. Now you've got it totally sealed, it's a struggle to bring it down again. Normally the big bypass screw is enough to cut the engine out when it's wound all the way in.
What's the bump-stop on the throttle butterfly doing? Has it been wound out so the throttle won't fully close? It's got to be a leak of metered air getting in somewhere, that's my bet.
It's possible that your tickover had been set up to counter a very small leak in the intake circuit, which then became a big leak when you carried out the other work. Now you've got it totally sealed, it's a struggle to bring it down again. Normally the big bypass screw is enough to cut the engine out when it's wound all the way in.
What's the bump-stop on the throttle butterfly doing? Has it been wound out so the throttle won't fully close? It's got to be a leak of metered air getting in somewhere, that's my bet.
Removed and refitted 75mm air intake hose improved it a bit, but give the man a silver spoon for the suggestion bump stop. Sorted.
Just one question how do you balance the Tickover screw with the bump stop is there a recommended number of turns the Tickover screw is turned out from a closed position as a average.
Rob
Just one question how do you balance the Tickover screw with the bump stop is there a recommended number of turns the Tickover screw is turned out from a closed position as a average.
Rob
What kitchski said - if the butterfly stop is allowing the butterfly to close, you should be able to stall the engine with the air by-pass screw. If you can't, air is getting in somewhere between the throttle body and the cylinder head. If it's more of a stumble and stall when you try to reduce below 1000rpm with the by-pass screw, then the mixture is probably off. It's hard to say if it's too rich or too lean, but I will say that the only way to get it right is to check and adjust the control pressure and fuel delivery pressure. I recommend owning a gauge set if you have the 2.8 engine.
All is working ok now, after ajusting the bump stop the revs can be dropped down to about 600 rpm and if I try to screw the air screw in it starts to stumble. Checking pressures is a bit over my head I think for another day.
I'm looking to get the old girl through the mot next month, when that's done I will get someone that knows a bit about the cologne engine to do a service and set up.
Rob
I'm looking to get the old girl through the mot next month, when that's done I will get someone that knows a bit about the cologne engine to do a service and set up.
Rob
greymrj said:
But if you didn't change the bump stop before, what have you changed that now requires the bump stop to be changed? If it was running right before why does it need to be changed? Something else has changed, wonder what it was?
That's what I wondered. After sorting out the vacuum hoses I got my tick over sorted out by balancing what you call the "bump stop" (*) against the mixture screw in the same way I would have done for a carb. It seemed to work because it sailed the emissions test.I wonder if the little lever and cam on top of the "bump stop" were sticking and fiddling with the adjustment screw freed them off?
(*) Ford call it the "base idle speed adjustment screw" - might be a clue there
Anyway, the important thing is, it's sorted
Edited by v8s4me on Wednesday 28th February 22:32
I think I might have had the problem with Tickover before I done the work on the rad. and changing the air intake hose etc. as the car was off the road for years before I purchased the car in 2016.
I've only run her in the garage and put the higher revs down to not reaching normal engine temperatures.
So the bump might have been altered before my purchase?.
When I get her through the mot I will get her checked out.
Rob
I've only run her in the garage and put the higher revs down to not reaching normal engine temperatures.
So the bump might have been altered before my purchase?.
When I get her through the mot I will get her checked out.
Rob
s1robert said:
When I get her through the mot I will get her checked out.
Rob
A good time to set the mixture adjustment would be whilst the exhaust probe is inserted to carry out the emissions check for the MoT.Rob
( As long as your friendly tester is familiar with the 2.8 Cologne and happy to do this. )
glenrobbo said:
....As long as your friendly tester is familiar with the 2.8 Cologne and happy to do this.
Honestly, if you can set the idle correctly on a lawn mower then you can do the 2.8i. It really is a very simple system. Providing of course all your hoses are in good nick and there are no random air leaks.Have a read of THIS
If you follow the old-skool "best lean" process then it should sail through the emission test. Mine did.
greymrj said:
But if you didn't change the bump stop before, what have you changed that now requires the bump stop to be changed? If it was running right before why does it need to be changed? Something else has changed, wonder what it was?
It could be that it had a small intake leak in the past, and the only way somebody could get round it was to jam the butterfly open slightly. Now it's no longer leaking, that's resulting in an idle that's too fast.s1robert said:
Removed and refitted 75mm air intake hose improved it a bit, but give the man a silver spoon for the suggestion bump stop. Sorted.
Just one question how do you balance the Tickover screw with the bump stop is there a recommended number of turns the Tickover screw is turned out from a closed position as a average.
Rob
You want to keep the butterfly closed, to achieve the best vacuum (as the fuel injection system is completely vacuum-driven). You wind them in totally, then wind them back out until they are just shy of kissing the butterfly 'arm'. You don't want to let it fully close without rest on the grub screw, otherwise it could stick.Just one question how do you balance the Tickover screw with the bump stop is there a recommended number of turns the Tickover screw is turned out from a closed position as a average.
Rob
Then, when you know you've got it sealed, you'll be able to stall the engine with the idle screw (which you now can). Through a combination of adjusting the air/fuel mixture (carefully - it's sensitive) and playing with the idle bypass screw, you should be able to get it to tick over quite happily.
One thing worth pointing out is that if you've got the idle too lean, it can idle fine cold (due to the cold start injector) but when you rev it once hot, it might splutter and try to die before recovering. Takes a bit of trial and error if you don't have an AFR gauge, but if you do it's dead easy to put right.
Gassing Station | S Series | Top of Page | What's New | My Stuff