Zetec screened crank sensor cable

[James c]

Hi link forum.  I posted a previous thread to do with hard starting/starter kickback on a Zetec engine running a link atom.  After some good advice we came to the conclusion the crank sensor polarity was incorrect which it was and this improved the situation greatly.  However it still had the odd time were it would kickback on the starter so today I put the timing light back on it and while cranking there is still spark scatter.  

Once running the timing is solid as a rock.

My thoughts are that it's getting interference from the starter while cranking which is upsetting the signal.

Looking in to this matter it appears that others have experienced the same issue just under cranking and there is mixed opinions about how the shielded cable should be terminated.  

Mine appeas to go to an earth on the block but a lot of people say the shielding needs to earth back to the ecu earth?

Any thoughts on this?  At this point I'm considering using a crank pulley triggering system to take the sensor/cable right away from the starter area.  Apparently even ford had this issue in early production of these engines and that's why in the series two engines the starter was moved to the oposite side of the motor.

Any help would be much appreciated. Cheers 

  

[Brad Burnett]

Could you post a copy of you calibration?

There are a variety of things that will cause kickback on the starter.  Including but not limited to cranking timing, fueling, trigger threshold levels, poor grounds, etc.

As for the shield on the cable, I always run that to a sensor ground at the ecu.

[James c]

Hi Brad

Attached is the PCL file. Currently ignition timing at cranking speed (500rpm) is 16 degrees. I have moved this down in various increments but the engine becomes harder to start if its firing to close to TDC.   If it stayed at 16 while cranking it would start great but using a timing light I can see it moves around a lot until it starts and the starter is released then the timing is nice and solid.

Let me know what you think.

Tune MK2 Escort.pcl

[Brad Burnett]

Have you tried increasing the arming threshold on the Trig 1?  Could possibly weed out some of the noise by bumping the low rpm values by about .2-.5.

 

[James c]

No I haven't touched the trig threshold yet.  I will try that today.  It will never be cranking over 1000rpm so you think I could just adjust the 0 and 1000rpm columns?

[Brad Burnett]

Just to get an idea of what you are after, I would look in the help file under "engine specific information".  Click around in there and look at some of the trigger threshold levels to get an idea.

I sometimes have to add a 500 rpm column to get what I'm after.

[James c]

I increased the trigger arming threshold by a small amount on the 0 and 1000rpm columns and it has fixed the issue.  The starter now spins freely as it should with no kick back.  

Thanks a lot for the advice Brad.  Such an easy fix when you know what to do. 

One other thing I was going to ask is what's the best way to make the idle stay constant on a cold start.  Currently the car will idle when stone cold but at around 7 to 800rpm which is a bit low for a cammed engine.  As soon as it starts to warm up its fine and idles at around 1000rpm.  If I could keep it at 1000rpm all the time regardless of temp that'd be good.

Cheers

[CamB]

Sorry if I've missed it in the above, but does the engine have any form of idle control (Idle solenoid, stepper, ethrottle)? Are you using the idle ignition table?

[James c]

Hi Cam

Attached is my pcl file but I have also attached a pic of my idle control table.  I made some changes in here but it didn't seem to have any effect on idle speed. Can you see anything wrong with it?

[James c]

Ok I just had a play around with the warm up enrichment thinking it may have been wanting more fuel at idle but adding more made it worse so I leaned it out and it seemed to run better.  If its getting to much mixture correction at cold idle do you think this would cause the idle to be down? Take a look at the warm up enrichment table and see if it looks to aggressive to you.

 

Cheers

[Adamw]

Hi James,

If I remember right you have race type ITB's correct?  You will possibly not get it much better - you can only do so much with ignition timing.  You dont see race type ITB's on many road engines and most race guys dont mind holding the throttle open a little manually until it warms up... 

However I think you could possibly rehash that idle ign table to make it a little more effective.  I would try something more like this:

With a table like this because it will be quite retarded at normal warm idle speeds you will need to open the throttle stop quite a bit more than it currently is. I think having the throttle open more will help when its cold.

So to set this up, warm up your engine to normal running temp using your existing idle table.  Once warm, change idle table to something like my example.  Start the car and adjust the throttle stop so that the normal warm engine idles around the zero target error cell. If it is not happy idling with zero degrees ignition you might have to bump that up a little but the idea is we want to give it the bare minimum it needs when warm.