the infamous horn honk csx stall.

Hello All,
Bucar says I have "the infamous horn honk csx stall". OMG Is it worse than COVID????
91 SBEC on 87 CSX,



1)Still causes Check engine light when I blow the horn. A super short toot is likely not an issue but a one second one is bad

2)Causes AF to drop to below 10, slowly recovers over a 10 second period back to normal

3)Seems to be worse on a warm engine.
4)switched to a different ECU and the issue appears to go away but need to check this again.

5)Was going to check if it is a load issue on the IGN or peizoelectric effect

6)I did not notice this issue last year.


Brian suggested to first examine the column and horn wiring and connectors for power feed to the ECU. Grounds too perhaps.
Any additional thoughts?

Solution found
Thanks everyone for your IM

I found a solution. First removed the connection to both horn to check for non horn/load problems. Engine ran fine with horn. Next hooked up the right side high horn, every thing was also fine. Unhooked the high horn and connected the left low tone horn. Problem with stalling. Replaced low horn with another high horn. Engine worked fine. So I have a solution for now, thank you for your ideas.

Odd I may order another low horn for testing.

What do you think it was about the low horn which caused the issue?

Quote:

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Originally Posted by cordes

What do you think it was about the low horn which caused the issue?

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Not sure, Warren's thought was reverse EMF aka flyback. this theory could be tested via reverse bias diode to ground. I was thinking either a volt drop on the 12V battery line was causing the odd behaviour or piezoelectric effect on the SBEC ceramic capactors, this is the opposite of what happens in your Quartz watch. Both are easy to test. I am going to order new horns for the spring and will retest. I will update when I figure out the issue.

That’s very interesting. I can’t wait to hear what the problem is.

does this happen regardless of other things being switched on or off in the car ?

I'm remembering old dodge darts.. you could hear the pulse of the flashers through the factory am radio if tuned to the left most side of the scale and you switched on something like the fan switch ..
fan switch was right above the radio so presuming the fan wiring brought the flasher pulse signal over to the radio..?

possibly simply re routing that low note horn lead around say the other side of the car would solve the issue (?)

- if "left side low note horn".. means it's on the left side of the car..?.. and presumably the wire is on the inner fender beside the engine controller

Quote:

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Originally Posted by Dr. Johny Dodge

does this happen regardless of other things being switched on or off in the car ?

- if "left side low note horn".. means it's on the left side of the car..?.. and presumably the wire is on the inner fender beside the engine controller

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I tried all sorts of different loads on both IGN and Batt circuits all were fine EXCEPT horn. Yes the low note horn was on the driver's side.
My thought was to power the horn from another external battery for troubleshooting, if it acts up we know it is either vibration or piezoelectric. If we remove the horn from the body and it still acts up than piezoelectric. If the car does not act up with external battery we know the issue is electrical and addition troubleshooting is required. Yes I was planning to place the low on the passenger side as well.