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This is on a Bosch ignition, not Regina. I have no spark at the coil. I have swapped out the coil, and the power stage, with known good ones, and still no spark. I have 12 volts on the low tension side of the coil, but no spark. This means that the required pulse is not reaching the coil from the power stage, which is required for the coil to generate a high voltage pulse.
I have had trouble with my ignition switch, primarly sticking in start position. Is it possible that the ignition switch has further degraded,and that it is not sending a signal to the power stage, which then can't send a signal to the coil?
John D
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Hi John,
I think you should have stuck with your other post so you won't be plowing the same ground again here. It also mentions installing "Hi Power" chips on both ECUs, which opens uncommon possibilities.
As for this post...
"I have 12 volts on the low tension side of the coil, but no spark."
• I would put an (incandescent) Test Light on it to be sure**. I'd put it on the ground side too, looking for blinks or dimming when cranking.
"This means that the required pulse is not reaching the coil from the power stage,"
• Agreed, if the coil has a solid 12V on terminal 15.
"Is it possible that the ignition switch has further degraded,and that it is not sending a signal to the power stage, which then can't send a signal to the coil?"
• That KO 12V circuit is also powers both ECUs and OBD box. Check with a Test Light at power stage 4. Also test for 0V to 2V DVM fluctuations on power stage 5 when cranking. Maybe even the EZK is starved for KO voltage?
Any FI action when cranking? (put a noid light on injectors) If not, the EZK isn't getting (or responding to) the CPS pulses to initiate FI operation.
** For what I call "ghost voltage", see the five short posts that start HERE.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Hi Bruce and thanks for replying. I think the reason I started a new post was that I was getting no response to the other one. Anyway, I now know that at least one person read it....!
You are correct, the problem may well lie with the chipping process. I am scrounging up another unmodified EZK to see it that is in fact the problem. Too bad the one in my 88 740 isn't interchangeable.
Bruce, I am unfamiliar with some of the terminology you use. What is KO voltage? Is that "switched" voltage, as in "Key On"? And I am sure I have heard of a noid light before, but for the life of me I can't remember what it refers to!
When you talk about testing for voltage at the power stage, do you mean pull the plug, switch ignition on, and test the female terminals on the plug?
Thanks
John Dymond
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"What is KO voltage? Is that "switched" voltage, as in "Key On"?"
• Hi John,
Sorry I lapsed into short hand (or maybe "text hand" nowadays?). I first stumbled on it in Ford terminology back in my V8 days and "assumed" it was probably universal by now.
"And I am sure I have heard of a noid light before, but for the life of me I can't remember what it refers to!"
• It takes the place of an injector and flashes if there is injector voltage and the ECU is pulsing the ground side. Probably under $10 at NAPA or similar auto supply stores. Here's a link to IPD's version as an example. Google noid light for lots of other sources.
"When you talk about testing for voltage at the power stage, do you mean pull the plug, switch ignition on, and test the female terminals on the plug?"
• Yes, and again I suggest a Test Light for the 12V check at terminal 4. And a low voltage DVM setting at terminal 5 (while cranking). This is from the Bentley 240 manual. Haven't tried it myself and don't have a Bosch system in house anymore.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Well, Bruce, we were right. I pulled the EZK contol tonight and opened it up. The EPROM daughter board I soldered in to weeks ago had a hot spot, and I rechecked some of the 21 other spots I soldered in and some of them were not done properly. Fortunately once I reflowed the sloder, and reinstalled the chip into the EPROM, the car started right up. Success at last.
The question, of course, is whether the problem lies with my soldering job, or if there is an issue with the EPROM or the chip. Time will tell. I have a spare EZK on the way from Vancouver just in case.
Thank you Bruce for your "lucid" relies. I have learned something through this exchange; I need to find a "noid light", a 12V test light is better than a multimeter in many cases, and now I know that KO means key on, or switched!
Now on to find and fix a few oil leaks, and swap out a noisy Ujoint. Ah the joys of older vehicles....
John Dymond
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