Checked L&T coil resistance... Problem?
01-16-10, 04:56 PM
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Checked L&T coil resistance... Problem?
I have realized I am getting spark from only one spark plug wire. The leading rear rotor wire. So, I decided to check the resistance of the leading and trailing coils. (I made sure the battery was fully charged.) This is what I got: Leading coil = .6 Ω Trailing1 = .9 Ω Trailing2 = 6.0 Ω
Information to know> I have an optima red top battery and the "modified trailing coil pack" for the Banzai S4 PFC adapter.
It is shown on the Banzai Racing website, in the "Tech Support" section, under "FC Coil Modification for APEXi Power FC Harness Adapter Kit Installation" (Was not able to link directly to that page.)
I know that the FSM says the stock resistance should be .2~1 Ω, but I have a different situation.
Does anyone know the resistance numbers for the leading and trailing coils, with this set-up? These numbers don't seem right to me... And I think that my problem lies within these coils.
Information to know> I have an optima red top battery and the "modified trailing coil pack" for the Banzai S4 PFC adapter.
It is shown on the Banzai Racing website, in the "Tech Support" section, under "FC Coil Modification for APEXi Power FC Harness Adapter Kit Installation" (Was not able to link directly to that page.)
I know that the FSM says the stock resistance should be .2~1 Ω, but I have a different situation.
Does anyone know the resistance numbers for the leading and trailing coils, with this set-up? These numbers don't seem right to me... And I think that my problem lies within these coils.
Last edited by dwb87; 01-16-10 at 05:00 PM. Reason: Changed "Title"
01-16-10, 05:33 PM
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All I can say is *the lead 1 and the lead 2* fire at the same moment in time. There is but one coil in the lead assy.
I'd suggest the problem lies either in the sparkplug wire or the method of checking out if both are firing at the same time.
Like pull both lead sparkplug wires out of their bores in the coil then loosely reinstall both. The idle the engine. Then pull one wire out of its bore appox 1/8" and watch the spark....reinstll it and then pull the othe wire out the same amount and watch for spark. Even if one of the wires is corrut, the spark from the coil will still come out of the bore and strike anything nearby.
IF using a timing light to determine if there is spark on the lead coil assy, reverse the direction of the timing light clamp on the wire that is not firing and then check it again. Probably is now sparking like it always wasl. Just a timing light issue/method.
I'd suggest the problem lies either in the sparkplug wire or the method of checking out if both are firing at the same time.
Like pull both lead sparkplug wires out of their bores in the coil then loosely reinstall both. The idle the engine. Then pull one wire out of its bore appox 1/8" and watch the spark....reinstll it and then pull the othe wire out the same amount and watch for spark. Even if one of the wires is corrut, the spark from the coil will still come out of the bore and strike anything nearby.
IF using a timing light to determine if there is spark on the lead coil assy, reverse the direction of the timing light clamp on the wire that is not firing and then check it again. Probably is now sparking like it always wasl. Just a timing light issue/method.
01-16-10, 05:47 PM
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Like pull both lead spark plug wires out of their bores in the coil then loosely reinstall both. The idle the engine. Then pull one wire out of its bore approx. 1/8" and watch the spark....reinstall it and then pull the other wire out the same amount and watch for spark. Even if one of the wires is corrupt, the spark from the coil will still come out of the bore and strike anything nearby.
01-16-10, 07:35 PM
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Just make sure no part of your body is touching the chassis of the car/engine and you'll be fine. Even if you do get shocked it won't do any permanent harm to you. Just don't let your body touch the engine/car when you do it. I do it ALLLLL the time.
01-27-10, 11:24 PM
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Okay... It had been a while since I had been around my FC to mess with it. So, I recently have tested for spark a few ways, and even tried the way that HAILERS told me to try... I'm getting absolutely no spark from any of the coils. What else should I check for or test?
01-28-10, 04:50 AM
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The coils are fed from the MAIN RELAY if the ENGINE fuse in the interior is good.
Key to ON feeds power from the ENGINE fuse to the MAIN RELAY. The MAIN RELAY closes and feeds power from the EGI FUSE in the engine bay to the lead and trail coils. MAIN RELAYs rarely fail. ENGINE fuses blow when people fiddle around with the coil assy's with the key to ON and short a power wire to gnd.
Check the ENGINE fuse and EGI fuses.
Key to ON feeds power from the ENGINE fuse to the MAIN RELAY. The MAIN RELAY closes and feeds power from the EGI FUSE in the engine bay to the lead and trail coils. MAIN RELAYs rarely fail. ENGINE fuses blow when people fiddle around with the coil assy's with the key to ON and short a power wire to gnd.
Check the ENGINE fuse and EGI fuses.
01-30-10, 08:27 PM
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I was hoping the engine fuse would have been the problem... The engine fuse was fine though. So were the EGI fuses. I mean you said that the main relay rarely fails, but couldn't it possibly be the problem? or even maybe poor grounding or something??
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02-01-10, 11:48 PM
#9
It should click when turning the ignition on and off. Also, there is a round two pin connector that is part of the relay which you connect both terminals from the battery to and check for continuity between terminals 1 and 2, and 3 and 4. Disconnect the battery from the two pin connector and check that there is "no" continuity between terminals 1&2, and 3&4. When the 4 pin connector of the relay is disconnected and looking at the 4 pin plug with the side that has the protruding piece on top, terminal 1 is the upper right with terminal 2 being lower right. Source: page 143 of Haynes manual.
02-02-10, 12:16 AM
#10
The coils are fed from the MAIN RELAY if the ENGINE fuse in the interior is good.
Key to ON feeds power from the ENGINE fuse to the MAIN RELAY. The MAIN RELAY closes and feeds power from the EGI FUSE in the engine bay to the lead and trail coils. MAIN RELAYs rarely fail. ENGINE fuses blow when people fiddle around with the coil assy's with the key to ON and short a power wire to gnd.
Check the ENGINE fuse and EGI fuses.
Key to ON feeds power from the ENGINE fuse to the MAIN RELAY. The MAIN RELAY closes and feeds power from the EGI FUSE in the engine bay to the lead and trail coils. MAIN RELAYs rarely fail. ENGINE fuses blow when people fiddle around with the coil assy's with the key to ON and short a power wire to gnd.
Check the ENGINE fuse and EGI fuses.
02-03-10, 11:55 PM
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It should click when turning the ignition on and off. Also, there is a round two pin connector that is part of the relay which you connect both terminals from the battery to and check for continuity between terminals 1 and 2, and 3 and 4. Disconnect the battery from the two pin connector and check that there is "no" continuity between terminals 1&2, and 3&4. When the 4 pin connector of the relay is disconnected and looking at the 4 pin plug with the side that has the protruding piece on top, terminal 1 is the upper right with terminal 2 being lower right. Source: page 143 of Haynes manual.
So, my engine fuse (inside) is GOOD, the EGI fuses are GOOD, the main relay is GOOD, the coils seem to be GOOD... Perhaps the spark plug wires are bad?? I checked them for resistance and they seem fine. Plus, they're not very old at all. I don't know what else to do.
02-04-10, 01:05 AM
#12
Thank you for this information satch. I tested my main relay using this method and found out that it is in perfect working condition.
So, my engine fuse (inside) is GOOD, the EGI fuses are GOOD, the main relay is GOOD, the coils seem to be GOOD... Perhaps the spark plug wires are bad?? I checked them for resistance and they seem fine. Plus, they're not very old at all. I don't know what else to do.
So, my engine fuse (inside) is GOOD, the EGI fuses are GOOD, the main relay is GOOD, the coils seem to be GOOD... Perhaps the spark plug wires are bad?? I checked them for resistance and they seem fine. Plus, they're not very old at all. I don't know what else to do.
02-04-10, 06:28 AM
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You should be getting 12 volts at the black and yellow wires at each coil, if you have that, and you are getting a switching signal from the pcm, then your know your wiring and pcm are good. You could check to see if you are getting signal from the Crack Position sensor. also You just make have a bad coil ignitor. there is a way to check it. But, Unfortantly I don't have the Mazda wds, I only have the adaptor to hook up to it. Is your ignition timing right..? basic stuff that a DVOM would be more then able to solve. Good luck. Also, the fuel injectors use the same circuit for power. Something to keep in mind.
02-04-10, 11:01 PM
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I wish I had an igniter checker, like shown on page 5-32 of the S4 FSM. See, I'm not sure that my timing is right though... I don't really know a whole lot about the timing. This engine was rebuilt a few years ago and I have never started it. I've just been troubleshooting and trying to get it rolling... I have a lot of time and money invested in this TII swap.
02-05-10, 06:02 AM
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It would have popped the fuse at best. But I doubt you did that. Set the meter to ohms and touch your leads together, you should get nearly .00 ohms if you do, then your meter is good. if it reads 'ouch" Or "OL" then soemthing may be wrong.
verify your timing then recheck everything.
verify your timing then recheck everything.
02-05-10, 09:45 AM
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The LEAD coil assy has a small, two wire connector. One wire is BLACK/YELLOW and the other is Green/Yellow.
Put your meters negative lead on a known ground like the batterys negative post. Put the other lead on the GREEN/YELLOW wire. Key to ON. Turn the engine over either by hand or the starter. The meter , if on DC VOLTS , should go from zero volts dc to 5vdc as the engine is turned over. That shows that the ECU is signaling the lead ignitor to fire. The 0-5vdcd will come and go as the engine is rotated.
If the ENGINE fuse is good, that black/yellow wire should have batt voltage if the key is to ON or better. Also shows the Main relay is working. You might also pull a plug off any of the solenoids on the engine and see if the Black/White wire on that connector has batt voltage when the key is ON or better. It should and that proves the MAIN RELAY and EGI fuses are good and no problem lies with those two items nor with the ENGINE fuse.
If all plugs are attached and you turn the key to Start and the tach needle makes very small bumps......that proves the trail coil is good along with the Main Relay/EGI fuses/Engine fuse/CAS /ECU.
Put your meters negative lead on a known ground like the batterys negative post. Put the other lead on the GREEN/YELLOW wire. Key to ON. Turn the engine over either by hand or the starter. The meter , if on DC VOLTS , should go from zero volts dc to 5vdc as the engine is turned over. That shows that the ECU is signaling the lead ignitor to fire. The 0-5vdcd will come and go as the engine is rotated.
If the ENGINE fuse is good, that black/yellow wire should have batt voltage if the key is to ON or better. Also shows the Main relay is working. You might also pull a plug off any of the solenoids on the engine and see if the Black/White wire on that connector has batt voltage when the key is ON or better. It should and that proves the MAIN RELAY and EGI fuses are good and no problem lies with those two items nor with the ENGINE fuse.
If all plugs are attached and you turn the key to Start and the tach needle makes very small bumps......that proves the trail coil is good along with the Main Relay/EGI fuses/Engine fuse/CAS /ECU.
02-05-10, 04:50 PM
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Before this inspection, check the specific gravity of the battery, and that it is at or near full charge.
Coil
1. Disconnect the negative battery cable.
2. Connect the ohmmeter as shown in the figure.
3. Check the resistance of the coil.
- page 5-32 S4 FSM
Anyway, thank you HAILERS... I will be sure to use these methods of testing.
Coil
1. Disconnect the negative battery cable.
2. Connect the ohmmeter as shown in the figure.
3. Check the resistance of the coil.
- page 5-32 S4 FSM
Anyway, thank you HAILERS... I will be sure to use these methods of testing.
02-06-10, 05:08 PM
#22
Ohmmeters work by pushing voltage through what you are measuring the resistance of. This is why it is imperative that there is no outside voltage interference to back feed the meter.
But don't take my word for it, I just use my Fluke 77 everyday at work.
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