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1G Dynatek ARC2 cuts 2 cylinders when hooked up

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GSXftw

10+ Year Contributor
381
78
Dec 16, 2009
Medford, Oregon
So I have been fighting spark blowout and getting a CDI on my car for months... I have done quite a bit of troubleshooting and talking with their tech support, They're clueless and so am I!
91 GSX, making about 500whp runs great without CDI, but blows spark out as expected at 30+psi.
Now...when the CDI is hooked up, it momentarily fires up on 4 cyl, then it drops to 2, cylinders 1/4 drop injector pulse, and car throws a DTC code 044 ignition circuit failure. The CDI box is brand new, it did this with a used one as well, the harness has been send to dynatek for testing and it tested ok, they sent me back the troubleshooting packet, all the switches/dials are in the correct positions. Rising/crank/restrike/revlimiters set at zero/off. The car has EXCELLENT spark on all 4, the cyl are dropping from losing injector pulse, which has both been verified on a waveform viewer and a noid light.
I have tried replacing (known good units)- the ecu, coil pack, igniter, injectors/plugs, injector resistor (now not using one), tested wire continuity from injector-ecu, have beefed up ecu ground pins. Nothing I do works. Ideas?
 
I am going to assume that this does not happen when the ARC2 is disconnected as you stated earlier. If this is still the case you should send the box to dynatek to have them inspect it. I saw that you sent the harness to them but you did not state you sent the box. All ignition boxes are finicky and this definitely looks like the case here.
 
So I have been fighting spark blowout and getting a CDI on my car for months... I have done quite a bit of troubleshooting and talking with their tech support, They're clueless and so am I!
91 GSX, making about 500whp runs great without CDI, but blows spark out as expected at 30+psi.
Now...when the CDI is hooked up, it momentarily fires up on 4 cyl, then it drops to 2, cylinders 1/4 drop injector pulse, and car throws a DTC code 044 ignition circuit failure. The CDI box is brand new, it did this with a used one as well, the harness has been send to dynatek for testing and it tested ok, they sent me back the troubleshooting packet, all the switches/dials are in the correct positions. Rising/crank/restrike/revlimiters set at zero/off. The car has EXCELLENT spark on all 4, the cyl are dropping from losing injector pulse, which has both been verified on a waveform viewer and a noid light.
I have tried replacing (known good units)- the ecu, coil pack, igniter, injectors/plugs, injector resistor (now not using one), tested wire continuity from injector-ecu, have beefed up ecu ground pins. Nothing I do works. Ideas?

You want to have it set to Rising Edge, Cam, No-restrike. The rotary dials won't matter, unless you connected the necessary wiring.
 
I am going to assume that this does not happen when the ARC2 is disconnected as you stated earlier. If this is still the case you should send the box to dynatek to have them inspect it. I saw that you sent the harness to them but you did not state you sent the box. All ignition boxes are finicky and this definitely looks like the case here.

Think I forgot to mention that part. I bought a whole kit used, and it did this. I immediately suspected the box, sold the used one back to the guy, and bought a brand new one, and it did the same thing. Felt like the harness was the last thing left, sent it in and they swear up and down its good
 
You want to have it set to Rising Edge, Cam, No-restrike. The rotary dials won't matter, unless you connected the necessary wiring.
Heres the dynatek instructions I followed
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So....Im a little embarrassed I didnt think of this sooner... But just today I thought... Hey why dont I try it on another car? Hooked it up on my bone stock 2Gb talon. It does the same thing! So I guess I need to make yet another call to dynatek tomorrow and let them know the problem is on their end.
 
Had the same issues with arc 2. But I ran mines it for years. out of nowhere it just started acting up the day before dyno. went back to stock coils and yielded better results. on stock coils and wires didnt even have any issues until 38psi then got spark blowout. but I was making round 620whp before 38psi.
 
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I guess I should have asked, but are you running a 1g CAS by chance? I'm not using a crank trigger at all because of the 1g CAS, so I set my dynatech to cam.
 
You aren't experiencing spark blowout, you are experiencing spark no start.

Did you have them check the tach adapter box in the harness when they looked at the harness?

I guess I should have asked, but are you running a 1g CAS by chance? I'm not using a crank trigger at all because of the 1g CAS, so I set my dynatech to cam.

The ARC-2 doesn't really care whether your input is a crank sensor or a cam sensor. What it cares about, is whether the ignition coils fire every 360 degrees(wasted spark) ie CRANK setting, or whether the coils fire every 720 degrees(sequential) ie CAM setting. This matters to the box when it does its calculations for rev limits, and also when it is calculating any timing retard settings. If you have that setting wrong, the box may rev limit at half the RPM you set, or at double the RPM you set.
 
You aren't experiencing spark blowout, you are experiencing spark no start.

Did you have them check the tach adapter box in the harness when they looked at the harness?


.
I didnt mean the ARC2 is blowing out, I meant I am blowing spark out, i need to get this ARC2 working, and this is what happens when I try. I did have them check it yes, sent back everything but the new module, they tested for continuity, but i think that lies the problem, I would think some kind of load test should be involved, but anyways I got a hold of them today, said it pretty much has to be the tach adapter and Id like to buy one. The rep I was talking to is one I dealt with months ago when this mess started, he said given these circumstances, theyre sending one out free of charge, it should be here tuesday. I will report back with the results
 
I didnt mean the ARC2 is blowing out, I meant I am blowing spark out

If you are blowing your spark out, then stop. It isn't a birthday cake candle!

I understood what you said. The problem is that you don't understand what I said. You aren't blowing out the spark. The problem is that the spark doesn't start. It could be because of inadequate voltage. It could be because your trigger signal(through the tach adapter) is getting some noise. It could be because you have bad wires, bad coils(you checked). Some of these issues could cause the spark to appear elsewhere, instead of at the plug. Other problems could result in no spark anywhere.

If your spark were getting "blown out", then the tach adapter won't solve anything. Because the tach adapter doesn't affect spark energy.

If you haven't tried it, examine your plugs and wires closely to see if you see any evidence of arcing across the wiress.
 
If you are blowing your spark out, then stop. It isn't a birthday cake candle!

I understood what you said. The problem is that you don't understand what I said. You aren't blowing out the spark. The problem is that the spark doesn't start. It could be because of inadequate voltage. It could be because your trigger signal(through the tach adapter) is getting some noise. It could be because you have bad wires, bad coils(you checked). Some of these issues could cause the spark to appear elsewhere, instead of at the plug. Other problems could result in no spark anywhere.

If your spark were getting "blown out", then the tach adapter won't solve anything. Because the tach adapter doesn't affect spark energy.

If you haven't tried it, examine your plugs and wires closely to see if you see any evidence of arcing across the wiress.

no no.... Without the CDI box, and on the stock ignition system, I am blowing spark out, at 30+ psi. So....in response to that.... I am trying to get this CDI working on my car. When it is installed, I am losing injector pulse on cyl 1/4, but have excellent spark on all 4 cyl.
 
no no.... Without the CDI box, and on the stock ignition system, I am blowing spark out, at 30+ psi.

No, you aren't. The spark isn't starting. You aren't blowing it out. It may take 30,000V to start the spark, but once it is started, it doesn't get blown out. The issue is that under higher boost(or bigger spark gap, etc), it takes MORE voltage to start the spark. But your stock system can't provide the extra voltage, so it can't start the spark. You aren't blowing a thing out. The issue is that you aren't starting it.

In your case, it sounds like the tach adapter has a problem in it, that makes the ECU shut off those 2 cylinders. And when it shuts off those cylinders, the spark doesn't start. It is NOT getting blown out. Very few people in these cars are ever going to actually experience spark blowout.

I know a bit about ignitions. Those instructions on the ARC-2 you posted, that is my 2G in the pic, back when I worked for Dynatek designing ignitions like the ARC-2 ;)
 
No, you aren't. The spark isn't starting. You aren't blowing it out. It may take 30,000V to start the spark, but once it is started, it doesn't get blown out. The issue is that under higher boost(or bigger spark gap, etc), it takes MORE voltage to start the spark. But your stock system can't provide the extra voltage, so it can't start the spark. You aren't blowing a thing out. The issue is that you aren't starting it.

In your case, it sounds like the tach adapter has a problem in it, that makes the ECU shut off those 2 cylinders. And when it shuts off those cylinders, the spark doesn't start. It is NOT getting blown out. Very few people in these cars are ever going to actually experience spark blowout.

I know a bit about ignitions. Those instructions on the ARC-2 you posted, that is my 2G in the pic, back when I worked for Dynatek designing ignitions like the ARC-2 ;)
Ok well maybe Im using the wrong term... Basically, we need more power captain. 29 psi is fine but 30+ starts to buck, did the full jazz of gapping plugs down and going to non protruding to get to this point, but yes really suspecting the tach adapter at this point, I cant wait for the day I can hook it all up and it all works.
So maybe youre the person I should ask then...Do our coils/igniter need to be externally grounded at their mounting points? Or do they rely on the wiring for grounding?
 
No worries. Instead of calling it a "spark blowout", you could call it a misfire.

Another thing you could do with your stock system to get a little more out of it(without going to a CDI) would be to add ignition timing. The more advanced the timing is, the less pressure there is right when you start the spark, and the easier it is. That, and ensure your voltage at your coil + is high, to improve the charging current for the coils.

The ignitor needs to be attached to a flat plate, for the heatsink properties, or it will overheat. I believe it is grounded in the wiring.

The coils don't really need to be grounded, if they are the stock ones. The current flows in a loop down the plug wire, across the head, and back up to the plug wire and coils. If you go to a COP style coil, you may need to add ground wires to ground the head a bit better. I THINK I may have shown this a little in the ARC-2 instructions, but it's been 10+years since I wrote them.
 
No worries. Instead of calling it a "spark blowout", you could call it a misfire.

Another thing you could do with your stock system to get a little more out of it(without going to a CDI) would be to add ignition timing. The more advanced the timing is, the less pressure there is right when you start the spark, and the easier it is. That, and ensure your voltage at your coil + is high, to improve the charging current for the coils.

The ignitor needs to be attached to a flat plate, for the heatsink properties, or it will overheat. I believe it is grounded in the wiring.

The coils don't really need to be grounded, if they are the stock ones. The current flows in a loop down the plug wire, across the head, and back up to the plug wire and coils. If you go to a COP style coil, you may need to add ground wires to ground the head a bit better. I THINK I may have shown this a little in the ARC-2 instructions, but it's been 10+years since I wrote them.
Ok... Ive been using the BR7ES for a little bit but still see a blip or 2 of knock on E77 so gonna try the BR8ES, and continue to get a stronger E85 mix in the tank, if I can add more timing I will try
 
Update-
Free of charge, dynatek sent a tach adapter, popped it in, good to go! Now can kinda figure out what was happening...ECU wasnt seeing the proper primary ignition signal, threw the 044 code, and in turn shut off injector pulse so as not to flood cylinders with what it thought was no spark. Im still experimenting with what the car is gonna like for plug gap, it was blowing out at .024, dropped it down to .020, and its pulling 31psi like a beast. Having a tough time finding what people run for gaps once the CDI is in... you would think the extra energy would allow you to run more
 
Glad to hear the tach adapter fixed it.

You can generally run a good bit more spark plug gap, because of the CDI having a higher output voltage to start the spark. It has more to do with the voltage, than just the energy. There are a few things to keep in mind, that will push you in opposite ways:

1) The CDI spark is much shorter but stronger. It can jump a larger gap, which may help if you are having problems with rough running at cruise conditions(when the engine is running leaner)

2) A larger gap means more voltage is required to jump the gap. The CDI can supply this, no problem. What will be a problem is the other parts in your system. Once the voltage to jump the spark gap gets high enough, the system may find it easier to create a spark somewhere else. Possibly on the outside of the spark plugs, or at the coil output terminals. So you need to keep an eye on that if you think you are having a misfire under boost with a larger gap.
 
Glad to hear the tach adapter fixed it.

You can generally run a good bit more spark plug gap, because of the CDI having a higher output voltage to start the spark. It has more to do with the voltage, than just the energy. There are a few things to keep in mind, that will push you in opposite ways:

1) The CDI spark is much shorter but stronger. It can jump a larger gap, which may help if you are having problems with rough running at cruise conditions(when the engine is running leaner)

2) A larger gap means more voltage is required to jump the gap. The CDI can supply this, no problem. What will be a problem is the other parts in your system. Once the voltage to jump the spark gap gets high enough, the system may find it easier to create a spark somewhere else. Possibly on the outside of the spark plugs, or at the coil output terminals. So you need to keep an eye on that if you think you are having a misfire under boost with a larger gap.

Well heres how my first raceday went with the new setup and the CDI on... straight after work, the first thing I did was use this part at work (auto tech) that adjusts out and measures how much spark gap will jump, I had it jumping .5", and still running the car no missing, because yes I did definitely suspect the spark jumping out and taking the easy way out... I also measured my spark wire resistance, no opens and checked out good, so on the way to the track, did a pull, thing was a freakin beast! Hit the track, and dealt with spark blowout all night long. I changed coil packs, igniter, and plug wires. No change. On the way home I said lets try it without the CDI, so unhooked it, and it was absolutely terrible, blew out at like 15 psi instead of 29. So gapping down to .020 its not breaking up at my 31 psi level, but I still dont think its right... Im suspecting I should look into my electrical system a little more...Maybe do a voltage drop test at the coil pack power wire? Do these wires have to be beefed up at all for the CDI? Even though my car holds 14.0v at cruise, it drops to 13.0v during pulls, it always has, and Ive done NUMEROUS things to try and solve it, maybe this is the issue also.
 
Well heres how my first raceday went with the new setup and the CDI on... straight after work, the first thing I did was use this part at work (auto tech) that adjusts out and measures how much spark gap will jump, I had it jumping .5", and still running the car no missing, because yes I did definitely suspect the spark jumping out and taking the easy way out... I also measured my spark wire resistance, no opens and checked out good, so on the way to the track, did a pull, thing was a freakin beast! Hit the track, and dealt with spark blowout all night long. I changed coil packs, igniter, and plug wires. No change. On the way home I said lets try it without the CDI, so unhooked it, and it was absolutely terrible, blew out at like 15 psi instead of 29. So gapping down to .020 its not breaking up at my 31 psi level, but I still dont think its right... Im suspecting I should look into my electrical system a little more...Maybe do a voltage drop test at the coil pack power wire? Do these wires have to be beefed up at all for the CDI? Even though my car holds 14.0v at cruise, it drops to 13.0v during pulls, it always has, and Ive done NUMEROUS things to try and solve it, maybe this is the issue also.

I can't help you with spark blowout.

In case you meant misfire, then there are a few things to look at. It doesn't take too much to get a spark to jump a 0.5" gap in free air, that probably wasn't as severe as jumping a 0.030" gap under compression and 30+PSI.

With the CDI on, the ignitor shouldn't matter too much, it is just a switch to tell the CDI to fire. The coil pack could be an issue if the plug wires are a poor fit. The spark plugs could also be a big problem. But you replace them both, and the problem didn't go away at all. Did the problem get better at all? If not, the problem was elsewhere.

The issue is that once you START firing outside of the cylinder, the spark creates a carbon trace that makes it easier to misfire. The misfiring will keep happening at lower and lower boost levels until you replace the problem part. So whatever components you replaced, were not where the problem was. My first guess would be your spark plugs themselves. Look for vertical burn marks/traces on the outside, that might indicate it was firing down the outside of the plug.

Also, as it gets cooler at night, the air gets denser and it makes your ignition work harder. What did you have your plugs gapped to?

As for as wires to the coil pack, the coil no longer uses much current. That coil 12V now just signals the CDI to turn on. Beefing up wires isn't going to do much, and the voltage drop shouldn't show much either. If you try to measure the wires on the coil itself, make sure your multimeter can handle 500V+. The stock ignition puts 12V across the coil, the CDI puts 500V. If you want to look at current draw, look at the 2 big wires going from the ARC, directly to the battery.
 
I can't help you with spark blowout.

In case you meant misfire, then there are a few things to look at. It doesn't take too much to get a spark to jump a 0.5" gap in free air, that probably wasn't as severe as jumping a 0.030" gap under compression and 30+PSI.

With the CDI on, the ignitor shouldn't matter too much, it is just a switch to tell the CDI to fire. The coil pack could be an issue if the plug wires are a poor fit. The spark plugs could also be a big problem. But you replace them both, and the problem didn't go away at all. Did the problem get better at all? If not, the problem was elsewhere.

The issue is that once you START firing outside of the cylinder, the spark creates a carbon trace that makes it easier to misfire. The misfiring will keep happening at lower and lower boost levels until you replace the problem part. So whatever components you replaced, were not where the problem was. My first guess would be your spark plugs themselves. Look for vertical burn marks/traces on the outside, that might indicate it was firing down the outside of the plug.

Also, as it gets cooler at night, the air gets denser and it makes your ignition work harder. What did you have your plugs gapped to?

As for as wires to the coil pack, the coil no longer uses much current. That coil 12V now just signals the CDI to turn on. Beefing up wires isn't going to do much, and the voltage drop shouldn't show much either. If you try to measure the wires on the coil itself, make sure your multimeter can handle 500V+. The stock ignition puts 12V across the coil, the CDI puts 500V. If you want to look at current draw, look at the 2 big wires going from the ARC, directly to the battery.
Yeah Im still getting the verbiage down LOL... Changing coil packs and trying a set of stock plug wires did nothing (I normally run big MSD wires) when I changed the plug gap from .024-.020 that was a definite improvement, Im just not too hot on running such a small gap on a street car. Despite a 90a saturn alternator, maybe I just need to go bigger on my charging system
 
You should not need to run that small with the CDI. You mentioned replacing the plug wires and coil pack, did you replace the spark plugs during this troubleshooting too? Or just gap them down? What plug wires are you using?
 
I know this is an old thread and I'm really going out on a limb, but would anyone, specifically GSXftw have any information/rmas/numbers that I could reference to Dynatek so they could see what I'm going through? I have the exact same issue with the 2 cylinders cutting out on startup and I verified spark, it throws the 044 code, and it runs fine if I go back to the stock coils. Scott from Dynatek sent me an RMA# and sent me on my merry way saying that the tach adapter has nothing to do with my issues but I can send it in for warranty anyhow. Apparently they don't do refunds either he told me so I can't buy a new one and test it while they're figuring out what's wrong with the bad one.
 
I know this is an old thread and I'm really going out on a limb, but would anyone, specifically GSXftw have any information/rmas/numbers that I could reference to Dynatek so they could see what I'm going through? I have the exact same issue with the 2 cylinders cutting out on startup and I verified spark, it throws the 044 code, and it runs fine if I go back to the stock coils. Scott from Dynatek sent me an RMA# and sent me on my merry way saying that the tach adapter has nothing to do with my issues but I can send it in for warranty anyhow. Apparently they don't do refunds either he told me so I can't buy a new one and test it while they're figuring out what's wrong with the bad one.
http://www.dsmtuners.com/threads/dynatek-arc-2-results-impressions.511466/#post-153653863

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