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PostPosted: April 15, 2019, 5:17 am 
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Hi All! I'm hoping for some insight from the more technically minded folks here. Engine is back together and in the car. All appears to be in order except for the no-start issue... I've got spark and fuel, but also a few fairly spectacular back fires from both the intake and exhaust. I realize that I do not have a full understanding of how a distributor-less ignition system works. If this were a distributor motor I would guess that my timing was off by 180 degrees. That got me wondering, how does my ignition - with a stock crank firing sensor - know whether it's firing on the power or exhaust stroke? (There are no cam position sensors on this by the way). Does it fire on every revolution like a motorcycle / magneto system?

To make matters a little more confusing I have no documentation on my stand alone Quad4rods ignition. John Ehrlich is MIA and the company gone. Another factor might be that I did not have the little crank sensor alignment tool but I did "eyeball it" carefully. Is there perhaps a phasing step for the ignition? Any ideas or thoughts greatly appreciated!

-Robert


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PostPosted: April 15, 2019, 10:07 am 
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I know nothing about Q4R ignition, But it sure looks like a pair of waste spark coils to this untrained eye. The numbers printed on the 2 coils would support that theory.

Is it possible that you have the purple/yellow and black/red wires reversed? I assume that you have the plug wires going to the cylinders per the markings on the coils.

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PostPosted: April 15, 2019, 10:37 am 
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I agree with Chuck, swap those 2 plugs. Did it ever run with this setup, assuming it did then the coil to plug relation ship will be correct.

Graham


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PostPosted: April 15, 2019, 11:12 am 
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I'm going to assume that the answer to Graham's question is "yes, it was running before", due to the dust on the coil connectors. If that is the case, then confirm the crank/cam positions. Pull #1 plug and put a wood dowel or some type of tube on top of the piston and rotate the piston to its highest point. Confirm the harmonic balancer is in the correct position (there's a pic in my build log of the trigger wheel gap relative to a rib in the front cover). If correct, pull the valve cover and check the cams to make sure neither of them slipped (cam slots are aligned with the top of the head). If the mechanical timing is OK, then focus on the wiring.

Yes, the ignition does fire 1 and 4 every 360 degrees of crank rev and fires 2/3 180 degrees from that.


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PostPosted: April 15, 2019, 1:26 pm 
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rx7locost wrote:
I know nothing about Q4R ignition, But it sure looks like a pair of waste spark coils to this untrained eye. The numbers printed on the 2 coils would support that theory.

Is it possible that you have the purple/yellow and black/red wires reversed? I assume that you have the plug wires going to the cylinders per the markings on the coils.

They certainly do look like “waste coils” but I can assure you system ran well for several years and several thousand miles before rebuilding the extra spare engine. The Q4R system was originally available at 2 prices. One with new hei coils and one with repurposed. I think the original builder may have opted for the used.


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PostPosted: April 15, 2019, 1:41 pm 
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Roadog7 wrote:
All appears to be in order except for the no-start issue... I've got spark and fuel, but also a few fairly spectacular back fires from both the intake and exhaust.

-Robert


Well, you have spark so that means whether used or new coils, they are working. A waste spark will fire at the tdc compression and the tdc exhaust strokes. A real quick check of the timing would be to clamp a strobe light on the #1 plug and see where it is firing. If close to 180 degrees off, then try swapping the wires as mentioned. Of course since you reassembled the new engine a lot of things could be "off". It happens to us all. You could have assembled the crank wheel off as already mentioned, if you have one. You could also have the timing of cams to crank way off too. I spent 2 full days changing the timing belt on my DD only to find out I had it 1 tooth off and had to do it again. A compression test should verify that. Try the simple, quick test first before going down the rabbit hole IMO.

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PostPosted: April 15, 2019, 1:52 pm 
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seven13bt wrote:
I'm going to assume that the answer to Graham's question is "yes, it was running before", due to the dust on the coil connectors. If that is the case, then confirm the crank/cam positions. Pull #1 plug and put a wood dowel or some type of tube on top of the piston and rotate the piston to its highest point. Confirm the harmonic balancer is in the correct position (there's a pic in my build log of the trigger wheel gap relative to a rib in the front cover). If correct, pull the valve cover and check the cams to make sure neither of them slipped (cam slots are aligned with the top of the head). If the mechanical timing is OK, then focus on the wiring.

Yes, the ignition does fire 1 and 4 every 360 degrees of crank rev and fires 2/3 180 degrees from that.

I’m pretty confident on the physical engine timing. I have also had the valve cover off to reaffirm it. I figured eyeballing the sensor would get me within a degree or 2 and running. So our cars do have a “waste” spark like a motorcycle? That would account for the backfires.


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PostPosted: April 15, 2019, 2:12 pm 
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rx7locost wrote:
Roadog7 wrote:
All appears to be in order except for the no-start issue... I've got spark and fuel, but also a few fairly spectacular back fires from both the intake and exhaust.

-Robert


Well, you have spark so that means whether used or new coils, they are working. A waste spark will fire at the tdc compression and the tdc exhaust strokes. A real quick check of the timing would be to clamp a strobe light on the #1 plug and see where it is firing. If close to 180 degrees off, then try swapping the wires as mentioned. Of course since you reassembled the new engine a lot of things could be "off". It happens to us all. You could have assembled the crank wheel off as already mentioned, if you have one. You could also have the timing of cams to crank way off too. I spent 2 full days changing the timing belt on my DD only to find out I had it 1 tooth off and had to do it again. A compression test should verify that. Try the simple, quick test first before going down the rabbit hole IMO.


Great idea on the timing light. Although there are no timing marks it should give me a reference. I'll triple check the engine timing as well.


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PostPosted: April 15, 2019, 4:10 pm 
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Interestingly enough, my buddy & I have just been going through the exact same issues with our Q4R ignitions on our Ford Zetec engines.

We had sent our bottom pulleys to Ehrlich (years ago, now - we're just getting the engines fired now), who installed reluctor wheels on them. Our first startup attempt (on an engine stand) didn't go well. Set fire to the carbs, and my buddy's shirt. Lots of backfiring.

We messed around with a timing light, and got extremely limited information, because of the "wasted-spark" issue. Plus, like your engine, the Zetec has no timing marks at all.

The wasted-spark thing is weird. The "second" spark is one where the polarity is reversed, and is a fair bit weaker than the "primary" spark. That could cause issues in deciphering the problem.

By the way - the plug wires for #2 and #3 can be swapped at any time, with no affect on running. Same with #1 and #4. This is because each coil fires both plugs wired to it simultaneously.

Our primary issue, though, turns out to be that Ehrlich installed our reluctor wheels 90* out of rotation from where they should have been, so ignition was occurring at 10* after BDC instead of 10* before TDC. Once we rotated the reluctor 90*, the engine fired instantly. Still a bit of fine tuning to do, but we're getting there.

We're also installing timing marks on the reluctor wheels, and timing pointers on the engine itself.

If I can help some, feel free to PM me. :cheers:

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PostPosted: April 15, 2019, 5:49 pm 
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rx7locost wrote:
A real quick check of the timing would be to clamp a strobe light on the #1 plug and see where it is firing. If close to 180 degrees off, then try swapping the wires.

The strobe light (I forgot I had one) was telling. Spark is random and intermittent but does coincide with some good backfires. I will still triple check engine timing but crank trigger setup now seems to be the issue. I will order the little alignment tool tonight as well.


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PostPosted: April 15, 2019, 6:09 pm 
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zetec7 wrote:
We messed around with a timing light, and got extremely limited information, because of the "wasted-spark" issue. The wasted-spark thing is weird. The "second" spark is one where the polarity is reversed, and is a fair bit weaker than the "primary" spark. That could cause issues in deciphering the problem.

Very interesting info! I’m now intrigued as to how the system determines which spark is the primary and the other weaker reversed polarity? I’m also curious about the “reluctor wheel” on the Zetec pulley. That must be necessary on the zetec? It is reassuring to know there are still some Q4R kits out there although it would better if they were all running!


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PostPosted: April 15, 2019, 7:03 pm 
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I’m also curious about the “reluctor wheel” on the Zetec pulley. That must be necessary on the zetec?


Reluctor wheel = trigger wheel. Your Duratec has one already on the front pulley, the Zetec didnt so it has to be added if you want to run a non standard Zetec crank position sensor. The stock Zetec set up has the 36-1 set up on the back side of the flywheel.

It just donned on me, you rebuilt the motor, right? Is the front pulley a non keyed type? If so, you might want to investigate where your missing tooth is compared to TDC etc. That could be root of the problem.


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PostPosted: April 15, 2019, 8:30 pm 
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^^^That’s what I was thinking too. In the Zetec, to accurately find TDC, you need a pair of extra tools - a special pin that goes in the side of the block, and stops the crank at TDC, plus a plate that will only go into slots in the back of the cams when the engine’s at TDC.

Thankfully, at least the Zetec does have a key way at the snout of the crank.

Nonetheless, timing is a challenge. We have the early version of the Q4R ignition, with only 6+1 slots in the reluctor, so being out by one slot is a HUGE error.

What’s also difficult is using a timing light, due to the wasted spark ignition. The light flashes twice as often as normal and, if you use an adjustable light, you need to set it at 0, as ignition advance is also twice what the reading says. We couldn’t see the difference in flash brightness between the main spark & weaker, reverse-polarity second spark with the light we were using.

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PostPosted: April 15, 2019, 9:54 pm 
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Is the missing tooth supposed to be aligned with the pickup at TDC? I know with a megasquirt, that can be programmed to be any number of teeth after the missing tooth. Just saying that they don't have to be aligned at TDC. What Q4R did, I have no idea.

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PostPosted: April 15, 2019, 10:06 pm 
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In ours, TDC does NOT align with the missing tooth. Just to make things more difficult, you understand!

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http://zetec7.webs.com/


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