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Old 07-19-2008, 08:46 PM   #1
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Default hope i didn't blow something, ignition problem

I recently rewired my toyota COP's better for their permanent placement but now my car only wants to run on two cylinders. I had the car running before, and now when I crank it it combusts immediately in cylinders 2 and 3, but its obvious that 1 and 4 are doing nothing so the car never starts. Checked the spark, and 2 and 3 operate normally, but 1 and 4 do nothing on crank. they all do the little primer spark when you turn the key to the 'ready' position though.

I did some research with a multimeter. when you touch the trigger wire to ground that controls 2 and 3 it has zero volts, but the one that controls 1 and 4 gets 2 volts. I checked the voltage at the wiring harness ends in the car too, and its the same story. The brownish grey wire is the one that's actually working, then the green/white one gets two volts to ground. So I know it's not my wiring, my wires are going to the same places as before when the car ran, but i'm getting that funny 2 volts on the 1 and 4 trigger wire. If this is a megasquirt setting, where should I look?\

Edit: another funny thing is that it ran before with 'spark output inverted' set to yes. with those settings this time the car just cranked and cranked with no sort of sign of life. i switched it to 'no' and boom, 2 and 3 started firing. I figured i might have had my trigger wires switched up from before, but i really don't get whats going on.
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Old 07-21-2008, 08:51 PM   #2
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another ignition issue is that in diyautotune.com's faq they show a base map of a miata, and in the spark settings its crank advance angle is set to 0, but in braineack's faq his is set to +22.5. My car is currently set to 0 crank advance angle, and it idles.

Thoughts?
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Old 07-21-2008, 10:25 PM   #3
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You're referring to the "Trigger Angle Addition" drop-down? This is a correction for the physical alignment of the CAS you make while setting the initial locked timing. If, with 0 in this box, you find that you need to put a number larger than 90 into "Trigger Angle (Deg)" then instead you select one of the two fixed adders and the total angle is the adder plus the number you manually enter.

It's a little bit different for every car. Back when I had a CAS, I had 76 in the first box, and 0 in the second.
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Old 07-22-2008, 04:34 AM   #4
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back when you had a cas? wtf? how do you get rid of your cas?
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Old 07-22-2008, 04:54 AM   #5
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Lurk more.
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Old 07-22-2008, 07:14 AM   #6
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If all 4 COPS give you a priming spark when you turn the ign on then you have power to all 4 and the problem is in the trigger wires. look look and look some more for dodgy connections and check that you havn't mixed up trig and tach. Did you cut the plugs off your old coils to make the harness? When I did mine I damaged the female socket on the cars harness by pushing a wire in while testing the setup. This caused me problems when I made the proper harness as when it vibrated it caused an intermittant earthing problem.
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Old 07-22-2008, 02:01 PM   #7
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i will continue to look, but answers to these questions will help me greatly.

1. I'm worried that i'm getting that 2v on the trigger wires to 1-4 because a coil pack is blown or something. if thats the case, i wouldn't get a primer spark though would i? Once upon a time I bought 8 coils from a v8 and accidentally cranked my car with one coil out. I figured this coil was fried and was relieved that I bought 8 and replaced it. Would having one coil out like that fry the other one on the same circuit even though it wasn't out?

2. here's what my car does right now, maybe this says something about the wiring. on a cold start, it takes 3 or 4 attempts at starting it. (I've cranked it while looking at sparks 1 and 4 and they don't spark during that time). Finally it will sputter for a sec then come to life. I think I've had it running on all 4 cylinders before, but last night it was running on 3 and i'm positive that's due to ignition. My exhaust pipe (no cat) was going puff-puff-puff with black smoke. But anyway, I feel like I've had it running on 4 before, so I feel like that's intermittent.

also, some background info if this helps: I don't have the plugs that go to my cops so I soldered wires to the 3 pins I needed and then filled the plugs with epoxy. I made triple sure that they were the right wires before I filled the plug in, as the epoxy would be slightly hard to remove.

Edit: also, due to me messing around with things last night with the car running on 3 cylinders, it backfired fiercely. Besides setting my friend's pant leg on fire, which was just more funny than anything, is there danger of that messing anything up? It felt like a pretty powerful explosion.
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Old 07-22-2008, 07:11 PM   #8
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Joe please feel free to correct/add

The coils (I assume here toyota cops) fire on a falling signal. i.e. MS supplies voltage (5v I think) to the coils this will make them charge from the 12v supply. When MS grounds the trig the voltage on the coil primary drops to zero and the change in flux induces a huge voltage in the secondary winding.

So when switch the IGN on the coils charge a bit, MS wakes up and then supplies 5v causing a small spark. IF this is on all 4 plugs then you have power and I assume trig (I don't think that the coils would make a small spark themselves)

I think I remember similar problems from a freind whom I helped change his original coil pack. We fucked with the thing for hours thinking the new coil was duff and then the leads. Turned out we had 2 leads mixed up. Simple thing to overlook especially when you are looking for a more complicated problem. Make triple sure that you have all of the coils wired to the right sockets and also on the right plug.

If you want to confirm that you definately have a spark on each coil then motor factors sell small "neon hats" they go between the sparkplug and lead/coil and flash when theres a spark. Put a set of those on the coils and leave the plugs on the rocker cover then get a friend to crank the engine. If you have 4 flashing lights then its a timing problem. 3 flashing lights and its a wiring problem in your harness. 2 flashing lights and its a wiring problem on either your harness or the MS and car harness.

You could also do this just buy putting the spark plugs in the coils, leaving the plugs on the rocker cover and cranking it in the dark but the "hats" are way cooler
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Old 07-23-2008, 02:35 PM   #9
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hm, well I'm very sure my wiring is correct, I'll go and quadruple check it when I've got time later today. I think it's my MS being screwy though. This is my first setup, and I wouldn't be surprised if I had several noobish mistakes in my msq. Can you guys look over it and tell me what a fool I am?

and by the way, currently my setup is a 1997 motor with fujiracing IRTBs, stock injectors, cleaned and flow tested about 50 miles ago and Toyota COP's.
Attached Files
File Type: zip itb 97 1.8l.zip (5.5 KB, 44 views)
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Old 07-23-2008, 06:34 PM   #10
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First diagnostic step is to pull the plugs from the engine leave them in the coils with their threaded housing touching the valve cover then get a freind to crank the engine whilst you watch for sparks from all 4 in the dark.

If you have 4 nice big fat blue sparks then there is a timing/MS issue if not then we have to assume wiring problem and maybe go back to where you started from get the car running and go from there.

Now shhhhh be vewy vewy quiet we're hunting sparks!
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Old 07-23-2008, 06:43 PM   #11
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Notes on MSQ

Are you running high or low impedance injectors? Your time threshold is setup for high impedance but your current limit is set for low impedance.

And I think I may have found the problem! You have LED19 in codbase and outputs set to acceleration rather than spark B

Is this a standalone or parallel install?
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Old 07-23-2008, 07:23 PM   #12
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standalone.

Oh really? I didn't look too closely on the outputs page simply because I changed what the LEDS did one time and my megasquirt totally CONFIG ERROR'ed me. I had to reflash it. I decided the lights werent that important.
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Old 07-23-2008, 07:25 PM   #13
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The lights flashing trigger our coils to fire. Edit those settings and give her a crank!
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Old 07-23-2008, 07:58 PM   #14
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so you're telling me theres no way my miata wasn't running on two cylinders before? Just 2 and 3? Jesus, that's impressive! Gonna try cranking it a little later when I've got a chance
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Old 07-23-2008, 08:08 PM   #15
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TBH I'm not sure how your car ran at all! Only one spark output enabled and spark output inverted set to YES (which normally cooks coils) maybe my megatune is ******* up your msq...it has been acting up recently.

But yeah set inverted to no and the LED for spark B
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Old 07-23-2008, 08:52 PM   #16
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just started it, it took a couple of cranks but it did start. I'll have to check my plugs on cranking, but it felt like it was running on all four. Didn't drive it or anything, I haven't set the base timing yet. My exhaust pipe smells like gasoline, but that could be because of my lack of a cat, my base timing not being set, and my AFR's being god knows what at this point. I just hope it doesn't after fire hugely the next time I try to start it. :E

Edit: so you're telling me that every miata thats functioning correctly has to use 2 leds to show what the sparks are doing? I just figured the LEDS were for whatever you felt like monitoring.
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Old 07-24-2008, 05:03 AM   #17
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Originally (when MS was just fuel) they were designed to show the user 1. when fuel was being injected 2. when warmup enrichments were being added 3. when acceleration enrichments were being added.

But when the MSnSe came into being those clever little ******* James and Phil decided that the LEDS were too much of a useful output to waste so used them for triggering the sparks. After all you can see much more useful information in Megatune.

Congrats on getting it running though. Now I would suggest loading the MSPNP base map from www.megasquirtpnp.com/downloads It will have all of these setting taken care of and in a SAFE configuration and then you will just have to change a few bits for your setup. If you download their "software package" rather than just the msq file it has a lot of different msqs with & without MAF .etc pick the one that is most suitable and it will save you messing around with easytherm.

Once its all loaded up with the base timing set and running fairly well I would go and give the megamanual a quick skim. It's not as bad most people think. Most of it will not be relavent to you as you are only interested in tuning the car not working out how to make it work on a Miata. The hard work has already been done for us

Keep us posted on progress
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Old 07-24-2008, 04:39 PM   #18
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Whew- a lot has happened since I checked in last.
Quote:
Originally Posted by N3v View Post
back when you had a cas? wtf? how do you get rid of your cas?
I guess I should have updated my sig with that, but here's the thread: https://www.miataturbo.net/forum/showthread.php?t=20241 Basically, I got tired of fighting with what turned out to be a defective CAS, and decided to go all-out and do a 36-1 crankwheel pickup. It was a fun project.

Quote:
Originally Posted by N3v View Post
1. I'm worried that i'm getting that 2v on the trigger wires to 1-4
It is indeed disturbing. I gather you've now overcome this, but did you ever discover the root of this evil?
Quote:
Originally Posted by Duckie_uk View Post
Joe please feel free to correct/add

The coils (I assume here toyota cops) fire on a falling signal. i.e. MS supplies voltage (5v I think) to the coils this will make them charge from the 12v supply. When MS grounds the trig the voltage on the coil primary drops to zero and the change in flux induces a huge voltage in the secondary winding.
Yup. Looking at the ingition pulses on scope, they are +5 squarewaves whose positive duration is equal to the dwell periord They go high to turn on the coil primary, and then go low again to turn off the coil primary causing spark.

Quote:
So when switch the IGN on the coils charge a bit, MS wakes up and then supplies 5v causing a small spark. IF this is on all 4 plugs then you have power and I assume trig (I don't think that the coils would make a small spark themselves)
Very close. The initial spark is actually unintentional, and a by-product of the way we tend to wire the coil drivers.

If you follow either the DIYAutoTune instructions or the writeup here: http://www.msextra.com/ms2extra/MS2-...htm#groundpull then what you have is a circuit that naturally tends to output +5, and must be actively pulled to ground by the CPU to turn off. As you see in the mini-schematic in the link I sent, +5 goes through a pullup resistor and then to the output. The collector of Q6/Q8 also connects to this point, and the emitter of Q6/Q8 goes to ground. The bases are connected through a 1k resistor to the CPU. (For those who don't understand NPN transistors, current flows from the collector to the emitter whenever a positive voltage is applied to the base.)

So when you first power up the MS, the CPU is "offline" and thus the bases of Q6/Q8 are floating. As a result, there is +5 at the output (from the pullup) and the coils charge.

As soon as the CPU boots up, it sets all of its output pins into the "proper" configuration. This causes it to send +5 to the bases of Q6/Q8, which cause them to turn on, thus pulling the output to ground. At this point, the coils all fire once.

It's not a desireable thing to have happen, and it serves no useful purpose. Quite to the contrary, this is why coils and igniters get fried when you re-flash the CPU. During the flashing process, all the CPUs outputs are inactive, so the transistors aren't operating and the spark outputs all float up to +5. This causes power to flow through the coils and igniters continusouly, generating excessive heat and destroying them.
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Old 07-31-2013, 02:58 PM   #19
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i had a similar issue... turned out to be this. http://i18.photobucket.com/albums/b1...r/IMAG0365.jpg
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Old 07-31-2013, 03:12 PM   #20
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OP hasn't logged in in over 2 years. He doesn't give a **** what you found.
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