HELP. DD is down. Weak to no spark on 1, 2, 3 outputs on the coils!!

[IwantMKIII]

Preface - title is wrong i meant 1,2,3, and yes this problem doesnt make sense, but its happening I've had symptoms of this before seen here: http://www.supramania.com/forums/showthread.php?t=57818&highlight=power+repeat

So my supra completely died out and lost power on a boost pull on my way home, i heard a type of popping sound when i lost power, its could have been my BOV though, not sure exactly. I checked everything. It will start up and just die out no matter how much throttle i give. My narrow AFR reads lean and the exhaust dumps gas.

I had 3 different guys come out and help from 9pm tonight until 130am in below freezing weather, 2 of them MKIII owners.

Whats good:

Vacuum
Oil pressure
Feul pressure
Op temps
Gas
Turbo
AFM sensor
TPS sensor
No CELS
All spark plugs tested ok
All wires tested ok
CPS good
Ignitor good
Coil packs good...but not??
Eng main relay
EFI fuse
IGN fuse

Bad:

Weak to no spark on 1,2,3

Yes this is wierd but we tried each one with the same GOOD wire/plug combo several times. 4, 5,6 fire strong.

We thought maybe coils were bad so we swapped them with another 90 mkiii with 73000miles on them, they did the same thing :cry:

We thought ingnitor and swapped that as well. Did same thing :3d_frown:


What now?!?!?! is it the wiring, is it the ECU? ARRRRGGGGGHHHH :icon_evil

Edit: this happened one other time a buddy found on supramania here: http://www.supramania.com/forums/showthread.php?t=2822&page=2&highlight=weak+spark no conclusion was found

 

[Frank Rizzo]

I would be suspecting the CPS if you swapped plugs, wires, coils and igniter.

Check all CPS wiring first, as it is pretty simple to find on this platform.

 

[red87tll]

did we actually switch AFMs? dont just assume its good. switch ecu's that would be the first step.

 

[IwantMKIII]

did we actually switch AFMs? dont just assume its good. switch ecu's that would be the first step.

No, SAFC registers it as well as TPS. Both check out ok

 

[MDCmotorsports]

Doesn't make sense...

1/6 fire off the same coil etc etc etc. Doesn't make sense why one plug in the pair would be healthy and the other not...

 

[IwantMKIII]

Doesn't make sense...

1/6 fire off the same coil etc etc etc. Doesn't make sense why one plug in the pair would be healthy and the other not...

I know, tell me about it. but it does. i've searched through the forums and only a couple people have run into similar issues but no one has posted a solution.

If you read through he had a similar problem but i don't really understand all the electrical lingo:
http://www.supramania.com/forums/showthread.php?t=43423&page=2&highlight=spark+coil

 

[jdub]

Did you check for codes?

When you swapped ignitors, did you bolt it to the body and then check the coils?

Check that the ground wires on the intake manifold (next to the #5 runner) are clean/secure.

 

[Dirgle]

Doesn't make sense...

1/6 fire off the same coil etc etc etc. Doesn't make sense why one plug in the pair would be healthy and the other not...

Right, the current flows through one plug and returns through the other. If one is weak then the other is weak, if one is healthy the other one has to be. The only way one could be weak is if there was a short to ground between the plug and coil. And since it's a wasted spark set up it fires twice once at the end of the compression stroke, and once at the end of the exhaust stroke. It's not coils 1,2,3 are weak, either you have faulty timing on 1,2,3 events(ecu), or you straight up have an intermittent spark problem(CPS or wiring). I would start, as was stated earlier, with the CPS.

 

[IwantMKIII]

Right, the current flows through one plug and returns through the other. If one is weak then the other is weak, if one is healthy the other one has to be. The only way one could be weak is if there was a short to ground between the plug and coil. And since it's a wasted spark set up it fires twice once at the end of the compression stroke, and once at the end of the exhaust stroke. It's not coils 1,2,3 are weak, either you have faulty timing on 1,2,3 events(ecu), or you straight up have an intermittent spark problem(CPS or wiring). I would start, as was stated earlier, with the CPS.

i understand if one side of the coil should work the other does.....but it doesnt. There were 3 people there that all saw it. 2 of them Supra owners, in fact one of them who saw the outcome posted in this thread Red87. I have a new (used) ECU and CPS on its way tonight from another supra owner that helped out. I also asked him to bring relays.

Keep in mind, this car has been running fine for 4K+ but i had symptoms of weak spark previously seen in this thread:

http://www.supramania.com/forums/showthread.php?t=57818&highlight=power+repeat

Also, every LEFT side of the coils have the weak/no spark problem if that helps target anything.

You mention there could be a short if only one doesnt work, where should i be looking???....how bout a bad ground? If so, where should i be looking?? ground from the packs to the black are definately connected. If the main block ground wasn't connected pretty much nothing would work. Any ideas?

 

[Facime]

In my case it turned out to simply be bad coil packs.

how I did my diagnosis: I purchased a spark tester, its a little device that plugs in place of the spark plug and allows you to alter the gap which is helpful in determining if you have no spark or just weak spark. I then pulled the CPS from the head and spun it by hand. I had 9 coils to chose from and while 2 sets came from running vehicles only 3 coils tested ok. The rest would only fire on one side.

my method basically allowed me to test the coils and the CPS at the same time and takes cranking and the ECU out of the equation. Like I said my problem turned out to be bad coils.

 

[IwantMKIII]

In my case it turned out to simply be bad coil packs.

how I did my diagnosis: I purchased a spark tester, its a little device that plugs in place of the spark plug and allows you to alter the gap which is helpful in determining if you have no spark or just weak spark. I then pulled the CPS from the head and spun it by hand. I had 9 coils to chose from and while 2 sets came from running vehicles only 3 coils tested ok. The rest would only fire on one side.

my method basically allowed me to test the coils and the CPS at the same time and takes cranking and the ECU out of the equation. Like I said my problem turned out to be bad coils.

can you get the spark tester at like an advanced auto? Also, pulling the CPS...how does that work? do you simply pull it all the way out, turn the ignition key to "ON" and simply rotate it??? Also, when you test a coil, do you have to have both plugs and wires attatched to get spark from both? i read that somewhere but am not sure its true?

 

[Facime]

can you get the spark tester at like an advanced auto?

YES

Also, pulling the CPS...how does that work? do you simply pull it all the way out, turn the ignition key to "ON" and simply rotate it???

YES

Also, when you test a coil, do you have to have both plugs and wires attatched to get spark from both? i read that somewhere but am not sure its true?

To be honest I dont know, but I tested each coil side with a spare plug wire I had. With all the plugs installed and all wires going to their proper plugs, I simply pulled one wire at a time from the coil, and plugged my test wire with spark tester already on it in to each coil output. Then repeated the process with 2 more coil packs marking the ones that gave spark to both sides, eventually finding 3 that worked.

 

[Dirgle]

Yes you have to have both wires attached to the coil to complete the circuit. Or it's just going to arc along the outside of the coil to the nearest metal/ground, you shouldn't do this as it is hard on the coils and can cause premature failure.

 

[Frank Rizzo]

Also, pulling the CPS...how does that work? do you simply pull it all the way out, turn the ignition key to "ON" and simply rotate it???

You better set the number 1 cylinder at TDC before you remove the CPS. There is also a proper way to install a CPS. Not something you want to fool around with unless you have the proper knowledge. And with a mod list like that, I would assume you would know how to install a CPS......

 

[Halsupramk3]

when spinning the cps to fake timing like this would the injectors still fire? Would it be a good idea to pull the plug on the fuel pump or its fuse?

If you have an extra good CPS you would not have to pull out your installed cps. Just put the engine at TDC and view how the installed cps is clocked. unplug that cps. turn the extra cps so the spinning tang is pointing to the same position as the installed one at tdc (this will make the timing the same on each cps altho it may not be necessary to sink timing between the two cps for this procedure/test). Then plug the extra cps into the engine harness. your engine is not reving so the installed cps will still be set correct. then you can spin the extra cps in hand and check the ignition and coils.

How does that sound?