Coilpack good. Not firing WTF?!

[kilo64]

Alright guys,

My car sounds like a wrx; something like put put put put put put put

So after numerous thread pillaging it turns out that it might be a dead coil or coil harness.

There are also signs that point to bad injector and such.

Heres how it all started
So the first time I did my swap, we timed it just to see if the engine would start. This was before it had a BOV and IC system attached.

After 2 weeks and finishing up all work we had to retime the system again because the engine would just crank and not turn over.

The first time we started the engine without BOV, IC, 60% vac lines uninstalled and no exhaust the engine roared to life and was the smoothest purest roar I've ever heard. It was sweet music to my ears.

Now, after all the installations and retiming the engine it fired up perfectly again but this time it sounded different. When I revvd it, it sounded different but I just thought it might be the new exhaust.

Now after more experience with the car it is definately not normal and that one of the cylinders are not firing.

So come today I test the engine's coils.
Heres what I did;
While car is on, pull each coil one by one to look for changes in idle. Starting from the front of the engine, cylinders 1, 2, and 3 all changed the idle. Come cylinder 4 nothing happens

So BAM, bad coil isolated or so I though. I swapped coil 4 to coil 3 and plugged it back in BAM idle returned to normal. Now I'm thinking wtf :( ???

So its definately not a bad coil. I then pull my coil harness out and test for continuity on the 4th coil's harness. White wire checks out. Red and green wire checks out and ground checks out.

Now, I'm thinking its my ignitor chip so I swap it out to my back up one and still the same thing.

I'm stomped as to what the problem might be. I'm about to go check out the ecu plug and see if loosening it will change anything. Back when I first tried starting the engine it would crank but no spark and it turned out the ecu plug was on too tight.

It still doesn't explain the problem very well. The misfire only started after everything was finally installed and retimed.

Cliff notes;
Checked all coilpacks and they work.
Checked continuity on coilpack harness and everything checks out.
Replaced igniter chip but same results.
Checked sparkplugs for foul but is clean.

Thanks for any input! :)

[burnsauto]

could be:
bad ecu
wiring bug

have you tested for ignition signal while turning over the engine? (using a power probe, the $5 testers short out electronics.)

[ghost]

Id say your ECU. Had the same problem on a bud of mines S13 with his rb25 swap.

[kilo64]

If its the ecu, how would I go about testing for the particular problem?

I could only shoot in the dark with the plug.

How do I test for ignition with the power probe?
I'm guessing pull out the 4 pin plug side and while cranking the car use the tester to see if anything flows through? I have a multimeter as well so I'll be doing the 20v vdc test tomorrow

Thanks!

The only thing is that thie worked perfectly fine before I retimed it and installed everything. Is it possible that timing could cause this?

[ghost]

First of all, his battery was grounded to the engine, not the body. Coils were getting a very low voltage. Second, the #5 coil driver was gone in the ecu causing it to quite literally heat and burn out the coilpack. Don't unplug the connection to your ECU, just back probe it.

[s13dan]

Same thing happend to me but it was my #4 injector... i just got it yesterday to fix my car. But going down the road sometimes it would drive fine then suddenly i would have a dead cyl. Or yea wiring could be screwy... K.I.S.S. Keep It Simple Stupid..<--always helps me--.Check Spark starting with battery and working to the plug, then Fuel, you gatta have both.

[flip3d]

haha... BAM.

Multimeter is your friend.

[kilo64]

Heres the skinny,

Out of nowhere I decided to do a spark test. So I pulled the 4th non firing coil out and removed the rubber piece. Touched the valve cover and SPARK SPARK SPARK

So this brings me to believe that the spark plug might of been defective. I swap it out to cylinder 2 and put it back in. Upon removing and swapping the spark plugs I noticed that the 3 cylinders that were firing the plugs had massive carbon build up. Meaning the tips were black and dry

Then proceeded to check the injectors to check out everything and it checks out.

Checked wiring and continuity and works out.

So right now everything is working but the 4th cylinder isn't firing... why!?!!??!?!

[Pure_JDM]

The better question is WHY didn't you come back and update this thread for future people having the same problems?

[Bentleyness]

um this a sr20? my friend had the same problem and after 2 weeks i over looked the ignition resistor and that was a prob the whole time

[Pure_JDM]

What do you mean by "ignition resistor"? The Ignitor chip? I'm currently getting spark only from the first cylinder, not the other three. Coil packs are good, plugs are good, harness is good, and I'm getting power to all four coils, just no signal.

[Bentleyness]

What do you mean by "ignition resistor"? The Ignitor chip? I'm currently getting spark only from the first cylinder, not the other three. Coil packs are good, plugs are good, harness is good, and I'm getting power to all four coils, just no signal.

yes thats wat i ment, my guy had the same issue and the pigtails where loose from the connector, just look at the cas and ignitior chip they both work together giving signals to the coils.

[Bentleyness]

im no sr expert as i dont own one but from the one i worked on this was the problem but his was #3 only, make sure both pigtails from the chip is not damaged (wires coming off clips) or exposed wire. if they are fix it and use liquid electrical tap on exposed wires.

[Pure_JDM]

Yeah, nothing seems to be loose on the pigtails and the connections look pretty solid. I noticed some continuity differences through the chip but don't have a manual or anything to go by for knowing what to look for. I'm assuming if I don't have the same readings through each of the four pins, then the chip is bad, but again I wasn't certain (I've never messed with ignition systems before). I have a new chip on the way. I hope that fixes it.

[Bentleyness]

i believe there like everything else and you have a limit to what u can be off to the specs and from each readings like you would on injectors and compression test.

I wish u luck, i have a kat build that ill be finishing next week and im hopping i wont have any probs too other wise i have 2.5k sitting around needing more money, and wishing i did an sr swap instead.