Multiple misfires after rebuild ** FIXED **

I also swapped all the coils and plugs from the good side to the nonworking side and it didn’t change. So the issue followed the bank not the coils and plugs.

 

Normally, I'd use an oscilloscope myself but since @N84434 has the scanner you're asking about and is confident that it shows PID or other info pertaining to the ignition coils, I'd go with that.

 

Are you saying you unplugged all driver side coils and from pin 4 of those connectors to battery terminal ground you have a short(0 reading) ?

 

i used my volt meter to test the ohm of the ground from pin 4 (the brown wire) at the coil pack to where it grounds to the back of the head. It read 0 which I think means that the ground is good. I only tested the first one, cylinder 1.

I couldn’t find good instructions on how to do it online. I have never texted a ground before.

 

should I have put the negative probe on the battery negative and used the positive probe to touch pin 4? And do they all need to be disconnected at the same time?

 

I’ll put this as plainly as I can and hopefully not coming across as a duche bag. This check in it’s most simplest form is checking continuity from point A to point B which can be used in many applications, not just auto checks. Take ground out of the equation, you’re simply checking that there is continuity from pin 4 to battery neg terminal. Sorry if I am getting off course but understanding continuity checks is a basic check that can be and should be understood for many troubleshooting applications, home and car. Simply google making continuity checks

Sorry for getting off course. I personally would unplug all 4 coils and check from pin 4 to battery negative. That will tell you if from pin 4 thru block terminal to battery is good but that’s just me.

back to peanut gallery

 

Not too bad, only mildly douchey

But very helpful information which saved the comment!! The crowd goes wild....

 

thank you. No douche tones detected. I will try your suggestion.

 

does the ignition power need to be on? I would think not, but that’s why I am asking.

 

Your thinking is right, does not need to be on.

 

last dumb question, (probably not) what should the ohm reading be? Should it be 0? Is that good?

 

There's no dumb questions and yes zero ohms indicates a dead short regardless even if it's a short length of wire laying on your work bench you're testing for continuity.

In re-reading and since you mentioned it twice, the 2 black wires of the physical oxygen sensor are for the heater circuit of the oxygen sensor. The heater element inside sensor is simply a coil and does not care which black wire goes where.

 

Ok guys, I have done it a few times now and the results are the same. I have the battery disconnected. I reconnect the battery and start it up. It starts fine but then idles very low and starts shaking. Then it throws the codes for misfire on 1, 3, 5, 7 as well as the igniter circuit codes for the same cylinders. I let it run (horribly) for a little while and clear the codes. I let it run longer and the codes do not come back on but it still sounds and feels rough. I stop it and start it a few times, but the codes won't come back, I assume that if it was missing the flashing check engine light would be on?

I guess I am wondering if it might not actually be missing, or when I first start it up the computer is trying to relearn things and it throws the codes. The next time I start it up I am going to try the key dance before firing it up then I am going to try the "brake let it idle in gear" trick to see if the idle will stabilize. If the problem all along has been that I haven't let it run long enough and that I keep disconnecting the battery I am going to be a little disturbed, but happy that it is fixed.

Am I way off on this? Or is it just wishful thinking?

 

I looked up igniter circuit codes and it appear to be caused by ignition feedback being off. If your coils are good, you’d probably want to verify the feedback pulse is present and aligns with the ignition pulse. I can’t think of anyway to do that myself without an oscilloscope. It’s either that or assume the ecu is bad and that’s an expensive assumption.

At least if I saw both ignition pulses coming from and going back to the ecu, I’d know it would have to be the ecu causing the issue.

Wish I had a better suggestion.

 

So my Autel MK808 doesn't have any test that I can run?

 

I’m no expert on that, so I can’t tell you. I’m just an electrical engineer who’s also a shade tree mechanic. I just read the Field Service Manual and ask others here when I have questions knowing someone has most likely been through my pain.

Your problem seems to be a little more complex and not easily debugged with simple tools. I could be wrong and maybe someone else found a way, but that’s all I can say.

My father is a lifelong mechanic and auto body man and he still amazes me from time to time solving difficult issues with a BFH and rounded off screwdriver.

 

I really appreciate all your help. I am still hopeful that it will be something simple that I can figure out soon. Being down to 1 car is getting difficult. I need to figure this out soon.

 

I went down that rabbit hole yesterday concerning IGF signal but he mentioned....

Initially, I did not notice it in the FSM but when he mentioned those same codes today, I relooked at FSM again and while this might not make a plausible answer, there are 2 IGF feedback signals, IGF1 and IGF2. Problem with that is IGF1 is cylinders 1,4,6,7 and IGF2 is cylinders 2,3,5,8 which somewhat matches Firing order 1-8-4-3-6-5-7-2. Cylinders 1-3-5-7(Bank 1 are failing)

Since O2 sensors can cause misfires(flooding cylinders if O2 is reporting Lean condition), I've tried to find where they also can cause these igniter circuit codes without luck ....unsure

 

@BubbaW Is there anything in the FSM to show how the ignition coils are grounded? Like is it a daisy-chained GND that ties at one point or do they each have their own individual GND?

I'm kind of curious if there's some pattern there throwing off the voltage reference like all odd cylinder ignition coils are grounded at one point vs all even.

 

@Brynden29, I am very curious to know what your Autel shows as far as Bank1Sensor1 O2 sensor. Should be approx changing from .8 to .1 Sine Wave.

 

Would that be in open or closed loop? Or constant regardless

 

I will check if it saved the historical data. Otherwise I can check it tomorrow.

i did disconnect the upstream o2 sensor last night and it didn’t seem to make a difference.

 

As discussed page 2 yesterday, All grounds come together and attach back of block. This is drawing he posted yesterday tying all gnds to EC gnd point.

https://www.tundras.com/threads/multiple-misfires-after-rebuild.110071/page-2#post-2844491

 

O2 sensors only start properly registering when in Closed Loop and Engine normal operating temp

 

Like a lot

 

And OP mentioned trouble with the O2 sensor originally. Maybe circle back and ensure they are functioning properly.

 

Yeah, the O2s (I'm fairly sure I mentioned this before) were suspect to me, especially when OP said he extended the wiring for the headers. They're already really sensitive to voltage, which I swear I might've said (but my memory is shite), I'm really trying to take OP with some faith here that it was done well and right, but I figured disconnecting (as I mentioned, in order mentioned) would've produced an alternate result if codes were cleared.

I'm still not convinced it's not O2 relatded. But without seeing live readings, or testing the O2 directly, who knows...

 

He also said he unplugged upstream O2 and no change…..

 

I am pretty sure I extended them correctly but I went ahead and bought an actual o2 extender cable. I will swap the up stream o2 sensors to see if the issue follows them.