ISFFUN

iTrader: (4)

EDIT - PROBLEM SOLVED - was the crank sprocket/reluctor/gear missing a tooth

So I thought I had my misfire problem solved but it's back and just not triggering enough to activate the CEL but they have appeared in the "pending" memory.. I can feel the car vibrating and pulsing at idle but it's VERY subtle.

I have a MX OBDLink and have been trying to poke around to find anything, but the point is even though this tells me I am getting misfires, I don't know why. It does not have the Toyota PID codes built in so I don't know how to pull the specific misfire cylinders, but the cylinders are 01, 04, and 06 that have shown misfires and the generic "multiple cylinder misfires"

New plugs have been installed SK116R11, new dis cap, new dist rotor new NGK wires

EDIT - ADDITIONAL INFO
-PCV cleaned and rattling and flows only one way
-distributor rotor sensor reading good on meter
-new spark plugs SK116R11, new rotor cap, new rotor blade, new wires
-primary coil readings are out of range (REPLACED w/ NGK coil)
-fuel / gas in oil really bad on oil change (haven't checked since)
-light clicking/rattle noise from rear cylinders somewhere
-don't know how long this has been going on the more i think about it
-Cleaned rear to center ground point and wire.
-compression checked 180-185psi with nearby plugs removed (cold/warm same readings)
-Exhaust manifold temps showed #5 being 20 deg., higher than the rest
-ECU checked and caps look good
-O2 sensors are within range
-New water ECT temp sensor (3/27/21)
-major misfires around 2300RPM at least one time (250+ misfires triggered CEL)
-Now hearing a sucking whoosing noise when opening the TB

This was right when the car was turned on after a few mins.


This was driving then coming to a stop. The numbers don't look out of range too much to be a concern +/- a couple percent is normal I believe.

Sc400HB

Is this car an SC? What year?

ISFFUN

iTrader: (4)

Ya, 97 5spd

Did a lot of research into this last night watching ScannerDanner's classroom vids on misfires and fuel trim and turns out it's difficult to correlate the two, so I don't want to go down rabbit holes that don't help. Fuel trim looks normal from what I can tell.

Just a reminder these misfires are extremely subtle and wouldn't be noticeable unless you really focused your senses. It's not like the car is bogging /clunking/RPM dropping etc, it's just like a very subtle vibration you have to listen and feel for. I did not change the plug wires but did the plugs/rotor/cap. I'm going to check PCV in a bit when I do an oil change later today.

Sc400HB

I see. I had a similar problem where I thought it was a misfire and it ended up being the coolant reservoir sensor. I have a 93 Sc400. I am not sure if your 300 has one... but the car would go in and out of thinking there was coolant in there and it would buck or make vibrations when you step on the gas. No lights ever came on or anything. Just a thought... Currently I am tracking down a problem with code 41. These cars and their sensors... pain in the ***!!

ISFFUN

iTrader: (4)

More testing today.

Changed oil and holy crap - it smelled like gas very bad. Also a little burnt, but it had been around 4K miles since it was changed over a year ago (don't do much driving these days). I wonder if the fuel was from when the TPS / misfires started recently. Won't know until next change.

Additional find - the resistance on the primary coil is 0.9-1.0 (maybe it was 0.01, can't remember) which is quite out of range for what the book calls of 0.36-0.55! I wonder if this is the issue.

Resistance on the distributor sensor was in range ~2kohm.

Sc400HB

if it is a coil pack then you can unplug the one you think is good and the car shouldn’t start. If you then switch and only have the good one plugged in it will start.

Ali SC3

iTrader: (10)

Sounds like he has a 97 5spd so sc300 and one coil only. you shouldn't be using platinum spark plugs, those are like dinosaur tech and can have issues, not saying it is the issue but use iridiums instead.
try the "bkr5eix -11" instead (NGK part number 5464). Also change your coil wires to new oem replacements or use the aftermarket ngk plug wires. lots of people have had the stock ones misfire after 20 something years.
you already did the cap and rotor, make sure to use only the OEM toyota rotor, the aftermarket ones have issues.

Also make sure that the timing is set correctly if you removed the distributor. if you did not remove the distributor it is probably fine, but if you did remove it at some point it has to be set with a timing light again or it will be off and misfire.
hopefully those help, check over vacuum lines etc.. a clogged egr can cause issues as well.. lots of small stuff to check.

ISFFUN

iTrader: (4)

They are Denso iridiums. I typed the model wrong. Here's a couple pictures of the #1, #6 and #5 plugs. Didn't pull others yet. I've removed the TB like 4x in the last couple weeks trying to check things so wasn't up to doing it again quite yet. I think I want to do a chemical block test soon. Dizzy hasn't been loosened or moved and timing was set about 5 years ago when head was changed and timing betl/tensioner /pump etc were replaced.

I ordered a new coil but they are hard to source. Part is discontinued and of course there are used ones, but I was trying to find a new one. There are tons of Chinese knockoffs but I eventually found NGK makes one that looks ldentical to the OEM (p/n NGK 48826) and I trust that more. Fortunately it just was marked as shipped - I was worried it was also discontinued and would be cancelled. Oreilly says they can't get that part anymore from NGK FYI.

Wires were replaced 7 years back w/ Denso 671-6174. But all this started after....edit - the longer I think about this the longer I think it's been going on with poor performance and smelling like gas.

Also cleaned the grounding point on the upper intake with contact cleaner and wire brush. Haven't checked others yet (where are all of them? One is under the fuse block right?)

Using SK16R11.


#6 plug

well

#5 plug, very white

#1 plug

Ali SC3

iTrader: (10)

water in that area will cause misfires as the plug shorts to the head. I would make sure its all been cleaned up, wires are dry then and keep an eye on it.
You wouldn't normally blow a headgasket from water on top of the engine. when you say water got into engine bay what do you mean, like flooded or sprayed?
could also be the ecu starting to have issues, or one of the injectors based on the fuel symptom.

ISFFUN

iTrader: (4)

Water flooded the plug holes and I vacuumed and dried it all out about 2 weeks ago, but that's when all this started.

I used a small amount of copper based anti-seize on the threads when I pout the new plugs in and just read that that can cause misfire on aluminum heads so I'm going to remove all that soon and recheck all plugs.

I know the ECU is a potential hotspot for this type of issue so I'm going to replace that coil and see how it goes.

Bimmerbill

I second the thought of removing the anti-seize from the plugs. I am very strong on using NGK plugs in everything I own, but before I found NGK I used Bosch plugs in my BMW's and read in a number of publications that Bosch did not want anti-seize or anything else on the threads of their plugs.

ISFFUN

iTrader: (4)

Hmm. Updates and not resolved.

I took the TB off and pulled all the plugs again. I removed all the anti-seize.

I also cleaned the rear side grounding points and wire that connects to the center top part of the firewall.

I replaced the coil with the NGK one.

Still getting very subtle misfires at idle.

Same issues as before with old coil and old plugs.

ISFFUN

iTrader: (4)

Inside of cyl #5 looks pretty burnt? I don't know. Did not take other pictures unfortunately. All plug tips are white like this one.

Maybe I should replace the wires too. I'm stuck wondering if this is a symptom of something more serious like a value/head issue.



#5

ISFFUN

iTrader: (4)

Here's a video at idle and rev to 2k rpm ish - is that clicking when I rev it normal?


Also, cold start is kinda rough, like there's water / unburnt fuel in the cylinders or something. It kind of 'garbles' for a second on cold start. I will try to get a video. This is a new issue.

ISFFUN

iTrader: (4)

Here's a video of acceleration from stop to 60 twice. You can't really tell there's a problem, but for example when parked at idle I can watch the primary distributor wire vibrate / jiggle around on each misfire, but like I've said multiple times it's so subtle you can't really capture it on video well.

Also ignore the low engine oil light - the sensor is broke inside the pan from when I changed the engine. Oil was just changed 2 days ago w/ 10w-30 and double checked often.