Attempting to Diagnose my Misfiring SC400...

[@JonathanMai]

I hope it's not what I think it is...

[@masertiz]

Wow, im glad i got a VVTI engine, diagnosing this is so much work. Very helpful video!

[@JonathanMai]

Hope you enjoyed!

[@273.45amg]

Solid video! You’ve convinced me to get one. About to get my own SC400 this week. Hopefully, it doesn’t have as much issues. 🤞

[@JonathanMai]

Good luck!

[@savvy6310]

That’s awesome! I’ve recently picked one up but sadly mine came with a lot of problems. I love this car though so I think all that pain was worth it. I hope yours comes great and if not I assure you the work will pay off 👍

[@KaiPonte]

I love your little assistant! Great way to get girls into the fabulous 1UZ engine. On my son's '93 SC400, he had a bad coil. Swapped that out and it ran like a dream. So glad I have a VVTI model so I can just hook up an ODB II scanner.

[@JonathanMai]

It honestly might be the spark plug wire, I'll probably do a compression test before I dump anymore money into it though

[@KaiPonte]

good lucK! @@JonathanMai

[@CamC-km4pr]

If you still haven’t fixed the misfire, I’d recommend replacing your distributor cap and rotors or at least pull them off to check. The rotor is red and sits inside the distributor cap. It has a gold metal tip that aligns with a notch on the cam sensor housing inside, if they aren’t aligned you will have misfires due to incorrect ignition timing. Also With high mileage and old age the rotors can break off and cause your ignition timing to be off and cause misfires as well. I had this issue before but they are very easy and cheap to replace if they are broken.

[@JonathanMai]

I figured out what the problem was, editing video and it will be uploaded soon

[@seniknine]

Good to know, nonetheless. Will be removing my distributor to replace it's mounting gasket but I wanna look it over, as well as test my wires and spark plugs.

[@jpeoples2644]

My 1992 sc400… I had misfire, running rich. My problem was the throttle position sensor.

[@JonathanMai]

Weird thing is that my misfire is only on one side?

[@osbaldorivas6200]

Love your vids chinito❤️

[@JonathanMai]

Appreciate you bro ❤️

[@jacobwebb8818]

4:25 you're not grounding the spark plug. It uses the engine as the grounding point to ignite gasoline Edit: Hey Jonathan. Good choice on a build. I started out somewhat like you. I had a GS300 a few years ago that was an absolute hunk of shit, I had to fix the injector and spark plug wires by soldering on new plugs. I luckily got a job as a vehicle electronics technician after that, partly in the fact I was able to fix my car that way. Toyota Denso ECU's from the 90's are notorious for failing. Like, renown. I genuinely recommend you try changing out the capacitors for yourself, it's not that hard I promise. You already did the hard work of getting the ECU open. Just make sure you get the capacity, voltage, temperature and orientation right. For example if you pull out a 220μf 16v cap able to withstand 80°c, replace it with a 220μf 16v 80°c cap. Where you can improve however is upping the voltage and the temp rating. So if you can only find 220μf 25v 100°c that works too. Just don't go excessive on the voltage. But a step or two up won't hurt ANYTHING. Just make sure to get yourself some solder wick/braid and take your time with it. Don't torch the board but don't be eager to rip the caps out. Stay on the pad for 6-12 seconds and it should pull it right out with that wick. I promise it's not all that bad. As for the O2 sensors, I would recommend continuity testing them at minimum before you order new ones. Disconnect them and test between terminals to make sure they're not shorting out, and that's the minimum test you can do for those sensors. Good luck! I wish you luck on your journey. I am very fond of these SC bubble coupes and I would love to see more staying on the road

[@JonathanMai]

I'll have to look into how to continuity test the O2 sensors, I did order and they are in my room but I'll fs test sensors out before I put in new ones. 😂 My pockets are hurting a little 😅

[@toshikiuchiha13]

Bro I've been waiting for this video

[@JonathanMai]

I gotchu!

[@toshikiuchiha13]

I'm looking forward to see the outcome of your sc

[@SeanNay]

❤❤

[@samuelmott7688]

Ayooo, so where the ecu is on the passenger side, there is a connector/harness area with hella wires. Check those. I believe it may be the thicker wires. I had the same issue with my 95 400. Could have corrosion inside of the wire and you couldn’t see it. It was causing a big misfire for me.

[@JonathanMai]

Yo Sam! Is the harness on the floor or hung up on the wall on the right?

[@aragornlesicka8995]

for me my sc400 has about 80k miles but there was oil in one of the spark plug wells

[@wiseg.s5872]

Change valve cover gaskets, spark plug wells have small gaskets, just buy the valve cover gasket kit oem part and change all of them

[@JonathanMai]

When I looked into the spark plug holes, didn't see much oil but I will check again!

[@MatthewOuk-c5y]

When I got my sc this year my oil cap did the same thing lol

[@OneWheelPeell]

LETS GO

[@aznboichiam]

where did you buy the connectors for the injectors?

[@SeanNay]

❤🙂

[@layoa4275]

did you fix it i could help it may be an easy fix

[@JonathanMai]

Did not fix the misfire haha

[@layoa4275]

@@JonathanMai injectors rarely go bad on this car as you may know the engine has been through extensive tests the only two main faults of misfiring really is the idle air control valve or the ecu which you can check for a burnt board or resistors

[@layoa4275]

i had missfire and car dying out problems before and I documented the process on facebook I could send you the link on ig if those two don't help but I'm sure its one of those