SC400 electrical/engine problems
Thread Starter
Driver
Joined: Apr 2007
Posts: 101
Likes: 1
From: Tacoma, Wa.
SC400 electrical/engine problems
I am at work currently and I don't have a lot of time to research right now so I am going to throw this out there to see if anyone can help out.
I was driving in this morning and all of a sudden my tach dropped down to about 400rpm and it felt and sounded like I was running on half my cylinders. The car has hardly any power and the engine bay smelled hot. I turned around and took my truck to work so I haven't been able to look at anything yet.
Going 30-40mph my rpm's are reading like 1200 and sometimes it bounces up to 4000 and down to zero. It idles at at 400 maybe. It will almost stall at a light when in drive. It struggles to get up to 30mph. When I parked it the exhaust was crackling WAY more than normal. I know the exhaust was getting really hot. I didn't check which bank was firing, but i think the left side was firing and not the right.
I haven't worked the 1UZ much so I am asking for advice on where to start. I am going to check fuses when I get home. The lady we got it from a year ago mentioned new plugs were just installed so I might check that out. Although I doubt that is a factor.
Where does the tach get its signal? does it use more than one input?
Any advice would be a great help.
Thanks-
Brian
I was driving in this morning and all of a sudden my tach dropped down to about 400rpm and it felt and sounded like I was running on half my cylinders. The car has hardly any power and the engine bay smelled hot. I turned around and took my truck to work so I haven't been able to look at anything yet.
Going 30-40mph my rpm's are reading like 1200 and sometimes it bounces up to 4000 and down to zero. It idles at at 400 maybe. It will almost stall at a light when in drive. It struggles to get up to 30mph. When I parked it the exhaust was crackling WAY more than normal. I know the exhaust was getting really hot. I didn't check which bank was firing, but i think the left side was firing and not the right.
I haven't worked the 1UZ much so I am asking for advice on where to start. I am going to check fuses when I get home. The lady we got it from a year ago mentioned new plugs were just installed so I might check that out. Although I doubt that is a factor.
Where does the tach get its signal? does it use more than one input?
Any advice would be a great help.
Thanks-
Brian
Moved to performance/maintenance. please try to post in the proper sub-forum.
sounds like you lost a coilpack, it is pretty common on the sc400. You have 2 of them on the v8.
unplug the connector for the coilpack one at a time, and the one that doesn't make a change is the bad one.
When you pull the connector for the good one it should stall out right away.
I mean the 2 wire connector that goes into the coil, not the high power wire going to the distributor, don't shock yourself now.
you can also disconnect them one at a time and then try and start it, if it starts you disconnected the bad one, if it doesnt start you disconnected the good one.
let us know how it goes and if that was it update which one in my Poll thread.
https://www.clublexus.com/forums/per...ason-poll.html
sounds like you lost a coilpack, it is pretty common on the sc400. You have 2 of them on the v8.
unplug the connector for the coilpack one at a time, and the one that doesn't make a change is the bad one.
When you pull the connector for the good one it should stall out right away.
I mean the 2 wire connector that goes into the coil, not the high power wire going to the distributor, don't shock yourself now.
you can also disconnect them one at a time and then try and start it, if it starts you disconnected the bad one, if it doesnt start you disconnected the good one.
let us know how it goes and if that was it update which one in my Poll thread.
https://www.clublexus.com/forums/per...ason-poll.html
Pole Position
Joined: Dec 2012
Posts: 393
Likes: 0
From: Delaware
A few things come to mind and sorry to say these small electrical issues are common in our cars.
Depending how old your car is, but the early SCs had resistors built into the ECU board. After they get old they tend to leak onto the surrounding board (in my case down to te lower board). If you are <95 this at be an issue.
However, it had been raining like crazy for two weeks here. With that said, if you are the same the driver side coil is susceptible to water and will short out if wet al(at te right moment). If you are missing the center under cover thingy it is even worse.
Also the coils don't fire desperate sides. Each of the two coils powers 2 cylinders per side (4 total).
Start by unplugging the driver passenger side (or top one), if that keeps te car from starting up then good chance the other coil is bad.
Hope that helsp
Depending how old your car is, but the early SCs had resistors built into the ECU board. After they get old they tend to leak onto the surrounding board (in my case down to te lower board). If you are <95 this at be an issue.
However, it had been raining like crazy for two weeks here. With that said, if you are the same the driver side coil is susceptible to water and will short out if wet al(at te right moment). If you are missing the center under cover thingy it is even worse.
Also the coils don't fire desperate sides. Each of the two coils powers 2 cylinders per side (4 total).
Start by unplugging the driver passenger side (or top one), if that keeps te car from starting up then good chance the other coil is bad.
Hope that helsp
Thread Starter
Driver
Joined: Apr 2007
Posts: 101
Likes: 1
From: Tacoma, Wa.
haven't had time to do anything really, but I pulled the plug on the drivers side coil and the car would fire but not run. I am off tomorrow so I am going to check out the other coil. Just from what you guys have said, it would appear the passenger side coil may be bad.
If not all the leads coming from your coil are firing through the distributor you could have a worn down rotor.
In my experience the wires never go bad on Toyota unless some one messed with them or pinched them.
Plugs don't sound like the problem either.
In my experience the wires never go bad on Toyota unless some one messed with them or pinched them.
Plugs don't sound like the problem either.
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Thread Starter
Driver
Joined: Apr 2007
Posts: 101
Likes: 1
From: Tacoma, Wa.
Pulled all the plugs from the drivers side rotor and it ran (barely). Pulled all the wires from the passenger side and it did nothing. Swapped coils and it ran. Went and got a new drivers side coil and it is fixed.
Thanks for the help. I will go fill out the poll on the other thread.
Thanks for the help. I will go fill out the poll on the other thread.
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No problem, sometimes you have to get in there and start disconnecting stuff till you figure out which one it is but glad you found it!! another one for the drivers side it looks like. And thanks for reporting back as well.
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