oldManTan

it was probably just the coils, and it will run rough for a little bit. when i replaced my coil, driver side one, it ran rough for about 20 minutes. after that it was fine. hopefully that's all that's the problem.

cobalt91

The gauge climbing, check it for air in the cooling system.

Ali SC3

iTrader: (10)

yeah don't worry about timing as I said its not adjustable on your car. if the timing belt was installed properly, then the timing is good. don't worry about it. TDC means top dead center its a term used in relation to timing a motor which you don't have to worry about.

BigOSC400

Well, my dad told me my eyes would go at around age 40. I'm 46, and maybe I have some dyslexia of replacing the the spark plug wires because I just confirmed I had 2 wires crossed on the intake side! Again, I hope I didn't kill the car. Thankfully, while I've been doing the digging, I went ahead and cleaned out the throttle body and will let it dry nicely for 24 hours. I will get a new temperature gauge sender tomorrow. Everything else looks good for now. I felt pretty proud because it only took me 10 minutes or so to undo that side (key is to do the air filter box, first, which will give enough wiggle room for the throttle body hose, if anyone wants a tip that I have learned).
I have been slammed at work this week, so I appreciate everyone's help and patience with my mistakes.
More soon. God bless!

BigOSC400

Ok, so does anyone want to go out for a drag race?!!
OMG, my car has gotten ALL of its power back. I cleaned out the throttle body while I undid the intake side for the spark plugs. I made sure all connections were clean. All wires are now in place, and the car started right back up, no problem. Just a tiny bit of smoke and smell of gas, but it burned right out once I took it out for a spin (easy at first, then reaching 70 on the highway, then returning home because my temp gauge still shot up).
So, I'll be working on that tomorrow or Monday. I have a new temp sender (to the gauge). I already have the temp sensor by the upper coil AND the radiator (brand new); brand new water pump and radiator. My upper hose is still collapsing, so I guess I'll put in my new thermostat and housing and burp the system from the top bolt. I did notice a little leaking now from the coolant reservoir (from those two little wires thingy). So, maybe that's it? I'll start shopping online for one of those or a used one (I know they're getting hard to find, though).
Anyway, just wanted to let you know that I'm tickled that i have FULL power, and I'm ready to put my forest greet, stock SC400 against anyone! It's fun to drive again! My family loves it, too!
God bless!
PS. Let me know if I'm missing something on the cooling side of things, ok? Also, should I put any Sea Foam stuff in the gas tank (1/3) once I reach half-way (in order to "help clean the fuel injectors")?

Sc400NL

another SC400 saved , it makes me happy to read these kind of threads with a happy ending
i had a leak (bubbles) next to the coolant reservoir sensor (the two little wires thingy ) and replaced the o-ring but that didn't fix it ,
it seems to be a not visible creak ( at least not for me because like your dad told you after 40 your eyes go bust lol )
and after searching and reading lots of info on the reservoir it can't be glued properly and a new or used one is the only option , they are expensive ! at least here in Europe so i got a used one from the states via Ebay and it still works
while you are doing all these replacements , check your coolant filler cap too , it has a overflow function at 0.9 bar and mine didn't open on time so the reservoir blow up a bit like a balloon , not very good for a brittle tank

BigOSC400

SC400NL, yes, sounds good. I went ahead and purchased a used one from ebay last night ($59). I will put that in next weekend once it arrives. I will replace the thermostat at that time, too, since I'll be dealing with coolant stuff then.
If THAT doesn't work, I just might replace the gauges. I already did the lights in the dash, so it looks awesome now. I just need the gauges to work (both the temp and gas don't seem to work well).
BTW, besides the eyes going at age 40 (still too stubborn to wear glasses or contacts and too poor to get lasik), I might also blame the tequila or scotch I may have been enjoying along with the 80s music while I was working on the car at that time...
Oh well, God bless!

BigOSC400

Ok, just to see what would happen, I disconnected the temperature switch/sender I just bought, and lo-and-behold, the gauge needle stayed at the bottom. That's what I expected. I also filled up my gas tank, and lo-and-behold, my gas gauge stayed in the middle. I expected that, too.
So, maybe the next step (while I wait for my reservoir to come in) is to consider new gauges. Where is the switch/sender/sensor for the gas gauge?
I may just buy a used cluster and switch it out with my old one (taking out the brand new bulbs I just bought for mine).
We'll see. Let me know if you have thoughts on this. Thanks!

gerrb

iTrader: (34)

Take out the liner that covers the gas tank in the trunk

Right there at the center of the tank, you will see a round tank cover with a wiring connector. That is where your fuel gauge sender is.

BigOSC400

Thank you, gerrb!
I'm going to try one more time to fiddle with the instrument panel/cluster to see if I can see any abnormalities with capacitors, resistors, and the gauges. I'll try to plug all back in and see what happens. It just seems like either user error (that's me) or too much of a coincidence that both the fuel gauge and the temp sensor gauge died at the same time... I think I'll be in the market for a used cluster and just switch out mine for those. We'll see, but thanks for letting me know where the fuel sender is. I love tinkering with the car!!!
God bless!

BigOSC400

Ok, I was going to pay $299 or $499 for an instrument panel on ebay, but one came up on craigslist for $50, so I took a chance on that one.
I went to pick it up from my local junk yard. As I was paying for it, I heard the phone for the junkyard, and an employee answered and said, "yes, the 1994 Lexus SC400 that just came in, yes, it's here. You want a what? An instrument panel? No, sorry, there's a guy that's just leaving with it." !!!
I got home, took out the gauges that I needed, put them on mine, and BAM! My temperature reading is now PERRRFECCCTTT!!! Right at the middle of the gauge (of course, I hooked up the sender/switch by the top coil; remember that I had disconnected it at one point to "trick the system"). The fuel gauge reads accurately now, but the needle did not turn red, but I am still very pleased with my $50 purchase!
So, for now, the car does NOT overheat. It FLIES! I "accidentally" hit triple digits in 3rd gear on the highway, oops.
This week, I will probably put on the coolant reservoir that I ordered last week (still not here), change the thermostat AND housing, burp the system, and hope it is still fine.
After that, I have 1 motor mount to go (passenger), and then the car should be good for the year.
After that, I may need to do the rotation and balancing and alignment.
But for now, I'm quite pleased with my SC400/Soarer. It's fun to drive. My family loves it. And I actually enjoy working on it and getting dirty.
Thank you ALL for your tips and kind words and videos and pictures all over the WWW. Without your help, I would not have even bought the car...
Thanks again, and God bless!

Ali SC3

iTrader: (10)

Glad you are making good progress and enjoying it at the same time. thats a key part of owning an SC... lol.
Keep up the good work when you get around to it remember we all love pictures around here =)

BigOSC400

Ali SC3, you got it! I will post pictures soon (not too good at technology stuff). My reservoir just arrived Monday and it looks so much better than mine. It looks solid, and the wires look good.
BTW, again, no smoke whatsoever. No overheating. My fans come on, no problem. No check engine light. So, if anyone has experienced the smoke or other problems, you MAY want to put in new coils. I think that was the best thing I did to the car (besides getting the spark plug wires properly aligned, and the sensors put in). The car just wasn't burning the fuel properly.
Ok, will work on the car this weekend (got to work this week), and will post pictures and let you know how it went.
Thanks again for your continued help and support! MUCH appreciated!

BigOSC400

Just wanted to give you all a follow-up in hopes that this might help others dealing with SC400 over-heating issues.
When I bought this car last September ($102k miles), the previous owner had just put in new water pump, belts, and everything having to do with the cooling system.
The first problem I had was the radiator (started leaking) which I promptly fixed by buying a new one and had the new sensors for same.
My temp gauge went up; bought a new gauge along with the temp sender right near the top coil. That made the temp gauge be perfect, right in the middle.
Got the two coils (easy fix, not expensive). New spark plugs, distributors, rotors, wires (my mistake for mixing one wire but solved that).
Recently, I noticed my radiator fan just wasn't coming on AND my reservoir was leaking, so I bought a $45 used reservoir from ebay. Once I put that in, my fans came on great AND the reservoir was nice and tight (I cleaned out the interior of the reservoir as much as I could with a degreaser).
My final repair, and one that ended up being crucial, I think, was replacing the thermostat. In the work report that the previous owner was given by the shop, I didn't see that the thermostat was done (it may have, maybe not). So, I bought a heavy-duty, NOT CHEAP thermostat just in case, and when I went to replace it, turns out that the other thermostat that was in there WAS, in fact, a CHEAP one!! It was tiny (one I had seen for $1.50 at rockauto.com.
This leads me to believe that ALL of my problems actually stemmed from this cheap thermostat. This would make sense that the radiator would go first. Then my gauges. My sensors were all screwed up. The temp just wasn't right. My fans stopped working. The temperature of the new radiator was extremely high (can't believe it didn't break).
So, bottom line: if you have a temperature problem, buy a brand new thermostat that is heavy-duty and not a cheap one, replace the old one (yes, it's messy, but you can do it). Then see if that helps your car. The sensors are easy to replace, too. My car is running like a top (still smoking a little when you first turn it on, especially when the temperature is 40 degrees or lower, but it no longer smells like gasoline, so I may have a head-gasket issue, but after I drive it for 5 minutes or so, no smoke).
Anyway, I hope this helps someone. God bless you, and thank you all for your help with my car and all of your posts which have helped me tremendously!

Sc400NL

thanks for the follow-up and lesson learned i guess
don't replace key parts with cheap flimsy parts , in the end it will cost you loads