misomeru

I just bought the car and it wouldnt start. I replaced the fuel pump and its filter with an oem one and it started but it sounded like a lawn mover (previous owner had car sitting for a while and then the owner who sold it to me had it a year and I dont know when it stop running for him so I know it sat a while) So the car had this white smoke coming from exhaust and I saw through the forums that the ECU was the culprit since it threw code 27. And since the one in my car had previously replaced with a A/T 2JZGE ECU, I purchased a 92 M/T ECU. Exhuast smoke has lessened greatly with new ECU. After that I changed the oil and flushed the radiator 3 times as it had nasty brown liquid in it. Its down to a vapor/light white smoke now. No Check Engine Light on at all now. I notice when I accelerate when shifting gears that the car almost dies on me and I have to gas it more to keep it alive and it bucks while doing so. Also when you get it to cruise speed and your keeping the pedal still the car will stumble every so many cycles.

Thank you whoever reads this. Everything on these forums has helped me with my 1995 sc400 and my new 1992 sc300 5 Speed.

SCSlug

Im no 5-Speed pro. But I enjoy troubleshooting.

My SC400 sat for almost 3 years. Wouldnt turn over. When it finally did after about $1500 worth of parts, This white smoke you speak of was pouring out pretty thick with a distinct smell. From what Ive gathered, this was nothing than a combination of moisture/ old gas/ and 3 years of whatever decided to crawl in my exhaust being sent out. Ive read ECUs do fail, I changed mine. But im tempted to say in your case it was nothing more than what I stated above. Moisture/Junk. It will decrease over time to nothing. I DD my SC400 now, And I havnt had that happen ever since.

I dont know what youve replaced other than the ECU on the car, But Id definately check into the MAF sensor/TPS sensor/ O2 sensor/ Plugs & Wires/ to start off with. Those seem to be the most common things that lead to the bucking,stalling etc.How many miles on it?

StiCk3

iTrader: (5)

+1 start at the MAF sensor, clean it out first and see what that does to driveability. Check the intake tract for any thing that might have made a home in it as a hold after the MAF in the intake tube will cause it to lean out your engine. plugs + wires + cap + rotor is a good idea especially for a car that's sat for this long. Also get some good gas and runs some injector cleaner through the fuel system to clean out any extra gunk (i use Chevron with Techron or seafoam works ok)

misomeru

The car was a one owner car that ended up in car lot and purchased and then sold 1-2 years later to me. The car has 127k miles on it. i'll be checking the maf sensor. I unplugged it while the engine was running and it didnt seem to matter until you revved a bit harder. I am going to just buy a coil along with wires, plugs, cap, rotor, pcv, fuel filter from sewell lexus dallas along with a few odds and ends for a little shy of 400 shipped. I will also run some injector cleaner in my tank and take it for a 50 mile trip to see how she acts so the ecu can adjust. I dont know how to check maf, or tps sensor. Thanks for all the help!

jwin

iTrader: (16)

Did you take a look inside the new Ecu you brought. The cap could be bad on that one too since its so old.

kez

iTrader: (4)

If the ecu has a leaky capacitor u can put ur nose to it and smell a fishy smell coming from it.

misomeru

I havent checked inside the ecu or the maf sensor or tps. I replaced the plain water I had running in the radiator with Toyota Red Coolant 50/50 distilled water mix approx I had checked one or two of the front area spark plugs and they looked the normal brown (maybe a bit darker than normal). They were not wet and cylinders looked dry. I took my car to get my local honey at a farm about 60 miles round trip and there was still some bucking and later drove it some more totalling over 100 miles and as far as I can tell the exhaust smoke and the smell is gone. I am just running car and topping off coolant now. I'm slowly burping it. Now the oil looks fine and smells great! Need to monitor the coolant as I fear I could have a headgasket leak since I have a mild-severe stumble to find power when I rev the engine with the rad cap off a ouple of times consecutively I also find that most of the bucking is gone but the is still some there. Smoke also came back when I changed coolant but after I went and bought a 16 dollar bottle of chevron techron fuel injector cleaner and filled my tank to full from empty with it I drove 20 miles and it seemed to have went away. I'm not seeing any check engine lights and its not throwing and codes via diag port. Car is FAST and drives STRONG minus the stumble/buck every now and then. If there is no headgasket failure I am inclined to think the stumble is from the W58 mounts or it needs a complete tune up with OEM parts.

carsmypnis

iTrader: (1)

mayb youre driving at too low rpms. my car buck when in too high of gear

misomeru

Thanks for all the help you've all given me. Gonna use to get to work and back this whole week and monitor all fluids and smells. We'll see how she does me.

Aron9000

These cars are geared so short from the factory its almost impossible to do that with it running right.

Another thing that might be causing it to run rough is bad gas. I'd get a syphon device, and suck all the bad gas out the filler neck. Before starting it again dump a full tank in there to dilute what little bit of bad gas and sediment is sitting at the bottom of the tank. Once you drive a tank of clean gas through it, change the fuel filter.

misomeru

So here is an update to those who are curious. I looked into bleeding my clutch system and when I opened the clutch rez tank there was a nasty looking rainbow film on the top and it was filled with a dark dark brown fluid which I guess means its so old, so I went and bought some valvoline dot 3-4 synthetic brake fluid and flushed the old one out by bleeder valve and just kept bleeding it till the fluid came out clean as I could get it for the moment. Now I notice the car is easier to shift from first and most if not all the bucking has stopped when I went for a test drive. Hope it was this easy to get rid of that nasty bucking. I'll post updates later on. Going to do a ignition tune up this week. Parts were 350 all together and I still need pcv valve. Engine is kind of noisy. Are the 2jz-ge engines a bit noisy? My sc400 sounds way smoother than this sc300...

KahnBB6

iTrader: (5)

I own one of these. Usually they need some TLC at first. 2JZ-GE's aren't exactly quiet but you'd have to define "noisy" for us. It's a smooth engine but it was designed as a sportier engine than the 1UZ. I've always felt it has a lot of character.

I highly recommend appropriate weight Redline Gear Oil for the manual transmission and rear diff. If you ever install an LSD (unless there are specific instructions for it) I recommend Redline Heavy Shockproof oil.

Aron9000, I have to disagree on the gearing. The 5-speeds were a bit lax in their gearing from the factory. 4.083 isn't a dog but it doesn't really allow one to effectively use the engine's powerband in all gears. It's hard to avoid being in too low or too high a gear on curvy roads with the stock rear end. Too docile compared to the way Supra 5-speeds of the era were geared.

misomeru, consider replacing the W58 transmission mount and shifter bushings. The trans mount can be sourced for a Supra MKIV non-turbo manual and the W58 shifter bushings (92-94) use, IIRC, 4Runner bits. There is a writeup/thread on it somewhere on the forums.

MDSC

iTrader: (3)

the coolant condition youre describing isnt good. Especially when it turns brown. The coolant wont discolor from just sitting, if i were you i would do the following.
1.Coolant pressure test.
2.Compression/leak down test
3.radiator Chemical h/g test.
I would do all 4 test before you waste your money on anymore parts. If all of those 100% negative then start looking elsewhere. Unfortenatly with the coolant color youre describing i think you will find that your h/g is a problem.

LexusFTW

iTrader: (7)

^ Listen to this man

Aron9000

What I'm saying its hard to bog the 2JZ if its running right. You know when you drive a little 4 cylinder Honda, you pretty much have to keep the revs up past 2k, the 2JZ, you can floor that ***** at 1500rpms in 2nd at 15mph and it doesn't complain.

As for the gearing, I'd say its fairly aggresive compared to some of the big v8 detroit iron I've owned. Had a 98 Camaro Z28, LS1 6 speed, 3.42 rear, that thing would cruise at 70mph@1700rpms and get about 28mpg, this in a convertible with **** aerodynamics. Best I've done in the SC with 2/3rds the power is 23mpg, these things really need a tall overdrive gear IMO.