paulzlexus

Well good evening all tonight I have one or two questions if any one can help. First do these cars have a [limp in] mode? If so what would put them in that mode?Second If they dont have a [limp in mode] what would all of a sudden make it run like the timing is retarded and not advancing at all ? Its not missing just no power. Please help as now I need the car

emoFTW

iTrader: (1)

Maybe your timing belt jumped a tooth?

paulzlexus

You know I Thought about that and it could be but it is a relatively new about 3 months with new tensioner and bearings.Should be unlikely. But I do appreciate your thoughts and insights,as I have no one else to bounce ideas off of.

paulzlexus

Yesterday sc400 suddenly started running very badly sounding almost like a tractor no power after taking home taking off battery cable thinking to reset computer started car no improvement and idleing in driveway the cats were glowing red WHY?

Studiogeek

iTrader: (6)

Hard to get up hills? for you, I'd guess Coil Packs. Check or replace.

Ali SC3

iTrader: (10)

give us some more info on your car, what mileage and stuff you have replaced recently or ever.
the timing on the sc400 is fixed, there is no adjustment.

most of the time these problems on the sc400 is a bad coilpack or ignition issue.
you are probably running on 4 cylinders, and most don't notice its missing cause the motor is so smooth.
get glowing cats is a sign of unburnt fuel entering the exhaust, which is either from a bad injector or no ignition on some cylinders.
you have 2 coilpacks so there is some troubleshooting involved to figure out which one.
Or it could be the 2 caps and rotors needs to be replaced.
do a search for sc400 and ignition there are 100's of threads on sc400 and ignition issues in the performance section.

sjc2467

There's no mechanical means of adjusting timing, but it is advanced/retarded electronically. Of course, I do not think that is the issue.

Glowing cats definitely indicates a dead misfire on at least one cylinder (two actually, assuming both cats are effected). In this case, the most likely culprit is a coil, coil wire, or distributor rotor, which is weakening or disabling a group of 4 cylinders.

Assuming both cats are glowing, testing is relatively easy. You should be able to disable an entire coil-group of cylinders by unplugging the coil. Try one, then the other, while someone watches the rpm. Whichever causes a smaller drop in rpm is the culprit (likely one will make very little if any difference, and the other will cause it to instantly stall). You could also do this on individual cylinders by shorting one cylinder's ignition (to ground) with a test light, but I don't think that will be necessary, in this case. Once you find the system with a problem (this test indicates which ignition system, but not which component), you need to narrow it down to a specific component. Often a visual inspection is sufficient to see distributor and wire problems (it will be the wire between the coil and the distributor). If you have a multimeter, check the resistance of the wire, and compare it to the other one, which you can assume is good (they won't be exactly the same--you're looking for a big difference).

Warning: try to run it as little as possible, and for very short periods, because this condition will very quickly melt (destroy) the cats, which typically means a very large repair bill. If you locate and repair the fault, and still notice a lack of power, there is a good chance the cats are already melted and are restricting the exhaust. There are several ways to confirm this, if it comes to that.

paulzlexus

Hey there guys thanks so much for all the input!!! Cant wait to get home and try a few of the things you said to look for.The coil thing is a real good possibilty as last week I back flushed the radiator and got some stuff on the engine wet it ran good when test driven that night but it has been acting up ever since. To allsc3;-I just recently[well 3 months ago]bought the car for 1300.The body is OK, interior is clean, but I had to put a new alluminum crossmember underneath the motor,while I was there I did upper aned lower bushings and had allighnment done.Also during that time I went ahead and did timing belt,water pump routine as I could find no evidence of it being done since like 88000 miles,it now shows 207000 miles.When I was all done with it it had been running warmer than I liked so I back flushed the radiator once about a month before all this happened got alot of stuff that looked like head gasket repair crap, or radiator stop leak and car was running very well for the miles shown no more running hot then here it is a month later warming up in merry old az..started creeping the gauge up maybe 3/4s of gauge,so I left radiator in car and back flushed it in place. Thats all I can tell you about the car except that I really like driving it and am determined to keep it running and you guys help and suggestions make total sence so THANK YOU ALL VERY,VERY MUCH.---Paul

Ali SC3

iTrader: (10)

Most toyota ecu's are electronically controlled but the distributors usually have a manual adjustment.
On the 1uz, the distributors are fixed because there are 2 of them and they don't want them to be out of synch with each other.

keep at it you will get it back to normal. probably whatever your problem is is making it run hotter than normal also.
check out the coils, do not unplug while the engine is running. replace the caps and rotors is good maintenance, stock wires are often alright.
If all that is working you can test the injectors by unplugging one at a time and seeing if it clears up, that would be the stuck injector.
If none of that works (what I call the easy stuff on a 1uz), I would do a compression test.

paulzlexus

I really wanted to thank all those good people that answered my thread because most of you that said that it was probably a coil pack, and bingo stopped on the way home found a LS400 in the local pickapart I picked up 2 coils,2 caps and rotors,all hooked up to a newer looking set of plug wires than what are on my car.Changed the coils one at a time and found the drivers side coil to be bad. Thank you so very much. Any advise on why it wants to idle to fast and speed up to 2000rpms and back to1100 unless as I have it now with vise grips restricting the 1/2 inch hose going IAC valve in front of motor intake plenum?

Ali SC3

iTrader: (10)

since you just recently buy the car with alot of issues I would guess someone adjust your throttle plate stop screw to let more air in to the engine to cover up some of the real problems. probably why they also poured stuff into the radiator. some people will try and add everything possible instead of figuring out whats actually wrong, which takes about 30 minutes of reading on this forum to know the coil packs are notorious for going out.

when you loose a coil your rpm's usually are very low, because you are running on 4 cylinders about half your idle speed. Some genius "mechanics" will crack open the throttle plate more to raise up the idle to normal, without bothering to fix the real problem. so your 4 cylinders are doing double duty to keep your rpm's normal.

Then when you fix the real problem, you find that your idle shoots way up, and its because you have 8 cylinders now working double duty so you need to undo what the last person did and close in the throttle stop screw in some, until your rpm's are back to normal.
try and screw in the screw some to where you get a cold idle around 1400rpm's and a warm idle around 7-800 rpm's.
Thats a good zone to start with.

Studiogeek

iTrader: (6)

I only had that answer from reading the posts of people like ALI SC. I couldn't help answering ONE without my usual disclaimer of "I know nothing but.......". (just to enjoy pretending I know something about cars for once ;-)
Hanging out here and reading obsessively is making a difference.

Ali SC3

iTrader: (10)

You did good Studiogeek, researching on here can pay off for those SC repairs that are tough to figure out from scratch, but happen so often we just know what they are by now. I can't even hear the words sc400 and problem without thinking about coilpacks anymore. they are forever linked in my head.

There was one thread where someone caught me making a mistake, I thought each distributor controlled its own bank for ignition, but it turns out each distributor fed by one coil controls 2 cylinders on each bank, so when you loose a coilpack, you don't just loose one side of the engine, you loose 2 cylinders on each side or every other firing event, which is why it can still run so smooth on 4 cylinders and is hard to diagnose.