I have a sc400 Lexus. Have no Idea where to buy repair manual or parts. Read below and please help.

Tiny
SHADOWBOXER50
  • 1994 LEXUS SC 400
  • 130,000 MILES

Sc400 was running great. Then started missing lunging and dying, died after two or three starts, auto parts store recommended sea foam, due to us having a hard rain. I found clamps loose around air meter box, tightened them, and noticed a lot of 10 mm bolts missing which hold that box in place. Yesterday, it ran rough until I returned home, and the a/c only worked when the car ran great. Today, I found a broken vacuum hose fitting and attempted to fix it, but the car worked so bad, I towed it home with another car. The A.C had stopped, clutch was not engaging. However, after I backed it into it's parking place, and turned it off, I turned it back on, it ran perfectly, and the A.C was cooling again. I still need to permanently repair the broken vacuum hose, and replace the 10 mm bolts, and I suspect that the clamp near the throttle body was not tightened either. And it may need new plugs, possibly a new fuel filter, could be a fuel pump. I would say I have my work for me. What does all this sound like to you and why the A.C quitting as well? Do I need to undo the neg on the battery and reset the computer? I just bought it last month, and I think I have found a lot of the previous owners problems. I have a car fax, and there was two owners. Obviously, one or both of them did not care much for maintenance. Help me please

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Saturday, March 17th, 2012 AT 6:48 AM

26 Replies

Tiny
FIXITMR
  • MEMBER

Dont get all done in by a minor glitch. Fix the vacuum thing and any loose clamps and drive it if it's runnin ok.

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Saturday, March 17th, 2012 AT 7:00 AM
Tiny
SHADOWBOXER50
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I repaired all of the vacuum leaks. I do not see any more. I removed the neg of the battery for five minutes. Started the car, drove around the block and a/c worked ok. Then all of a sudden, the car started missing, the a/c stopped, and it went dead. I got it back home, and I can remove the neg on the battery and re-install it, then the a/c works car runs great for about two minutes, then it dies. When I turn it back on, it is idleing much faster. And A/C does not work. Something is bad and the computer is finding it. I am not sure I can make it to the auto parts store in it to find the fault code

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Sunday, March 18th, 2012 AT 4:19 PM
Tiny
KHLOW2008
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http://www.2carpros.com/articles/lexus-trouble-codes-obd1-1990-1995-code-retrieval-procedure

Try above link for trouble code retrieval.

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Sunday, March 18th, 2012 AT 5:59 PM
Tiny
SHADOWBOXER50
  • MEMBER

Ok, we started it from a cold start and it ran terrible, we pulled in a shop. The mechanic put it up on the rack and went right away checking dual catalytic convertors, resonators, etc.
Then they started saying that the check engine light would not respond or come on at all. They were wanting to keep the car at 80 per hour and go into the dash. (I am not paying for an idiot light, that would make me the idiot) They claimed at first the car was too old, that they had newer meters, then they tried and older meter and claimed the ECU wouldn't keep flashing long enough for them to get the code. Then he started checking the coils, one was newer and had been replaced, the other was original, so he ordered a coil. $215, out the door and the car ran great. Until the next day. From a cold start, it takes three or four tries until it stays running, and when you go it has half power, running slow until it builds up speed. Then stopped at red lights it is idling higher, we pull over turn the thing off and go in a store or something and come back out, start it and it runs great again. After that, there are no more problems the rest of the day.

I am considering a plug job, and a fuel filter replacement and see if it helps. It can't hurt anything but my wallet, since I do not know when they were replace last.

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Thursday, March 29th, 2012 AT 7:06 AM
Tiny
KHLOW2008
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Do you have coolant losses issues?
Check the engine compression and let me know the results. Do it on a cold engine.

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Thursday, March 29th, 2012 AT 12:41 PM
Tiny
SHADOWBOXER50
  • MEMBER

Ok, I had a compression testor, but since it is from the 70's, it has about had it anyway. No coolant lost. Put in the plugs, All plugs looked the same, carbon with no damage, changed fuel filter, and found two loose vacuum hoses. They are like hoses that just got hot and they are plugged on, but loose. I pushed those way on really hard. Car was running great for two days, and then when the fuel light came on, added gas. Then it went back to it's old way of spitting and all that stuff. The A/C will not pull in the clutch when it runs rough and the RPM tops 1200 at idle and then it starts skipping and running rough from 1200 down to rpm of 600. The other day, it cleared up on its own riding down the highway and we had really cold air all the way home. I had another shop tell me it may be the a/c compressor dragging things down. But I do not have the a/c on all the time yet. I am still leaning towards these old vaccum hoses and will not stop until I am sure there is no loose ones anywhere. I would probably pay $700 for another a/c compressor and then it still do the same thing. So, ruling out the simple things are for me. I love being under the hood of this car. Everything is in such great order. I like organization.

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Monday, April 2nd, 2012 AT 6:20 AM
Tiny
KHLOW2008
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Recheck the vacuum hoses. If there are loose, snip off the ends and reinstall.

I don't think you need a compressor. When engine idling speed is too low, the AC would not work. Since the problem affects the A/C, I woudl suggest checking the ECT.

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Monday, April 2nd, 2012 AT 1:58 PM
Tiny
SHADOWBOXER50
  • MEMBER

Well, I have been busy moving. The place where I lived was a gang hood, I had two tires cut and slashed, and a neighbor had water put in her gas tank. My car runs great most of the time, with the exception of startups. Sometimes it will start up and rev up and then it runs with no power at all. We have just gotten used to turning it off, waiting a few mintues and then start it again and then it is all right, while waiting we smell gas fumes.
And that A/c compressor quit. The clutch engages, squeals and then with a thump it stops and the light over the a/c switch starts blinking. I know the compressor is locked, I see the clutch slipping on in trying to move it. Otherwise Texaco gas seems to make the car run a lot better

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Friday, May 4th, 2012 AT 4:09 AM
Tiny
KHLOW2008
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Symptoms indicates a possible fault with the PCM or its wiring. It is intermittently not working correctly and restating sometimes solves the problem.

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Friday, May 4th, 2012 AT 4:30 PM
Tiny
SHADOWBOXER58
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I got sick, and found out I have fainting episodes, or possibly seizures. So I have been away for a while.

The way all of this started, we have gotten used to turning the car off when it starts up and idles too fast, and the next time she runs perfect. It is intermittent. But now to the real worse problem. We will look for that first problem later, or may solve them both at the same time who knows?
We had the coldest air, until if got really hot. Then one day there was a squeal under the hood. I noticed that the clutch is pulled into the compressor, but a large center piece with a bolt in it is not turning. It tries intermittently and this is what makes the noise. I put my gauges on it, and of course the compressor is not pumping. I took a large screw driver and the end of the clutch is like a magnet making the driver stick to it, however the cent part of the hub with the bolt in it will not turn, it appears to be broken off of the clutch, Could this be the case and I just need a clutch, or is it possibly a new compressor. Makes me sick knowing it is so hot and I am so sick. I gotta have it cooling. The belt is ok and it all is turning, just not the end of this plate with the nut in it.I feel like that bolt and plate is what turns the compressor and makes it pump. Anybody?

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Friday, May 25th, 2012 AT 5:21 AM
Tiny
KHLOW2008
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Seems the clutch is bad and has detached internally causing the compressor not to turn. For some model designs, this can happen. With engine off, manually turn the center bolt with a spanner and if it turns easily, you need a clutch. If the bolt seems seized, you need a new conmpressor.

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Friday, May 25th, 2012 AT 12:29 PM
Tiny
SHADOWBOXER50
  • MEMBER

What I replaced was the clutch drive plate that went on the very front of the clutch and viola, A/C worked again

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Thursday, August 30th, 2012 AT 7:35 AM
Tiny
KHLOW2008
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Good to know you have the problem fixed.

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Thursday, August 30th, 2012 AT 7:49 AM
Tiny
SHADOWBOXER50
  • MEMBER

However, the speedometer stopped working while on a trip and the O/D light started flashing. Not many mechanics can test OBD I in Tallahassee, I found out that some one (Probably to sell the car) moved the check engine light so it would not burn, I went into the cluster and moved it from Trac Off to the proper place. Now the engine light stays on all the time, and even jumping out like the page says to doesn't make that light flash. I removed the fuse, I also removed the negative battery cable, and nothing changed to clear any codes, and to make matter worse, the very first problem I wrote you about has started again. You crank the car, it idles high, no power on take off, but that O/D light quit flashing. I tried to jump the terminals to check it, but only the ABS and Cruise lights flash off and on. The speedometer, odometer, and cruise all quit. Everyone says speedsensor. But not everyone agrees as to where it is, transmission, or tires, or more than one. I think I have multiple problems, and not just any mechanic can handle it, and we have NO LEXUS dealer in town. A Toyota Dealer that is it. I want to slap the man who sold the car, and my wife for buying it, it is the 2nd piece of crap she has bought. I will from now on pick the car MYSELF. I am sick of this one. And its age is the problem, no one has the crap to work on it, you have to order parts for it, and I do not have a credit/debit card, no repair manual, nothing. So what in the world could be causing all of these problems? I feel like running it into a dang tree

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Thursday, August 30th, 2012 AT 6:00 PM
Tiny
KHLOW2008
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The speedometer not working is related to the O/D light flashing. When you bridged the diagnostic terminals, didn't the O/D light flash the codes?

When the MIL stays on, it could be a fault with the circuit or there are trouble codes. When bridging the diagnostic terminals, did it stay on or blinked.

You might have some wirring issues that needs some time and effort to resolve. I need to know the exact situation in order to be able to help you.

I would like you to list whatever things you need to do and we would go through them one by one. I am sure we can get it done since you know what you are doing.

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Thursday, August 30th, 2012 AT 6:09 PM
Tiny
SHADOWBOXER50
  • MEMBER

Well, I do have a check engine light now, at least, but it burns all the time. I did pull the fuse, and neg on the battery to try and clear the codes. The light still stays on. Nothing ever blinked. With the car reved up again and no a/c that O/D light went off and stopped flashing. I bridged the terminals to try and get the codes from the check engine light, but it never blinked. I tried to bridge the terminals to check the O/D light and the ABS light blinked and the Cruise light Blinked, but it was just blinking, not codes. Yesterday, we drove it and a few miles into the drive, (before I fixed that check engine light) the car idled down, the a/c started working and then the O/d light went to flashing again. At no time did the speedometer ever work again, but the odometer has moved about 6 miles in the last two tanks of gas

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Thursday, August 30th, 2012 AT 6:21 PM
Tiny
SHADOWBOXER50
  • MEMBER

Oh and I did notice that there was NO BULBS near that check engine light bulb. There should have been three, one for Trac Off, one for check engine and one for the AirBags. But there was only the one bulb. I would have to order the bulbs from Lexus, and there could be faults within the Airbag system, or any of the other bulbs that were gone. Screws were missing where someone entered that cluster and dropped the screws by not having a magnetic screwdriver.

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Thursday, August 30th, 2012 AT 6:53 PM
Tiny
KHLOW2008
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The first thing you need to do is to check the wirings and confirm they are in working order. The MIL not blinking and others not flashing codes are most likely to be due to faults within the wiring circuit. This can also contribute to the faulty vehicle speed sensor. We need to get them resolved first.

The wiring diagrams won't show up well if I post them here and if you could let me have an email, I can send the PDF files to you.

As to check confirming if the MIL is working correctly, I can send the procedures to you as well. For all correspondence, please keep them here as we would like to have the history of what we have done to be here in one post.

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Thursday, August 30th, 2012 AT 7:27 PM
Tiny
SHADOWBOXER50
  • MEMBER

I went to a transmission shop, the car started working good, and the a/c went to cooling again and the O/D light started blinking. The guy at the shop had the meter to check the codes but it would not work, but he did manage to somehow get the check engine light to flash. Code 21, code 28, and code 71. He said it was O2 sensors, and EGR problems. Nothing showed up on the speed sensor, but I think you have to short two other terminals to make those lights blink. My email is Shadowboxer50@gmail. Com

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Thursday, August 30th, 2012 AT 10:20 PM
Tiny
SHADOWBOXER50
  • MEMBER

http://www.lexls.com/tutorials/intro/codereading.html is what I am following to get codes, I stand corrected, the TE1 and E1 jumper should have gave that man a code for the speed sensor, and he said it did not, that is was probably the motor head in the cluster. That cluster did not come out, I tilted it to get to those bulbs because the steering wheel must have seized up gears, it doesn't want to move out enough. Something else I guess I have to fix, I see now this Lexus is something to collect, not something to rely on

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Thursday, August 30th, 2012 AT 10:48 PM

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