Frustrating 1992 Ls400 !

[Daniel091]

Glad you found the problem and are fixin it. Thanks for posting the diagnosis.

[curiousB]

...after tearing down my engine today, I had a blown head gasket between the no. 6 & no. 8 cylinders ....

Great news. Not that you have a blown gasket, that at least that you know what the problem is. Its funny how puzzling these things are until you finally diagnose it to root cause and then the picture snaps into perfect focus and seems obvious. I don't recall seeing many blown head gasket cases on this web so I don't think it is a rampant problem with Toyota/Lexus. I have had it happen to me twice with a couple of Ford vehicles I have had.

Keep us posted on the reassembly process for the benefit of others in the future. This is one of the more involved repairs we see owners do themselves on this site. That isn't evident from some of the talking down you received. You have the last laugh though, since you've solved it! Congrats.

[landar]

I am glad to see that you are making progress. It is very difficult to try to help someone who is many miles away and all we have to go on is limited clues, not having first-hand and up close inspection of the problem. But let me see if I have this straight. You are the 'mature' one, yet call SRK an a-hole and tell him to play with a Barbie???? That is not mature. He may have ruffled your feathers, but he did not call you names. Just sayin.

[BangEmBoy]

You are 100% right Landar, I was wrong to reply in kind and I apologise to SRK and anyone else that I may have offended . I just have this peeve about people with condescending attitudes ....If I can't help you, I won't mislead you or look down on you, because none of us are perfect or know it all...

I want to thank Landar, Curious B and 1992Lexus personally for all the advice, support and help that you gave . You all helped me to see it as a problem, and not just a Lexus problem . If I would have just used my mechanical common sense, this problem would have been diagnosed and fixed a long time ago; so in that aspect, SRK was right . I trully hope that my experience will help the other member's on this site ....... I found some Lexus only quirk's when I was disassembling the engine to take the head's off . Where can I post these, so that other member's can be aware of them if they ever have to take thier head's off ? Also where can I post pic's of the disassembly/reassembly ?

Once thank's everyone for all your help, advice and support .

[landar]

You truly do seem to have good intentions and caring attitude and I am impressed, Randall (good name BTW.., "landar" is just randal with the first/last swapped).

I would like to see the pics. You can post them in this forum and maybe start a new thread titled with head remove and repair or something to that affect. To post pics, you hit the"More Reply Options" button on the lower right of the screen, then browse for the picture file, upload and post. Its not bad once you get the hang of it. If you have problems with it, let us know.

[Daniel091]

I would also be interested and a step by step. My valves are startin to get loud. I was thinkin about swapping the heads for a rebuilt set. Might be cheaper...

[BangEmBoy]

Before I get started on my progress, I just want to thank each and everyone of the memebers of this forum that have provided help, advice and feedback .......

Other responsibilities have kept me away for awhile, that and the purchase of a 1994 SC400 . I've had so much fun (and problems lol) driving the d#m trhing that I kinda put the old LS on the back burner . I have the new heads, but have decided to pull the engine and do a total rebuild, and have puchased a used engine to put in the LS until I get the other engine done . I will be posting some pics soon . I am about to start a new topic (D#m SC !) about my recently puchased SC400 that I am having problems with, and I would appreciate any and all feedback concerning the issue's/problems that I am having with it .

[Tony B]

While driving my 1992 ls on trip back home it started bogging down and finnally just stopped. It wouldn't go over 10 miles per hour. . I took the center piece of the exhaust out and knocked the cats material out which was causing the exhaust sytem to clog up. Now besides it burning tons of gas it don't bog down any more. Also, I replaced to MAF sensor, which was part B of the problem. Now if I can find out why its burning so much gas. Another post.

[mainstreet23@hotmail.com]

Hello, I have read all of your post and my car has the same problem. Did you ever get it fixed. I just bought the car, a 92 LS 400. I have owed toyota but this is my first lexus. It has 180,000 miles on it.

Please help. Thanks, David.

[landar]

David, lets start from the beginning...what are your symptoms? Need detail. It may or may not be the same as outlined in this thread.

[mainstreet23@hotmail.com]

Thanks!

It seems like it is starving for fuel. It will not accelerate more than about 1200 rpm. It runs rough and it will not go over 5 mph. I floored it today and it very slowly reached 3000 rpm, then died. I thought i should start by changing the fuel filter just to eliminate it as the problem, do you know where it is located?

There are no check engine or any other lights on. Sometimes it is difficult to start but once it is started it will idle okay.

[landar]

David, since your car is a 92 with 180k on it, there could be several issues. When 'attacking' problems, I have always found it helpful to take a 'divide and conquer' approach. First, it would be nice to know the maintenance history on the car. Being a 92 with coils, distributors and wires, there could be some issues with the aging of those components. But, I would start with a basic triage.

That basic troubleshooting starts with a separation of the problem into either fuel delivery or spark delivery. Seems fundamental but a lot of folks take a stab at replacing components. So, what I would do, is to remove the air cleaner so that I had access to the throttle body. I would examine the TB for deposit build-up and determine if the TB butterfly seemed to move smoothly. It is very common to get carbon build-up which keeps the butterfly from operating smoothly. Then I would take a can of starter fluid and with the engine running, spritz a little into the TB to see if it changed the operation of the engine at all. It may not make the engine run correctly but if it even helps a little bit, it strongly suggest a fuel issue. (a helper with this would be useful to work the throttle while you spray).

Now, if the TB looks ok and the starter fluid did not seem to help, you could turn your attention to the spark. It is fairly common for one of the ignition coils to get weak or go out completely. Then you have your distributor caps/rotors and wires that could be end-of-life. Spark plugs could be pulled to check for condition. Ignition problems are suggested by your earlier post where you mention that "it runs rough and it will not go over 5 mph". Glowing, red hot catalytic converter(s) is a classic sign of a coil that has gone out.

However, as a first step, I would check for any codes despite not having a CEL on. I do not know if you have seen the LexusLs tutorial site but it is excellent info for your vintage. Under "Introduction" you will find a way to check for codes. http://www.lexls.com/tutorials/

Just some thoughts on things to try.

[mainstreet23@hotmail.com]

Randal, Thanks for the Information. I will check some of these things tomorrow. By the overall condition of the car inside and out, the previous owner did not appreciate it. The inside is filthy and needs a good cleaning, well outside also. I like this car and I think it will clean up good. It was owned by a young girl and she probably only did maintenance just enough to keep it rolling if any.

Thanks again.

[curiousB]

I lean toward ignition as first item as well. Fuel starvation is more of an engine under load issue. Rev'ing an engine in park is not much of a load and doesn't tax the fuel system much. Ignition on the other hand is RPM sensitive but not much to do with engine load.

The simple test is while engine idles. Unplug one side coil. If engine stalls replug and restart engine. Try the other side.

The theory is that if one bank is dead or poorly working disconnecting it will make little difference to the idling. A good bank though once detected should be very noticeable. No parts required to try this.