1994 Ls 400

[Havoc123]

Okay I am about at my wits end trying to get my car running like it used to. I unfortunatly cannot afford to take it to the lexus dealer. I did take it to a certified mechanic and he diagnosed blown head gasket and possibly burnt valves. My car doesnt have either of those problems. So I have for the last 2+ years been trying to get friends that I know who are mechanics, who I have seen work on and fix cars regularly, to look at my car and listen to me about what I know and the circumstances surrounding my car not running properly. I have listened to so many theories and guesses on what might cause my car to be running the way it does, my head is spinning.

1.Rough idle

2.loss of power, but gradually gets up to speed.

3.Dash lights come on for a quick second when starting the car, but then flash off. Normally they will eventually come on after driving for awhile, then they usually stay on after that. Until you turn car off and go to restart the car. the process then starts all over.

4.The exhaust smells bad, like carrosene.

5.#26 trouble code

6.From a stop the car will not make it up a steep grade, no power. But ones going will do okay on hills.

7.The drivers side pipe underneath the car was red hot one night when we were running it for a mechanic friend. He said it was the cat converter. But when we put the car on a hoist and lifted it into the air and removed the bolts and checked the cats they were fine. I didnt think it was the cats cuz Ive read they dont mess up in these cars.

8.I have assisted with changing the spark plugs,wires,checking compression,fuel pressure check,changing fuel filter. One thing I noticed is that a few of the spark plugs on the passenger side of the car were clean like brand new, all the other spark plugs were powderd black ontop and looked used. The spark plugs have been changed atleast 4 times. Thats where everyone starts. Im always sure to check and make sure I buy the proper plugs, wires, battery etc.

9.The 120 amp fuse was blown, and replaced. No noticeable change in the way the car ran. What would blow a fuse that big?

10.The gas miliage is not good. Eats gas up, costs alot to drive the car. I try not to drive it at all.

11.I have taken the battery out completely to reset codes etc. still no changes.

I will get the codes again this week and see what I get and post them. Can the computor be reset? And if I were to change the computor in the car as a last resort, can a used computor be used to save money ofcourse. And could anyone explaine where I could get a good used computor, and the process of installing it? I have spent so much energy and time on my car because I dont want to drive anything else. I refuse to believe my car cant be fixed. I think its going to be something simple. I cant afford the repair manuals for the car. Can the gas go bad causing the icky smell of carrosene, or is that probably due to #26 code air fuel rich malfunction?

I have shed many a tear over the last 2 years about my car. I just dont understand why and what is so difficult in figuring out what is wrong with it.

If any of you can shed some light on my problems with my car ide sure be grateful.

Thank you guys,

Havoc123 :cries: :cries:

[1990LS400]

If you can't afford to take your car to a professional mechanic and cannot even afford the repair manuals for your LS, my advice to you is to get rid of your LS ASAP and a get a car that you can afford to maintain.

Lexus LS cars have been my daily drivers for over 21 years (right at 281,500 miles) during which I never had a problem that could not be resolved quickly and at a reasonable cost by a competent Lexus trained mechanic.

[SRK]

You have a bad ignition coil. Simple. Cheap. Fire your mechanic who couldn't decide between valves and a head gasket.

There are two coils. When one fails, the engine runs on four cylinders.

Find somebody with an old school ignition oscilloscope and the problem coil will be found within minutes. Or go to the dealer.

[steve2006]

You have a bad ignition coil. Simple. Cheap. Fire your mechanic who couldn't decide between valves and a head gasket.

There are two coils. When one fails, the engine runs on four cylinders.

Find somebody with an old school ignition oscilloscope and the problem coil will be found within minutes. Or go to the dealer.

I'll second that diagnosis

The coils are not always easy to test as they may break down under load or due to heat,for what one costs,around $40.00 buy one and use it to replace the driver's side 1st.

If you have been running like this for some time you may also have damaged the cats.

[jaswood]

Lets see, driver's side cat pipe glows red, passenger side sparks look okay, driver's side not.

Plugged cat will cause red glow.

Fouled plugs indicate misfires, misfiring will result in unburned fuel combusting downstream causing the cat to glow red. Rich mixture code might mean failed, open, injector, but is also indicative of poor spark ignition.

But multiple fouled plugs leads us back to ignition coil, not a single failed injector.

Multiple failed injectors is a possibility but much less probable than a single failed component, the ignition coil or ignition firing module.

Without digging out the factory owners manual does anyone know if each of the ignition coils service all four plugs to a side...?

Swap the ignition coil firing control module wiring/connection left to right and see if the problem moves.

Woodinville.

[Havoc123]

Okay, I had the codes read and got #31, #41,#13 and #24. Did it by jumping the Te & Te1 underneath the stearing wheel. Can any of you guys give me some advice on diagnoseing my car? And thank you for responding to my last post. The coils seem okay, unplugged each one to see if car ran different, no real difference noticed. Please help.

Thank you

Havoc123