Member1115

I took my 92 SC400 to the Lexus dealership for a diagnostic since "literally" overnight my car took a toll for the worse. Symptoms were misfires, complete loss of power, turned off at stop lights, hesitations, ackward exhaust sound, and that hot metal cooling off sound that usually is heard when you turn off your car (its that ping ping ding ding sound... i know... that was a stupid description ). Once again... this was literally overnight. Because the day prior I had gone out to dinner, came home and parked, went to sleep, woke up, I was going to take my son out to breakfast, turned on the car, attempted to drive... and bam... the symptoms mentioned came up.

So anyways, after some thought process , I figured it to be an exhaust situation like clogged up cats or something. But since it happend overnight I couldnt imagine that to just pop up and be a problem.

Well according to my local Lexus dealership, they are saying it is related to water in the spark plug areas possibly due to washing the engine. Well yes... I have washed the engine twice in the last month, but the last time I washed the engine was at least 2 weeks ago. Since then I have driven the car up and down with no related problems showing. All of a sudden, overnight this happens.

Would have the water not dried up in there by this time already if that was to be the problem as they state? Is it possible for negative engine washing results to take place this far out even after a good 100 miles have been driven since?

I dont know... it just doesnt make sense to me. Worse yet, Lexus states that the resolution will be to change out the spark plugs and wires to solve this problem. They are quoting me $580 for such . $10 per plug, $140 wires, and $300 labor.

Do you guys feel this diagnostic is legit? Thanks.

LEXZILLA

iTrader: (1)

Hey Man Save You Some Money Get Someone To Check The Coils....

Had The Same Problem Car Was Real Slow Ran Like A Motorboat Stalled Etc.
Took Car To A Real Mechanic And Replaced Two Coils Run Fine Now

Member1115

Out of curiosity... where are the two coils? I did some search on the forum and found that one is right up front by the inlet hose above the pulleys . But I havent been able to find out where the other one is located, and/or if it looks the same so that I can identify it visually.

Oh and Lexus sells the coils at $111 each. Anyone NOT recommend going non OEM? Thanks.

mkorsu

Looking at the engine in front of you: Right hand side, below the front of the valve cover. Gray in color. To see if a coil is bad. Unplug one and start car. Plug back in. Unplug other and start. If the car does not start on one or the other, then it's a bad coil. If one coil goes, one "bank" of cylinders will not fire. Causes, misfiring, bad noises, etc. Basically everything you described. If both go, then the car no starty. Sooooo, if the car doesn't start with only one plugged in, that one is bad.

aliga

iTrader: (147)

i have the two coils, 70 shipped for the pair.

DasBach

iTrader: (7)

What is wrong with the ping ping noise? My car does that.... what does that mean??? Is something wrong with my car? It always makes that noise.. It happens when I get done driving..

One_jZ_SC3

iTrader: (2)

yeh..mine does that also..I neber paid any real attention to it, should I?

Luxor

iTrader: (15)

My SC does that too, I just got used to it. I thought it was something bad but it is actually just cats/exhaust system cooling down after you shut the car off...Normal.

Member1115

MKORSU... Your idea sounds interesting. Not too sure I follow though.

I unplug one of the ignition coils and then start the car or attempt to start the car? Plug it back in... is this assuming the car does not start, or if it does start? Not too sure on the conclusion if the car "does not start on one or the other, then its a bad coil". Forgive my stupidy , but how do I identify the "bad ignition coil"?

Should the car be able to start with only one ignition coil plugged in? Or should the car only turn the engine but not start completely? Doesnt one ignition coil juice up 4 of the spark plugs? Is it possible to turn the engine and start it with only 4 valves running?

Once again, sorry for the idiotic question since I just dont get it.... But I wanna give it a shot.

Thanks again MKORSU

Oh... and as far as the ping ping noise of the cats/exhaust cooling off... I dont think I had ever heard it on my car before. Ive heard it on many others, and I know that to be normal on them, but since my Lex never did that, I figured it to be an issue. Not to mention burning smoke and smell coming from underneath (cats and/or exhaust). Sorry to put a scare on a few of you guys.

np20412

Unplug the coil on the left. Go start the car. If it starts, your coil on the right side is GOOD. Turn off the car. plug the left coil back in, unplug the right coil. Go start the car. If it doesn't start, then it means the coil on the left is bad, and vice versa.

The car will start when you unplug one of the coils. It means that only the 4 cylinders on the side you left plugged in will fire.

mitsuguy

iTrader: (2)

water may indeed be the cause here... Their prices don't seem too out of line except labor - good god $300?

My book calls for 1hour labor for plugs and 1 hour labor for wires - if you do both, I knock .5 off, so, 1.5 hours and we charge $79 / hour... $118.50 plus plugs and wires at a reasonable shop...

I would, as suggested above, check the coils as well... it's quite easy to do yourself - get the car running, and pull the coil wire off each coil (please wear rubber gloves), one at a time, and listen / look for a spark to jump the gap... also, clearly the engines performance should change when you do this - if it doesn't change, you most likely have a bad coil... if it dies immediately, the opposite coil is most likely bad.... if it idles still, but worse than before, then most likely both are good, and wires/cap/rotor/plugs are the culprit...

Member1115

Thanks for the clearing up NYLEXSC!!!

Just one final question... wouldnt an ignition coil problem of this kind or even water in the spark plugs trigger the check engine light?

Thanks!!!

Member1115

I just went outside to my car, did the ignition coil tests you guys told me about, and here are the results:

Ignition Coil #1: I disconnected ignition coil #1 (leaving only ignition coil #2 connected), turned the key, and just got a turn, turn, turn sound then a quick vrooom, but the engine did not stay on (continue running) despite keeping my foot a bit on the gas pedal during the process. It always sounded like it almost wanted to, but hesistated itself off.

Ignition Coil #2: After connecting ignition coil #1 back in place and disconnecting ignition coil #2, all I got was the engine turning, but no vrooom sound.

Does that mean that both coils are bad? Wouldnt it be abnormal for both to go bad at the same time as opposed to just one or the other? If so, then with that thought in mind, could I weed out the possibility of the ignition coils being the problem? As a reminding side note, this literally happend overnight.

Also, I forgot to mention that with the symptoms of the situation, I also get a faint paint-like smell coming from the bottom of the car and/or exhaust.

Sorry for the stupid sound effects (vroom-vroom), but not sure how to describe.

Thanks in advance and thanks again to all for your continued assistance with all this...!!!

mkorsu

Not necessarily. And my personal experience has been no.

mkorsu

As Cody said above, water can also be involved here. It's possible that you have 1 bad coil (ignition coil #1) and some water in the spark plug valleys fed by coil #2. Also, check those caps and rotors. I picked up my SC4 with 180,000 on the odo and when I did my tune up, both caps and rotors were more or less fried.

Ultimately, I would say do the work the dealer mentioned, but do it yourself. Platinum plugs can be purchased for roughly $5-$6 ea. (they are more than adequate on a stock motor), new OEM wires for roughly $90, 2 distributer caps and 2 rotors for $30-$40. All said and done, that's about $180 out the door!