Several Problems With My 93 Ls400

[itzdaviboi]

I have a crap load of problems on my LS400 and I just can't figure out whats the problem.:chairshot:

1 Car underpowered when accelerated.

2 Car rumbles like it has sub woofers, but doesn't

3 Smelling weird fumes after fully start.

1. After I fully start the car, not much happens. I tried to floor it, but it doesn't do anything because when it reaches 15mph, it slowly climbs up. 0 - 60mph in 2.3 min.

2. When I go to a complete stops at a stop light, it rumbles like it got mass farting problems. <_<

3. For some reason, I smell weird fumes and I can't figure out where its coming from. . Whenever I go to work, I've become light headed as I step out of the car :D

If you guys want to help me out, I can grab some pictures of my car.

Just before I forget these are what I did in a recent week

- Oil Change

- Fuel Filter Change

- Power Steering fluid

- Switch out spark plugs [use platnium ed.]

- and kicked the tires.....remember....always kick your tires....

[sha4000]

you should do a full tuneup distributor and rotor,spark plug wires, air filter plus all the things you already did and be sure to check the condition of your tranny fluid. you might need a flush if you cant accelerate, hopefully you wont need a rebuilt tranny

[itzdaviboi]

Oh yeah.... forgot to do some of those... :chairshot: ... Thx

[alsalih]

This rumbling I beleive is related to misfiring at several cylinders due to the plugs. I hope you used OEM plugs (NGK or Denso) and not the Bosch platinum and you did check the gaps. Second, as SHA4000 mentioned you need to do a full tune up with replacing the dist rotor, cap, and wires. FYI if you pressure wash the engine and get water inside the spark plug tube you will also get that rumbling sound! Once you resolve the misfire/ignition problem up should see power restored!!

[SRK]

Sounds like a blocked exhaust system to me. Maybe the cats have collapsed internally. Whatever it is, diagnose it before spending huge money on parts you don't need.

[monarch]

I agree with SRK and would also do an engine compression test because if compression is low on some cylinders it would mean the engine has mechanical damage (such as poor valve sealing, broken piston rings, etc.) and therefore you wouldn't be able to get it to run smoothly unless the damage was repaired or the engine was replaced.

[akewlguy]

Exhaust blockage was a problem in the past with someone on this LS blog thing.

[ROYT]

Go for a fresh set of plugs first, make sure all HT leads in correct firing order,

and are good........if no better, only then throw money at it.......!!!

[nc211]

bad performance, rumbling and a bad smell........makes me think cataletic converters. Is the smell one of fuel? How many miles do you have on your car?

[akewlguy]

Does the cat get red hot?? Burning insulation or something under the drivers seat. Everyone should keep a fire extinguisher in the trunk. Man I can not tell you how many fires I have put out personally. There must be 10 a year in every little town in America. Obviously older cars or ones with poor maintenance are more common to smoke and go up in flames.

[itzdaviboi]

Right now, my milage on the car is

ODO - 200k+.

Thinking about engine swap the car with a RB24DET.

Molding the R34 front on it now.

I bought some BOSCH PLATINUM Spark plugs, maybe thats the reason.

200k on my milage <-----owned me real bad..... Probably need to change out a lot of parts, but gotta ask a mechanic though first...

Anyone here in Texas and know a good mechanic, care to recommend me one?

[alsalih]

Actually I'm also in the Dallas area however if and when I do take my car anywhere it would be Park Place Lexus of Grapevine. In this case, your solution is just what I noted to you earlier, replace your spark plugs with OEM NGK, you can get at a good price at O'Reilly auto.

[SRK]

I bought some BOSCH PLATINUM Spark plugs, maybe thats the reason.

←

So are you now saying that the problems started AFTER you changed the spark plugs? Geez, maybe that could be helpful information. If the problem did start after you changed plugs, maybe the trouble is the plugs and or the plug wires?

Did you happen to drop one or two of them on the ground before installation? Happen to check the firing end of the porcelain afterwards?

Of course if the problem existed before the plug change, and remains the same, ignore my post.

[itzdaviboi]

- UPDATE -

-Switch out the spark plug wires which is a pain in the &#33;Removed&#33; to do. Tested it out by driving around. Performance remain unchanged. Shaking, Rumbing sounds and underpowered still remained.

Change 1 one side of the distributor cap, Shaking, Rumbling sounds seems to disappear. Speed slowly picks up within 15-20 secs.

So I needed to change the distributor cap [both side] and probably rotate rotors [if that possible for a simple man like me]

Thanks everyone!!

[kcpth]

Hey... i just want to let u know that I am no expert mechanic. But this just my thought since I had some problems recently with my younger sister's boyfriends 93SC400.

Last sunday i helped him do a partial tune up. I changed the wireset and plugs. I suggested him to get NGK's which he did. He bought cheap-o wiresets... which i wasn't too happy about... in order to save him some money. He bought the Duralast brand which in my opinion was crap . I installed it for him... thinking it was new wiresets i shouldn't have a problem. He started the car... n took it out n it wouldn't even accelerate that much. As a matter of fact... it took him forever to get down the block... hahaha . It felt underpowered n was rumbling a bit too. When he came back... i tore it all apart looking for the culprit.

Then i remembered on www.lexls.com he mentioned that the wireset should have a resistance lvl of 25 ohms.... for our cars... if we can get a resistance lvl of 3ohm's that would b great. I checked the old wiresets... it carried a resistance lvl of 5-8ohms... so they were fine... n then i checked the new duralast... n they were pretty shot n pretty crappy. They had a resistance lvl of like 30+. Since some of the old wiresets were torn... i can only put back 4 originals n 4 new ones.

That fixed the problem tremedously. It now drives like it was back to normal before i did the tune up. N remember... it has 4 of the crappy wires too. He is suppose to be getting the NGK wireset today... so hopefully by the weekend i'll find out how much the partial tuneup would have improved the car.

Well good luck to u B) . If u get a chance... check with a multimeter n find out the resistance lvl on ur wiresets... n dont forget to reset the multimeter too. Again... this is my opinon.

On different note... i have a problem that came with the problem of changing the plugs n wires , he now has low coolant light showing up. We topped it off... but still comes around. Y is that? I dont believe it's leaking, n I didn't even touch the coolant when changing the plugs n wires.

[itzdaviboi]

Even though i switch out both of the distributor rotor and spark plug wiring, still underpowered. Must be something wrong with either the wires or the rotor. Something feels like its being misfired. At night on Nov 18. the performace dropped tremendously and I looked in the rear view mirror and see large amount of smoke coming from the exhaust. I swear I can smell gasoline.

After fixing a problem, new one keeps on coming...

[itzdaviboi]

My underpowered problem is fixed. I replace the Ignition Coil and check the firing system. Everything is 100%. The burning problem deals with my manifold though...