Drive it into a ditch?

[griff199]

Hey, new to the forum. I was really shocked to see so many people doing so much with the old Lexus LS400's!

I have a 1990 Lexus LS400 that I bought a few years ago for $2k.

It has:
237k miles
Sun baked front seats, center console "armrest".
Back seat leather torn from the kids that used to ride back there
Dull paint
Stuttering motor
Noisy electric antenna
Blown speakers (yep, all of them)
Bent rear control arm
Leaking power steering pump
LCD long gone on the climate control

All that being said, this car still starts every time I ask it to, and up until recently, had pretty good pickup. Lately, the motor stutters bad, especially at low rpm. Power is gone.

What would you guys suggest? I'm torn really. Should I put the effort into this one or just drive it into the ground? It's given me 50k good miles for $2k - the car owes me nothing at this point.

 

[jibbby]

Try a full tuneup first if it hasn't had one in a long time.....Change the spark plugs, caps and rotors, wiries, air filter, clean the throttle body, clean the fuel injectors, etc.. If the power is really bad and feels like a few cylinders aren't firing it could be that you have a bad ignition coil and or spark plugs..

Idle is poor and sluggish at low idle and out of the gates then maybe try cleaning out the throttle body and changing the air filter...

That's what I would do first.... Is the check engine light on?

 

[griff199]

The check engine light is not on, but it lights up at start so I know it's not burned out.
I recently changed the spark plugs and air filter, but did none of the other things, advance auto parts wanted $212 for a wire set - hard to swallow 10% of the price of the vehicle on WIRES!
It also has some blow-by, which I mostly notice at start. Seems like it's a crap shoot, sometimes when I start there's a big cloud of smoke, sometimes not.

 

[jibbby]

I think Ebay has a Lexus wire set for around $100 or so...Don't know if they will hold an adequate electrical feed though...Ebay specials are sometimes hit or miss... My D/S brake rotors were hit off Egay and they were a no namers brand too..

It still sounds like you still need a basic full tuneup and throttle body and injector cleanup... Good luck...

 

[griff199]

Should I change the timing belt at this point as well?

 

[jibbby]

It's timing belts and yes if it's been over 100,000 miles since they were last changed it may be a good idea.... However, The new timing belts won't make the car run any better if that is what you are after..

 

[cribbj]

Umm, there's only a single timing belt, John. And it can help the car run better if there's too much slop in the old one, and the timing isn't accurate anymore.

And if it's so sloppy it may have jumped a tooth and the engine is running like cr*p, replacing the belt will make the owner think he's got a brand new motor again.

 

[jibbby]

Ooops brain freeze, my bad...Of course it's one timing belt on the 1uz's...I guess I was half asleep on that last post...Thank you John..

However, I must disagree with you John on changing the belt and how it can affect the way the car runs..In most cases there is not much slop or play to throw off timing when changing out a used belt on 1uz-fe motor.. I know this because I had a used dealership for years and must have changed a dozen timing belts out on a dozen different sc400's and ls400's...Not one time did they run any better after a timing belt change... That is my experience with timing belts and these motors...I also always changed out the water pumps at the same time because I didn't want the cars breaking down on my customers within a few months.. Repeat business was always important to me and I didn't want to sell a bad product either.....

If the belt is severly worn out and stretched then of course a change would effect the way the car runs and it's timing but that is not usually the case from my past experiences.....

 

[1UZPWR]

i'd say start with the spark plug wires. Over time, they get brittle, and in changing the plugs, you probably weakened them. Honestly, I'm surprised it didn't start running bad the first time you started it after doing the spark plugs (unless it was already running badly, or it did start acting up right after you changed the plugs).

 

[XR8tt]

Do an ECU scan? The engine sensers maybe deffective ...
02's are realy like spark plugs, they need changing every 80,000 or so...
Often the coolant, inlet temp sensers fail ??
Check correct thermostate as efi engines run rich when cold...

 

[jibbby]

i'd say start with the spark plug wires. Over time, they get brittle, and in changing the plugs, you probably weakened them. Honestly, I'm surprised it didn't start running bad the first time you started it after doing the spark plugs (unless it was already running badly, or it did start acting up right after you changed the plugs).

Curious? Why would the car start running worse if you changed out the spark plugs and not the wires? Unless the plugs were not gapped properly I don't see that happening.. Maybe you can create a non firing effect in one of the cylinders if you create a non contact point with one of the brittle old wires but again not likely and that would be so obvious... Still changing and gaping the plugs is always a good thing to do if the old ones are in bad shape, wires too if old...

What I did to really get my 1uz-fe flowing electricity effectively throughout was to do this...

- change plugs and wires
- change both caps and rotors
- change out battery to deep cell..
- change out ground and positive battery cables and added copper battery connectors
- Rebuilt the alternator
- Added a battery voltage stabalizer...

My goal was to make the electrical flow like new, but this is taking it to the extreme........What I got is crispier throttle response, no more dimming of the head lights at idle, etc.. It really made a noticeable difference as I did that all at one time...

 

[Zuffen]

Jibby,

The wires become brittle and you break the core when removing the wire from the plug.

You can't see it but it shows up on a meter.

It is quite common for a new set of spark plugs to make an engine run worse because the leads have been damamged whilst fitting them.

This isn't so common on pushrod V8's because the wires hang over the rocker covers and are easy to remove from the plugs.

On OHC engines the wires are under covers and run through clips etc. Just getting the plug lead out of the head can be enough to kill it.

 

[jibbby]

Zuffen, Well if that's the case - the blame should more then likely fall on the mechanic or person doing the job..

I have installed many spark wire sets in my life time and maybe once or twice broke the tip core of the inside of a spark plug wire (new and used) and when it happened I new it every time..During install you can feel and hear a click as the back tip of the spark plugs sink and slides into place with core and wire end... If the wire is brittle and core breakage happens upon removal the core end tip that broke off usually sticks to the back end of the spark plug and you should clearly be able to see that if that's the case....So if you have decent mechanical skills you should know if the spark plugs and wire sets have good connections on a stock and daily driven SC400.. You should also give it the wiggle test to make sure there is a firm connection between the two.. If the wire core breaks during install then there is more then likely going to be alot of wiggle and play where the connection should take place also.. Another way of confirming good connections..

If it did happen (spark plug core wire breakage) and you missed it during install, I would have to say more then likely the motor will only be firing on seven cylinders rather then eight and you would have to a moron not to notice that immediately too..

Zuffen, however I do see your point as that can happen, and a weak spark plug connection would make the car run a little funky... Thanks..

 

[XR8tt]

Check body to engine, battery connections also...
If fireing order is right ? It's quite possible to have new deffective plug ?

 

[jibbby]

So Griff what's the verdict?

Are you going to try and fix it or are you going to drive it into a ditch and collect the insurance money?

 

[Zuffen]

Jibby,

How many times have you removed the spark plugs from your UZ?

A Chev 350 is a walk in the park by comparison and the plug leads will survive the odd remove and instal.

The "wriggle test" as you call it is just the thing to destroy silicone wires.

 

[ed_ma61]

jibby - its not the 'plug' is the 'wire'... jiggle does nothing but fuxxor the wire... moreso

$10 says you couldnt tell a buggered wire from a new one by feel

 

[jibbby]

Ed speak English....No comprehende senior...

Zuffen, I have changed the plugs on a 1uz-fe motor atleast a dozen times in my life time.. It worked out great for me every time and never had one problem... Deep wires, removal of the plastic spark plug engine head covers, etc..Yes Zuffen the 350 Chevy is a walk in the park compared to the 1uzfe's..

The wiggle wire plug test did apply more so on the older Chevy's I worked on in the past, good eye and point there Zuffen... I was really generalizing on that statement.. The older Chevy's have a completey different wire set housing and fit with the plugs when comparing them to the 1uz-fe's..

The 1uz-fe's have a long gated wire end which sinks in the head and spark plug hole to meet with the plug.. I would sometimes give each wire a good pull and tug to make sure the connection between the plug and wire cores were solid...You can do that or you don't have to, it's just another way to insure proper connections... Maybe the pull term should have been used and not the wiggle term when talking just about the 1uz's.. Chevy's and Fords wiggle does apply..

So technical gents.... Hmmm, I think we all know what I was getting at?