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CanadaCraig

Any Idea What It Might Be?

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Hi Guys!! :)

I hope you're having a great day!!

Can you believe it? I still have my 1993 LS400.

Trouble is - she's not doing to well.

It all started a few weeks ago as I was driving away from a friends house. The moment I pressed on the brake pedal the headlights dimmed to nothing and electrical power to everything was cut off. [To the point where the clock would reset to 1:00] The engine would have stalled [The RPM's dropping to around 200 or so] if were not for the fact that I immediately took my foot off the brake, shifted into neutral and pressed half way down on the gas pedal. The plan worked. The engine revved up and the lights became bright again. But every time I braked after that - the same thing happened. I was on a dark, winding road [About 2 AM] where I would normally have to use the brakes a lot - so I downshifted to 2nd gear and tried to keep the speed up to around 40 km/h or so. [25 mph] After about 3 minutes - I had to use the brakes again. But this time - everything was fine. The lights stayed bright and the engine rpm's didn't drop. There was no threat of stalling. And it stayed that way all the way home - and for the next a couple of weeks. Then it happed again just as I was turning onto the street where my brother lives. It was fine up to that point but all of a sudden - the moment I pressed on the brake pedal - the car stalled. [it took me by surprise] I quickly shifted into neutral and started the car. I braked again - it stalled again. Fortunately I was only about 200 feet away from where I wanted to park - so I started and stalled my way to the front of my brother's home! I tried to start the car a few hours later - and the same thing happened. [Although this time the car was parked and IN 'Park'] As soon as I pressed on the brakes - the engine died. So that was that. I had no choice but to leave the car there. A couple of days later I tried it again. This time - other than hearing something that sounded a bit like a 'short' - nothing happen. It was dead as a doornail. So I disconnected the negative battery terminal cable and walked away. A week later I called BCAA [AAA] and had them tow it back to my house. A few days after that - on October 4th, 2010 - I reconnected the battery cable and took note of the fact that the dome light was bright. But as soon as I tried to start the engine - I heard that 'short' sound again - and everything was dead. [including ALL interior lights] So I got curious and wiggled the battery cable. As soon as I did - the dome light came back on. And this time - the car started. And it kept running. [With a little help from the gas pedal] So after a couple of minutes - I eased up on the gas pedal and noticed that the idle speed was dropping fast - hovering around 200 or so. But it didn't stall. So I revved it up some more. I then tried the headlights - fine. I even pressed on the brake pedal - fine. The idol was low and irratic - but it didn't stall. No matter what I did with the brakes or power window switches or anything else - there was no threat of the engine stopping. All lights were bright. I'm still not willing to drive it - because I need to know what the problem is.

Any ideas?

I am quite seriously hoping that it is not what I have been fearing - an alternator being destroyed by a leaking power steering pump. [The PS pump was replaced about 4 years ago] And I say that because if it is - according to my local Lexus dealer - those two parts - put labour - plus HST tax - are just under $3,000. [$2,840 to be exact] The entire car isn't worth much more than that.

Some websites have mentioned an IAC or a brake booster as a possible cause. I'm hoping it just needs a new battery cable. [And a good wash! lol]

Any help would be very much appreciated.

THANKS

Craig!! :)

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I just skimmed over that because it's a ton to read this early in the morning.

Check the alternator for fluid intrusion, it's pretty easy to see from the top and bottom. If so, it's shorted out, common and as you mentioned something you've already done, but I'm betting they never replaced the idle up valve on the power steering pump, which is the main culprit. If so, remove and plug the valve, pull and have the alternator rebuilt. You won't pay more than $200 total and be back on the road. There is no need to have Lexus do the service or pay Lexus new part prices.

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Hello CanuckCraig,

Beautiful place up there in BC.

Sounds like two issues to me.

1) Loose battery connections. Take them apart, clean them up with a wire brush and re torque everything tight. You should not be able to budge a battery lead either at the post or at the other end of wire. This explains your electrical issue. You neighbors in Saskatchewan know this as starting their cars in -40 degrees requires every ounce of current to get to starter motor.

2) Stalling engine might be your PS brake vacuum booster. Maybe it has a leak and when you apply brake you are creating a large intake manifold leak and leaning out the engine, hence the stall. Maybe disconnect vacuum line to brake booster and plug it up. Then see if engine runs smooth with or without brake pedal depressed. I would't drive it like this as brakes will be very weak and pose a safety hazard. Just do it in the driveway as a diagnostic.

3) Double check brake electrical circuit fuse and make sure someone hasn't replaced the fuse with a higher value one to compensate for some sort of short in the brake light circuit. I think this is unlikely because if a brake light circuit were enough to stall engine (IE load up alternator) then other things like headlights and blower motors would too. Anyway its easy enough to a do a quick check

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Have you ever checked or repaired the trunk wiring (chafing issue) that is common to this vintage?

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Hello!! :)

I checked everything out - seems OK. The wires in the trunk seem fine. The PS fluid reservoir is full. [At the level it should be] And I saw no signs of it leaking or dripping. As of this minute - it seems as though the problem was/is caused by the negative battery cable. After I sand-papered off any signs of corrosion and dabbled a little Petroleum jelly everywhere - the car started GREAT. [it didn't start off on a high idle - which puzzled me - but it sounded and felt fine] Trouble is - the head of the bolt on the negative cable end [The metal part that goes over the terminal] broke off - now I can't tighten it up. Grr.... Truth be told - all I had to do was giggle it off. And it was a 'screwed on' as can be. So I wonder if the terminal on the new battery that I bought a few months ago is smaller in diameter than the OEM [Lexus dealer supplied] one that I had in there before. Hmmm. What could I do about that?!

ANYWAYS....

TWO QUESTIONS:

Can a person buy just the metal part that goes on the terminal? I see positive ones for sale - but no negative ones.

And IF you can - could you tell me how to re and re it?

Thank you very much,

Craig!! :) )

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Just go to CanadianTire auto department. They will sell several types of battery clamp replacements. This is a common problem.

Also cleaning the surface with sandpaper isn't helpful. You have to clean the mating surfaces which might be what you meant. In the end battery connections cannot budge. You're pulling hundreds of Amps over this connection when starter is engaged. That requires a very tight mechanical connection, just touching isn't good enough. Torqued down and immovable by hand.

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Hi,

I can't understand why you cannot find the negative battery terminal

Loads on Ebay

http://shop.ebay.com/i.html?_nkw=car+battery+terminals&_sacat=0&_odkw=battery+terminals&_osacat=0&_trksid=p3286.c0.m270.l1313

Hi Steve!! :)

I appreciate the link.

Not sure why couldn't find a negative battery terminal. I guess I assumed [Like practically everything else on the LS] the battery cable end had to be Lexus-specific.

Is 'terminal' the same as 'end'? [As in 'negative cable END'?] Even in this one message thread there seems to be three names for the exact same thing. 'Terminal', 'end' and 'clamp'. Are they the same thing?

Craig!! :)

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Hi curiousB!! :)

THANKS!!

Two more questions.

- Are the 'clamps' truly universal? How would I know which one I need? The battery that's in the car now actually came from CanadianTire.

- What sort of tools would one need to replace that 'clamp'?

Thanks again,

Craig! :)

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Thanks again.

:cheers:

The car is running fine again [Knock on wood] and it only cost me $4.99 for a new 'universal' negative battery cable end. After getting everything done - I reset the clock - entered the radio security number - and drove around for about an hour or so. It was fine. In fact - it was better than fine. Thinking back - I remember noticing how the headlights would dim a bit whenever I touched the brakes. Now the lights don't seem to dim at all.

Craig!! :)

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