CLRH2O

I own a beautifully maintained full service record "Preferred Customer" Lexus of Ft. Meyer's (Florida) Single owner garage kept 1993 SC400 with an intermittent starting problem. (whew, that's a long breath innit?!)

The one key point to my experience is that EVERY time (this is without fail) the car has a problem starting, and fails to start - the in dash digital clock is reset to 1:00 o'clock. What this tells me, is that it's an electrical issue most likely relating to GROUNDING. Since I have searched and searched and asked and begged and pleaded for a full engine ground wiring schematic here on the forums for months (in other existing threads first of course) - and no one either has one or is willing to provide one... I'm likely to just buy an after market grounding kit and follow it's instructions in order to locate the myriad grounding points spread high and low through out the engine and engine bay of the 1uz-fe.

It might also be useful to note that in my case, the car will always eventually start. Either on it's own power or with a quick jump. It's just the first few times it wont start if it's feeling cranky.

Otherwise it starts and restarts 5 or more times a day for weeks on end before a fit of 2-3 days of this bullox before going away again for days and days and days. This btw has been a constant since I bought the car in Oct 2006 from the Mercedes Dealership here in Tampa.

The battery is new and OVER rated in terms of cranking amps for the needs of the Lex (but it's not the incorrect battery for this car of course) with sparkling clean terminals and brand new (replaced 2 months ago by myself) wire end hardware at the battery side.

So..... what do you think?

sc250tt

is it turning over?

CLRH2O

Always turns over... but on the times it fails to start and it resets my clock, the cranking is slow / sluggish then slows until stopped and all lights, and other electrics go dead or go very very dim while the key is still pressed to the start position.

At that point, when I release the key from the start position, everything turns back on to normal electric levels (dash, radio, fans ect) and the clock is reset to 1:00. If I continue to try to start the car with more attempts, on average after another 2 go's and it almost always fires up... But I have wait at least 30 seconds after the first failure to try those next few times or it's just a repeat of the first non start fail.

And here is some additional info about when the car wont start up on it's own after multiple attempts: If I need to get a quick jump to turn it over and start it up, I notice that the negative cable and negative cable lead connected to the battery are so hot they would easily severely burn you if you touched them. (found out the really REALLY F'ING hard way the first time and have an angular smooth scar to remind myself forever more about it..)

This of course is why I don't hold the key in the START position for very long if it's not just firing right up. Last thing I need are melted cables or worse an exploded battery in the engine bay.

I'd have thought that this would be a bad battery, but it's brand spanking new and over rated for my cars cranking needs. I've also had it checked (at 3 different stores, Napa, Autozone and Discount) along with my Alternator (at only Autozone and Discount on the alt) with the rolling unit they have. Both check out.... Which all brings me back to the grounding possibility.

What do ya think?

sc250tt

sound like your ground wires man .there is 3 for the engine
1.on the firewall behind the engine
2.on the tranny/bellhoushing
3.the battery cable connecting to the chasis
you should get some sand paper and clean the grounding points and/or replace battery ground wire

CLRH2O

At one point some number of months ago I stopped by the Toyota parts department and asked if they sold the ground wire loom for the 1uz-fe when I was first exploring the possibility of the grounding being the culprit. I was told yes, and no - yes I could buy it - but that I had to buy the ENTIRE ENGINE WIRING HARNESS.... which subsequently he quoted me a price in the 3000+ dollars range for.

Needless to say I don't have a new wiring harness and loom for my car right now

So, if I do have to replace the negative battery cable it's self, then maybe an actual after market grounding kit it's self would be the order of the day yeah?


Also, and this is a lastly; what makes you think I'm right on all this. Granted I think I'm looking toward the right direction, but there again I'm not certain of it - which is exactly the reason I'm here asking this question in the first place

over40driv

I would like to buy an aftermarket hi-perf. grounding kit as well.

mkorsu

The intermittent electrical signal (ie clock resetting followed by the car actually starting) points VERY strongly to a grounding issue. I doubt you're in need of a new loom as much as you may just need to claen each grounding point. Make sure each location is free of grease, grime, & paint. Reattach wires.....should be good to go.

mitsuguy

iTrader: (2)

quick question... what type of terminals did you use? mind taking a picture?

I have seen people do their own terminals, and some are very badly designed...

are they the ones that are red and black, have two 8/10mm bolts that hold down a metal clamp? if so, I'll bet that is part of your problem... what happens is the paint gets on parts that shouldn't be painted, like inside the terminals, in the groove that you put the cable itself, and inside the threaded holes... I bought a set of these myself before I realized their shortcomings, and modified accordingly...

mitsuguy

iTrader: (2)

no need for aftermarket wiring loom - just go to a car audio store and buy some 4 and 8 gauge wire and wire ends... essentially, you would want to reattach the battery to ground (I used the shock mount bolts), and then jump to an engine ground (any nice sized engine bolt), then some smaller wires to go to anything else that something electrical is attached to that uses a ground...

over40driv

As important as grounding is, I would still like to here some positive feedback on custom fit ground kits.

mitsuguy

iTrader: (2)

SCC made like 15 wheel torque on an older stock Talon TSI a few years ago with nothing more than a grounding kit... granted, I've owned many dsm's in my day, and the electrical systems were definitely not the greatest to start, and after 15 years of corrosion and deterioration, it might have been nothing more than restoring it to stock grounding, but, I feel it's a worthwhile mod that can do no harm, and is fairly inexpensive if you do it yourself...

CLRH2O

Well, this sounds like the ticket for me then. I get great pleasure out of working on all of my cars (I'm a record label owner, music producer and graphic designer - so working on real physical items is kinda my *zen* outside of everything I guess) and this is most certainly something I should be able to accomplish.

I've snapped a few shots of the terminals. They are full metal, but who knows - I'm more than happy to show them to you in the chance they have anything to do with the scenario.

Ultimately finding a resolution to this problem for me will fill other's needs in the present or future who have the same problem. So the more info all around the better right?

Mitsuguy, here they are:

over40driv

CLRH20 not to skip your question, I am a starter and alt. rebuilder, and for the problem your describing, I would start by proffessionaly testing the battery first, then load test the pos. and neg. main battery cables with a carbon pile load tester. If you do not have acess to the tester, I would start by repl. the cables one at a time after you first clean all connections.

markesc

iTrader: (2)

I have an SC300, mine starts everyday, but always takes alot more cranks than anyother cars I've owned (I've had some pos cars too!). I'm guessing a grounding kit would cure this problem? I have new termanals and the battery is strong as well...this has just been an ongoing thing for the past 3 years I've owned the car...

Supra Dr

iTrader: (14)

You dealer is incorrect, try a different dealer or one of our vendors here.
Replace the battery ground cable. Clean the bolt hole on the frame & the
engine block w/ a wire brush or a thread tap. Also clean the bolt threads.