93 Ls400 Having A Hard Time

[Blk Blood]

hello people,

damn, I havent posted hear in a while!!

well it finally happened, after 3 years of almost flawless running(since i bought it) My car has *BLEEP*ed up!

I was driving about 35/40 mph when my car suddenly bucked and started running real rough. The car wont go faster then that anymore (40mph),

has rough start and idle. And has completely lost all electronics on the inside (lighting,acc. etc.) It had the flickering dash and sticky needles

problem before...

I read in a mechanics shop manual (ALLDATA) that in the event the PCM was ever to short or give out; that the car would run a back

up system with only the fuel pump active. (NO IGNITION TIMING OR SENSOR SIGNALS) which could explain some of these symptons?!?

Sound familiar to anyone??

I mentioned it to a friend and he said that he had heard of computers failing on these cars, but hes only a car salesman? Lol

THANKS for any help/advice!

[1990LS400]

What diagnostic codes? http://www.lexls.com/tutorials/intro/codereading.html

[landar]

FIrst check when lots of things go wrong simultaneously? Battery and all battery connections. Highly suspect.

[Blk Blood]

What diagnostic codes? http://www.lexls.com/tutorials/intro/codereading.html

THANK YOU FOR THIS!!! lol that is really interesting. i will do it right away when i get the car out for summer!

And yes, my battery is VERY suspect.. i did a load test on it and whilst bringing up the amperage to the cca, the Voltage dropped so low that is

shut off the machine!

Can i use a PCM from any 1st gen. LS400 or should i find one specially from a 93?!

[landar]

Can i use a PCM from any 1st gen. LS400 or should i find one specially from a 93?!

I would wait until you correct the battery issue and check codes before replacing the PCM. Your PCM may be fine.

[Blk Blood]

I know, i know Lol, just wondering!

But do you really think that changing the battery will fix this?? Im looking into the Optima yellow-top, but it might be tooooo pricey a battery.. well see!

THANks again !!!! g

[landar]

I know, i know Lol, just wondering!

But do you really think that changing the battery will fix this?? Im looking into the Optima yellow-top, but it might be tooooo pricey a battery.. well see!

THANks again !!!! g

The battery is crucial to all of the electronics. I am not claiming that a new battery will magically fix all of your problems but it sure is a leading candidate for the root cause.

You don't need any special battery. Just a $75 Exide, Energizer or you name it. Available at Sam's Club, CostCo, etc.

[VBdenny]

Costco has the Red Tops and Yellow Tops for $140. I have one in my truck and they are great. At the first sign of a bad battery, put in a new one. As others said, the LS400 is an electrical hungrey car.