srikrishna

Hi,

My 2005 Lexus LS430 which has about 92k miles (yes low) stopped after driving it for 20 min or so in a parking lot. Both the check engine, battery lights came up. I tried to start it a few minutes later and it would crank but not start. This time also both the check engine and battery lights came. After a few days I tried to start it and it started like a champ. This is the first time it did that. I took it to a repair shop and they are running diagnostics. Searching previous posts I have this info:
1) It could be either timing belt, alternator and fuel pump.
2) Since it started I am suspecting fuel pump.

My questions are:
1) Is it fair to suspect the fuel pump? The posts said it's too low miles to have fuel pump give up but this is experiential so could be just this case or age?
2) Do we suspect the fuel pump circuitry (more likely with age) and if so which ones, fuel pump relay (doubt it as it started), TPS, MAF etc.?

Any other suggestions welcome...

2KHarrier

Fuel pump is a slight possibility, however they are very robust. Perhaps something in the charging system or battery? Maybe a latent smart key issue?

Johnhav430

Just any old car I would wonder about electrical right off the bat.....I did notice on my car, when I replaced the battery with one I bought from Costco, my negative post was not snug, even with the nut tightened all the way down....I had to "reshape" the cable terminal if you will.....

I have never tried it myself, but my understanding is a vehicle cannot run without a battery, and of course the charging system can be damaged if the battery is bad....meaning I would never simply undo the connections with the motor on. On mine, I observed the igntion going off and on when I jiggled the cable, with the key but not the motor on...

Gronemus

First off, welcome to the forum.

Without the codes from the OBD system its really difficult to give you good advice. Ask the shop if they have retrieved any codes yet. I can confidently tell you it isn't the timing belt even if you might be due for one. I really doubt that it's the fuel pump also. First thing that I would have looked at was to get the battery tested but since it's already at the repair shop that bit of advice won't help you now.

How old is the battery?

srikrishna

The battery is about six months old but is a Walmart battery. It failed in the past after 2 years and had it replaced this Summer for free. At that time AutoZone did an alternator test and said it's lower on volt/ampherage but turned out to be incorrect as later test showed nothing wrong. I asked the shop to check the electrical system of course. They came back and said it's the fuel pump. It passed pressure test initially but failed after running it for hour and half it seems. I can get codes if you suspect something else. Thanks for all the advice.

srikrishna

BTW if it's battery it would not stop a running engine cold and start like champ later, does it? I think it all falls in place when they reproduced it, at least that's what they said. However when it first dropped dead I only drove 20 minutes. Also after it dropped dead when I restarted it cranked fine but engine simply didn't turn engine on. Thanks for warn welcome...

srikrishna

Thanks for warm (not sure why my phone changes it to warn) welcome....

05ls430518

iTrader: (1)

Your battery is used to start your engine while the alternator is what keeps electricity going to the motor and replenshises the battery as you are driving, if you have a bad battery the car will stop running eventually due to to much load being placed on the alternator and the alternator inability to supply the electricity.

When the car died and the battery light and check engine light came on did the entire dash light up like a Christmas tree such as when you turn the car to a.c. power to listen to the radio while the motor is not running?

Another thing it could be is how is the ground on your battery these cars are super touchy with the ground i know this first hand even if the terminal is on and loose the car will start not start sometimes and will die after starting. I discovered this after my alternator died and I was doing a start up test to make sure everything was hooked up properly and the new alternator was not defective.

rkw77080

Do you remember if your tank was near empty during that 20-minute drive? The LS430 has a submersion-type fuel pump, and running on near-empty can cause the pump to overheat.

Based on your description of the problem, the pump motor overheated after the 20-minute drive and the protection circuit shuts the pump off. You tried to re-start the engine but with the pump turned off, the engine cranked but would not fire. After a few minutes once the pump cooled, the protection circuit reset, and you were able to once again run the engine normally.

A "healthy" pump motor should not overheat easily even if the fuel level is low, but with a failing motor, or possibly a clogged filter, overheating can occur. If such is the case, the pump motor and filter should be replaced. Check out the link below for additional discussions on this topic...
https://www.clublexus.com/forums/ls-...fuel-pump.html

coug66

http://www.import-car.com/step-step-...p-replacement/

I followed the threads, I am so happy to hear that Toyota has an easy replacement of the fuel pump!!!

I just did my wife's Yukon and I cut an access hole, It seems like a factory access hole makes so much sense.

This turns a couple hour job with challenging access into an easy access job and no jacking the car up and crawling on the floor.

srikrishna

Thanks for the input. The mechanic came back and said it was the fuel pump. They ran the car for hour and half and it stopped. At that time the fuel pump failed pressure test. So it was replaced. I then had him test the electrical system (based on this and other threads) and he said the only thing defective was the alternator. It was cranking hardly 13.2 V it seems. He said they inspected the alternator and the copper was disintegrating so he suggested replacing that. I approved that too thinking lower voltage could hurt other things. Now that it's all done we'll see how it goes. The whole thing sounds unlikely as the car has 92k miles (from what I read) but I don't have direct experience so trusted the mechanic. I asked him to keep the old parts and I'll send pictures so it would help me, others etc.

Thanks
S

srikrishna

BTW the tank during all this was almost full.