jimisbell

This is the third time in six years that this has happened. Car is running fine then I park and when I com back it wont stay running. Will start \, run a few seconds and die. Battery is good, fuel in tank, Then after an hour sitting, it will crank and run and continue for a couple of years, then it will do it again.

What in hell is causing this?

Up till today it always happened in a parking lot. No big deal...but.....This time it happened in the middle of the main down town intersection and AAA had to come tow it away. I am sure that in the morning it will run fine again.
But this has to stop.

intermec

Have you tried to clean the MAF (mass air flow) sensor? My old Camry used to do that and I clean the MAF and throttle body, seems to help.

jimisbell

I will try that. The car has less that 95K on the clock.

The problem with a problem that happens every two years and then goes away before you do anything is that it takes so long before you will know if what you did actually helped. And all the time you are waiting for the other shoe to drop.

I once had a truck that has a piece of paper in the gas tank and every now and then it would float over the the fuel line connection and stop the fuel. After some cussing and waiting it would float away and the truck ran fine. It took years to find the problem. Another time I had a Cadillac Seville that had a plugged up fuel filter inside the tank. A couple of blows to the bottom of the tank and it would then drive on. That one was, at least, relatively easy to diagnose.

jimisbell

do you have any idea where the MAF is located on the 2004 LS430 ?

Jabberwock

Assuming no leaks and water issues that would be affecting electrical system like ECU, it could be a fuel pump or fuel pressure issue. Its important to get the stored error codes read when this problem occurs so you can get to the root cause.

jimisbell

After the car is running again, is it too late to get the codes??? Also is a fuel pump issue consistent with to "once every two years occurrence" and the immediate disappearance of the symptoms without any action?

Aus430

Without any codes present, the symptoms do seem consistent with lack of fuel.

Definitely worth starting with popping the back seat up and taking a squiz in the tank for contamination, or as you say something floating around in there. A quick look at the pump filters (I think there are two, a floppy bag and a cartridge) to be sure they aren't clogging up. Being a return less fuel design, the fuel pressure regulator is there too.

If everything there checks out mechanically, I guess next logical step is electrical....just maybe worth checking the fuel pump ballast resistor - which is the heat sink looking thing on the left hand strut tower in the engine bay. It gets hot under those plastic engine bay covers. As i understand it, it's function is to reduce the current to the pump at idle to make the pump run slower and hence quieter.

There is a check with a multimeter which is floating around in a post somewhere on the forum to see if it's working in spec (Sorry don't have the link handy as I'm typing on my dumbphone). The connector can also can be bridged which meaning that the pump always runs full current by bypassing the resistor altogether if the resistor is bad.

jimisbell

How involved is it to "pop up" the rear seat? I have the knowledge, to do the work (150+ cars in my lifetime)but no books on the Lexus and at 84, heavy lifting is out of the question. Nearest Lexus dealer is 240 miles away and I dont trust a "chebby" dealer to know what he is doing. Would probably screw up more than he fixed.

TominPT

The MAF sensor is located on the top of the black tube leading from air filter housing to the throttle body. Open the hood and look directly down slightly to the left. Its held on with a few screws and has a large electrical connector going to it. Go ahead and clean that with a MAF cleaner (I used CRC brand in an aerosol can), see threads here about how to do that. I doubt it will solve your problem. Fuel supply seems more likely to me. Aus430 has good ideas.

jimisbell

Stroke of very good luck. 24 hours later it still wont start. In the past it would always start after about an hour so I had no idea what had fixed it since I had done nothing. NOW I will be able to find out what the problem is. Tomorrow I start with the easiest one, cleaning the MAF sensor. Fuel is fine, 1/2 tank full. Verified by the mileage since fill up.

It was a good day...my car wont start!!!!!

YODAONE

Try starter fluid to determine if fuel related.

I have encountered crank position sensors that work when cold, then the engine stops running when warm..

Jabberwock

Recent error codes are stored and can be read for some period of time after a problem has occurred. Take it down to local national brand auto parts (pep boys, autozone, etc) and they can read the codes for free.

jimisbell

Well, if it had started this morning, like I expected it to, but didnt, I could have taken it to autozone. But with it in my driveway immobile it may be a while before I can do that. But I may have an OBD reader here somewhere if I can find it. If not it will have to wait till its running again.

Romanova

A dirty MAF should not prevent the car from starting. If the MAF had an issue, it should trip a code. That being said, I don't think cleaning the MAF will correct the no start issue.

As someone stated, using starter fluid can help to determine if it is a fuel issue or not. If the car starts briefly with the starting fluid, then you can assume that the vehicle is not getting fuel. If it doesn't start with the starting fluid, you might be looking to see if you are getting spark, or if there is a fuse for the COP circuit.

Checking for codes is great and this might be an easy fix, but on the other hand, you might get a code and end up firing the parts cannon at your car and still not having it start. Try the simple things and if it still doesn't start, don't be afraid to throw in the towel. Of course, we are here to help if needed.

Good luck and keep us posted!

YODAONE

Autozone should allow you to use the code reader, provided you leave a deposit.

Call ahead.

If deposit required, then use cash..in that way you get it back immediately vs 2 weeks if by credit card...