drseth

Hi,

My mother's 1997 LS400, with 135K miles, would not start after cranking ten times one morning last week. I had the car towed, and the shop owner at first said it might be spark plugs, so some NGK Iridium plugs were installed, and still would not start. Fuel pressure within normal limits. A shot of starter fluid and she fired up.

Coolant temperature sensor, possibly?

Any ideas?

aptoslexus

Sure sounds like a fuel problem to me. When a shop owner fires parts at the car before diagnosing the problem, you're going to the wrong shop. Did you read the codes? There's gas in the car, right? And the pump is working?

Banshee365

First of all, you need a new shop. One that actually knows what they're doing.

Secondly, you have a fuel delivery problem. I would still be looking at the fuel pump and fuel pressure. They said it's good but I wouldn't trust that given their ridiculous 'diagnosis' with the plugs.

Losiracer2

It could be something ECU related since you said it had fuel pressure but it wouldn't start. Something related to the injectors I would guess is not making them fire.

I read in the ECU thread that one guy had an issue with injectors not firing and after countless hours if troubleshooting, it turned out to be the ECU caps leaking causing that specific failure.

If the ECU has never been inspected, it's most likely time to replace the 5 capacitors you need. They cost under $5 shipped from DigiKey...Ive purchased mine ahead if time in case the time comes.

Banshee365

Yes, the ECM is a very plausible possibility. At this point with these cars it's worth at least visually checking the capacitors when dealing with really any weird issues. I would still rule out the fuel pressure via a professional diagnosis process rather than what some half-rate shop has to say about it. Checking injector pulse would certainly be a good idea as well.

dicer

I'm surprised the shop hasn't installed some new injectors, caps and wires etc. with the new plugs. Maybe a new air and fuel filter, radiator cap, new hoses, serpentine belt and an oil change to fix the problem. Oh and a tire rotation as well.

Losiracer2

I wish there was some clause of holding these types of shops accountable, like if it doesn't fix the problem, then they give you back half the cost or eat the labor, etc. Someway of keeping them honest. Because ultimately, that's why the customer is there, to get a professional's opinion and diagnosis of the problem, any amateur can install new parts until you're basically out of money or fed up enough to move on and sell the car to the next person.

drseth

As it turned out, it was the Crank Position Sensor that had started crapping out. So, I got a set of spark plugs and a Coolant Temperature Sensor that I probably didnt need.

Anyway, it starts now ok. By the way, what uF/voltage capacitors are needed in the ECU?

Yamae

Following s capacitors are needed for 1995-97 LS400.
Qty. 2 of 10uF - 50v
Qty. 1 of 47uF - 63v
Qty. 2 of 100uF - 10v
Qty. 1 of 220uF - 16v

Be sure to use low ESR ones. You can find the details here.
https://www.clublexus.com/forums/ls-...capacitor.html