bdruff

No previous issues while driving. I stopped for about an hour and then went to drive it again and it acted like it was going to die and had no power.

I had it towed home and left it over night while I read several threads. I decided to look at the fuel pump relay and fuel pump resistor. It did start and have no issues in the morning; throttle responded, idled fine. I shut it off after just a min but then it showed the symptoms again when I restarted it a few minutes later.

I was hoping to do it cheap and fast because this car has little value. The junkyard had a 96. My resistor measured 1.1(Off the car), and I read that spec was between .6 and .7 rounded. I assumed the resistor was bad but the resistor off the junkyard ls400 read exactly the same. (I know that it could be possible for that one to be bad also but not likely) I also swapped out the relay as both were easy and cheap.

Swapping each and separately did not help. It would start but idle erratically before dying. I tried to source the problem while the car was running for about 3 min, having to restart the car several times, but now, the car won't start at all.

I exchanged the resistor for the fuel pump and was going to swap that but it's a little bigger job so I have a few questions.

1. Is there a way to jump the fuel pump, bypass relay and resistor, on an obd-II model? The diagnostic box under the dash on the drivers side does not have a F or B+ port. Is there another box under the hood and where is that?

2. Can anyone confirm the specs on the resistor? My meter has different settings down to 20 ohms. It shows down to .01 on that setting. If both resistors show 1.2-1.1 and settle at 1.1, are they just possibly, both bad?

I think I'll wait to hear some feedback before swapping the fuel pump. It was easy to remove, I'm looking for suggestions also.

Thanks,

oldskewel

iTrader: (1)

I responded to the other thread too. Here's the relevant link with info for my 1991 (not OBD-II). I don't know how many newer years that covers.
https://www.clublexus.com/forums/ls-...ml#post9777959

Having recently been through a similar situation, symptoms, debugging, that you've been through, here's my guess and suggestion:
I would not worry about the resistor = probably OK, but yes, curious why both match exactly and appear to be a different spec.
I'd just replace the fuel pump. OE ones cost $300+, I put in a Denso for about $100, but if you really want to save some $$ and make the problem go away for now, you should be able to find China brand fuel pumps on eBay or Amazon for around $30.

bdruff

Fuel pump replaced. Problem solved

CaliLS

Sad that you had to go the expensive route, I was experiencing a similar issue. I had your symptoms exactly, it would idle rough and sometimes not start, but replacing the EFI relay in the box under the hood solved the problem.

bdruff

Tried the relay and resistor first. Neither fixed it