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Thanks for the info armyofone. I am waiting to see what Lexus wants.....no doubt a lot more. I have had so much fun doing this I may go to the wreckers and see what I can get. I doubt there are too many LS400's in the scrap yard though. Yeah the relay would have been nice. A 20amp fuse would have been even better :D Thanks for all the help everyone. Erik

Don't worry. The pump is out already. I put the cleaned up pump in the tank....the car started I knew the pump was the problem. I pulled it back out and am awaiting the arrival of a new one. I don't think I ran it for more then 30 seconds, just long enough to unhook the jumper on the diagnostic box and establish that the ecu worked. It won't be driven until the new pump is installed. It sounded pretty bad, I don't think it would make it to the end of the driveway. How much should I be paying for a new pump? Lexus is checking the price and availabilty for me now. Is their a better source?

Ok, It runs. I opened the bolts on the fuel rail and got nothing. I put a length of hose on the metal line inside the tank and blew air through it. It bubbled out at the rail so I knew the line wasn't blocked. I took the pump out of the tank and hooked it up to a spare battery. I could see the impleller spin at about 5 rpm and the pump started to smoke!! I took the pump off the bracket and pulled it apart. Inside it was full of gum and varnish. I soaked it in carb cleaner and worked the motor until it spun freely. I put it back together and tried it again. This time the pump spun fast, I popped it back on the bracket and put it back in the tank. Hooked up the battery and fuel sprayed everywhere at the rail, I tightened everything up and the car started. So it in fact was the pump. The ECU is fine, its running without the jumper on the diagnostic connector. The pump is noisy as heck now....I will have to buy a new one this week and put it in, I don't think my repair is long-term. Daffy: If you have never been in the tank I would suggest you open it up and take a look. I found at 350 000 there was no rust or gum in the tank. But the filter screen on the pump was glazed up, and some how my pump was full of gum. Thanks for all the input. :D

Sorry I'm new to this whole thing......Lexls I knew I should have typed that differently . I disconnected the yellow cased (pump) wire and tested the hot terminal (black wire). So with everything normal I get no voltage at the terminal the pump hooks to. When I jump the fp to the B+ on the diagnostic connector I get 12v at the back. The pump gave me 2.2ohms resistance, so its ok? I guess I have a bad pump ecu? (sorry for the following bad description) Now the "fuel rail" I assume to be under the black plastic covers on each side of the engine, just above the valve covers? There is a 14mm (if I remember correctly) bolt with alloy washers that has a hose hooked to it (like a motorcycle brake hose) just to the rearside of the engine lift hook on the passenger side of the car. This looks to be attached to the fuel rail? Should I crack this open and crank the car? Daffy: The car was running fine with no noticable noise from the fuel pump. It just wouldn't start one day. Pumps from the dealer look to be worth a couple of bucks. I would wait until it goes. If your lucky like I was it will die in the garage.

I guess I will pull the pump out this afternoon and test it. I can't figure why I don't get a voltage reading though. I have been reading that the fuel pumps last a long time. Theres only 350 000 on the car :D

Hey, I just found this forum and read a bunch of stuff on lextremes site (nice work). I have a 91 LS 400 that has had no previous problems until now...it doesn't start. I verified that there is spark. I reset the alarm and tested it out just in case that was the problem, it seems to work as normal. So I sprayed some ether in the air filter and got the car to cough and stumble. So I figure I have a fuel problem. I checked all of the fuses, both under the hood and in the kick panel. I checked the M4 EFI relay and switched it with the horn. I pulled the fuel pump relay and tested it with a 12v source - it works. With the key "on" and the yellow cased wire to the pump unhooked in the trunk I get no reading on the voltmeter. I also get no reading at the terminal where the fuel pump relay goes. I just read that I can bypass the fuel pump ecu by connecting fp to B+ on the diagnostic connector. This should give me a V reading at the fuel pump right? I will try this in the morning. Any other ideas or suggestions ? Thanks, Erik