Ls400 Cranks, Turns Over, But Shuts Off Immediately

[whiteout1990]

I just replaced my water pump, timing belt, thermostat and radiator in my 1990 lexus ls400 due to overheating problem. Drove it to oreillys just fine, let it run for a few minutes then turned it off. I then started it pulled out onto the main road and not even a minute later the car just shut off. I pulled over and tried to start it and it cranked up and turned over for about a second and just shut back off. Tried again and it started so I tried to drive it and it shut right back off 15 seconds later. Now everytime it just cranks, acts like it's turning over then shuts off. It was running fine after I had replaced everything so I know it's not the timing or spark plugs, need help please.

[sha4000]

Well if it's not the timing then you have to make sure all hoses and connectors are on correctly and the battery has a proper charge.

[Daniel091]

Make sure your wiring harnesses for crank and cam sensors are not rubbing the accessory belt.

[whiteout1990]

Would it not be something to do with fuel pump? It's not getting enough gas

[landar]

It could be the fuel pump but since you just did the timing belt, check all of the connectors that you removed and make sure that they are all properly seated together.

If you think it is fuel, spray some starter fluid into the intake snout when trying to start and if it does, you have a fuel issue. If it does not help, then it is most likely electrical.

[whiteout1990]

Thanks for all the information guys. I looked all day and replaced the fuel filter just because it was looking real dirty, but it ended up being the fuel pump relay.. so alot cheaper fix then I thought.

[landar]

Good to know Dwight. Glad you found the root cause and got her back on the road. Thanks for posting the fix.

[Henry786k]

So I have a 1997 ls 400. I blew my head gasket so I ended up getting a swap with another 1uz engine with less miles. When the swap was done I  drove the car out from the mechanic shop and it was running for an hour and it just turned off on me. I towed it back to the shop and the mechanic put a new relay. The car was running for 15 mins and it turned off. Then he changed out the fuel pump because it was coming up. I got a new ecu and the old ecu wasn’t reading that I needed an ignitor for ignition OEM. I bought that part and installed it but my car just turns on and turns off. Can anyone help me out?