Hey all. I apologize in advance if this has been covered before. I did some searching and couldn't find anything that specifically related to my problem.

I bought a '92 LS400 a few months ago, and up until now it's ran absolutely flawlessly. However, last night I was driving it, sitting at a stoplight, and the car just shut off, completely out of nowhere. I went to start it back up, and it just cranked and cranked. I waited a few seconds, tried again, and it fired right up! Strange, I thought. No CEL's or anything out of the ordinary displaying on the dash.

So I started driving, about 200ft down the road, the car shuts off again. I coasted to a stop, went to start it back up, and it started no problem. One of the guys in the car with me is a Volvo technician, and he's also my mechanic in general. He un-plugged the MAF and told me to start it up. It started, but of course didn't do anything if I tried to rev it. Plug the MAF back in, the car goes back to normal. I shifted to drive, went to give it gas, and it dies. I go to start it back up, just cranks and cranks. Wait a few seconds, go to try again, fires right up.

At this point I parked the car, but left it running with the hood up. My friend put his hand over the fuel pump relay and had me rev the motor. At first it was revving just fine, wasn't missing a beat. Finally I floored it and it died, and when it died he said he felt the relay click like it was trying to do something. What's strange though, is the car is either on or off. It doesn't sputter or choke, just shuts off as though it were on a switch.

I recently did a big tune-up on the car. Replaced the plugs (NGK Laser Iridium), Wires (NGK), Caps, Rotors, Fuel Filter, Air Filter. Also, the car had a full tank of gas while this was going on. Any help would be greatly appreciated. I really hope this problem isn't ECU or MAF related, because I'm broke as a joke. Haha.

 

I own a 1993 ls400 and am experiencing the same problem as you. Please tell me what the solution to this problem was!
Kindest regards!

 

I would imagine the ECU controls the fuel pump relay. So when it clicks, it's probably shutting off due to something the ECU is receiving (or isn't)

Does it click as the car shuts off? It would seem as if the ECU is shutting the car off for some reason. No fuel, no run.

 

Hey, thanks for the reply Jason.

I actually found out what the problem was, I should have posted earlier. It ended up being the 20 amp fuse on the ECU main relay circuit. It's called the "EFI fuse". When we went to pull the fuse, it was really hard to get out. Once we got it out, we noticed a lot of corrosion on the blades and on the inside where the fuse plugged in. We cleaned things up, replaced the fuse, and I haven't had an issue with it since. That connection was going bad, and the ECU wasn't getting power, which was obviously making the car die.