TheOneChen

Hello everyone, I just finished replacing the fuel pump on my 1991 LS400. However, I am still having a problem starting my car. I know the fuel pump works because I can hear the fuel surging under the hood every time I turn the key to crank the motor. I even bridged the B+ and FP pins in the diagnostic port under the hood to make sure the fuel pump is working, and that I am getting fuel into the engine. However, the engine will not stay running. Whenever I crank the motor, it will come on for a split-second, rev to around 2000 RPM and then die. Could someone please tell me what could be causing this?

TheOneChen

Ok, today I worked on the car a little bit more. The engine will now occasionally run for a little bit longer, more like around 3 to 5 seconds, and then it will die again. This happens every time I use the deflooding procedure, by cranking the car a few times with the gas pedal all the way down on the floor. I also did some diagnosis, and I got code 13 from the check engine light, which has to do with "RPM signal 2." Could someone please help me with this problem?

TheOneChen

I don't know if this will help, but I also want to add that stepping on the gas pedal doesn't keep the engine running at all. Sometimes, it seems like stepping on the gas pedal actually kills the engine even faster.

TheOneChen

Ok, I pulled the relay under the hood labeled "Main Engine Relay," tried to start the car without it, and it did the exact same thing. I was wondering, since the car displayed the same symptoms without this relay, if this might be the problem and the relay is bad. Also, the EFI relay (not the fuse) seems to get pretty hot whenever I try to start the car. Is this normal?

TheOneChen

I was also wondering if the problem could be a bad alternator? Every time I try to start the LS400, it has been by jumping it with my other car, because the battery in the LS400 is dead. The guy from whom I bought the car said the battery was new, but it has been dead since when he first showed me the car. Would a bad alternator cause the symptoms that I have described previously?

BIGBADDAD

have you had any luck yet?
I just came across this. Let us know where you are...as far as the car is conserned.
Mark

TJW98LS

iTrader: (1)

Autozone should be able to check your alternator...that is if you can get it there. But yes, that would cause similar problems.

BIGBADDAD

You do need a good battery, if your battery is fully charged the car will still run even if you alternator is bad, these cars take a lot of juice run. TJW98LS is right, you can take it to Autozone and have it checked. I wish I could be more help, but there are so many things it could be, this is one of those cars that I would need to meet in person.
Sorry.
Mark