lex8000

188k 93 LS400

After driving the car during a particularly hot week the car sat for about 2 hours then wouldn't start. Next morning same behavior. I had it towed to my mechanic where it started right up. They kept it for a while and it never misbehaved. The car has no hesitation or stuttering issues; it really runs great. Mechanic said if I wanted to throw parts at it he could replace the fuel pump but he wasn't sure and other things could cause the behavior.

After looking up the fuel pump swap it doesn't seem too hard. I'm a somewhat decent DIY mechanic, just basic stuff. Does this sound like a fuel pump on the way out? If so, any gotchas on the fuel pump replacement I should be aware of or is it out of the reach of a basic DIY type?

Thanks in advance.

python

iTrader: (4)

ur joking right? ur actually thinking of throwing parts at it? these fuel pumps rartely go out..i mean rarely if ever. take it to a mechanic that knows what he is doing..do not take it back to wherever u took it

j2b4o

Could be a myriad of issues from the info provided...
I would atleas pop the fuel line off the rail and see if any fuel comes out while cranking if the issue re-appears. Quite a few members have had fuel pumps die but the symptoms are usually loss of power while around a quarter tank of gas on a hot day that is instantly remedied by getting more gas.

But before we go down that road .
Is there a CEL?
Have you checked for spark?
Have you done any repairs recently?
Do you have an aftermarket alarm?

lex8000

Good info about those symptoms. Those definitely were not mine.

-I *assume* they checked for a code but don't know for sure. It worked when the car came off the tow truck and they said they could not find anything wrong with it. I trust these guys completely but of course no mechanic is perfect.
-Right now the car runs fine so there is no reason to check for spark but if it occurs again I could do so.
-No repairs done recently.
-No aftermarket alarm.

Driving it on a very hot day it simply ran normally and would not start 2 hours later nor the next morning.

Speaking to a friend who knows old Porsches he mentioned pressure in the gas tank. My cap does let out a lot of gas when I open it to refill but it's never been an issue. Possibly related?

Thanks again.

3UZFTE

You need to find out if you have fuel pressure when you get the no start. I know it's difficult, but without knowing, your likely just wasting your time. You could have a faulty fuel pump relay, and it would cause the same issue of a faulty pump. I would bring it to a trust mechanic if it continues to act up.

rscippio

My 1993 ls400 with 279000 miles was running great very reliable. One day it just died while I was driving, I drifted to the shoulder and it wouldn't turn over like it was out of gas. After a few minutes it started and I drove it to my mechanic (had to keep foot on the gas and brake to keep it from turning off). Once I got to the mechanic the car actually was running normally. Drove home and the next day it died again and restarted 2 times Finally I had it towed to the shop and the diagnosis begins. To make a long story short after checking all of the usual suspects. It turned out to be a bad fuel relay pump fuse