'88 240 "vaporlock" symptoms - hot start problems

I posted the following message on the "Swedishbricks" board but this is
still unresolved, so I thought I'd try hear. Basically, the car has lots
of problems starting after a short ride in hot weather. Any help greatly
appreciated. See below, lots of other strange things!!

Joe

---------------
Dear Bricksters,

I've been away from this newsgroup for a long time, but now return asking
for help! I'm trying to diagnose a hard-start (usually when hot) problem
on my 1988 240DL wagon. It's driving me crazy -- car starts fine when it's
cold or dead of winter, but difficult on hot days and difficult/impossible
at times if car has been running and is then shut down and let to sit for
many minutes (also happens sometimes if I start up and drive a couple of
blocks and shut down).

I'm looking into the "fuel pump check valve", but before doing this I
decided to check the fuel pump relay. AND THIS IS WHAT's driving me nuts:

1) I can't be sure I've found the right relay. Behind the dashboard near
the steering column is a small (about 1inch cube) 6 terminal metal-box
relay. Could this be it?? It doesn't look at all like the pictures I've
seen on the Swedish Bricks web site. Also, I went to my local dealer and he
showed me what he said was the part -- a white plastic box relay which is
much larger than what I've found. WHERE ARE THE RELAYS on this car!!

2) This is where it REALLY GETS STRANGE. In trying to diagonse the problem
I pulled the in-tank and main pump fuses (4 and 6) from the fuse box
(located in the drivers footwell just forward of the door). THE CAR
CONTINUES TO RUN WITH BOTH FUSES PULLED!! I crawl under and the fuel pump
is still running!! Also, pulling the relay I mention above doesn't stop
the pump.

I'm looking to talk to anyone who knows where things are on this car and
what normal behaviour is regarding the fuel pump and fuses. I'm totally
baffled as the why the car continues to run. Also, if I did have a relay
problem wouldn't the car sometimes die when running?? It has never died
when running, only very difficult to start particularly when hot.

Thanks,
Joe


--
Joseph P. Levantino
Quality By Design - "One Call Does it All"
Complete Home Improvements - carpentry - ceramics - painting
732-747-1974

 

On an 88YM the fuel injection combined relay is clipped to the floor
carpet bracket forward of the floor duct and above the underdash mat on
the passenger side of the car.

Once the computer latches the relay "on" the power feed is through the 25
Amp fuse under the hood.

Either the fuel pump check valve on the main pump is faulty or the
prepump quits after running for a while.

Bob