"Ian Field" wrote in
:


"Boris Mohar" wrote in message
...

Took apart a Volvo 850 fuel pump relay. Cracks everywhere.

http://www.viatrack.ca/Misc/FP%20Relay/


I thought automotive was exempt - after all you wouldn't want the solder
falling off your FI relay half way through an overtake.




Honda fuel pump relays have the same solder problems,have had them for many
years.
my 1994 Integra had it,I resoldered the PCB and it worked fine for many
years afterwards. I saved at least $50 for a few minutes work.

the relay failure mode was that on a hot day,the car would start
briefly,then die,and only crank for 15-20 minutes(no fuel pressure),then
the car would start and run normally(after the car's interior cooled
down).No further problem until it got another heat soak.
In the mornings,the car would start and run normally.

I think the solder crystallizes with age,then thermal cycling cracks it.

the automotive environment is very tough,hard on electronics.
lots of thermal cycling,shock and vibration.

--
Jim Yanik
jyanik
at
localnet
dot com