Fuel pump relay

I finally tracked down my intermittent no start condition on my 92 prelude
Si. If it is a hot day (90+), the car needs to sit until cool or it won't
start. For some reason it wouldn't start today when I tried to start it
this afternoon after it sat all day in the afternoon sun. I put my fuel
pressure gauge on it and it read zero. I tried tapping on the relay I
thought controlled the fuel pump but it didn't help. I decided to take the
car apart tomorrow and let the car sit and cool off this evening. Sure
enough, the car started fine tonight. Would temperature effect the relay
like this or the pump? Or the ground taps? Pressure, when I have it, is
right on the manual's specifications.

 

tegger.com. main relay.

 

As jim beam says, classic main relay symptoms (including the trouble when
hot). The cracked solder connections inside the relay assembly just seem
more troublesome when hot.

Look at the pictures TeGGeR has and verify you are looking at the right
relay. Dunno for sure about the Prelude, but if it was easy to find I bet it
is the wrong one.
http://tegger.com/hondafaq/startproblems.html#mainrelay
http://tegger.com/hondafaq/mainrelay.html

Mike

 

Thanks guys. Those sites make sense. I am ordering a main relay now.
Actually, I plan on doing the pump and cleaning grounds, later on, as
preventive maintenance for a 192k mile car.

 

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Forget the pump, unless your goal is to put 500,000 miles on the car.
(even then, why not wait?) Use google (groups) to see how many Honda
owners have no-start-on-hot-day problems. It's NEVER the fuel pump.

'Curly'

 

You could save yourself considerable money by resoldering it yourself.
If you already have a soldering iron and electrical solder(not plumbing
solder).

 

http://www.marklamond.co.uk/howto/electrical/main-relay/main-relay.htm

 

Repairing the relay worked great. It was faster than installing a new one
since the relay could not be removed without removing the guages. I just
pryed the tabs apart and removed the circuit instead of the whole thing.
Sure enough, the solder joints for the coils on the relays were cracked.
Not just the fuel pump relay but also the EPU relay. Funny thing is that I
repaired relay boards for interphone systems in my old job. The relays
themselves were what failed most often so I have lots of experience
unsoldering and resoldering in new relays. This was a lot easier.

 

This is a very common problem. My son's car had the problem. It is
caused by a bad solder joint on the relay. It can be fixed with a
solder gun, once you get the darn thing out! Or, since you went to
all that work, replace it.