Volvo 240 main FI relay wiring?
 

OK.... it's an intermittent fault so the mechanic will NEVER find it. I
of course suspect the main relay (replaced once, like 10 years ago).
So... thought I'd wire in a switch across the terminals which I could
use to bypass it when it is being uncooperative, and either prove or
disprove the relay theory. And make the car run, if I am right. But I
can't find my Volvo wiring manual. So... which terminals would be
appropriate to bypass/jump?
Thanks.

One of ours used to have water running down the antenna wire and drip
right into that relay which was upside down. One reason I got it so
cheap was it wouldn't run in the rain and no mechanic could figure it
out.

I also have had issues on several of them with the fuel pump fuse. The
heat takes the temper out of the fuse holder so it doesn't hold the fuse
tight. The test for that is to see if the fuse is physically hot. If
so, a good clean and bend of the contact is in order.

That said why not just replace the relay, they are something like ten
bucks. You also can pop off the cover to see if the contact points
inside are arced out.

A normal Bosch relay's pin out is pin 30 and 87 for the main power with
pin 85 and 86 as the trigger. My old 240's used this number system and
bosch relays.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

wrote:
>
> OK.... it's an intermittent fault so the mechanic will NEVER find it. I
> of course suspect the main relay (replaced once, like 10 years ago).
> So... thought I'd wire in a switch across the terminals which I could
> use to bypass it when it is being uncooperative, and either prove or
> disprove the relay theory. And make the car run, if I am right. But I
> can't find my Volvo wiring manual. So... which terminals would be
> appropriate to bypass/jump?
> Thanks.

On Fri, 15 Jul 2005 wrote:

> OK.... it's an intermittent fault so the mechanic will NEVER find it. I
> of course suspect the main relay (replaced once, like 10 years ago).
> So... thought I'd wire in a switch across the terminals which I could
> use to bypass it when it is being uncooperative, and either prove or
> disprove the relay theory. And make the car run, if I am right. But I
> can't find my Volvo wiring manual. So... which terminals would be
> appropriate to bypass/jump?

Not enough info, not even close.

Volvo sold 240s from 1975 through 1993. During that time, they used
several different variants of Bosch K-Jetronic and several different
variants of Bosch LH-Jetronic. First, you need to tell us what year,
engine, transmission, emissions package and induction system
(turbo/nonturbo) you have. Second, you need to find your Volvo wiring
manual. Trying to diagnose an intermittent electrical problem on a 240
Volvo is hard enough WITH a manual...trying to do it without is a waste of
time.

Daniel J. Stern wrote:
> On Fri, 15 Jul 2005 wrote:
>
> > OK.... it's an intermittent fault so the mechanic will NEVER find it. I
> > of course suspect the main relay (replaced once, like 10 years ago).
> > So... thought I'd wire in a switch across the terminals which I could
> > use to bypass it when it is being uncooperative, and either prove or
> > disprove the relay theory. And make the car run, if I am right. But I
> > can't find my Volvo wiring manual. So... which terminals would be
> > appropriate to bypass/jump?
>
> Not enough info, not even close.
>
> Volvo sold 240s from 1975 through 1993. During that time, they used
> several different variants of Bosch K-Jetronic and several different
> variants of Bosch LH-Jetronic. First, you need to tell us what year,
> engine, transmission, emissions package and induction system
> (turbo/nonturbo) you have. Second, you need to find your Volvo wiring
> manual. Trying to diagnose an intermittent electrical problem on a 240
> Volvo is hard enough WITH a manual...trying to do it without is a waste of
> time.

Yeah, that's why I'm throwing myself on the mercy of the newsgroup....
it's an 89 manual trans nonturbo 49 state with the white FI relay.

On Fri, 15 Jul 2005 wrote:

> it's an 89 manual trans nonturbo 49 state with the white FI relay.

Fix one: Jump fuse 4 to fuse 6
Fix two: Jump relay 30 terminal to both 87 terminals
Fix three: Remove relay cover and resolder broken solder joint therein

Also, inspect the main fuse holder, located on the relay bar on the left
inner fender. Relay failures are common but so is corrosion/heat
damage to this fuseholder. If in doubt, replace.

Daniel J. Stern wrote:
> Also, inspect the main fuse holder, located on the relay bar on the left
> inner fender. Relay failures are common but so is corrosion/heat
> damage to this fuseholder. If in doubt, replace.

Well, I checked this fuse and it's OK, and I opened the plastic case
and the little board looks OK but I'll resolder anyway, hook up two
leads for jumping at the same time.

Why don't they use solid state relays?

"Daniel J. Stern" wrote:
>
> On Fri, 15 Jul 2005 wrote:
>
> > it's an 89 manual trans nonturbo 49 state with the white FI relay.
>
> Fix one: Jump fuse 4 to fuse 6
> Fix two: Jump relay 30 terminal to both 87 terminals
> Fix three: Remove relay cover and resolder broken solder joint therein

Daniel, I thought you of all people understood how a relay works.

You even have a write up on your website.....

I cannot see any situation where you would jump 'both' 87 pins to
power. This make absolutely no sense at all.

Pin 87 is a normally open pin until power is applied to the relay
trigger. Pin 87A is a normally closed pin with power all the time
'until' you activate the relay.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

On Sat, 15 Jul 2005 wrote:

> > Also, inspect the main fuse holder, located on the relay bar on the
> > left inner fender. Relay failures are common but so is corrosion/heat
> > damage to this fuseholder. If in doubt, replace.
>
> Well, I checked this fuse and it's OK,

No, check the fuse HOLDER for that fuse, not just the fuse itself. There
is often corrosion deep within the fuse HOLDER.

> Why don't they use solid state relays?

$$$$$$. But there's nothing stopping *you* substituting a solid-state
relay or putting in a more robust conventional relay.