'83 240 GLE fuel pump relay

I just went through fuel troubles in my '83 245. I was going to say on the firewall, under the carpet on the passenger side. That's the relay for the main pump. I hadn't thought about the relay for the in-tank pump. I'll be watching this thread...

I've never understood the in tank prepump to have its own, separate relay.

If this is true then it pretty much confirms that the pump itself is dead. Looks like i've got some replacing to do. Thanks for your help.

Dunno about the 240, but I thought it had a dual section relay module like the 740 does. Those are notorious for becoming intermittent when warm - cracked solder connections. It matches your symptoms well enough that I think you should verify whether yours is one of the affected relays and if so, where to find it.

Mike

Definately sounds possible, but I think since the time the car cools is directly proportional to the time the car runs, a cracked solder is not too likely.I will still check it out though. I am also a little confused. Doesnt metal expand upon being heated, therefore making a break in a circuit less likely to show itself in hot weather?

I don't know the details of why the failures are more common when warm, but it is that way not only in Volvos but in Hondas, which have the same problem. (In Hondas, the relay assembly is known as the "Main Relay.") If it means anything, the cracks show up as circular hairlines in the solder where the heavy relays are mounted. When my eyes were younger I could see the cracks in mediocre light, but now I need sunlight and a magnifying glass. (Come to think of it, I need sunlight to find the magnifying glass!). TeGGeR's excellent Honda FAQ site has a good picture at

Mike

It does, but just the fact that movement takes place when it gets warm can break a circuit. It's always a good idea to resolder the relay even if it isn't causing problems, it will some day.

Dont just resolder it remove the solder and replace the solder with new silver solder ,quickly so as not to cook the joint and solder .

i shall have a look at the relay in the morning, try resoldering it and see if it affects the car at all. I've gotta do some soldering under the hood anyway. We are getting some freakishly cold summer weather so it may be some time before i know if this is the fault :-P. Thanks for everyones help

I favor reusing the old solder with a dab of rosin. I don't know where to get rosin flux separately any more (the tin I had was from a store that went out of business when I was a kid), so just a touch of rosin core solder to freshen the joint is a good substitute. Failing that, remove the old solder and start over as you say. I agree - just reflowing without flux produces an oxidized (dry) joint. Not as bad as a cracked one, but not still not as good as you want.

Mike

I opened the relay and bingo! cracked solder. However, the cracked join was not actually linked to any other component, it was one that was holding the relay coil in place. Could this have been the culprit? The crack was quite large, maybe it was enough to let the coil vibrate and in turn the plates. i resoldered the second join to this coil just in case the cracked solder had also damaged the second join - this one was linked to the battery power. I wont know how the relay is going until i get some more hot weather, any suggestions on how i can safely test the relay?

No need to use silver solder, ordinary rosin core tin/lead electronic solder works fine.

my volvo mechanic told me the other day, the lead content in newer soder is not as high as in older soder, making it not "breathe" and expand/contract with heat, thus cracking after limited cycles.....the s80's are having trouble w/some sodered components....

use silver solder, ordinary rosin core tin/lead electronic

The new manufacture stuff is made with lead-free solder. I'm all for reducing the use of toxic materials, but lead-free solder is crap. Wouldn't surprise me if the waste levels increased due to lower reliability.

The body of the relay, called the armature is where these cracks usually occur. The armature is the par of pump current switching circuit.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

void _-void-_ in the obvious place

Indeed. Just look up Tin Whiskers.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

void _-void-_ in the obvious place

I've confirmed that the relay is working properly by testing for voltage at the pump. voltage exists, but the pump doesnt run. Thanks to all for help isolating the problem, i am in possession of a new pump, i just need to install it this afternoon. Would any of you know a good way to get fuel lines off the pump? They are jammed on too tight to just pull off. The guy who sold me the pump suggested heating the fuel lines, is there a way to do this without the risk of igniting the fuel?

I usually use an impact wrench to get the banjo bolts out. Be careful not to twist the fittings and kink the lines.

Thanks for the suggestion, i followed the fuel line until i found a banjo bolt and undid that instead of messing with the connection at the tank, fed the line through and that gave me enough play to remove the hatch. I replaced the pump with no problem and now hear the soft buzz which i couldnt hear with the old one. Ran the car for about an hour today (quite hot) and it went beautifully, also fixed up a little bit of chugging at idle, guess the fuel pressure was too low.