Fuel Pump Relay 9434225 Examinations 1998 v70 non turbo

[MrAl]

I’m trying to remember if I have these in my “ send me a pm and I’ll mail them to you” box in my North office.

I think I do, I’ll check Tuesday

Oh wow thanks much. It would be interesting to even just examine another one to see if the contact wipe action is the same as mine or better than mine.
If i had access to a completely junked one, i could probably unsolder the parts one by one to draw up a schematic.
The main problem with that is of course it takes time, but the part number of the chip is often unknown. For this though it is clearly marked on top so there is a good chance a schematic can be made and design improvements that could make the relay last longer than our lifetimes.

[abscate]

I’ve got the caps. If they are in the right drawer I’ll mail them Tuesday. How many are needed in a fuel pump controller ??

[MrAl]

I’ve got the caps. If they are in the right drawer I’ll mail them Tuesday. How many are needed in a fuel pump controller ??

Well actually there are two different ones:
22uf, 25v
100uf, 25v

I thought you had a relay i could examine.

[jreed]

I also found cracks in the solder joints for the relay. It would be a good idea to check those joints too -- if you haven't already -- to make sure they're still good and solid.

Fuel Pump Relay Volvo 850 cracked circled.jpg (253.65 KiB) Viewed 594 times

[abscate]

My spares are in cars dispersed in time space. I probably have a spare in storage. I started hoarding when I got up to 4 1999s in fleet

The OE Stribel is $49.99 at FCP. Add a 50 cent brake bleeder cap to hit the $50 free shipping threshold.

At my self annointed $25 an hour rate , I wouldn’t put more than one hour into a refurb

I can drop the caps into usps mail if you send me address

[MrAl]

I also found cracks in the solder joints for the relay. It would be a good idea to check those joints too -- if you haven't already -- to make sure they're still good and solid.
Fuel Pump Relay Volvo 850 cracked circled.jpg

Wow that one looks bad. Ok i'll check that too thanks.

[jreed]

There are some more images of the relay and locations of the cracks available here:
viewtopic.php?f=1&t=33696

Volvo850FuelPumpRelaySolderJoint2.jpeg (86.8 KiB) Viewed 496 times

[MrAl]

My spares are in cars dispersed in time space. I probably have a spare in storage. I started hoarding when I got up to 4 1999s in fleet

The OE Stribel is $49.99 at FCP. Add a 50 cent brake bleeder cap to hit the $50 free shipping threshold.

At my self annointed $25 an hour rate , I wouldn’t put more than one hour into a refurb

I can drop the caps into usps mail if you send me address

Ok thanks Steve, and i'll get back to you when im ready to do the repair.

Right now i am still working on the schematic. It's a bit difficult to follow the part traces around the board because it's double sided. I did make some progress though. The coil driver is a fairly standard NPN bipolar that is in turn drive from that dual monostable multivibrator chip (16 pins SMD).
I did run into one snag though. There are two traces that run UNDER that chip. The problem is that in order to correlate to the Ohm meter readings one trace would have to jump over another trace, but UNDER the chip. This isnt common and seems like some sort of mistake, but i've checked and rechecked and the two traces go to two pins on the IC chip as measured, but one has to jump over the other to get to the right pin and it has to happen underneath the chip which is hard to believe.
Unfortunately there no way to see under the chip because it's an SMD part. That means i'd have to unsolder and remove the IC chip to see what is under the chip for sure. Of course i dont want to do this on my board, so if anybody has a burnt out relay they know they can never use again, if they send it to me i can check for sure. Alternately, if they are willing to unsolder it themselves and send me a snap shot of the board that is under that chip that would be good enough too. They dont have to put it back on unless they want the board to work again, but i dont recommend anyone doing this without a lot of experience in resoldering SMD IC chips. If they never intend to use it again no problem, but if they intend to use the board again they should have experience soldering new SMD chips to PC boards or else they could easily damage the chip and maybe even the board. That's why i wont pull mine off, because it is difficult to get it right even though i have the right equipment to do this.

So if anyone has a totally burnt out board they can send or if they are willing to unsolder that IC chip and take a pic of what the board looks like underneath, that would help me solve this.
Without verification i will still go ahead with the schematic and hope i can make sense of it once the whole schematic is drawn out.

Thanks to anyone that can help with this. Now all we need is a schematic of the ECU and we can fix these cars for all eternity Unfortunately that would have to take the form of a Sams Photofact or direct info from Volvo including the programming info.

[abscate]

There are some more images of the relay and locations of the cracks available here:
viewtopic.php?f=1&t=33696
Volvo850FuelPumpRelaySolderJoint2.jpeg

You probably could just touch those solder spots with a needle point and reflow them

[foggydogg]

This is the hardest working device in the electrical system; it is energized from just before startup until the key is back in your pocket. Aside from an academic interest, spending many hours of bench time replacing caps and reflowing joints, then putting a 25 year old relay back in the car, doesn't strike me as progress. The windings on the coils are still 25. The contacts are still 25.
I just bought four from one of the vendors I posted earlier, and have replaced them in each of my cars.
If the original post on the other thread was about getting your car running, this seems to be quite a distraction. My suggestion on that thread was to replace this relay with a new item as a matter of routine maintenance; I consider the piece to be consumable, somewhere between spark plugs and O2 sensors.
Robert goes on several rants in his videos about getting original relays out of any P80 at this point due to age.