Volvo 850 starts, then stalls

SaithCR · Post by **SaithCR** » 02 Apr 2021, 12:25

Hello everyone, I'm a long-time lurker of the forums, but this is my first post!

First of all, a little backstory. I'm the happy new owner of a 1996 Volvo 850. I bought her like a month or so ago for not a lot of money ($1500 USD which is junk car money in my country) She ran nicely for the first 2 or so weeks and then the headache began. I'm not a mechanic, but I am mechanically inclined and like to do things by myself (and deeply distrust mechanics in my country

)

With that said, I'm having an odd problem with my car. Sometimes it starts and runs great, but most of the time it starts runs for a few seconds/minutes and then stall, some other times it just shuts off right after I started it.

I've been tinkering with the car, checking wires, continuity, voltages, etc, and found some nasty nasty stuff, like cables just twisted together and relays soldered to their respective socket pins.

This is a very rainy country (I live in Costa Rica) and found that a previous owner/mechanic wrongly installed the cowl and water was getting into the cabin through the relay/fusebox causing most (if not all) of the relays to be completely rusted on the inside, and by rusted I mean that they look like it was pulled off of the Titanic. I disconnected all the relays that I know are not essential for the car to start, like the central locking, alarm (no immobilizer), and seatbelt reminder, but I'm not sure what the other relays do and if they can cause my problem.

To this date i've checked:

[*]Fuel Pump Relay (both new relay and bridging the pins)
[*]Fuel Pump
[*]Fuel Filter
[*]Main Relay (the one near the fan)
[*]Fixed the wiring of the coolant sensor (was twisted together with tape)
[*]Checked the connections from the ECU to each of the terminals in the harness
[*]New Spark Plugs

Just today I found that a piece of the green-red cable on the ignition switch was cut and replaced (twisted together) and I'm planning to fix that properly.

But I'm lost with this problem and need your help, this is my only car and I need it to transport my kid and go to work, so any help or hint you can give me will be very much appreciated.

PS: Sorry for the long post, and sorry for my english, i'ts not my main language!

Post by **matthew1** » 02 Apr 2021, 12:46

Check B+ cable https://www.matthewsvolvosite.com/b-battery-cable/

SaithCR · Post by **SaithCR** » 02 Apr 2021, 12:58

matthew1 wrote: ↑02 Apr 2021, 12:46 Check B+ cable https://www.matthewsvolvosite.com/b-battery-cable/

Will do and report back, thanks!

SaithCR · Post by **SaithCR** » 02 Apr 2021, 14:36

matthew1 wrote: ↑02 Apr 2021, 12:46 Check B+ cable https://www.matthewsvolvosite.com/b-battery-cable/

So, I checked the battery cables and found it melted a little bit near the starter motor, the insulation on the cable that connects to the alternator was also broken, and the cherry on top of the cake, I found a LOT of the cable was broken near the battery, under a full roll of electrical tape. The negative cable doesn't look very good either.

Anyway, I'll change those cables and report back. Do you know by any chance what gauge those cables are? Parts availability here is scarce at best and the few places that sell them charge up to 5 times the price because "if you have a Volvo, you should have money", so I figured it'll be much cheaper to have them made to spec.

Thanks in advance!

Edit: Pictures of the cables attached!

Post by **matthew1** » 02 Apr 2021, 14:52

That's not terrible, and might not be the source of your stalling. But you do want to do that correctly. Sorry, I don't know the wire gauge. Park at a electrical shop and have them come out and show them.

I'd check grounds viewtopic.php?t=69375

SaithCR · Post by **SaithCR** » 02 Apr 2021, 15:02

matthew1 wrote: ↑02 Apr 2021, 14:52 That's not terrible, and might not be the source of your stalling. But you do want to do that correctly. Sorry, I don't know the wire gauge. Park at a electrical shop and have them come out and show them.

I'd check grounds viewtopic.php?t=69375

Will do, thanks

Post by **erikv11** » 02 Apr 2021, 20:09

Tons of great info for DIY battery cable jobs: viewtopic.php?t=61747

Post by **abscate** » 03 Apr 2021, 05:18

I’ll measure them today to give you an idea on making them up

SaithCR · Post by **SaithCR** » 03 Apr 2021, 20:18

erikv11 wrote: ↑02 Apr 2021, 20:09 Tons of great info for DIY battery cable jobs: viewtopic.php?t=61747

Thank you very much, very helpful! Do you recommend using crimp-on battery terminals or the ones with screws to add the cables?

SaithCR · Post by **SaithCR** » 03 Apr 2021, 20:18

abscate wrote: ↑03 Apr 2021, 05:18 I’ll measure them today to give you an idea on making them up

I will appreciate that very much, thanks!