95 Volvo 850 Turbo won't start Topic is solved

volvokid · Post by **volvokid** » 21 Apr 2021, 11:26

Im a young and aspiring mechanic. I've recently took on the challenge of replacing the water pump timing and serpentine belt. I followed all the proceeders for doing that task, but since the car had been sitting for a while the battery died and did not start. All of my dash light were working at this point. So I go to jump the car and with my 95 Toyota camery and out of excitment I wasn't paying attentions to the jumper cables and I accidental reversed the cables on the volvo. Now the car won't start, non of the dashboard light turn on when I put the key in the on posistion and non of center console buttons work.

I checked the check the fuses and the ones that don't light up with my HF test light are the fuel pump, central locking, radio/ amplifier, L.H. R.H. High Beams, L.H. R.H. Low Beams, position lamps L.H. R.H.

I replaces the Fuel pump fuse and relay with known working ones and still nothing.

If anyone anyone can steer me in the right direction that would be great, because I don't know where to go after this point.

Post by **misha** » 21 Apr 2021, 12:20

If you were lucky,you didn't fried ecu and other modules.
In rare cases some people got away with fried alternator,battery and some relays under fuse box.

It would be a miracle if you didn't damaged electric system on jumper car...too.

Not fun.

Post by **erikv11** » 21 Apr 2021, 20:46

Usually just the J relays are cooked, could be one, two or all three of them. You can get these from a junkyard for next to nothing or I don't know what they cost new. I've got s stash of them but probably you can find some closer by. I would replace all three and give it a try.

Post by **abscate** » 22 Apr 2021, 03:48

Ouch, it hurts to read that. Most of us have done that in our lives, we will get through this.

Break it up into three systems to begin.

Is the battery still good? Take it out,charge it. See if you can get 12.5 volts steady on it,

Now for the starter circuit, put the good battery back in,watch polarity of cables, and use the bypass pin to see if the starter cranks.

Finally go to the main relays and test voltages there to see if any are missing.

Somewhere in this forum is a thread where someone documented what blew on a similar learning expedition. I’ll try find it...and here it is

viewtopic.php?f=1&t=77274&p=572464#p572464

Short version. Every relay has a snubber diode on it , which protects the relay from the little current spike when it opens. Those diodes don’t like reversed polarity and probably are all popped. The main J relays, pointed out by Erik above, are the likely one to have blown diodes

volvokid · Post by **volvokid** » 22 Apr 2021, 06:54

Thanks for the help so far. Imma try to get my hand on some replacement relays and replace as many as I can. I will keep you guys posted if things get better. At least this will be a good learnings experience.

volvokid · Post by **volvokid** » 22 Apr 2021, 19:54

I replace the three J relays and the battery with known working ones. It started right up and all the dash lights started working. Now the only potential issue now is that the engine is making a loud ticking noise, but I read some where that it could be because it sat for a while.
But thanks for everyones help I greatly appreciate it. And now I know to not to get to cared away because I can seriously break something.

Post by **abscate** » 23 Apr 2021, 01:20

It can take a week of daily running to get the lifters fully pumped up after a long sit.

It helps after you start your car to stand in front and yell “ Go, Lifters , Go!” Of course

Volvo says to keep revs below 3000 until they pump up, so stayin thst slow NJ lanes for a week

Fresh oil helps too!

Well done on that reversed battery save!

Post by **misha** » 23 Apr 2021, 03:53

Good news!You got away this time!
At this point...i would check alternator output with digital multimeter...on battery terminals first.
You should get 13.8-14v at battery terminals with engine idling,headlights,heater blower at lower speed and radio ON.

volvokid · Post by **volvokid** » 29 Apr 2021, 06:55

So by drive slow do you mean drive the speed limit, because the unspoken rule of thumb is going 10-15 over the speed limit is the real speed limit here at the shore. lol

@abscate

Post by **abscate** » 29 Apr 2021, 16:09

volvokid wrote: ↑29 Apr 2021, 06:55 So by drive slow do you mean drive the speed limit, because the unspoken rule of thumb is going 10-15 over the speed limit is the real speed limit here at the shore. lol @abscate

Im the crazy old guy in the slow lane on I287, doing 75 while the rest of Jersey passes me at 90 mph

I forget what the recommendation is but 3000 rpm sounds like a good 'not to exceed'

Manuals are online, so you can look that up from the Swedish Horse's Mouth, too.