Of so I looked around for a while I cant seem to find anyone with a similar problem...

So to start off the story, my volvo 850 has had an on going problem with a freezing fuel pump relay when its cold. just means i had to pull the fuel pump relay every time i parked it so it stayed warm, still works.

So here it is summer and my father, usually a great DIY mechanic changed the oil, started it, parked it checked oil finished it up. And now it doesn't start. not sure if its related, just putting it out there.

So here's what I have.

Car: Volvo 850 glt sedan, 20 valve fuel injected, non turbo, manual 5 speed LHD.
* car turns over (starter works)
* fuel at the injectors plenty of pressure(fuel pump works)
* spark plugs fire properly
* injectors read 3.3ohms resistance, but i see no voltage with cranking, could be multimeter reading issues, but i suspect electrical
* no error codes on A6, ignition system(haven't checked others)

Odd things that go along: will try to crank when in gear(not sure if it did before, but it does now)

Where should i go from here?
Is there a certain loose wire i should look for?

I'm going to try checking the cam position sensor, engine speed sensor/impulse sensor.

I should be back with those in a while as ill be eating lunch too.

As always i love this forum, always helpful advice, I've found answers to many problems with my Volvo's thanks to this forum.

 

Replace relay, check wiring at relay connector for failure.

 

If you're fuel pump relay is "freezing" then replace it; that's not normal.

But the thing i noticed is you're not seeing voltage at the injectors; should see a continuous 12v (when cranking) on one side and pulsing 12v on the other side of the injector. That's the red voltmeter lead on the injector wire (one side, then the other..) and black lead on engine ground.

If no voltage at injectors then ck the fuel system main relay on the fan shroud; four wires going to it: two red (hot from batt), one violet (relay control goes to ECU; should go to 0v when cranking), and green wire (hot feed from relay to injector harness).

 

typhoon,
super excellent vague advice man, replace relay check wiring, seriously dude? that's like saying theres food in the cabinets to a guy who cant cook but says he's hungry.
at least point in an educated direction, like check the fuel system relay first...

thanks for actual good advise gdog,

the fuel pump relay's an old problem, i live in the frigid north (-5 *C is normal day in the winter). they say it would be a every 2 years replacement here because the dramatic temperature changes. if its cold it freezes, will start (click on to starting pressure), (not kick down to normal pump) start to idle then die (pump not in normal running, not starting mode but in between). if the relays warm or in use not a problem. and its not worth 50 bucks every 2 years, i can just take it in my pocket each day(put a nice key chain on it) i need the tank(what i call my old volvo) out in the winter.

on a note about your post, my injector leads are green and white,
i haven't compared the voltages on the injectors to the battery yet,
was checking the voltage across the injectors while cranking to see a difference when i measured it, but ill try and check the voltages at injectors and the relay you mentioned in the morning

Sorry i didn't get back that evening, was busy with dinner and stuff, left the headlights on and had to charge the battery that night.

i was swamped yesterday, had to work and i had to start getting a pair of '81 yamaha 400's, and an '81 750 V-twin running for a friend. oh how i hate things that sit a winter without being winterized, excessive carb cleaning/rebuilding commenced.

tomorrow I'm off so car work it is if the girl lets me.

 

-5*C is not that cold. Plenty of people from this Forum have 850 up North. Volvos, you know, weren't built in the tropics.

Typhoon is right on the money -- since you have an ongoing problem with the relay, he advised you to replace the relay and check if it is the connector or the wiring that is compromising the relay. Relay does not belong in the key-chain.

This particular relay is known to be a problem to many people, and the fix is in fact of opening the relay and re-soldering the joints. Run a search in this forum for the procedure.

What year is your Volvo? You can also download the FSM at k-jet.org if you plan to DIY.

What is your fuel pressure at the rail?

 

So in 2 posts you've managed to insult a long time member (who actually really knows his s***, as you would have found, had you bothered to research..) who suggested you replace the fuel pump relay (from the context of your post..), as i did.

Are you the guy who can't cook, but is hungry, in this scenario?? Good luck w/your car problem...

BTW: -5 Celcius is about 23 F; not that cold. When i lived in MI it got much colder than that and never had an issue with relays freezing...