94 850 won't start, thinking it's the cam position sensor but should CEL be on?
 

So this morning went to start the old gal to take to work and it took about 5 starts to get it going (normally starts right up although I had a few issues in the summer where it would stall on me and not want to start right away), took it across the street to get Starbucks and left it running. Came out and the car was dead, wouldn't start again. It turns over but just won't fire and from reading on here it seems like it's either the sensor or the fuel pump (have to try the sound test when I get home to see if I can hear it). Problem is my CEL isn't on and I seem to get mixed results when searching (some say it won't trigger the light, others say it does). What is the consensus on that? Anything else I should be looking for?

At the end of the fuel rail is a schrader valve. Turn on the ignition then holding a rag under the schrader valve press it in, if fuel squirts out then the pump is probably working.

Ya was gonna try that little trick when I get home. It could very well be the relay as well so will check that out.

When you say needed 5 starts to get it running. Did it actually start up, run on it's own a second or two and die each time ??

You can think it's anything but that doesn't really help you get it running again. Why cam sensor and not the crank/RPM sensor or a bad coil :confused: Is there some reason you chose the crank sensor as a possible reason ??

The CEL is questionable. I'm not positive on an 850 but on most ECMs if the engine isn't at or above the idle speed the computer will not sense or set a trouble code for a component. Never hurts to read it just in case.

Be careful of your eyes when you push open that schrader valve. You are on the right track checking fuel by listening for it to run when you turn the key and then checking for pressure at the valve. Also check for spark at the spark plug end. You might have it at the coil but could be losing it inside the cap.

Well from reading the posts on the starting issues it seems like the majority of people had issues with the cam sensor (that had the same symptoms as mine). Car finally started and stayed running and drove across the street to starbucks just fine. It just died while I was in starbucks and then wouldn't start again.

Well now I'm really confused. Went across the street to see if I could it and move it back to my garage and starts up right away. Let it run in the garage for about 15 minutes or so and didn't stall out or anything. No idea what it could be since it seems to be running fine again. Nonetheless I need to figure it out because it's my snow/crappy weather vehicle for the winter and don't really want to get stranded somewhere!

You know a friend just made a really good point actually, any of you guys think it might be condensation from the gas tank or in the cylinders themselves? I haven't driven it in about a week and it recently went from 70* yesterday to 38* today, wondering what part that may have played

Nay, I don't buy that one. If it drove across the street, any condensation would have brunt off.

If you do NOT have a CEL, the likely culprit is the fuel pump relay. You will need to listen for the pump running when it doesn't start. Then check for the other 4 vital signs.

Ya I think it's really starting to point to something electrical since it seemed to run fine when I got home this evening. I checked for fuel pump sound and of course it was there since it started up again. Think I will buy the relay and give it a shot. I suppose it could still be the pump itself but it's weird that it magically worked again.

You need to be ready next time it dies. I would start looking for a used fuel pump relay to carry with you or order a new one. Could also look up the info on jumping it with a paperclip for testing only. If I had to guess that's what I'd think it might be. But , , , it's just a guess.

If you never need it you can always sell it. Be ready with whatever you need to test to see if you have spark. Narrowing down no spark or no fuel will help lead you in the right direction for a cure.

Mine did something similar and it turned out to be the fuel pump it self. I had changed the relays but it still would not start sometimes until I changed the pump. It turned out the pump was intermittently cutting out.

That video shows people how to jump the relay socket to get the pump on.

Well went out this morning and did the sound test for fuel pump, sound was definitely there and fuel is getting to the fuel rail. Checked the pump relay and it appears to be the original but here is the kicker..thanks to one of Robert's videos I was able to see how old the spark plug wires are (didn't realize they have the date stamped on them) and mine are definitely original! And I'm assuming the distributor is as well. I'd say it's due for a change lol..going to try to replace the wires and the relay and see if it still acts up.

Cool, go with Volvo or Bougicord wires. Volvo's are finicky about their wires.

If the wires are really old you might want to consider changing out the distributor cap and rotor at the same time.

Same problem
 

I got a 1994 volvo 850 NA. I dont have insurance so i can only drive around. One day my car started stalling and stoped at a stop sign. Had to let it parked for one day then it worked again. Same thing happened few more times. Now my car has a strong crank and wants to start but its not working. I changed the MAP and also my idling sensor and my cam sensor … didn't work. I got strong fuel pressure. I dont know what else to look. I am planning on checking my plugs … but i dont know how . Do i just take a flat screw driver and put it on top of the plug and try to lisent for some spark noise or do I check my crank sensor? I need help ! Thank you.

The 1994 850's had really great diagnoistic capability in that little telephone switchboard up next to the right side headlamp. They're really good. So you'll need to learn about that system and then you won't need to buy any random parts anymore. That system doesn't really check sparks, though. That's too hard to measure. But it will absolutely report on your crank sensor. There are probably dozens of places to read about this system, but I'll choose this one:
https://www.volvoclub.org.uk/tech/se...s-NonTurbo.pdf
It even has a diagnostic mode which is really nice. You can command it to report to you that it sees the crank sensor.

There's a big workshop manual posted at https://www.volvoclub.org.uk/volvo_w...techdocs.shtml and above I'm just pointing out the one that explains the diagnostic doodad.

The easy way to check spark is to run the engine for 1 second on starting fluid. When you do that, the check is over.

You mention here that your car "wants to start" and I'm sure folks would like to know what you mean by that.

Also, this is a 10 year old thread, and so just try to guess when people respond whether they're responding to you or the old thread.

volvotips.com should also have some factory documentation on how to use the 93-95's diagnostics box.

850 na
 

First of all thank you for both answers ! So i diagnosed the A2 and A6 which is ignition and fuel system and i got nothing . Plus i tried cracking again for a long time and i heard a pop and fumes started coming out of the engine bay … i couldn't pinpoint the location however my idle sensor tube came off and fume was coming out … now i am scared to started again. Also last time i change MAF sensor and idle sensor and the car started … i didint drove around just went 40 metres then parked back because i was scared . Now the scar isnt starting ever since. However there is one thing worth mentioning and its that every time i crank it and shut the ignition … the engine rumbles . Like if it want start after i stop cranking. And also i wanted to checked the spark plugs. One of the plug wires tip is full of oil. Tank you