Hello everyone. This is my first post. Our '95 850 was running quite well. Then, out of the blue, it simply wouldn't start while out on business in town. At first, thought out of gas and maybe the needle was off. Put in $15 from a gas can - several walking trips to gas station. No go. It turns over well, but won't ignite and start. Towed it home. Changed fuel pump. Changed fuel filter. Changed fuel relay (#103). Fuel is coming up to the rail. Started looking ignition-ward. Changed rotor. Cleaned Distributor cap. It turns over well, but won't ignite and start... seems like it WANTS to though! Looking at coil - but before I changed that, I decided to get your advice. What should I do next? It's a '95. How can I pull codes and where is it I pull them from?

blamaustin

 

camshaft positioning sensor?

 

there should be a box passenger side front put the jumper in each hole push the button to get the code count the flashes key has to be in the run position
http://www.matthewsvolvosite.com/volvo-repair-database/volvo-850-trouble-codes/

 

start with the basics; does it have spark?

 

+1

start with the small stuff...

 

OK... Thanks for the replies. Thought about camshaft positioning sensor and other stuff, but i'll work on the gdog and regime tips first. There seems to be no spark at the coil. Since I changed plugs and the rotor already, how do I test old coil, or should I get new coil?

 

These cars have two discrete electronic control modules (ECM) for engine control; one for spark, or iginition, control and the other for fuel control.

They obviously work together to manage engine control, but that's why when diagnosing a "crank but no start" you want to isolate which of the two basic systems is having a problem.

Now that we've established you don't have spark, I am wondering why you immediately assume the ignition coil is bad?

The ignition control module has various input signals that are used to determine proper spark timing; I would suspect one of those inputs has failed; the camshaft position sensor is one of them for example...

Do you have any diagnostic tools like a digital voltmeter?

 

No I don't - but I can get one. What specifically do I do with it, please? I am quite able to do what I'm told - been working on cars for many years - just not at all familiar with Volvo's. And would it help to tow it and get a diagnostic read from, say Autozone?

 

For clarity, my previous post was based on the assumption this is a NA engine; is that correct?

Also since this is a '95 model, you can pull any/all engine codes yourself; here's the link for the how-to:
http://volvospeed.com/Repair/a2.html

Do you have a manual for this model? If not, i would suggest getting one (clymer or equivalent); otherwise we're going to have to have hold your hand every step of the way; a manual will at least get you familiar with where things are.

The camshaft position sensor is (apparently) a common failure point on these cars and it's failure likely will cause loss of spark. If you already know where it is, we're halfway there.

It's near the back end (drivers side) of the exhaust camshaft. It's a three wire Hall-Effect sensor. Without unplugging the 3 wire connector near the sensor, you'll need to probe two of the wires with your DVM while someone else cranks with the key. Should see constant 10V on the yellow/red wire and on the signal wire is the blue/yellow. You'll likely need to peel the harness back to see the wire colors. The signal wire should alternate between 0 and 5v as the engine turns over.

 

OK, I did what I was told, and here's what happened: I got the voltmeter ready to do the readings and report - then I sat and thought about it all. Since the consensus said it was probably one of three things - the cam sensor, crank sensor or the ignition coil - I just decided to buy them all used. Paid $125 from Austin VeeDub (great service!) and started with the coil. Was about to replace the crank sensor (saving the cam sensor for last for some reason), but then decided to try to start the car one replacement piece at a time. The vehicle started instantly! I have two parts that I don't need now, but may need later. But heck, all three cost less than one new cam sensor from Autozone or the like. Gonna put it all back together and see how it drives for a day or two. Thank you all very much for you help!

 

Great glad you got it running. Seemed pretty simple, I like simple

 

I have the same symptoms that you mentioned. Did you also experience your dash gauges not working as well?