So just recently my car has now encountered a new problem. So I'll give the run down on what exactly happened. 1996 Volvo 850 turbo.



About a few weeks ago the car started running really rough. There was a light on the dash which is green and yellow and almost looks up an upside down "Y". I looked it up and apparently it was suppose to be an O2 sensor problem. Then after I found the battery was dead in the car. So I put the battery on charge, but the car only turns over and will not start at all, not even fire. So I had already bought plugs for the car (platinum), the stock plugs were pretty bad so I did replace them. Car still doesn't fire. I can hear the fuel pump working and there doesn't appear to be any fuses burnt out. So I checked the spark, and the car has no spark. I took the cam position sensor off and sprayed it with contact cleaner. Still no spark... I'm also getting a obd2 code which is P0120 which is supposed to be a TPS problem. Now I have taken the plug off the TPS and plugged it back on with no resolution. Also took the plug off the coil, inspected the wiring and everything seems to be fine. Along with clearing the code previously, I disconnected the battery and let the car site for a 1/2hr to see if that helped and nothing still.



Any ideas???

 

If you don't have fire you need to find out way. Maybe the ignition coil is bad.

 

I had a problem with my wiring in the front near the radiator awhile back, could be a cam sensor as well. Make sure you get OEM for parts.

 

So anyway, bumping up an old issue. Just want to keep everything together and I haven't had much time to look at the car before so the problem never got solved. Now that I sold my daily driver, this needs to be put on the road.



I was getting a transmission arrow error on the dash so I moved the shifter back and forth numerous times to clean the contacts in the switch, light still seems to stay on. I'm still getting the same P0120 code thrown by the car once I turn it over. If I clear the codes, the transmission light disappears, soon at I turn the car over, it comes back up. It'll also pop up if I hit the winter mode button and it doesn't make a difference if I have sport mode on or off. My reverse lights do work and the car also won't turn over in neutral(not sure if that's normal).



I bought an analog meter the other day... I tested the blue switching wire off the coil while the car is turning over and I'm only getting 0.19V (Not even 0.2V. Also tested the wire at the cam sensor unplugged with the key on, pin 2 is 2V and pin 3 is a full 12V. Then I left the cam sensor unplugged, turned the car over and I'm still receiving 0.19V at the blue switching coil wire. Is that normal??? Or it is just receiving a signal from the crank sensor???



Then I also picked up another coil from the wreckers to see if that was an issue, swapped them out and still not firing. But this other coil I picked up was slightly different, not sure why, but I do think it came off a non turbo'd model. Newish coil on left, original on right.

 

Where is the car?

Location: London, Ontario, CA

First thought was the PNP, second is the seating of the ECU. I had a car once that would not start and it was the relief relay but on that car there was no voltage on the coil and no fuel pump.

The car should start with the TPS unplugged, it will just throw a cell and reset when its plugged in again.

 

Oh I'm In Canada. London is the closest city to me, I actually live just outside of London.

I know some has tinkered around with the wiring before and it had a third wiring going to the coil which I was leaving disconnected just to simplify things. Someone did hook up a stock Volvo keyless entry, not exactly the nicest install. Anyway, after hooking that wire back up just now, that transmission flashing light magically disappeared

Unplugged the TPS and still no difference with trying to start it. Also disconnected the battery, let it sit for about 15min and then pulled the ECU. Checked the contacts and everything is perfectly clean. Plugged it back in, still no go.

And yes the fuel pump is working and the coil is getting power too.

 

When you say the coil is getting power ... is the coil getting triggered to fire or just a constant positive voltage ??

Check these out for diagnostic ideas.

http://www.matthewsvolvosite.com/for...hp?f=1&t=36665

http://www.matthewsvolvosite.com/for...hp?f=1&t=52479

http://www.matthewsvolvosite.com/for...hp?f=1&t=37956

http://www.matthewsvolvosite.com/for...hp?f=1&t=28780

 

This is what I've checked out from previous.
-full battery voltage at the primary wire
-0.19V at the blue switching coil wire
-checked for spark directly off the coil with the engine turning over and it's a very weak yellow spark
-grounded out the switching coil side (negative side) directly to the battery while checking the spark and still weak yellow spark
-checked the resistance between the primary and secondary on the coil a while back and it was good... If I remember right, it was 8000ohms

 

So I finally got in my new cam position sensor (took forever to have them ship it out), replaced it and the car still won't start. Now it seems to have a new problem. Honestly I'm really hating this car... Soooo, moving along. I did previous tests with the cam sensor before with it plugged in with no signal from pin #1 while the car was turning over. With the key on and the sensor unplugged, pin #2 was reading about 5V and pin #3 was full battery voltage. Now pin #2 is reading 0.5V and pin #3 is at 2.42V. Haven't touched the car since I ordered the parts. Really need some input on this because this car is causing quite the headache for me.

 

If you have NO spark, maybe you have a bad cam shaft (speed) sensor. I can ship you one from our junk yard if you'd like. Is timing ok?

 

Robert . . . . he just put a new one in.

 

Yep the car has a brand new Bosch cam position sensor installed now. Now it has low voltage at the cps plug.

 

I meant crank sensor. Sorry about that.

 

Well I did test the crank sensor before and it was reading 280ohm.

 

Making progress, but still haven't fully sourced the problem though. Just had the car fire today.

Anyway... Long story short, traced the wires from an ecu schematic which lead to that grey relay at the top of the rad with one connector including 4 wires. So the relay isn't closing the circuit when the ignition is on or the car is turning over. Popped the cap off the relay to check if it was okay inside and everything is clean. Also jumpered the relay and it works fine. So, plugged the relay back onto the car without the cap, closed the circuit and the relay on the other side switch, turned the car over, fires right up. So as the relay opens the circuit, engine quits. What is this relay controlled by or what would cause this???

 

Cooling relay, main relay ??

 

Main relay.

 

Found it... Broken orange/black in the harness just behind the rad where is comes out of the plastic duct.

Thank you

 

Maybe it's just me, but I am confused. Is it possible to generate codes on a scanning tool if the engine cannot be turned on? By replacing so many parts, before conclusively diagnosing the true source of the problem(s), it's now made it exponentially more difficult to find the problem source(s), some of which could have been newly created from faulty parts and/or faulty installation.

Provided the car's year, "2000", wasn’t a typo, this car is 21 years old! It obviously was running well enough when sold.

With the above said, I'm still sympathetic to the buyer's frustration but, per Kenny Roger's ... , "You got to know when to fold 'em".

 

This is an eight year old thread. Sure it's fixed by now.