96 Volvo 850 cranks but won't start

five_w_coupe · Post by **five_w_coupe** » 25 Nov 2011, 10:53

My '96-Volvo 850 GLT Wagon with 280K miles is on the fritz again. Other than using a little bit of oil it won't start. It does crank, is getting gas, but no spark. This has happened once before (140 thousand miles ago) and I can't remember if it was the camshaft position sensor or if it was the crankshaft position sensor that had to be replaced. I usually do my own work but that time I was on vacation with my children and wife when we broke down in the middle of nowhere. I had it towed to a garage then went back a week later to pick it up. I do not have a code reader so I am really in the dark about what it is. Help please...

Post by **JDS60R** » 25 Nov 2011, 12:10

Usually the cam sensor.

I moved your post to the 850 forum so you would get more replies.

hirdan · Post by **hirdan** » 27 Nov 2011, 20:25

I'm having the same problem with my 96 850 turbo wagon. Battery checks good, I have ignition to the plugs (verified with a timing light), I pulled the starter and had it checked (it's good), when I prime the fuel rail by turning key on/off a few times I seem to get a pressure build in the lines. I can't get my fuel pressure tester on the schrader valve due to clearance (will build a 90 degree adapter tomorrow). But still the fuel spurts out so I'm thinking I have pressure in the fuel rail. Fuel + ignition + starter crank should = engine start. But it doesn't.

I verified all the circuit breakers are good and locked/unlocked with the key to ensure the immobilizer isn't the problem. I scanned for codes and got no codes. I'm stumped. If you solve you problem please post/I'll do the same.

Thanks. Andy

Post by **Ozark Lee** » 28 Nov 2011, 12:53

The clearance to the schrader valve is a real problem. I have just used a real cheap tire gauge - it isn't as acurate as a fuel pressure gauge and it will pretty much destroy the tire gauge but you can get an idea of where you are.

If you can find a 90 degree adapter for the fuel pressure gauge please post a link or a source.

...Lee

hirdan · Post by **hirdan** » 04 Dec 2011, 15:59

I found a fuel check kit with a 90 degree elbow, rented from autozone. However, the elbow seemed to not build up any pressure at all even though I knew there was some pressure in the line. So I gave up and disconnected the trottle body/vacuum junction/throttle linkage... Not that bad, just a lot of bolts.

Now I'm really stumped. I have 40 psi in the rail, I have good spark to all the plugs, I checked each spark wire for spark and I pulled #1 plug and watched it fire. I replacedthe cam sensor and the engined started, but then quit. The engine now starts a normal start, runs up to about 1200 rpm for a few moments (like it used to), then settles down to about 800 rpm and hangs on for a moment then sputters out. Just can't seem to hold idle. So I suspect the crank sensor. I pulled the crank sensor connector and checked resistance. Resistance max, so it was an open connection. Also with it disconnected the engine won't start at all. That tells me it could be partially working, but for some reason isn't working at idle rpms. So I ordered a crank sensor. If anyone else has another idea other than the crank sensor please let me know. Thanks, Andy

Post by **rspi** » 04 Dec 2011, 19:38

I'd check the MAF. Start the car and unplug it. If it keeps running, you can try to clean it but from what I've read, cleaning the MAF is a temp fix if it's broken.

Post by **Ozark Lee** » 04 Dec 2011, 22:53

hirdan wrote:I found a fuel check kit with a 90 degree elbow, rented from autozone. However, the elbow seemed to not build up any pressure at all even though I knew there was some pressure in the line. So I gave up and disconnected the trottle body/vacuum junction/throttle linkage... Not that bad, just a lot of bolts.

Now I'm really stumped. I have 40 psi in the rail, I have good spark to all the plugs, I checked each spark wire for spark and I pulled #1 plug and watched it fire. I replaced the cam sensor and the engined started, but then quit. The engine now starts a normal start, runs up to about 1200 rpm for a few moments (like it used to), then settles down to about 800 rpm and hangs on for a moment then sputters out. Just can't seem to hold idle. So I suspect the crank sensor. I pulled the crank sensor connector and checked resistance. Resistance max, so it was an open connection. Also with it disconnected the engine won't start at all. That tells me it could be partially working, but for some reason isn't working at idle rpms. So I ordered a crank sensor. If anyone else has another idea other than the crank sensor please let me know. Thanks, Andy

40 PSI is a fuzz low but not the end of the world. It should be closer to 44 PSI. Did you happen to monitor the fuel pressure after the car died? We are at the "shoulder season" (spring and fall) where a flaky fuel pump relay always rears its ugly head. If the fuel pressure fell to zero or quite low as the car died I would suspect a bad fuel pump relay.

Cam and crank sensors can be a bear to track down. The car won't even start if either one is bad but they won't post a code until after the engine is running and the ECU can compare the signals.

...Lee