I have a 2001 Volvo S40 that sat for almost 3 years. I replaced the battery, oil and air filter, camshaft, and crankshaft sensors, added fresh fuel. It runs rough and almost dies at star up. It will completely die if I don’t give it gas. It’s shooting a P0017 code for the crankshaft and camshaft sensors. But those have recently been replaced. I’m at a loss. What could be causing this rough start and codes?

 

Codes do not necessarily mean a sensor is bad. It means a control unit does not like the signal it sees. You could have those codes because the timing belt is not timed correctly. ECU expects cam signal at certain engine signal - if off by a few degrees - you get cam and crank sensor codes. If the car has been sitting - I would make sure the timing belt is not about to break, has no visible cracks on the outside of it, (and is timed correctly). If it breaks or comes off the repair cost will be greater than the value of the car.

Rough running when first starting - what do the spark plugs, ignition wires look like? Does the engine use coolant?

Stalling - that engine (99-04 sv40) has a electric idle control valve unlike any other Volvo. All other Volvos after 1998 use a drive by wire throttle, and your car still has a throttle cable. Have replaced many s40 idle control valves but usually the car won't idle at all or stalls frequently when bad.

 

common cause of long cold start cranking in gen 1 S40s is a leaky fuel pressure regulator due to a torn diaphram. The FPR sits on the right hand side of the fuel rail - a quick check is to pull off the S shaped vacuum tube on the bottom and if fuel drips out, time to replace. Note the part is rather expensive ($150 or so!) so best to do some tests before swapping out on a guess. Good news is the part takes about 10-15 minutes to install.

 

So I went with everyone’s advice and checked the timing. It seemed to be slightly off on the left cam sprocket. It was just passed the mark. Right side and crank sprocket both lined up perfectly but the belt was loose and seemed pretty worn. So I figured I’d just replace the belt while I was in there. After removing the belt, the left cam sprocket turned about an inch clockwise. I was able to rotate it back into place but it keeps rotating back when there is no pressure applied. Can this be fixed by just aligning the mark while under pressure and replacing the belt? This one is new to me. I’ve done timing jobs with chains and never had this issue.

 

check out youtube for guidance on how to reset timing for a Volvo VVT gear on the exhaust cam. You may need a cam lock tool to set the base timing before doing the rotation of the gear...