Crank no start condition during cold temps...

[dubsetter]

Hi,

I would like to start by thanking you guys for all the advice I have received from this site, I have saved a lot of money thanks to the resources and advice on this forum.

My 96 850 non turbo wagon had been running great all summer. I purchased the car last January. During the early spring I had some fuel system related issues and a dead starter. I replaced the starter, fuel pump, pump relay and main relay (fuel injector relay). The car had been running great all summer with the exception burning oil which my mechanic suspects to be stuck piston rings, which we are trying to treat with moa additive during regular 3k mile oil changes.

I live outside the dmv area in the mid Atlantic region, so this fall has been really mild. I have had random crank no start conditions with no check engine warnings whenever the temp is lower than 45 degrees. If it is around that temp there is a slight hesitation to start and if it is 50 or above it starts up perfect.

I have done a little research with the limited time I have and figured I would start by replacing the distributor cap and rotor since I know that was not done before I bought the car and also remove and clean the MAF while I'm at it. Other suggestions I read included replacing crank sensor, cam position sensor and temp sensor. My mechanic suggested buying testers for the spark plugs and fuel injectors, but I would rather borrow the tools or just bring it to him when it's warm enough to start so he can test them. In the mean time I will start with the cap and rotor and clean the MAF since it can't hurt.

My question is, which of these possible causes would not throw up a check engine code? I thought about testing different areas by warming them up with a hair dryer and then starting to isolate the trouble area....silly idea?

Again thank you all very much and as always your suggestions are greatly appreciated.

[scot850]

Can you clarify a little for me. When you say it won't start, is it turning over but not starting, or not even turning over? The reasons for either are naturally different for us to try to help.

Have you changed the coolant temp sensor by the thermostat? The helps the engine to determine how much to enrich the system when it gets cold. It sits under the thermostat. Also check the connector that is mounted on the rear of the power steering pump as it can get corroded. This is assuming the engine is turning over.

Another possibility is the throttle position sensor, again assuming the engine is turning over.

These cars are particular on brands of parts fitted in the ignition system (plugs/wires/dist. cap/rotor), also the temp sensor is advisable to be OE.

Can sensor is a possible, but I would have expected it to be an issue at all temps, but again check the connector for corrosion.

As your car is a 96 I am going to guess you don't have the underhood test system that was fitted to early cars. Not all non-Volvo system testers catch all the warning codes, so it could be they are being thrown but not seen.

Neil.

[dubsetter]

Thanks for the reply. The car is definitely turning over but not starting (in the cold). Today it was 50 and it fired right up. I just took it for a spin.

Looking over the few maintenance records I have on the car it states that a new radiator, thermostat and fresh coolant was put in as well as new spark plugs, but no mention of cap and rotor. I would think they would put a new temp sensor with the thermostat but who knows, I will have to investigate.

[dubsetter]

After having a quick look I noticed the connector and wire to the temp sensor look pretty old. I saw no corrosion but I would say this sensor has not been replaced unless for some reason they replaced just the sensor and used the old wire and connector (doesn't seem likely).
The distributor cap looks pretty old as well and I noticed a small crack in it while inspecting it. So I will definitely be replacing both. I will let you know how it goes. Thanks

[rspi]

Temp sensor.