My 2005 S Type 4.2 has been really struggling to start this winter. It cranks fine, but the engine never catches. The only I can get it to start is repeated cranking and giving it some gas. This only happens when the car has been sitting outside for 12+ hours without being started. Once it starts, it runs fine. And I can turn the car off, walk away for a couple hours and it will also start fine.

I've been pouring over the forums (this questions has been asked several times before) and there seem to be 2 different answers proposed, but unfortunately, the people who asked the question never chimed in with which suggestion solved the problems.

The two schools of thought on the forums are:

1) It's fuel related
2) It's battery related

I'm skeptical of it being fuel related because if it was say, a bad fuel pump, it seems like it either wouldn't run smoothly, and/or would have a hard time starting all the time. Unless there was enough water in the gas to freeze in the line/injectors...

I'm leaning towards the battery, but it fits with the cold temps and time between starts. But that doesn't explain (I don't think) why pumping the gas would help start it.

Any suggestions?

 

All pumping the gas will do on a modern EFI car is allow more air into the intake. And that may not even be the case with an electronic throttle. You're not going to increase injector duty cycle until it fires.

Now does it crank strong and hard, or is the cranking anemicly? All a battery is going to do in this situation is spin the starter motor, and run the electronics. If it can maintain 11.5+v during the crank cycle then the problem lies elsewhere. Have you put a multimeter on the car and check voltage under cranking load?

Once that's been eliminated as a potential suspect, it's time to look at fuel.

When's the last time the fuel filter was changed? There may be moisture somewhere in the lines... Once it runs does it run fine and smooth? Does it ever feel starved for fuel? If not, prob not the fuel pump...

Just food for thought... Another thing u could do if you dont want to multimeter the car. Take a known good battery OR a running car with jumper cables, and then crank it. If you fire right up, battery voltage is the issue. If you still struggle, it's somewhere else.

 

If you have acces to a scanner. Look at the coolant temp. If the ECM thinks that the engine is still warm it will keep the mixture lean making it very difficult to start in cold weather. Hope that this helps.lol

 

It may be useful to place a fuel pressure gauge on the car to monitor what the residual pressure does upon sitting for extended periods of time. You can also watch to see what the pressure does when the "long crank" occurs. Sounds like a fuel issue to me. If you have no access to a pressure gauge, try cycling the key on (but not starting the car), then off again....repeat 2-3 times, then actually start it. If it starts fine doing this (you are priming the pump upon cycling the key), then there may be a bad check valve (part of pump) allowing fuel to bleed back, and pressure at the rail to be lost. This is why it may exhibit extended crank, but run fine once it starts.

Worth a try anyway.

 

Had it in to my regular mechanic.

It was the crank sensor. They replaced that ($200 including labor) and it's been starting fine since.

Thanks for everyone's input.