Hello, I am from Sweden and this is my first post here.

A couple of months ago my v70 t5 2005 started to have some problems. When it sits overnight it won't start at the first crank, just spins on the starter no matter how long. But the second time it fires up right as it should no hesitation. And when the engine is warm it starts on the first attempt but has a long cranking time, about five seconds. This problem does not change, it's always exactly the same every day. The car has been in a workshop for almost 3 weeks and they can't find anything wrong, and its no error codes at all.

I have checked/replaced:
Replaced all spark plugs and coils
Replaced the battery
Checked the fuel pressure and its always as it should
Cleaned the throttle body

After I replaced the battery it started normally for like two days then the problem came back again. The workshop has no idea, the only thing they said is that it could be a faulty ECU, but I don't want to replace such an expensive component if I'm not guaranteed the problem will be solved.

Now I'm looking for other people who have or have had the same problem and could give me some advice on what I should do next! Thanks

 

Have you left a fuel pressure gauge on the engine overnight and watched what the pressure does when first started? Or is the pressure being read after the car is started, shut off, gauge attached and restarted?

And it's not going to be a bad ecu.

Does your engine have a fuel pressure sensor on the end of the fuel rail? That fuel system has a fuel pump controller, cars without a fuel pressure sensor have a more normal fuel pump. If the fuel pump controller was still mounted to the side of the gas tank in that year - the electrical connections were subject to corrosion - worse in areas where solutions are used on roads during the winter.

 

Hello, yes this car dont have any fuel pressure senor, instead it have a so called PEM-unit which controlles the fuel pump. The PEM-unit is not bad because I replaced that a year ago.

I have checked the fuel pressure both via OBD and manually at the fuel rail. The pressure is good both at the first try to start and also when it starts. I have also checked the pressure after it have stand for a couple of houres to se if it looses the pressure but it dont.

 

I had the same problem on a personal car of mine - very frustrating for I could not find any value or component that was bad. Never wanting to replace parts I can't prove are bad I replaced the coolant temp sending unit - and that solved the problem. This was a 2001 xc70 with the 9125463 sending unit with a pigtail. Your car probably uses the later style sensor - a 8653103 which I have no sales history of - meaning I've never sold one to a customer. However that sensor comes on the thermostat housing when you replace the thermostat, so that may explain why I've never seen a bad one.

 

Ok, thank you so much. Maybe I should try to replace that sensor, I mean it's not so expensive. But I wonder, should it not set an error code then? Did you have any error codes on your 2001 xc70?

 

No, no coolant sensor codes - very frustrating because the rule at my shop was to not replace parts (and charge the customers) unless they could be proven bad. Did have boost codes sometimes from a bad ECU tune - but that's another story

 

Ok, I have ordered a new one now. Hope it will solve the problem. Because the engine gets harder to start the longer it stands, so something with the engine temp is very possible. Thanks for the help, I will get back when I have replaced it.