I need help. My v40 is flooding when cold and causing low compression along with no start. As soon as it is started the compression is good to go when checked again and it will start the rest of the day. If I leave it overnight and try to start again is floods again. WHat can I check to fix it?

 

what year is your V40? if its the gen 1 model (say 2000 to 2004), check the fuel pressure regulator - its attached to the end of the fuel rail with the fuel line coming into to in. At the bottom there's a small vacuum line - if fuel leaks out when you pull off the vacuum line, the FPR has a torn diaphram allowing fuel to get into the air intake and it needs to be replaced. If that checks out fine, I'd suspect you have a leaky injector.

 

Thank you so much for your reply and efforts. I have changed the fuel pressure regulator and the injectors and well as the temperature sensor near the thermostat. For some reason it is getting too much gas when cold. It has been to three different mechanics and they are baffled. My next guess is the throttle body might be getting stuck. Any other suggestions? And yes it is an 04.

 

did the mechanics measure the fuel pressure after its been sitting? how do the plugs look? It may be you don't have a hot enough spark - the 1.9Ts its not uncommon for the harness to the coil packs (and associated connectors) to crack or break down. I just recently dropped in a new harness/coils/wires/plugs on our 2000 S40 and it made a huge difference. It can certainly be throttle body related - there is a throttle position sensor Volvo #9146315 involved that could be off at idle...not a cheap part to just randomly throw into the mix but worth a look. Curious what happens if you try starting with your foot on the pedal (say half way).

 

I measured the fuel pressure myself and it dropped to 20 after about an hour. Another mechanic said the fuel pressure was ok. The fuel pump is new as well. The plugs are brand new. The coils look as if they are brand new. I didn't replace them but I think the previous owner did. I bought a throttle position sensor but I didn't put it in yet. I can't find it in the engine. No change if I put the pedal down all the way, half way, or not at all. One mechanchic said it needed a valve job but I don't think so as it only has 40000 miles. I think the excess gas is washing the oil off the rings and killing the compression. The compression reads 40 cold but after it starts the compression in all cylinders shoots up to 150 or above after it is started once and shut off. When it is started and shut off then started again it runs like a dream. The codes read misfire and small vacuum leak. It will start in the summer and won't start at all in the winter months. I live in so cal so it really doesn't get that cold but it is cold enough to cause a problem.