2004 xc70 occasional hard start when warm

raquette · Post by **raquette** » 15 Apr 2026, 08:15

engine will turn over fine but not start occasionally when the engine is warm. new plugs, gas filter. has been doing this for over a year. does not do this during the winter in the colder northeast climate.

when this occurs the vehicle will always start after several attempts. I have tried securing shifter into park , tried neutral, securing brake pedal, and it it starts after 3-5 tries. Worried one of these times it will not start.

any suggestions on what to look for the cause of this?

Post by **cn90** » 15 Apr 2026, 10:55

Could be bad ECT sensor.

raquette · Post by **raquette** » 16 Apr 2026, 05:15

ok makes sense I'll check into that thanks

Post by **vtl** » 16 Apr 2026, 08:12

Crankshaft position sensor very likely. If the plastic plate holding the wires above starter disintegrated, the CPS wires drop to the starter and suffer electromagnetic noise that starter produces. Zip tie the wires away from the starter and see how it goes.

Porkchop32 · Post by **Porkchop32** » 22 Apr 2026, 14:33

May be a long shot but check ground wire to fuel pump

Post by **chrism** » 22 Apr 2026, 18:38

Carry a fuel pressure gauge that you can quickly attach to the injector rail the next time you have a no-start. At least then you can see if the pump is delivering. If you have an assistant that can turn the key you use an old tire gauge to check for pressure.

Post by **jonesg** » 22 Apr 2026, 18:50

raquette wrote: 15 Apr 2026, 08:15 engine will turn over fine but not start occasionally when the engine is warm. new plugs, gas filter. has been doing this for over a year. does not do this during the winter in the colder northeast climate.

when this occurs the vehicle will always start after several attempts. I have tried securing shifter into park , tried neutral, securing brake pedal, and it it starts after 3-5 tries. Worried one of these times it will not start.

any suggestions on what to look for the cause of this?

read the codes for direction.

Post by **jonesg** » 22 Apr 2026, 19:44

raquette wrote: 15 Apr 2026, 08:15 engine will turn over fine but not start occasionally when the engine is warm. new plugs, gas filter. has been doing this for over a year. does not do this during the winter in the colder northeast climate.

when this occurs the vehicle will always start after several attempts. I have tried securing shifter into park , tried neutral, securing brake pedal, and it it starts after 3-5 tries. Worried one of these times it will not start.

any suggestions on what to look for the cause of this?

read the codes for direction.

Post by **br0dy519** » 22 Apr 2026, 21:08

I'm thinking a vacuum leak. Check gas pressure in the morning after leaving a gauge on it overnight.