Petrol in a D5
 

Car is a 2004 V70 D5 163hp. With low fuel in the tank I accidentally put 4 gallons of petrol in the tank and drove a mile home before realising my mistake. I then drained the tank and put 4 gallons of diesel in and a new filter. After a bit of coaxing it started and ran fine. I added more diesel to the tank.
Car now starts and runs fine from cold but has hot starting problems. Rail pressure is about 5000psi when idling and tank pump seems to be working. Ive also tried another make of filter. Any help appreciated.

its possible that the injector tips may be damaged/ melted remove and check them.

Thanks for reply. I'm not ruling anything out at the moment but if the injectors were damaged wouldn't that affect most aspects of running. It starts fine when cold and runs fine especially with the Shell V power in it. It is only hot starting that is affected. I'll try and do a rail pressure check when cranking.

Its possible that the wrong fuel is still in the lines. You put 4 litres of petrol in accidentally, then put 4 litres of diesel in, but only drained the tank.

You need to add more diesel than you added in petrol. So if you added 4 gallons of petrol, you need to add more diesel than 4 gallons to get rid of the wrong fuel. Keep changing the filter until you're 100% sure its diesel only in it and not a mixture.

Thanks for that. Will try more diesel. After I drained the tank I put 4 gallons of diesel in. When I got it going I put another 4 in and I have probably done about 20 miles altogether since.I would have thought that would clear it. No smoke. I maybe wrong. Still poor hot start. It goes if I use a bit of brake cleaner but don't like doing that. Starts first time from cold.

Contrary to popular myth, putting petrol in a diesel on the odd occasion rarely causes any damage.

I'd fill the tank completely, then again when half full, I'd expect it to be back to normal then.

I hope you're right. i somehow suspect a problem on the low pressure side of the fuel system. Could I have damaged the fuel filter housing or something so it is letting in air? There are no leaks but it appears these cars are fussy about the fuel filter. I have tried 3 different makes now and have never had trouble with these before.

I agree. In the old days, it was not unusual to add perhaps 10% petrol to a DERV in winter to facilitate cold starting and mitigate against 'waxing' of the fuel.

Regards, John.

No it won’t have damaged any housings. For fuel filters use genuine Volvo or Mann - you won’t go wrong with those.

Still no luck. There is now 12 gallons of diesel in the tank. Everything works as normal except for hot starting. Not sure where to go next. No relevant codes come up. Only a code for no signal from CEM to AUM. Aftermarket radio fitted.