View Full Version : Ooops! Petrol in diesel....

24-10-2008, 07:05 PM
Hi folks; Just wondered if anyone had starting issues on at tdi bug after being a goon like me & put some petrol in their diesel tank.
Put 10 petrol in an empty tank,realised error,topped up(without starting it) with 48 diesel. Since then starts fine from cold,runs lovely,but is pig to start nearly every time if left 10mins to an hour. Fitted new fuel filter/no warning lamps on/no codes in engine management system. Put another 10 diesel in today,but still the same.......:aargh4:

24-10-2008, 09:23 PM
I used to work for VW assistance and the official line was up to 25% petrol in a diesel was ok. that was in 2003, so might be different now.youve done right to fill up with diesel, keep doing that when down to 1/2 tank or so. this shouldnt have any affect on starting at all though.

24-10-2008, 10:51 PM
Hi Zollaf;thanks for prompt reply. I cant understand the starting thing;the lift pump in the tank seems to buzz up ok to build pressure,but its very reluctant to fire.Dont fully understand the PD implications-assume old school tdis are normally more tolerant. Just found a thread on an American VW Tdi site that says bung some diesel cetane enhancer in the tank so will try that tomorrow(was reluctant to add usual fuel-system flush/treatment as assumed the petrol would be cleaning everything out well anyway!....) Thanks again.

24-10-2008, 11:03 PM
it might just be that the petrol isnt firing up as well as diesel when hot, though it shouldnt make any difference. It might clear itself once all the petrol is out of the system.

09-11-2008, 07:11 PM
Hi; just a follow up to round up this topic & thank those who replied.
As suggested I added some cetane booster in the form of Millers Diesel Power Plus. Doubling(well a bit more than that actually...) the dose.
The car continued to start well from cold,ran & sounded as normal. Restarting after a break of 10 minutes to half hour still needed a good 10 seconds plus of cranking before the engine would fire. Even a refill of the tank when half empty with fresh diesel still didnt solve it. It has taken another running down to empty & total refill of fresh diesel to cure & return to normal starting;-just as I was beginning to think the worst!
So,if you have the same,then hang in there,try the additive & keep everything crossed. Better still dont be a **** like me putting in petrol in the first place!:Blush:
Thanks again,A.

01-12-2008, 07:56 PM
There is a hard to start when hot issue: