TR-icky Posted February 5, 2017 Report Share Posted February 5, 2017 Hello all, Took the car out for a quick run this morning just to shake off any cobwebs before her MOT next week. I normally use standard unleaded and car has always run reasonably well but this morning I filled her up with super unleaded and nearly didn't make it home again. Could filling with super have caused severe back firing, with plumes of black smoke with each bang, lack of power, stuttering and dropping off at least one cylinder? It seems to get worse the harder I press the accelerator pedal. Any suggestions greatly appreciated Regards Gary Quote Link to post Share on other sites
RogerH Posted February 5, 2017 Report Share Posted February 5, 2017 Hi Gary, the better quality fuel shouldn't do that. Are you happy that the fuel at the garage pump has not been contaminated. Allowing the car to lay idle for any length of time is always a recipe for disaster. The fact that it is backfiring suggests the fuel is working. I think you will need to check all the ignition parts - rotor arm etc. Perhaps in blowing the cobwebs off some got into the fuel. Roger Quote Link to post Share on other sites
oldtuckunder Posted February 5, 2017 Report Share Posted February 5, 2017 Hi Gary, the better quality fuel shouldn't do that. Are you happy that the fuel at the garage pump has not been contaminated. I'd probably go with Roger's suggestions, however will admit to an embarrassing incident last year with super unleaded. Day before an eventI drove the Vitesse to the nearest BP station (not that near) to put half a tank of Ultimate Unleaded in. Drove away and about 1-2 miles later car started misfiring, power dropped off, very unhappy engine so pulled over. After 10 mins checking everything was starting to conclude that it was bad fuel, then noticed said bad fuel wasn't evaporating, sniffed hard, bug..er Diesel! Anyway not too major a problem to resolve and the drained diesel went in to the truck. However I was confused how I had got it so wrong, but on returning to the garage for some proper Ultimate I could see how easily I made the mistake, both the Diesel and Unleaded pump signs both prominently feature the word "ULTIMATE" with the type in small print, and both use Blue on the sign and the pump handle to indicate its "ULTIMATE" its just that they are two slightly different shades of blue. I just hadn't been paying close enough attention and had picked a Blue Ultimate pump, but not the right Blue Ultimate pump! Alan Quote Link to post Share on other sites
Peter Cobbold Posted February 5, 2017 Report Share Posted February 5, 2017 Gary, After filling up It probably started OK and ran for a few yards OK. Then started misbehaving as the diesel/petrol mix reached the carbs. Drain and refill the tank. Peter Quote Link to post Share on other sites
barkerwilliams Posted February 5, 2017 Report Share Posted February 5, 2017 Gary, Is yours a pI? PI's run on 5 cylinders reasonably happily, so one stuck/sticking/grumpy injector could give the symptoms you describe. Let the car cool down, park outside, remove injector clamps and start engine and withdraw each injector a couple of inches and look to see the fuel spray. Work through all six to check if you have a bad injector. Alan Quote Link to post Share on other sites
marki Posted February 5, 2017 Report Share Posted February 5, 2017 Diaphragm in the meeting unit ? Mark. Quote Link to post Share on other sites
Ben Freer Posted February 5, 2017 Report Share Posted February 5, 2017 Condensation in the dizzy cap? Quote Link to post Share on other sites
Sapphire72 Posted February 5, 2017 Report Share Posted February 5, 2017 (edited) Back firing: check that spark plugs are dry. Edited February 5, 2017 by Sapphire72 Quote Link to post Share on other sites
Peter Cobbold Posted February 5, 2017 Report Share Posted February 5, 2017 Remember Occam. It is most often the last thing you did that caused the problem. In this case adding fuel to the tank. Peter, with razor at the ready. Quote Link to post Share on other sites
Bill Bourne Posted February 6, 2017 Report Share Posted February 6, 2017 I'd probably go with Roger's suggestions, however will admit to an embarrassing incident last year with super unleaded. Day before an eventI drove the Vitesse to the nearest BP station (not that near) to put half a tank of Ultimate Unleaded in. Drove away and about 1-2 miles later car started misfiring, power dropped off, very unhappy engine so pulled over. After 10 mins checking everything was starting to conclude that it was bad fuel, then noticed said bad fuel wasn't evaporating, sniffed hard, bug..er Diesel! Anyway not too major a problem to resolve and the drained diesel went in to the truck. However I was confused how I had got it so wrong, but on returning to the garage for some proper Ultimate I could see how easily I made the mistake, both the Diesel and Unleaded pump signs both prominently feature the word "ULTIMATE" with the type in small print, and both use Blue on the sign and the pump handle to indicate its "ULTIMATE" its just that they are two slightly different shades of blue. I just hadn't been paying close enough attention and had picked a Blue Ultimate pump, but not the right Blue Ultimate pump! Alan Oh it's good to hear someone else did this. Me toooooo ! a long time ago at a "BP station" One interesting sight though, was the incredible smoke rings it made from the exhaust. Huge and they lasted for about 30 seconds. I even got a nut of the year award, and called diesel dan for about a year. No doubt I'll get ribbed for mentioning it again. Best Bill Quote Link to post Share on other sites
Clarkey Posted February 6, 2017 Report Share Posted February 6, 2017 HI Gary. What super did you use? I doubt it would be that like Roger has commented on. How long had it been since you last started/ drove the car? I have had something similar in the past when i had the car laid up and didn't start it much over the winter. Mine was misfiring quite badly then there was an almighty backfire and she ran like a dream after that Quote Link to post Share on other sites
TR-icky Posted February 6, 2017 Author Report Share Posted February 6, 2017 Thanks for all your help guys. Firstly I'm 99.9% sure I did not put diesel in. I have noticed that it runs much better when cold and on the choke. i haven't had much time to get this sorted but as per Roger's suggestion I checked the ignition and changed plugs etc., I did notice that a slight timing adjustment (by ear) seemed to make a bit of a difference. i also checked the injectors as Alan said and all have an umbrella shaped spurt of fuel into a glass jar. Hopefully it's just a matter of setting up the timing properly. I hope to get back at it during the week so I'll let you know how I get on. Cheers Gary Quote Link to post Share on other sites
Peter Cobbold Posted February 7, 2017 Report Share Posted February 7, 2017 Octane, low or high, makes no difference to the optimum spark timing ( except when knock threatens - which is does not here) I'm with the 0.1% probability. Peter Quote Link to post Share on other sites
TR-icky Posted February 7, 2017 Author Report Share Posted February 7, 2017 Ah Peter, I didn't know that! Ok, before I go to much further I will drain the tank, just to be sure. Thanks again. Quote Link to post Share on other sites
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