Picked up some bad fuel.

[Maverick24]

Hi guys, I seem to have picked up some bad fuel in my 4.2 Petrol Mav, at least I hope that's what it is. I'm going to drop a bit of metho in the tank.
I'm after some opinions on whether I should put the metho in and let it sit overnight or just before I go for a drive to get it through the system.
Also, how much, just a capful or 2 or more.
The car does'nt seem to run bad on the open road just seems to be coughing and spluttering a little when I turn corners or start to climb a hill.
I have also just put a Pertronix ignition and extended rotor in, so it's not the points.

[mike_nofx]

Stupid question, but did it start doing it right after you fitted the petronix and rotor?

[oldmate]

Is it a carby motor? That's what it sounds like. May or may not have been caused by bad fuel.

[Maverick24]

Not a stupid question and yes it is carby.
Bear with me while I tell the story!
I fitted the Pertronix kit and the car started running like a dream, that was for about 60 K's, then stopped for a while and the car started idling really rough and down around 300 RPM, nearly stalling. Started driving and was'nt getting a miss but could tell we were under powered and when I backed off some, was getting some prety big backfiring.
Still driveable this problem continued for about 120 K until we stopped again for about 45 minutes, then seemed to be driving ok again, Revs about 7-800 RPM.
Got home checked plugs, leads, and timing etc. all seemed ok.
Thought the coil might have been overheating so I made a heat sheild for it.
I have only been doing 30 k runs to and from work for a few days and car seemed to be ok but did seemed a bit spluttery when I turned a corner and drove up a short hill.
The other day went for a bit of a longer drive and the splutering got worse and was under power trying to climb hills.
The reason I'm thinking fuel is because the last 2 tank fulls, one before the kit was fiited and the other mid last week were from the same servo which had pretty cheap fuel (114.9), although it is a Mobil, but don't think that means that much these days. The tankers that go in there are'nt Mobil tankers.
Any suggestions appreciated.
Dave.

[RAY185]

Drain some fuel from the tank into a glass bottle/jar and hold it up to the light for a look. If you know what clean fuel looks like then you'll know fairly quick if your fuel is contaminated. You could have a carby problem or an issue with your petronix system.

[chimpboy]

I would suspect your pertronix over the petrol, sorry.

I once thought i had a fuel problem and went through lots of metho. In truth it was an earth problem at my ignition amplifier.

[Maverick24]

Well, I thought I'd give the Metho a go anyway, what harm could it do. Does seem to have made a bit of a difference although only had the short 30 k trips to and from work.
Other suggestions have been carbie needs some work!
So this weekend I will double check my fitting of the Pertronix, might throw in some new plugs and leads (again), give the tank a drink of Premium and go for a long drive.
If it's still happening after that. looks like we're off for a carbie overhaul.

[351ciofgrunt]

My problem was similar to yours and turned out to be ignition leads.

They can crack in the carbon core causing intermittent problems.

[Maverick24]

Didn't bother with plugs and leads as yet just put half a bottle of metho with half a tank of fuel and then put some premium unleaded (95 octane) in and is now running a hell of a lot better. Don't think they like the low octane fuels.

[BadMav]

The lower octane rating of the fuel won't bother a TB42, they only have about 8.3:1 compression (this makes them easier to turbo). Contaminated fuel will cause any engine trouble regardless of the octane.