coldturkey Posted October 20, 2010 Share Posted October 20, 2010 Hi, My Vauxhall 1256cc is running on 3 cylinders a lot, sometimes it will start on 3 and then when it warms up the 4th will kick in. Being that it is Carbueretted, its most likely to be electrical thats the problem right? I haven't checked spark on that cyl yet, I will tonight but is there anything else i can check? Last night when I checked it was cylinder 3 that was the issue so since its one of the middle cylinders the problem is likely to not involve lack of fuel? Or could it be something like a sticky intake valve or something? Cheers Quote Link to comment Share on other sites More sharing options...
UTERUS Posted October 20, 2010 Share Posted October 20, 2010 Whip the plug out and see what colour it is, that can tell you a bit about what is going on. Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 20, 2010 Author Share Posted October 20, 2010 Whip the plug out and see what colour it is, that can tell you a bit about what is going on. True, Black/wet = no spark? Dry = no fuel? Quote Link to comment Share on other sites More sharing options...
Raizer Posted October 20, 2010 Share Posted October 20, 2010 Whip the plug out and see what colour it is, that can tell you a bit about what is going on. True, Black/wet = no spark? Dry = no fuel? Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 20, 2010 Author Share Posted October 20, 2010 Sweet picture. Thanks. I've also heard that if it the leads are bent too sharply it could cause a gap and the spark will be wrong? The leads are new, but they were basically whatever we could find that would fit. One of more may be a bit tight and be bent a bit too much Quote Link to comment Share on other sites More sharing options...
tortron Posted October 21, 2010 Share Posted October 21, 2010 I always got asked if my shuvit was a rota au. when it was on 3 cylinders. so i say keep it like that Test if there is spark getting to the plug. Test them all again just to be sure. Has the engine been sitting a while? Quote Link to comment Share on other sites More sharing options...
Unclejake Posted October 21, 2010 Share Posted October 21, 2010 Sweet picture. Thanks. That picture, whilst helpful, is not as valid for unleaded fuel Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted October 21, 2010 Share Posted October 21, 2010 ^yuh. unleaded sux plugs, leads, dizzy cap maybe worthy lokoing at. if it picks the cylinder up when it warms up and the abovementioned is all sweet, you could have a poorly seating or bburnt out valve. I had a mini back in the day that owuld run on 3 cylinders for the first 5 minutes then pick up the 4th. was burnt out valve. very lol. Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 21, 2010 Author Share Posted October 21, 2010 I always got asked if my shuvit was a rota au. when it was on 3 cylinders. so i say keep it like that Test if there is spark getting to the plug. Test them all again just to be sure. Has the engine been sitting a while? Haha mine doesn't sound like a rotor. It sounds like a tractor. It hasn't been used much of the last couple years, and does sit for extended periods of time occasionally (2 weeks or more). I did just get new leads (couple were toast), and I have new plugs and a new dizzy cap to put in aswell so that might fix the problem. I can compression test it, and this would tell me if there is valve trouble right? From what I have found it should be 8.7:1, i.e. all cyl around 128 psi ? Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted October 21, 2010 Share Posted October 21, 2010 from cold it'd probably show up poor valve seating. I'd pop the valve out of the compression tester so it doesn't go all 'cumulative' on you. might jsut need an italian tune up Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 21, 2010 Author Share Posted October 21, 2010 from cold it'd probably show up poor valve seating. I'd pop the valve out of the compression tester so it doesn't go all 'cumulative' on you. might jsut need an italian tune up Aye, explain? Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted October 21, 2010 Share Posted October 21, 2010 italian tune up - thrash the shit out of it. Quote Link to comment Share on other sites More sharing options...
cletus Posted October 21, 2010 Share Posted October 21, 2010 modern fuel is not good for older engines that sit for longtime- fouls plugs easily. if you start it and hold rpm at steady 2500-3000 at a light throttle opening that usually clears it out pretty good, you will hear the fouled cylinder start popping and eventually clear itself. pumping the throttle will make it worse, dumping more fuel into a cylinder that isnt firing will make it harder for the plug to sort itself out thats if somethings not fucked like a valve etc as previously mentioned sometimes a leaky headgasket will cause the same thing Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 21, 2010 Author Share Posted October 21, 2010 Hmm maybe that is my issue, cause normally I pump the gas for a while. Well anyway, I changed all the plugs and at the same time did compression test. The plugs didn't look worn but most were pretty black, cyl 3 was black and wet. Once I changed cyl 3 plug it ran sweet as a nut on all 4. However, now my concern.... Compression test results: Cyl 1: 128psi Cyl 2: 103psi Cyl 3: 70psi Cyl 4: 99psi Uh oh.... maybe I just have some sweet blow by cause its been sitting dormant for a while? The car was pretty cold when I tested it, but I let the engine start and run for 2-3 secs for each cylinder I tested. What you guys reckon? Cyl 1 tested sweet, like factory, but is it feasible that the engine could wear so unevenly? Quote Link to comment Share on other sites More sharing options...
KKtrips Posted October 21, 2010 Share Posted October 21, 2010 Sounds lke a classic case of tight tappets - if you don't run valvemaster or some shit the valves seats will recess and reduce the valve clearance - check those and report back... good boy.. Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted October 21, 2010 Share Posted October 21, 2010 if it's been sitting for months on end without running it could have corrosion on one exhasut valve or something if that one's been sitting open? i'd be inclined to give it some herbs then see what goes down Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 21, 2010 Author Share Posted October 21, 2010 Sounds lke a classic case of tight tappets - if you don't run valvemaster or some shit the valves seats will recess and reduce the valve clearance - check those and report back... good boy.. Never done valve clearances before, could be interesting. So you reckon the clearances will be too small, and I should increase them? And, So I should be running a fuel additive? Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 21, 2010 Author Share Posted October 21, 2010 if it's been sitting for months on end without running it could have corrosion on one exhasut valve or something if that one's been sitting open? i'd be inclined to give it some herbs then see what goes down lol, you honestly speak a language I dont understand What do you mean by "Give it some herbs then see what goes down"? Quote Link to comment Share on other sites More sharing options...
KKtrips Posted October 21, 2010 Share Posted October 21, 2010 Sounds lke a classic case of tight tappets - if you don't run valvemaster or some shit the valves seats will recess and reduce the valve clearance - check those and report back... good boy.. Never done valve clearances before, could be interesting. So you reckon the clearances will be too small, and I should increase them? And, So I should be running a fuel additive? I mean the valve clearances may be zero - if you are not sure on how to set them - it may pay to bribe someone with a box of beers to set them for you.. they need to be set precisely - or at least more than zero clearance between the rocker and the valve stem while the cam is on its base circle.. If you don't know what these mean - get ya wallet out and pay some labout or a box of beers.. Yes run a fuel additive.. if it's been sitting for months on end without running it could have corrosion on one exhasut valve or something if that one's been sitting open? i'd be inclined to give it some herbs then see what goes down lol, you honestly speak a language I dont understand What do you mean by "Give it some herbs then see what goes down"? Give it a fang up the highway and get a few km's under its belt to blow the cobwebs out.. Then see if the compressions are any better Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 21, 2010 Author Share Posted October 21, 2010 I mean the valve clearances may be zero - if you are not sure on how to set them - it may pay to bribe someone with a box of beers to set them for you.. they need to be set precisely - or at least more than zero clearance between the rocker and the valve stem while the cam is on its base circle.. If you don't know what these mean - get ya wallet out and pay some labout or a box of beers.. Yes run a fuel additive.. Good advice. Anyone in the tron thats keen for a cashy, im keen to help out and learn etc Quote Link to comment Share on other sites More sharing options...
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