olie05 Posted February 13, 2006 Share Posted February 13, 2006 I'm hoping some of the GN guys will chime in here... My dad has an Olds cutlass with a buick 231 V6. he has done a top end rebuild (replacing the heads, new gaskets new hyd. lifters) The problem is that it is running on 5 cyl. The car is missing on the #6 cyl. Is there any comon problem that we should start looking out for in diagnosing this thing? The engine is the odd fire 1984 version. btw the way we checked for this was by pulling a spark plug wire at a time and grounding it, to see if the engine changed idle characteristics, and when we got to #6, the idle did not change. There is spark to that cylinder, so what would be next on the list? thanks -Oliver Quote Link to comment Share on other sites More sharing options...
AK-Z Posted February 13, 2006 Share Posted February 13, 2006 For the rebuild mentioned, I'm guessing that you guys already change/check the plug. Does the plug on the cylindar that doesn't fire spark? You can check by having the car idle in a dim area and pulling th plugwire from it and holding it about half a inche from the plug, you should be able to see a spark jump across. If its good then could be the injector or something related. Might want to see if the cap is cracked, sometimes unnoticable and commonly overlooked. Quote Link to comment Share on other sites More sharing options...
Mike C Posted February 18, 2006 Share Posted February 18, 2006 I'd do new plugs and wires for sure. ANything over 5 years old probably needs replacing. Also make sure it has an odd-fire cap and rotor... I'm not sure if they are interchangeable, but a crossfire could spark the plug when there was no cylinder pressure, but fail to fire under load. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted February 18, 2006 Share Posted February 18, 2006 The engine is the odd fire 1984 version. Did not think there was such a combination. AFAIK, Buick stopped producing the odd-fire engine for production cars back in -77 or '78. Is it a turbo engine with the turbo sitting on top of the intake? If so it should be EFI. Regardless, if you diagnosed as missing on #6, and all others are OK, then it can only be a few things: bad inj, bad inj connector somewhere between the inj and the ECM, dead coil (but more like would affect 2 cyls, not one), dead plug or bad plug wire, very low compression in that cyl. if it is a carbed engine then ignore what I said related to EFI. Start by swapping a pair plug wires. If that is OK, pull the plug and read it to detrmine if it running lean or rich or it completely coated with oil (which you should have seen out the tailpipe). Put another good plug in it and then based on what you saw on the plug, chase an ignition or fuel problem. HTH Quote Link to comment Share on other sites More sharing options...
olie05 Posted February 18, 2006 Author Share Posted February 18, 2006 Thanks for the replies! We have checked the spark plugs and wires. It has a new dizzy cap, so for now i'm ruling that out. The car is carbureted, so the next thing i'm going to do is check the compression on that cylinder and see if anything is amiss. Btw Scottie, the car is an 84 olds cutlass supreme (4 door) and this is a N/A carburated engine, taking a closer look this engine is even fire. You are definitely right because looking at the FSM for this car, the only engine options were even fire. I thought it was odd fire because the spacing on the dizzy cap where the plugs go on, are not evenly spaced at all, but once you look inside, the actual contact are evenly spaced. Odd... (or should i say even... haha) Quote Link to comment Share on other sites More sharing options...
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