Crispyc Posted June 14, 2009 Share Posted June 14, 2009 (edited) When my engine idols cold it has a problem with what my brother described as "sucking valve". When it warms up to normal operating temperature it stops doing it. I need a list of possibilities? Edited June 15, 2009 by Crispyc Link to comment Share on other sites More sharing options...
MY1PATH Posted June 15, 2009 Share Posted June 15, 2009 if its tap-tap-tap like a nickel on hardwood than it may be a lifter. the valve may not be fully opening because of this. Or I'm totally wrong and it's something I don't know about. Link to comment Share on other sites More sharing options...
Crispyc Posted June 15, 2009 Author Share Posted June 15, 2009 Although I do have a tap, I'm making referance to a seperate issue. If you hold a piece of paper an inch or two from the exhaust pipe it will periodically suck the paper toward it. I have had a slight prblem with this for a while, but this weekend I changed the sparkplugs, wires, rotor cap and rotor button. After changing them it started doing it a lot, to the point where some times the engine cuts off. When the temperature needle stars to go up it starts to smooth out and when its hot it does not happen at all. Link to comment Share on other sites More sharing options...
nismothunder Posted June 16, 2009 Share Posted June 16, 2009 Are the rpms going up and down? Link to comment Share on other sites More sharing options...
87pathy Posted June 16, 2009 Share Posted June 16, 2009 the only time i've ever seen that happen is when the cam timing is off. Link to comment Share on other sites More sharing options...
Crispyc Posted June 17, 2009 Author Share Posted June 17, 2009 (edited) Are the rpms going up and down? It does go up and down a little bit until the engine warms up. I have not checked the timing yet. Edited June 17, 2009 by Crispyc Link to comment Share on other sites More sharing options...
landis Posted June 23, 2009 Share Posted June 23, 2009 Could just be a bad MAF sensor. Link to comment Share on other sites More sharing options...
88pathoffroad Posted June 27, 2009 Share Posted June 27, 2009 "Sucking a valve" or "dropping a valve" is what happens when a valve breaks at the stem end and drops into the combustion chamber with catastrophic results. I'd check the timing first. Link to comment Share on other sites More sharing options...
nismothunder Posted June 28, 2009 Share Posted June 28, 2009 (edited) "Sucking a valve" or "dropping a valve" is what happens when a valve breaks at the stem end and drops into the combustion chamber with catastrophic results. I'd check the timing first. Usally caused by extreme Rpms I'd check for a hose missing...causing A vacum leak...mine did this and it was a missing hose on the back of the engine.The Fuel pressure regulator hose.It plugs into the intake. It would suck if you checked the timing and it turns out to be a hose. Edited June 28, 2009 by nismothunder Link to comment Share on other sites More sharing options...
Crispyc Posted June 29, 2009 Author Share Posted June 29, 2009 The timing is advanced by about 3 degrees and I sprayed carberator cleaner with the engine running trying to find a vaccum leak. Nothing so far. Link to comment Share on other sites More sharing options...
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