View Full Version : engine misses


Brett
12-13-2002, 01:20:00 AM
I got a miss in my new engine in my Z28.I does not do it all the time.When it is idling it stumbles a little bit but not like its everytime.same if you give it gas and hold it there you can here just a little miss.everthing is new or rebuilt except for the distributor the cap and rotor is new.
engine is 350 bored 40 over performer intake,quadrajet,flattops,extreme energy 262 cam headers.new plugs and wires.could the old distributor do this?It is a hei?
Thanks Brett

81Z4ME
12-13-2002, 10:55:00 AM
I've only had one problem with an HEI dist. in 25 years through 5 vehicles. It just died. No miss, no stumble, it ran great right up to the point the engine cut off. Bad module. I'm not sure an intermittent problem would be spark related. I've seen quadrajets get worn to the point were idle, stumble, bog problems, etc. require regular fiddling with the adjustments to keep temporarily "fixing" the problem. Due to those sticking, worn linkages, levers, shafts, etc. I occassionally spray lubricant around the outside moving parts of a carb.

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81Z4ME

Brett
12-13-2002, 11:18:00 AM
The quadrajet has been rebuilt with new bushings put in.The man that rebuilt it is real good at carbs.Ill try to adjust on it some more.
Thanks

archemedes
12-13-2002, 03:43:00 PM
It could be module, they can do all kinds of strange things, also check all the wire connections to be sure they are tight, and check for a good ground, any of these will cause a low power situation to the coil and would cause a weak spark

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Joekool
12-13-2002, 08:52:00 PM
Double check your spark plug wires, espacially around the exhaust, pull the plugs and check any for fouling or other abnormal signs. Check the porcelin area of the plugs real well, a cracked plug will cause the engine to miss. Also pull the dist. cap and make sure that you put the spring and button under the coil. An HEI will run the engine without the coil button for awhile but the arcing will melt the coil and cap making the spark weaker and weaker.

You could try to do a cylinder drop test if you have a pair of insulated spark plug wire pullers. Bring the engine rpm up to where it starts to miss using the idle adjusting screw. Then using the spark plug wire puller, pull off one wire at a time. If you come to a cylinder that doesnt not drop the rpm very much or not at all then you found the bad cylinder. Using a good tach like the ones found on some timing lights will help.

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70 camaro 350 th350
74 trans am 400 th400

dgrewhl
12-17-2002, 11:30:00 AM
maybe try going over each wire with a timing light,,,see if you can nail down which cylinder that way,,or try Joekools way,,,checking the button to is a good ideer,,make sure it aint upside down,,,not like I've ever done that http://www.nastyz28.com/ubb/rolleyes.gif
g'luck

Brett
12-17-2002, 01:15:00 PM
Well havent had time to mess with it yet But got alot of good ideas from you guys.Thanks for everbodys help.