1986 E 350 Van, Small block, Tries to turn over but won't. Sounds like weak battery. New battery, If I pul;l the spark plugs motor turns perfect, Put plugs back in won't turn over. Pull starter and hook it to jumper cable and it seems fine. Put it back on motor, won't turn over. ANY THOUGHTS

What type of plugs are you trying to use? I had a serious performance issue with the 1999 Dakota after putting platinum plugs in it for a tune up . I found out that with the old-style ignition coil and distributor cap setup that there was not a hot enough spark to fire the platinum plugs properly. Went back to the old copper-core OEM plugs and everything ran fine. High performance plugs on a "low performance" ignition system equals major headaches. Here was one case where better wasn't better.

by start do you mean it won`t turn over or turns over but not start up. if you mean not turn over it could be weak battery, bad starter motor, bad wire connections. if you mean won`t start then it could be no spark, no fuel, worn out plugs, dirty or bad injectors.

Although more info would be helpful, the first thing that comes to mind
is that, somehow, the power to to ignition system was disconnected
when the starter was installed. Easy to check... take off a spark plug
wire at the spark plug, put a small piece of wire in the end, and place
this 1/4 inch away from engine block... be sure there is no gasoline or
gas fumes near. Have someone crank the engine and look for spark
from the plug wire to the block. If no spark, may well be the ignition
system (do this in shaded area so you can see the spark). If you have
spark, then the problem is elsewhere.

have you checked for spark? it has been my experience that most chevys have a problem with electrical stuff when cold. i would check for spark, it may be present but weak. i have a 95 k1500 suburban, and things like window motors and seat motors lag alot when its cold outside. if spark is weak, u may need a new coil

Car not starting or turning over indicates towards multiple possibilities. It can be issue with battery or weak battery. But if battery checks out ok, then it can be starter issue or faulty alternator or problem with low fuel pressure or no spark at spark plugs due to dirty spark plugs or faulty ignition coil or injectors getting cracked or dirty and needs to be cleaned.

To confirm the problem, the basic troubleshooting is required.

Click this link below and follow the troubleshooting:------

http://technoanswers.blogspot.in/2012/02/car-starting-issues.html

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This will help.

Thanks.

Do you notice crank when you turn over the key in ignition to start. Does it turn over but does not start, or no start nothing at all. ---------- If its not cranking and nothing happens when you turn the key, then its battery and starter related problem, both needs to be inspected.Either battery is not completely charged or its weak battery,that is not holding charge or its faulty battery or its connections are loose.-------- BUT if it is cranking and not starting, this clears that battery has juice in it and battery is doing its job and other possibilities needs to be checked. -------- The other possibilities are ,is the fuel pump coming on when you turn the key to start,is the spark is noticed at spark plug, is the check engine light coming ON. For more troubleshooting regarding this problem,click the link below:--- http://technoanswers.blogspot.com/2011/10/2000-chevrolet-astro-van-wont-start.html -------------- This should help.Thanks.Helpmech.

had this happen to me turns out one of the pistons was loose an smashing the spark-plug had to get home the same way time for a new motor unless you want to remove the oil pan and try to put in a new piston bearing and tighten it back down also replace damaged spark-plug

Double check the wiring to make sure it has perfect contact on battery, solenoid, voltage regulator (also check the regulator and starter relay)
You also may want to check the current on ignition module.

After sitting for a long time my Honda has a hard time starting. I have forun that it isn't a ignition problem rather a compression problem. Try about a tablespoon of 10w30 down the spark plug holes. turn the motor over then replace the plugs.

Needs Crank sensor. Good luck