87century starts cold but not hot

[69chevy]

I have an 87 century that I rebuilt the 3.8L multiport injection engine (didn't run when I got it, one of those "good deals that didn't end up so good"). It starts OK, not great, and seems to run good until it gets warm, then it gets a little rough, but doesn't ever die. The real problem is that If I turn it off after it warms up it won't start again. It fires occationally, but not nearly enough to start. I've been told that sounds like a coil problem, but the coil-pack is new. Any other Ideas ? ?

12/27/04
p.s. When I try to start it when warm there is absolutely no spark. Is there any sensor that could be malfunctioning to cause this? There is also an elusive electrical short that drains the battery overnight, could this be related?

[infoenterpriseltd]

I cannot be certain. Sounds like symtoms of a crankshaft sensor???

[NakedDancer]

Try having the ignotion module tested, it is responsible for spark, then if that checks out you can try the ecm. Both can be tested for free at autozone.

[computerdude14]

Originally Posted by 69chevy

I have an 87 century that I rebuilt the 3.8L multiport injection engine (didn't run when I got it, one of those "good deals that didn't end up so good"). It starts OK, not great, and seems to run good until it gets warm, then it gets a little rough, but doesn't ever die. The real problem is that If I turn it off after it warms up it won't start again. It fires occationally, but not nearly enough to start. I've been told that sounds like a coil problem, but the coil-pack is new. Any other Ideas ? ?

12/27/04
p.s. When I try to start it when warm there is absolutely no spark. Is there any sensor that could be malfunctioning to cause this? There is also an elusive electrical short that drains the battery overnight, could this be related?

my buddy had a dodge colt E with the same sort of problem... ended up being the distributor cap and rotor was shot. id look into that. also try new plugs and wires and stuff like that too. wouldnt hurt for a lil PM (preventative maintainence) anyway, even if those things dont end up being the cause of the problem. hope this helps.

mike

[MoNsTeR`ImPaLa]

safe bet on the spark control module and its easier the pulling the harmonic balancer off

[computerdude14]

yea, my 96 century is startin to do something very similar too... just started doin this within the last week or so tho... it starts great just as it should when the engine is cold or has been sitting for a couple hours etc, but then if i drive it around for awhile, then like stop to get gas, it will act like it doesnt wanna start, but if i crank it over for like literally 10 seconds or more, then it finally starts and then if im at a stoplight or something, it will act like its tryin to jerk forward even wen my brakes are all the way pressed in, but it doesnt seem to miss very noticably, but yet it definately tries to jerk forward at idle when my foot is on the brakes. seems to run fine tho when im just driving around normally though, so thought maybe before i start replacing stuff id check for sure with you guys. one other thing i have always wanted to know is how the heck do i tilt the v6 motor to get at the rear spark plugs, i know that i gotta take off the front dogbone, but i donno what else i have to take off. thanks

mike