My 1984 Chevy 1/2 ton 4x4 will not start after the engine gets hot. It is a
5.7 liter. The starter will not crank the engine. I have replaced the
starter (twice), alternator and battery to no avail. Can someone help me
First thing to do is check the timing. Too far advanced will make a hot
engine not start. Check the initial, running & if all else fails the cam
(ie make sure your timing marks on cam and crank line up with not chain
Ignition timing has nothing to do with how fast or slow a starter cranks
when the engine is hot or cold. Your problem is likely caused by bad
battery cables/connections, especially the main ground. Check all cables
for corrosion and clean all contact points.
As temp increases so does resistance, so what's happening is your marginal
connections are fine when cold, but don't flow enough juice when hot and the
resistance is higher.
Retarding timing for easier HOT starts is a OLD Demolition Derby trick.
Basically when a Engine is past XXX degrees it spins over slower then it
does at ambient.
A heat soaked, weak, or dying starter compounds this problem.
As does a weak battery.
Now when it comes to Old SBC's over the years timing chains can
streach, heads can crack, starters lose there "ass"( or some jason puts
a low torque in place of a high torque). If the timing is advanced for
say 92 or 93 Octane, and the truck is running on 87 Octane, with worn
parts, Retarding the timing some will help it start better.
I'm not saying it doesn't work, I'm just saying it's band-aiding a problem
caused by something completely different. The ECM assumes base timing is
set correctly and advances from there in closed-loop, so if the base has
been bumped down a few degrees it's going to be running less advance once
started, causing decreased performance and fuel economy.
All he needs to do is clean/replace the battery cables and connections and
he'll be good to go, with the timing set correctly.
It's a 1984 1/2 ton. That means CCC & CST Distributor. The engines
still can having timing advanced or retarded for fuel grades.
The CCC (Computer Controlled Carburator) is known for having Choke issues.
Those engines use vaccume & Computer controlls that basically fight
each other. A bad vaccume line, or someones attempt at circumventing the
emmissions controlls can make them run like total crap.
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