1987 tbi hard to start when hot

[doublearrow]

Again I come asking for help. I really appreciate the help I have received.
My 1987 350 tbi has been giving me fits for the last month or so. Anytime my truck engine is cool it fires right up. The problem comes when I drive home. I drive home 22 miles and when I get home if I want to do anything else I have to wait for the truck to cool off. If I try to start it, it acts like the battery is drained, engine drags or just turns reall slowly and never fires. If I let it cool it fires right up. Battery is less than 3 months old and shows good. Father in law says it's the coil, but before I go to throwing parts at it, I thought I'd ask you guys. Thanks for any help.

[buffle]

It could be the starter, trucks with headers are notorious for hard hot starts. If you can short across the posts on starter and it works when hot , that is your problem.

[rfmaster]

A slowly turning starter would indicate a high resistance in the main battery to starter and battery to chassis lead wires (or heat soaked starter). The most common culprit is the oxidation on starter to battery wire junction. Over time it gets progressively worst, especially when temperatures rise. OE starters are also known to slow down when heat soaked. I would clean all cable junctions and inspect battery cables for broken wire or flaky terminals.
Starter is next. When replacing starter I always install a new HD 2/0 gauge battery wire - a little bit more money, but it keeps voltage drop to minimum.

//RF

[wilkin250r]

The fact that it fires up great when cold doesn't sound like a corroded connection, they generally aren't very heat-sensitive. Then again, cleaning the connections is never a bad thing.

My first suggestion would be a starter heat wrap, a whopping $20 and simple to install. That fixed the problem on my 72.

[NorthwestGrudgeRacer]

heat is getting in the starter heat rap or shield. hope this helps

[gchemist]

Have your ignition module tested. Sounds like it's going bad. Not firing when hot is a good indicator. If it's old, replace it.

[wilkin250r]

I'd rule out the ignition module, for now. It would indeed make it difficult to fire, but it wouldn't cause the motor to crank slowly.

[gchemist]

When starter and wires are hot, electric current does not conduct as well as cold wires. One good reason to use a battery with high cranking amps. If the wires are open ended, check for crossion. Corrossion eventually builds up down into the wire. When corrsion builds, current is reduced for start up. I've seen plenty of people change starters only to find bad battery cables.

[doublearrow]

Just got back to this and wanted to say thanks. I went to the parts store with the intentions of buying a module, new battery cables, and a heat sheild for the starter. I know that's just throwing parts at it, but the parts combined weren't going to cost a fortune so I thought I might as well do it all.
Long story short all they had was the ignition module and I still have the not starting when hot issue. So looks like I will be finding the cables and shield as well. Thanks again

[grs]

Originally Posted by doublearrow

Again I come asking for help. I really appreciate the help I have received.
My 1987 350 tbi has been giving me fits for the last month or so. Anytime my truck engine is cool it fires right up. The problem comes when I drive home. I drive home 22 miles and when I get home if I want to do anything else I have to wait for the truck to cool off. If I try to start it, it acts like the battery is drained, engine drags or just turns reall slowly and never fires. If I let it cool it fires right up. Battery is less than 3 months old and shows good. Father in law says it's the coil, but before I go to throwing parts at it, I thought I'd ask you guys. Thanks for any help.

It is not the coil. I bet it is the starter. How old is the starter. Get a good rebuilt one. Not a cheap one. Lets us know what you find out.