97 GMC k1500 help

[Mikemarks]

I've got a 97 GMC k1500 sle with5.7 having problem with it starting in the mornings has new battery, plugs and wires cap rotor  coil. It cranks good has compression  and spark can smell fuel the only it starts is with jumper cables with both hook to the terminals or grounded to motor and after it starts it runs fine.you can even shut it off and restart it with out cables  any help would be appreciated thanks in advance

 

[TW97C1500]

Mike, I would guess a bad electrical connection.  New battery, but requires jumper cables to start would be because extra "oomph" is required to get the starter to work.  When it has been running and you shut it off, then restart, the battery is fully charged and electricity has been flowing, perhaps having arced and created a circuit path that re-opens as it cools.  I said "connection" but I don't necessarily mean one of the ends.

 

On my Grand Cherokee, it developed your same issue, but intermittently.  One day it wouldn't start (dead key, no click).  I already had material to make new battery cables, so I made up a negative since it looked way worse on the end where someone had put on replacement clamp-on terminals.  I put it on and the Jeep started right up, I didn't even charge the battery.  It has never had a problem starting since.  I cut open the insulation on the old negative cable and an inch or so down the wires were corroded real bad, green with flaky white stuff, and some of the wires were a lot thinner due to loosing material to the corrosion.  Thinking back now, I should have done a resistance test on it.

 

Does your's have the original cable ends?  If they are the clamp-on replacement type, there might be corrosion there.  You can take them apart and wire brush it clean, or replace them.  Also, an electrical problem might simply be at a ground location where it needs to be wire brushed clean.

 

All that being said, a bad starter can cause your issue.  Maybe just "sticky" or on its way out.  If your engine's rear main seal leaks (likely), oil can be getting in the starter and with a little dirt, gums it up.  I've read people on forums say that starters themselves rarely truly fail, it is the electrical solenoid or this dirt & grime problem that keeps them from working.

 

There are more exotic things that can cause your issue, but it seems to me those 2 are the most likely.  I've had them both.