Hot start

Coolio

Coolio

Not-quite-so-new-guy
Apr 23, 2018
23
9
3
#1
I have a pontiac 400 with manifolds an mini starter with heat shield wrap. When the car temp reaches between 190°- it only turn over but won’t start. I’m not too sure what else to try any suggestions?
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
23,754
4,368
113
Kitchener, Ontario
#2
how fast does it turn over and what carburator do you have. ? It could be timing is too far advanced if it is struggling to turn over or the gas is boiling in the carb.
 
Coolio

Coolio

Not-quite-so-new-guy
Apr 23, 2018
23
9
3
#4
how fast does it turn over and what carburator do you have. ? It could be timing is too far advanced if it is struggling to turn over or the gas is boiling in the carb.
When I cold start the car it cranks almost instantly with no problem, the carburetor is 600 holly.
 
Coolio

Coolio

Not-quite-so-new-guy
Apr 23, 2018
23
9
3
#5
Vapour lock? Fuel getting hot somewhere? Check your fuel line for heat.
The fuel line is kind of close to the heater hose/valve cover gasket
 
bob64

bob64

G-Body Guru
Mar 30, 2017
610
330
63
Niagara Falls, Canada
#6
The fuel line is kind of close to the heater hose/valve cover gasket
Try it isolate fuel line from any heat source.

Does it turn over basically the same hot or cold? If it's dragging when hot you might want to check timing as already been mentioned. If it turns over the same speed hot an cold, check for a heat source causing Vapour lock or bowl boil. Feel the fuel lines an bowls on carb trying to eliminate things.
 
Coolio

Coolio

Not-quite-so-new-guy
Apr 23, 2018
23
9
3
#7
Try it isolate fuel line from any heat source.

Does it turn over basically the same hot or cold? If it's dragging when hot you might want to check timing as already been mentioned. If it turns over the same speed hot an cold, check for a heat source causing Vapour lock or bowl boil. Feel the fuel lines an bowls on carb trying to eliminate things.
I checked the timing and it’s a couple of degrees before tdc an when I touched the fuel lines neither of them was hot.
 
P

paul.m

Greasemonkey
Oct 20, 2018
181
62
28
#8
Sounds like vapor lock , also verify fuel filter is clean , bypass or remove temporarily to confirm . This will also let you know if your losing fuel psi when the engine gets warm.
 
bob64

bob64

G-Body Guru
Mar 30, 2017
610
330
63
Niagara Falls, Canada
#9
Was the vacuum for distributor unhooked? Did you feel carb? When hot an stalled out, pull throttle lever on carb an see if fuel enters air horns, l should but a warning on this, lol!! If it's a stock engine l believe the timing should be 8 btdc but don't quote me on that, as mentioned before SBC ain't my thing.
 
Turbolq4

Turbolq4

G-Body Guru
Sep 25, 2017
847
788
93
Boise Idaho
#10
Well known that vapour lock only effects cars north of the border🇨🇦
 
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