75 With HEI wont start
Thread Starter
Instructor
Joined: Dec 2013
Posts: 104
Likes: 19
75 With HEI wont start
We have a 75 convertible, 59,000 miles, that is stock,except for headers.Nice little car. It has always started during the 4 years we have owed it. The vette has been sitting in the garage with the trickle charger for about 4 weeks since last driven.
Today I filled the float bowel thru the vent tube as I do when the cars sit for more than a couple weeks and it would`nt fire. Motor cranks over just fine, strong battery but will not fire.
The 75 has stock HEI ignition. I checked an ignition wire for spark and no spark. Here`s the strange thing, I noticed that when I cranked the engine over with key and then release the key the motor spins about half a turn backwards and a spray of fuel droplets comes out of the carb.
Not a backfire, no flames but a half spin and a spray of fuel. So I then pulled the RED power wire off the HEI and cranked it over again and NO backwards spin when the key was released. I did this 4 times and never a backward spin with fuel spray.
Could it be the ignition switch behind the dash that`s mounted on the steering column?
Any thoughts you guys would have I sure would appreciate
Thanks
Rick
Today I filled the float bowel thru the vent tube as I do when the cars sit for more than a couple weeks and it would`nt fire. Motor cranks over just fine, strong battery but will not fire.
The 75 has stock HEI ignition. I checked an ignition wire for spark and no spark. Here`s the strange thing, I noticed that when I cranked the engine over with key and then release the key the motor spins about half a turn backwards and a spray of fuel droplets comes out of the carb.
Not a backfire, no flames but a half spin and a spray of fuel. So I then pulled the RED power wire off the HEI and cranked it over again and NO backwards spin when the key was released. I did this 4 times and never a backward spin with fuel spray.
Could it be the ignition switch behind the dash that`s mounted on the steering column?
Any thoughts you guys would have I sure would appreciate
Thanks
Rick
Pro
Joined: Sep 2017
Posts: 516
Likes: 72
From: Modesto California
If it has been starting all along I would imagine you fouled the plugs when you filled the float bowl thru the vent tube. If it just sits for a few weeks to a few months there's no reason to pour gas down the vent tube because the fuel pump will fill the bowl before you can whistle the first two bars of Dixie. The HEI will throw a spark over an inch but during the day it's awfully hard to see the spark. Try it again after the sun goes down and with your garage pitch black.
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
If it has been starting all along I would imagine you fouled the plugs when you filled the float bowl thru the vent tube. If it just sits for a few weeks to a few months there's no reason to pour gas down the vent tube because the fuel pump will fill the bowl before you can whistle the first two bars of Dixie. The HEI will throw a spark over an inch but during the day it's awfully hard to see the spark. Try it again after the sun goes down and with your garage pitch black.
Racer
Joined: Jul 2009
Posts: 344
Likes: 5
From: oak harbor wa
No spark on hei(my checklist)
power to dist?
good 12v
check module below cap they can be tested
no good for 12v
ignition switch trouble shoot ( not bad just tideous)
module test good
change coil
module test bad change it
cap and rotor rarely go bad just sitting unless it has water intrusion or unless you live with high humidity
good 12v
check module below cap they can be tested
no good for 12v
ignition switch trouble shoot ( not bad just tideous)
module test good
change coil
module test bad change it
cap and rotor rarely go bad just sitting unless it has water intrusion or unless you live with high humidity
Thread Starter
Instructor
Joined: Dec 2013
Posts: 104
Likes: 19
Not sure how adding two-three ounces of gas to the float bowl would foul the plugs. Its just enough gas for the accelerator pump to work so the motor fires in a couple of spins. I did shut the lights of in the garage last night and check for spark. No Spark
Thanks
Rick
Thanks
Rick
