New LS480 Starts-Dies
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Teching In
Joined: Jun 2018
Posts: 6
Likes: 0
New LS480 Starts-Dies Recently installed a GMPP LS480/4L70E Connect and Cruise in my ’68 Camaro. Turning the switch on, the fuel pump primes and the check engine light comes on (I’m told this is normal and will go out once the engine is running), then hitting the starter the fuel pump runs and the engine will start every time but die after a second or two. Chased problems enough to know it’s not a ground (see my Grounds thread). I also isolated the fuse/relay and ECM from the ignition switch by connecting another hot battery to the fuse/relay center horizontal lug plus connected the ECM ignition wire and fuel pump to that battery with another hot wire through an on-off switch. This changed nothing. I have checked all fuses in the fuse/relay center – good. The fuel pressure is good.I’m really at a loss as to what to try next. Any suggestions?
On The Tree
Joined: Apr 2014
Posts: 192
Likes: 1
So you have a gauge and it maintains fuel Pressure through the die event ?? Does the fuel pump continue to run after it dies ?? ..........Have some one watch the fuel pressure gauge if not in the cockpit...
Do you know if the spark to the plugs is being cut by the ecm to cause this or if it continues to be present during the die event until it stops, ...........Can Verify with timing light flash ...
With these two things you can understand what may be causing the issue and make it easier to troubleshoot. You will be able to determine if it is dying due to a tuneup issue that is wrong or or if something else is shutting it down. If fuel and spark continue and it still dyes then that is at least something you can rule out.
Do you know if the spark to the plugs is being cut by the ecm to cause this or if it continues to be present during the die event until it stops, ...........Can Verify with timing light flash ...
With these two things you can understand what may be causing the issue and make it easier to troubleshoot. You will be able to determine if it is dying due to a tuneup issue that is wrong or or if something else is shutting it down. If fuel and spark continue and it still dyes then that is at least something you can rule out.
