Need help fast LS2 in a Chevelle

[Jeff70]

I don't know a whole lot about LS engines, this a LS2 from a 05 GTO now in a 71 Chevelle.

The issue is I exited off the freeway coming to the stop light and the car just died. It turns over fine but will not fire up.

Anybody have any ideas of where I should start first?

[kochevy67]

First off check for Spark and fuel, it may be the fuel pump.

[absintheisfun]

Like ko says, fuel air and spark...its pretty much certain that you have air, so that leaves fuel and spark.

Easiest way to check for fuel is spray some throttle body cleaner in the air intake (a good 5-10 seconds) and turn the key. If it sounds like it is trying to catch and run, you have spark. Keep in mind it won't actually run, but it will sound like it wants to.

If the above is the case, you most likely need a fuel pump. If you change the pump, change any and all filters you have as well. A failed pump can send particulate matter into the lines and clog filters.

If it doesn't sound lke it is trying to run, you have a spark problem. If it is a total failure, it isn't the coils or plugs...check your wiring to the coilpacks and to the ecm.

[Jeff70]

1st i tried to check for spark the "old school" way, pull the spark plug keep it connected to the plug wire and touch a ground point and I got nothing.
Then I realized that I could not hear the fuel pump in the Ricks tank thats when I tried the starter fluid and It tried to fire so I knew it was a fuel issue.
The shop that did the LS swap on this car cut some corners on the stuff that most people do not see like under the dash, it's a mess! I chased down a blown fuse, replaced it and it fired right up.


Thanks for the input!

[absintheisfun]

If you can, check what else is on that fuse, or for a grounded wire. Fuses don't pop for no reason! Something put too much load on the circuit.

[BulldawgMusclecars]

So the fuel pump was run off the fuse box (or an inline fuse) rather than a relay? That needs to be fixed.

[Jeff70]

To be honest I have know idea, I was looking for popped fuses and found one. Not labeled just a small fuse block with 4 15amp fuses. Im sure it has a relay, maybe? For a LS harness to cost $800ish you would think it had a relay built into it.

[kochevy67]

I would dig deeper because chances are if it happened once it will happen again. Like somebody else said they don't pop for no reason.

[rrstroker71]

So the fuel pump was run off the fuse box (or an inline fuse) rather than a relay? That needs to be fixed.

X2, the pump needs to be on a relay with 12 battery and 12v switched. Otherwise you will continue to have problems.