5.7 not exceeding 2500rpm after breakin

[lord1234]

I put in a brand new Vortec 5.7L to replace my VP 5.7L. It broke in great, went up to 4k and even above...but after break in for some reason it doesn't want to go beyond 3200RPM, even full throttle to the engine. It will go well beyond 5k in Neutral, no problem, but under load, no go.

Mechanic is guessing timing, but I was hoping not to adjust the timing. Where else can/should we look?

 

[Scott Danforth]

in neutral there is no load, the motor would run there with very little fuel or only 1 cylinder

however under load, you need lots of fuel.

most likely you have a fuel system problem

why are you adverse to verifying the timing?

 

[alldodge]

Serial number please

 

[lord1234]

Serial number please

serial number for what?

 

[Bondo]

serial number for what?

Ayuh,.... The motor,.... The 5.7l has been built in many configurations,.....

I'm guessin' ya got a fuel delivery issue,....

 

[lord1234]

Engine Prefix 2143. Serial number 10084

 

[alldodge]

Engine Prefix 2143. Serial number 10084

The motor serial number is about 10 digits

Let's put it this way, right not we know its probably a VP because its in the VP section
Its a 5.7L but other then that we don't know

It could be a carb, efi, mpi, and don't even know what year,

Good luck

 

[lord1234]

Its a 2017 5.7L Vortec, that was used to replace a VP 5.7GL-PLKR (1997).
It's got a 4 barrel Edelbrock carb.

Note I didn't see a Vortec forum to post in so I posted here.

 

[alldodge]

OK its a 1997 5.7 GL which was up dated to a 17 vortex. Cool know much more about what your working on, thanks
Vortex just means different heads and intake, same basic motor

Assuming it still has the Delco EST ignition system, only the GL-A had prestolite and rest had EST

Timing would be at 8 BTDC
Connect a timing light and see if the timing is advancing as rpms increase, and by how much

Also leaning toward not getting enough fuel if the timing is advancing

You getting any backfire when at WOT?

 

[lord1234]

So the good news its none of these:
The connectors on the fuel pump were coming loose at random and causing fuel starvation! Figured that out and all fixed