I have just rebuilt my LS VTEC and I am trying to break it in. I am having problems with it bogging under part throttle, then it catches up and runs fine at WOT (this is hot or cold). Also, after it warms up, I stall often on decelleration before a stop or at a stop. It idles fine (although I have set the idle a bit high). But at a stop it wants to die all of a sudden. It does not choak or slowly die, it just dies. Sometimes I can catch it with the throttle but it happens quickly. I am also running a rich. The stupid narrow band meter pretty much reads all the way to the right at rich and leans out a little bit after it warms up but generally stays in the rich area.

I have searched and I am going to check my O2 (the four wires fall out easily and I could have switched the two black wires) and I am also going to double check my dizzy timming. The plugs look fine... just on the rich side. Plug wires look good and there are no leaks.

One other thing... the boost gauge is reading a relativley low inhg... like around 25 at idle. I am not sure if that is related or what is causing that.

Thanks for the help!

 

I am thinking it might be b/c it is too rich but I did not think that being too rich could cause such bad stalling and I though it would choak before it would stall.

I am running a basemap from a GSR with about 10% fuel leaned out. I am thinking that the base GSR map is going to be really rich in my 9.0 c/r LS VTEC. That along with the base maps being rich to start with may be my problem. I only have a narrowband meter as my wideband is having issues. The narrow band basically reads full rich (all the way to the right) when it is cool. When warm, it is still rich but fluctuates across the green area.

I checked my plugs and they are not that bad, just a little carbon. I have only been driving it about 40 miles after the rebuild.

Any suggestions?

 

Anyone there to help a bro out?

 

bump

 

i kinda had the same prob with my LS turbo, when i first started it up it would want to bog and die, only everyonce in a while. then the other day i went to the dyno and my tuner advanced the timing 4 degrees and since thne it has fired up very nicely. good luck with everything