Hey guys. Need some help fast.


Got my truck dynoed last week and my af went up to 13.5 Thought something was possibly wrong with the RWTD tune so I got ahold of James and everything on the tune is fine.

Dyno still running really lean, so I bought a SCT from the dyno guy and getting a custom dyno tune. Well whatever he does he cannot get the short term fuel trims correct at the upper rpms. He tried adding up to 30% fuel and it still leans up at upper rpms.

Anyone know what can be causing this?

Please help

 

Maxed out MAF?

 

I'd go checking out the fuel supply. New filter first, then check for pressure and volume.

Rich

 

Just an update. Seems I installed the tune wrong, forgot to reset parameters, also have some problems with fuel delivery. James helped me do some tests and they are 100% as well as his tune, hopefully I can get to the bottom of this

 

Check your fuel pump relay. If the relay is shot then the truck won't raise the fuel pressure in the upper RPMS and will lean out. Put a pressure guage on it, if it never jumps out of the 30s chances are it's the relay.

The relays are only a couple bucks, swap out the high side relay.

 

you haven't posted what mods you have so I'll take a shot in the dark based on yourdyno chart info.
If you are still runing stock injectors you may have maxed them out. With a 4lb lower pulley and a 2.69 upper and port and polished heads I had my injectors @ 98% of their duty cycle.

For the HP your making you may be starving at top end. also check for any broken vacuum lines that will cause the same issue. Sal helped me find that out.

Peace,

Suavy