Hey guys,
I just got the car put back together.
An 86 IROC 355 TPI T5.
I installed a new cam, comp cam 08-304-8. 1.6 roller rockers, Holley afpr, Bosch 22lb injectors, ported intake(plenum, runners, base), edelbrock aluminum heads.
It is running great!. A lot more power!... But I'm having some issues. The engine idling rough in closed loop, but pretty smooth in open loop.

The engine idled pretty smoothly before the recent upgrades. I have been able to make the problem a little less noticeable by advancing my initial timing from 6* to 10*.
I have read conflicting information about messing with the initial timing on the TPI. Some say to leave it at 6, others say to advance it more with mods. I read a great article in superchevy about gains from advancing the timing and getting great results with a stock PROM. ( I had mine tuned when I swapped my 700r4 for the T5)
I have tested all my sensors for proper operation, and checked for vacuum leaks. I have played with the fuel pressure ( it's set at 43psi now)

Any help would be awesome!!
Thanks!!

 

Sounds like it's lean at idle, maf 1 table or the maf scaler needs to be adjusted to compensate for this.

 

Thanks for the reply! I was hoping to get some info on timing and fuel pressure as it relates to idling performance as well as wot. There are many threads on here about those topics, but it would be great to get some opinions on my particular setup.
No ses, no stored codes, I have a heated O2. It goes into closed loop pretty quickly after start up.
Thanks again!