1G need help, really lost

[white_rice_tsi]

hey guys, in new to tuners but not the DSM world. Please move if in the wrong section, I need some expert intel.

I recently rebuilt the top end on my 90 TSi AWD. It ran and drove great prior to t belt idler exploding. So anyways, everything is brand new, semi built head (Delta regrinds, Crower springs, oil port mod), ARP studs, everything else OEM. The only things different from last year are the head and the STM open dump O2.

Got everything done, grounded and set base timing (5 deg BTDC, set TPS, grounded and set BISS) and its running vr1 20w/50. When it starts up it will idle poorly and if held steady for a few seconds it will idle on its own but if you try to rev it, it backfires and studders and runs extremely rich. But once fully warm runs perfect. If you shut it down and let it sit for 5-10 minutes and start it again you have to wait til it warms back up again.

Mods are stock short block, the head mentioned above, Evo3 16g, FP manifold, VRSF FMIC, Wally 255, Fuel Lab regulator (set without vac line to 38 psi) stock injectors, STM open dump and full 3 inch, heat barrier intake spacer. No DSMLink yet but boost is only at 12 psi for now. No boost or vac leaks, new ECT sensor and no check engine light.

Sorry for the novel but i wanted to give all the details and skip the 20 questions. I have a track day quickly approaching and cannot figure this out for the life of me... thanks in advance.

 

[442powerstroke]

hey guys, in new to tuners but not the dsm world. please move if in the wrong section, i need some expert intel, i recently rebuilt the top end on my 90 tsi awd,ran and drove great prior to t belt idler exploding. so anyways everything is brand new, semi built head( delta regrinds, crower springs, oil port mod) arp studs, everything else oem. the only things different from last year is the head and the stm open dump o2 , got everything done, grouned and set base timing( 5 deg btdc, set tps, grounded and set biss) and its running vr1 20w/50. when it starts up it will idle poorly and if held steady for a few seconds it will idle on its own but if you try to rev it it backfires and studders and runs extremely rich but once fully warm runs perfect. if you shut it down and let it sit for 5-10 minutes and start it again you have to wait til it warms back up again. mods are stock short block, the head mentioned above, e316g, fp manifold, vrsf fmic, wally 255, fuel lab regulator( set without vac line to 38 psi) stock injectors, stm open dump and full 3 inch, heat barrier intake spacer. no link yet but boost is only at 12 psi for now. no boost or vac leaks, new ect sensor and no check engine light. sorry for the novel but i wanted to give all the details and skip the 20 questions. . i have a track day quickly approaching and cannot figure this out for the life of me... thanks in advance.

i have same prob did you figure it out man?

 

[inthemidst]

Check all basics first compression fuel pressure mechanical timing boost leaks etc....

 

[greddy_1700]

Sounds to me like the engine coolant temp sensor. Double check the wiring too for continuity, our cars are getting old and the wires around the coolant housing are always causing some issues.

 

[4Gwannabe]

I Was going to say the same Coolant Temp Sensor, same issue with my 2g wouldn't idle till it got to a specific temp then would run perfect. Lol crazy how a simple sensor can make our cars run like straight dog Sh**