Turbo LQ4. Need help with getting it running.

[SuperStepside]

Hello all, new member here. I have a 95 silverado with a turbo lq4 6.0 (yea I know, great starting platform). Details are front mount 76mm turbo, ZO6 cam and springs, 72lb injectors at 4bar, cobalt SS map sensor, switched over to COS3 with speed density.

Basically it wont run. When I start it it idles low and rough and then dies. Smells like its running pig rich and I took out a plug and it was wet.

Now the strange part is that it will run (somewhat) on a previous tune that was done from PSI harness when they reflashed my PCM for the 6.0. Its a stock style tune (no COS) with incorrect injector values and the stock MAP sensor put back in.

Heres my current tune, the best running tune (psi harness), and a stock tune. I know you guys like looking at the tunes and a log but could I still do a log if it doesnt run? Thanks for the help.

17791
17792
17793

Now I read some of the open loop tuning threads and applied that to the current tune but I dont know if Im just digging myself a bigger hole.

[joecar]

Hi SSs, welcome to the forum :cheers:


Do you have a MAF installed...?
Do you have front O2's installed...?

[SuperStepside]

Hey Joe, Ive been seeing you around the forum alot. Nice to meet you.

No MAF, speed density.
Has front O2s.

Also BIG update. I had a feeling that the 2bar MAP sensor and/or values were off so I put the stock MAP sensor and values back in and she started right up and idled beautifully. Also revved up pretty good. The 2bar and stock sensor are BWD (Advance Auto premium line). Im not sure if its the 2 bar values or not. Or if i have a bad sensor. :nixweiss:

I'd still like someone to look over the current tune if possible to see if anything else doesnt look right.

[400ss]

Hey Joe, Ive been seeing you around the forum alot. Nice to meet you.

No MAF, speed density.
Has front O2s.

Also BIG update. I had a feeling that the 2bar MAP sensor and/or values were off so I put the stock MAP sensor and values back in and she started right up and idled beautifully. Also revved up pretty good. The 2bar and stock sensor are BWD (Advance Auto premium line). Im not sure if its the 2 bar values or not. Or if i have a bad sensor. :nixweiss:

Post your new MAP sensor part number, with the KEY ON engine OFF it should read 100-102 Kpa

[SuperStepside]

EC1636P and after doing some research on that number, I dont think this is the correct sensor even thought its for a cobalt ss. Looks like the cobalts have a MAP/IAT sensor and a baro sensor. I think I have the map/iat sensor and I need the baro sensor. With the 2bar sensor and values it reads 105 kpa though. Just doesnt run with it installed.