86LG4Bird

iTrader: (1)

Newb' here... 1st post!

We recently acquired a clean '86 Firebird as my daughter's 1st car. It's a gem except for the valve seals (smoke on startup) and the peeling clearcoat. The previous owner had added the complete exhaust system/manifolds/gutted cat from a TPI car plus a set of 3.73's with a Torsen diff. It runs great and has turned a 15.70 @ 87 mph in 97 degree heat.

Question for the 3rd gen ECM gurus: How much of the clutter under the hood can be removed without upsetting the ECM so that performance/economy suffers or tripping the CEL? I'd like to get rid of all the AIR plumbing for one. No concern with visual/E-check. I just want to clean it up since I work on my own stuff.
I like the idea of the feedback Qjet and want to keep that functional.

I'm familiar with the later OBD1/2 systems from tuning my 1996 ImpalaSS, but haven't found much info on how much interaction this older ECM has with the engine or other vehicle functions in the '86.

I've already gotten some very good info from this board since getting the car.

Thanks,

Pat

naf

iTrader: (7)

Most of the info on the ccc-qjet system in these boards you'll find in the carb forum. The ECM is simple enough that there's been little desire to re-program them, at least here.

At the risk of oversimplification, the ecm adjusts the primary mixture by varying dwell (rate) of the Mixture Control Solenoid based on throttle position sensor (TPS is inside carb) and vacuum sensor readings. It rewrites these blocks constantly based on O2 readings. It will control timing advance (a weak timing curve is a common complaint) and will also control converter clutch lock up, EGR and purge valve operation for some later models. I don't specifically recall if it engages the AIR system, but the system can be removed without affecting ecm operation or setting trouble codes.

If you remove the pump ensure you re-install a short bolt into the mounting hole on the front of the block that opens into the fuel pump pushrod cavity or you'll suffer the infamous 'Sofakingdom leak'.

Full throttle operation is not controlled by ecm except for full ignition advance and full rich on primaries. The secondaries for the ccc-qjet operate the same as any other non-computer controlled q-jet.

86LG4Bird

iTrader: (1)

Thank you, naf!