esc493

I have had this car for 10 plus years. Finally did some work to it rebuilding engine. Car is all back together, starts/runs drives ok. No codes present but power is off. PCM of NC took a look around the Datamaster files and I am running way lean. Fuel pump is walbro 255, new filter and injectors are from FIC bosch 3 30lbs with 16.2 ohms match set. Fuel pressure is 41 on prime and holds. No vacuum pressure is 47. I pulled plug of injectors and ecm and ohmed wires. No breaks. 12 volt present at injectors with key on. I suspect some sort of injector driver fading in and out. 16.2 ohms to much? Spare computers are non existent. If anyone has any ideas, that would be great as I am struggling.

JimLentz

Is it lean open and closed loop? What was done to the engine when it was rebuilt? Do you have a custom tune to go with the 30 lbs fuel injectors?

esc493

It goes into closed loops fine. Bottom end rebuilt and balanced with forged pistons. Lloyd Elliott le1 top end with 218/224 cam, 1.6 roller rockers, tpis 58 mm throttle body, stainless works long tubes. Tune done by pcm of NC. They are the ones looking at datamaster files. They said it is tuned for more fuel and it wants a lot more. Lean under load. Not putting power down it should. I suspect ecm, but fear sending mine in for repair as nothe much out there if it goes bad.

9T3VETTE

Did you check the small stuff like vacuum:exhaust manifold leaks?

FWIW, SIA electronics did a rebuild of my ECM on the 93. Customer service sucked *** but the repair seems solid. Car was acting all sorts of crazy when the ECM went bad...

esc493

I removed vacuum lines from manifold and plugged them to see if any change. There was none to speak of. Manifold gasket are new with rebuild. Spark plugs are very clean.

Kevova

If you disconnect fuel pressure regulator does int/bln move?

esc493

Int/bin? Pressure does rise with lack of vacuum.

Kevova

Disconnecting FPR raises fuel pressure adding fuel. Integrator ( short term fuel trim) should lower. Block learn ( long term fuel trim) will move lower slower than int. You need a scanner or datalogger and someone who can analyze your data to guide you as to what to do.

esc493

So for an update on this. I recieved my money back on tune. The guys are very respectful just something off with my car and they are to far away to look at it. I put the factory tune back in with factory injectors and car runs rich as it should. Idle is very slow so I opened it up to keep it running. Power in the car jumped way up. It needs a lot of fuel. Seems like factory tune is close to fuel needed. I checked ecm grounds and power. All checks good and car will perform so I am close.