90 - Running out of breath at 5000 - No Codes

[scottfab]

First off keep your momentum. Your tenacity will pay off.

Some ideas below. But what if it's not fuel and not the secondaries opening that is the problem? What if the CATs are blocked by soot etc on the front end? The symptom would be loss of power at higher rpm. My brothers vett had this issue. The bad new is I haven't the slightest idea how to check for that. On my brothers car I took the header off and looked down in there. I saw blockage and punched a long screw driver through the ceramic CAT. This fixed his problem but he then had to get new CATs. See below for ideas on secondaries.

Originally Posted by dondon

...snip...
CKT 930 is the connector to C17 (prior to removing plenum during previous diagnosing). Which when shorted operates the actuators... so can it be assumed from the above I have a bad ECM or are there some other tests I can run to avoid a potentially unnecessary parts spend or is it a case of just suck it up and try to source an ECM?

Based on the fact that you get some secondary action up to 5000 I'm going to say the ECM is ok. Based on the charts at the bottom of this page it the secondaries were not opening at all you'd get no big pull up to the 5000 mark which I assume you are. That shows the ECM signal works. You could also verify the voltage at C17 while driving. It should go to 0V and stay there at WOT. If it does and the car still flattens at 5000rpm that shows the issue is not with the ECM and likely not with the secondaries based on the other C17 test you did.
http://www.zr1netregistry.com/Inform...Diagnosis.aspx

Originally Posted by dondon

I have the plenum off and will likely leave it off until I'm sure I've tested everything that could be a miss. So any other good tests to get through would probably be good to get out the way.

Thanks Again

Before reassembling rig a wire onto the each actuator such the you can physically pull on one and then the other as you are at 5000rpm and you feel the sag. You have to be creative in routing the wire using the wiper shaft as a pulley then around through the window. If power returns you need to stay looking at the secondaries and not fuel or CAT blockage.
ALSO before reassembly.....
Just for grins. Can you disconnect the pump way up where it connects into the vacuum reservoir tank? Then turn the key on to activate the pump. Does it continue to run >60 sec? Now plug the line you pulled. Does it run <10sec? The "re-verifies" that the pump is not blocked AND that it's vacuum contribution is making it to the reservoir.