Quick Advice: Secondaries not opening

[Billy Mild]

In the process of preparing my car for a NASA HPDE event on Saturday. I replaced the coolant hoses, and oil hoses as my oil hoses were leaking. Tonight was my shakedown run. At first the car seemed to run great and the secondaries were definitely opening as it was throwing me back in the seat and moving rather well.

The more I drove the car it seemed to have a little less power. Not breaking the tires lose in 1st or 2nd gear like normal. It also didn't make a difference whether I had the power key on or off. (The scanner did show a difference between valet mode on or off)

I hooked up my MT2500 before the test drive so I could monitor the engine, and oil temps. My oil temp sensor has finally went bad as it read -40 degrees, but outside of that everything seemed normal. I set one of the LED to be ON if the secondaries were closed. At first the car would flip the light off meaning the secondaries were opening, but after a while I noticed no matter what RPM I was at that light would just stay on. This indicates my secondaries were not opening. Even reving the engine my secondaries wouldn't open.

I just did a quick check of vacuum lines with mity vac and they are tight. No loss of vacuum at all. My vacuum pump is working as well.

TL;DR version: Car runs great up until it has been driven maybe 15-20 minutes or fully warmed up. The secondaries quit opening at that point. Any advice is greatly appreciated.

[We Gone]

I may be wrong about this but the system needs to see a preset oil temp for the secondary to operate. Check Dynomite's sticky at the top, you will find one on the operation and how to check out the system.

[LT5Vette]

Steve is correct, the oil temp has a minimum before allowing secondaries to open. see below from Dynomites posting about fault code clearing.

Basic Conditions that allow Secondaries to open:
"In order for the Secondary Port Throttle Valves (Secondaries) to open, the following parameters must be met:

Coolant Temperature 20 Deg C (68 Deg F) or above
Oil Temperature 20 Deg C (68 Deg F) or above See ECM Code #52 Item #3. ZR1 ECM CODES 1990 TO 1992
System Voltage 10 V. or above
Trouble Codes (SES Light) None
Power Key On"

Am going to have to try the paper clip method just to see if I have any fault codes. Anyway you will need to replace oil temp sensor to get secondaries operational.
Tod

[Billy Mild]

I just called up Advance Auto Parts, and they have the part in stock locally. I should have a new one by end of business tomorrow. Hopefully this will fix the issue and I can open the car up on the track Saturday.

http://www.corvetteactioncenter.com/forums/c4-corvette-zr-1-a/14272-1990-1995-zr-1-secondary-port-vacuum-diagnosis.html

I found this site that has the same info as above.

[Billy Mild]

Car is fixed. The oil temp sensor was the issue.

[LT5Vette]

Have fun at the track! we want to hear about it. My turn next weekend at Road America.