Slight lose of HP

[financialman]

Question for you guys. On my 94 I have noticed a HP loss at around 5800rpm to redline under full throttle. The CEL will come on as well for about 3 or 4 seconds and turn off.
It runs very strong up to that point and then feels "flat" until you hit the next gear. Only mods are a Chip from Marc and a cat back.

Any thoughts.

Sounds like you are running out of vacuum for the secondary system.

Pull the codes and let us know what you got. Ground pin 4 and 12 on the ALDL port.

[financialman]

Thanks for the reply, I will pull codes on Monday.

[financialman]

Code 61. I think that is secondary valve or something close to that.

Just had the plenum removed for painting and I told them to change the acuators and anything that was not perfect while they were there. Looks like something went together wrong! This time its on there dime though!

[tccrab]

Code 61

Vacuum sensor voltage was between 0.76 and 4.89 volts when secondary port throttle valves were commanded closed, or the vacuum sensor voltage was below 1.7 volts when the secondary port throttle valves were commanded open.

<from Troubleshooting section of the ZR1 Net Registry.com>
http://www.zr1netregistry.com/ZR1_troubleshooting.htm

On all year models, if the SES comes on during hard acceleration, then most probably a code 61, Secondary Throttle system error has occurred. Test your vacuum pump (located in the right front headlight cavity) by turning on both ignition and power keys (do not start the engine) and disconnecting the secondary vacuum connection coming from the pump. The pump should turn on immediately and run continuously. Place a finger over the open line and the pump should suck down and quit running. Check all other vacuum connections. Particular to the '93 model year, we have seen a tremendous amount of problems with the Exhaust Gas Recirculation (EGR) systems. This may also be compounded by a faulty PROM (Programmed Read Only Memory) calibration. There is an updated replacement PROM available from your dealer.

T

[financialman]

Originally Posted by tccrab

Code 61

Vacuum sensor voltage was between 0.76 and 4.89 volts when secondary port throttle valves were commanded closed, or the vacuum sensor voltage was below 1.7 volts when the secondary port throttle valves were commanded open.

<from Troubleshooting section of the ZR1 Net Registry.com>
http://www.zr1netregistry.com/ZR1_troubleshooting.htm

On all year models, if the SES comes on during hard acceleration, then most probably a code 61, Secondary Throttle system error has occurred. Test your vacuum pump (located in the right front headlight cavity) by turning on both ignition and power keys (do not start the engine) and disconnecting the secondary vacuum connection coming from the pump. The pump should turn on immediately and run continuously. Place a finger over the open line and the pump should suck down and quit running. Check all other vacuum connections. Particular to the '93 model year, we have seen a tremendous amount of problems with the Exhaust Gas Recirculation (EGR) systems. This may also be compounded by a faulty PROM (Programmed Read Only Memory) calibration. There is an updated replacement PROM available from your dealer.

T

I will check this out. The thing that bothers me is everything was fine until getting the plenum repainted, they must have done something wrong.

The car has a prom from Marc, brand new.