Code 26 problem, can't find root cause

[ReggieD]

Code 26 problem,

1992 LT1 vette

My fear is I will not be able to pass Georgia Vehicle Emissions due to the “Check Engine” light being on.



Symptom 1: Upon starting car all is OK. If I drive car in very hot weather for about 10 minutes the “Check Engine” light would come on.



Symptom 2: Upon starting car all is OK. If I drive car in normal weather on highway for about 30 minutes the “Check Engine” light would come on.



Symptom 3: Upon starting car all is OK. If I drive car for about 15 minutes, with NO trip of the “Check Engine” light (engine nice and hot). Turn off car for an extended period of time(less than 3 hours). Get back in car start engine. Upon touching the accelerator within 3 minutes or shorter the “Check Engine” light would come on.



Once Check Engine Light is on, it stays on until car sits in off mode for about 6 hours.





Listed below are all the things I changed. I still have the symptom above.

a) New Battery

b) New Alternator

c) A.I.R. Pump (Air Injection Reactor)

d) EGR Solenoid

e) EGR Valve



Can this be a vacuum problem, canister purge solenoid, or (Electric Divert Valve) EDV solenoid?

I need knowledgeable help with this problem.

 

[nyernga]

I don't show a code 26 in my service manual but it's for an 88 so no suprise there. What IS a code 26 for a 92?

It's obviously something that takes heat to trigger. My uneducated guess would be the 02 sensor.

Len

 

[stu]

Code 26 problem,

1992 LT1 vette

My fear is I will not be able to pass Georgia Vehicle Emissions due to the “Check Engine” light being on.



Symptom 1: Upon starting car all is OK. If I drive car in very hot weather for about 10 minutes the “Check Engine” light would come on.



Symptom 2: Upon starting car all is OK. If I drive car in normal weather on highway for about 30 minutes the “Check Engine” light would come on.



Symptom 3: Upon starting car all is OK. If I drive car for about 15 minutes, with NO trip of the “Check Engine” light (engine nice and hot). Turn off car for an extended period of time(less than 3 hours). Get back in car start engine. Upon touching the accelerator within 3 minutes or shorter the “Check Engine” light would come on.



Once Check Engine Light is on, it stays on until car sits in off mode for about 6 hours.





Listed below are all the things I changed. I still have the symptom above.

a) New Battery

b) New Alternator

c) A.I.R. Pump (Air Injection Reactor)

d) EGR Solenoid

e) EGR Valve



Can this be a vacuum problem, canister purge solenoid, or (Electric Divert Valve) EDV solenoid?

I need knowledgeable help with this problem.

Checking my Haynes manual, code 26 is the Quad Driver Module #1 Circuit. It says to check the resistance of the EGR, Canister purge, and AIR pump relay coils, which should all be over 20ohms. Replace any solenoid less than 20ohms.

(I think this is the first time I acutally got some useful information out of the thing.)