1988 Corvette Service Engine Soon...
#1
1988 Corvette Service Engine Soon...
Dear friends, I hope that you can help me, like other times. Thanks in advance for your time and support.
I have a 1988 C4 Corvette. When I purchased it, EGR temp sensor was DISCONECTED, I mean the wire was not attached where it was supposed to do so.
Due to some emmission problems, a year ago I replaced the EGR valve and re-connected again the temp sensor.
Emission problems persisted, so few weeks ago I replaced also the O2 sensor and the EGR solenoid.
At first, no problems, but TODAY, just few seconds after start the engine, the Engine Service Soon light turns on.
So, considering that my car does not have ALDL and I can NOT read codes from ECM, what do you thing that can be the cause?
1) EGR temp sensor switch is the problem from the beginning. Previous owner disconected it just for this. But then, why the SES light turns on only now? I have used the car during a year with the sensor re-connected with no SES light. Can be due to the recent EGR solenoid replacement, that affects the temp sensor readings in some way?
2) It must be one of the last parts replaced by the mechanic: EGR solenoid or O2 sensor. Maybe some contact, or bad connection. The strange thing is that I have driven the car four or five tims since then with not SES light.
3) Can be coincidence, but another part needs to be replaced, for example the MAF sensor.
The only clue that I can provide is that the light appears just after few seconds from start the engine, and at the moment the car has low gas and it has not been started from more than two weeks. Performance and RPM seem normal.
Any idea???
I have a 1988 C4 Corvette. When I purchased it, EGR temp sensor was DISCONECTED, I mean the wire was not attached where it was supposed to do so.
Due to some emmission problems, a year ago I replaced the EGR valve and re-connected again the temp sensor.
Emission problems persisted, so few weeks ago I replaced also the O2 sensor and the EGR solenoid.
At first, no problems, but TODAY, just few seconds after start the engine, the Engine Service Soon light turns on.
So, considering that my car does not have ALDL and I can NOT read codes from ECM, what do you thing that can be the cause?
1) EGR temp sensor switch is the problem from the beginning. Previous owner disconected it just for this. But then, why the SES light turns on only now? I have used the car during a year with the sensor re-connected with no SES light. Can be due to the recent EGR solenoid replacement, that affects the temp sensor readings in some way?
2) It must be one of the last parts replaced by the mechanic: EGR solenoid or O2 sensor. Maybe some contact, or bad connection. The strange thing is that I have driven the car four or five tims since then with not SES light.
3) Can be coincidence, but another part needs to be replaced, for example the MAF sensor.
The only clue that I can provide is that the light appears just after few seconds from start the engine, and at the moment the car has low gas and it has not been started from more than two weeks. Performance and RPM seem normal.
Any idea???
Last edited by mitcher; 12-04-2014 at 01:48 PM.
#3
Your '88 should have ALDL : http://www.corvettebuyers.com/c4vettes/codes.htm
So, any suggestion regarding the Service Engine Soon light?
#5
Team Owner
#6
Race Director
I have heard of people who found the ALDL connector stuffed in behind the HVAC controller. For some reason people unbolt it from its normal mounting place and then put it inside the dash to get it out of the way.
#8
#10
Race Director
To find out what the SES light is trying to tell you, see here:
http://corvettephotographs.com/c4vettes/codes.htm
http://corvettephotographs.com/c4vettes/codes.htm
#11
Safety Car
We will all be shooting in the dark with diagnosis until you get the codes. There isnt really any way to check the components that I know of.
Have you pulled the hush panel off yet?
Have you pulled the hush panel off yet?