OK I struggle with where to place my questions on this site but I THINK if you bear with me I have this one in the right place? I recently replaced the manifold gaskets, fuel injectors and valve seals on my 88 IROC . When I got it back together it would not idle right so I spent a couple evenings searching here on the site and checking this and that. Unplugged the MAF and ran it and messed with the EGR some too. Come find out I had laid the hose from the drivers side valve cover up next to the intake and neglected to push it on, DUH! Once that was fixed the car runs like new, THANKS 3rd gen forums!!

On to my question All that has caused me to wonder why through all that even with sensors unplugged I had no SES light? When I turn the key on nothing lights up on the dash except the seat belt light. Is that correct or do I have issues? Only thing I have done is check the fuse on the fender by the battery.

Thanks in advance!

 

At key-on, engine-off, the SES light should be illuminated. Good possibility that the bulb was removed due to EFI issues.

Check the GAGES fuse, it powers the SES light. Can test the circuit at key-on by grounding pin A5 at the ECM. That should light up the SES.

RBob.

 

 

Second vote for the bulb, either blown or removed. The wire from the ECU to the cluster runs through a connector under the pass dash. Look for connector C207 schematics, you can put a test light on it at this connector since its easier to get to than the cluster. Cycle the key (no engine start) the test light or the SES light should light. Look up how to get trouble codes on the OBD1 (its a jumper wire that makes the light flash) that would also be a good test as it will blink out 12 I think if there is no codes.

The SES light also doesn't turn on for a single fault, the computer has to see the fault more than once and has to have enough data to average it. Example my EGR use to be bad I could drive the car for 2-3 trips before the code would set so if the light cycles on with the key or will blink out the code then that could be it.

 

That is dependent on which code you are talking about. Some will set more quickly than others. There are many parameters in the BIN that can effect how and when codes are thrown. Run time, temperature conditions, number of discreet failures seen.... every code has a different set of criterion.

GD

 

True, was more thinking why no check engine light with something unplugged, there are things that set it instantly but the thing unplugged may not set it idling in the driveway.

 

Well I pulled the cover and guess what? No bulb in the SES hole, Check the simple things dummy! Guess I never will learn that lesson. With a bulb in the socket the SES stayed on while running, big surprise eh? Years ago I had purchased an out dated OTC Nemisys for cheap at an auction and had forgotten about it. Son said why dont you try that old scan tool??? It has a big pile of cables for the older model specific stuff and the GM cable was in the box. Installed some fresh batteries, plugged it in and pulled the codes. The sensors I had unplugged all set codes plus one for having the ignition control unplugged to set the base timing. Once resset the light stayed out sitting in the shop running,cant drive it right now until the salt gets washed off the roads. Those old OTC scan tools with outdated programming sell for peanuts on fleabay but a person needs to be certain he gets the cable,, guess all you tech savoy youngsters know that, LOL

 

I typically just use the paperclip method. Jumper pins A and B on the ALDL/OBD1 connector with the key on and engine off and count the blinks of the SES light .
Glad you solved the issue.

All the best !

 

Yup, I knew about the paperclip deal from reading it here. The scan tool gives a fellow some options, I didn't explore them as i was too excited about tbe SES light staying out!😄

 

Yep absolutely! If it works, go for it. Glad you can now enjoy your ride.
Have Fun!!