Need help with CEL

[93Leg-c]

I need help with my blinking CEL.

Background: I bought my '93 ss with the radio ripped out and bare wires (radio wires and other wires) hanging all over the place. The CEL was on solid in the test drive but the car responded well with nothing wrong with it. I just assumed the CEL was on because one or more wires somewhere were not connected.

The other week my fuel pump died and I replaced it with a Walbro unit. The next day my engine's idle was erratic and high, sometimes idling in neutral at 1200 rpm, sometimes at 2200, and once at 3500 rpm (imagine going down the level street at 45 mph with my right foot off the gas pedal). I replaced vacuum hoses that were hard and not tight and that brought the idle down to normal rpms most of the time. I then reset the ECU and the idle seemed finally normal and stable. However, the CEL started blinking steadily, roughly once every 3/4 second.

So, I spent an hour trying to locate the black connectors to get the codes but I could find no black connectors with a single wire. Finally I found two wires with apparently the housing broken off on both wires. I tried holding them together while turning on the ignition but the CEL still blinks constantly about every 3/4 second.

So, does anyone have suggestions on why the CEL is blinking and what I can do to find the problem? Any help is much appreciated! TIA!

[IronMonkeyL255]

What about the green connectors? Sounds like those may be connected and it's telling you the codes are all clear.

Just a suggestion.

[93Leg-c]

Thanks for the response. The green connectors are NOT connected.

[vrg3]

I don't know what to tell you. Our ECUs are never supposed to flash the CEL unless the green connectors are connected. Maybe check if the ECU's "test mode" pin is grounded somehow else, since it looks like something screwy's been done with some of that wiring?

I guess it's in principle possible that there's some CEL-triggering problem that is appearing and disappearing at a constant rate. Seems a little out there, but maybe.

I think you'll have to pull codes using a technique I've discussed in earlier posts, where you ground the ECU's test mode and read memory pins directly instead of hooking up pairs of connectors.

[legacy92ej22t]

Hmm, either the green or black connectors should be hooked up for you to be getting the all clear ECU flash.

The black connectors can be a bitch to find and are sometimes taped up in the wiring harness. Are you sure they aren't up in there hooked up somewhere?