Sometime my stock 91 civic will be cruising along omn the highway and just quit. It wont start back up without turning the key all the way off then back on. Even if I let the clutch out to start it back up rolling on the road.

Tonight the car tried to quit again but I kept it running, the tach jumped around and went back to normal but no matter what gear or even neutral it wouldnt rev past 3200 rpm. The engine light came on for the first time and once I got home I turned it off and started it back up... The light went off and it ran fine.

I couldnt get it to show any listed codes. It always blinks once then pauses and blinks quickly 16 times even when nothing is wrong with the car. Is that normal because it has always done this when the check engine light is off?

I have checked all the fuses and the car normally runs fine. Wires seem to be ok.
I need some ideas as to what to check.

 

The ECU is throwing codes 1 and 16.

Code 1 likely indicates a bad O2 sensor or fuel pressure regulator.

Code 16 suggests a problem with the fuel injectors. Nonetheless, first consider that the main relay is faulty.

By the way, download the 88-90 Civic service manual at the link in my signature. It tells you how to troubleshoot the CEL codes.

 

From what I understand the light blinking longer than usual is a number of 10, then a quick blink is a number of order 1. The thing is mine doesnt have the cel on when I see this... the ecu blinks once when you turn the key on. Then it goes through 16 quick blinks, then 16 blinks again, 16 blinks again, and so on. The one blink only happens at turn of the key. If the cel is not on, is this a normal signal from the ecu?
Am I correct that if the main relay is bad the car wont run at all?

 

Your ECU only has short blinks, as indicated by the 16 short blinks. I am not sure why the ECU makes one blink before the 16 blinks. Does the CEL on the dash work? If so, the ECU may store codes even when the sensor no longer detects a problem. A common cause of code 16 is a bad main relay. In your case, the main relay problem may be intermittent. If the main relay is fine, then check the fuel injectors.

 

How do you check the main relay and where is it?

About a year ago when my timing belt broke (before I knew what the problem was) I had a cel on, it was the same 16 blinks, I checked the fuel injector and the ohm reading was fine. So thats why I ask if the 16 was normal when the cel is not on.
I did replace my negative battery cable and clamp as it was loose and corroded today, so that should have reset the codes, but the problem still happened after I replaced the cable. I just took it out for a spin to try and get the cel to come on but it didnt and I had no problems.

 

The diagrams below show how to check the main relay and the fuel pump circuit.

The constant presence of code 16 indicates that a problem persists. If the main relay, fuel pump, and fuel injectors are fine, then the fuel injector wiring or the ECU may be bad (see service manual).

 

Might be the same reason. I havent had a chance to get home and check with my voltmeter, but where is the relay, I see what it looks like but it is not visible as shown in the picture above. Is it near the fuse panel undernearth? Trying to start my car at lunch the car turns over but as soon as the key is released to the on position it quits, I noticed that my gauge warning lights dont come on when the key is in the on position, and the motor off. If I start it and hold the key just past on it will run. My radio comes on as usual with the key in the on position. So is my ignition switch bad maybe? Or is this a bad relay symptom?

 

Yeah, sounds like a bad ignition switch. Here's how to verify:

 

Replaced the switch and it seems ok now, thanks for your help Ron.