1991 civic DX 1.5 liter DPFI

Went out Thursday morning to go to work, start car, ran rough for 2 seconds and died. Checked oil for fear of no oil situation, had oil. No start since then. Crank till the cows come home.

I have spark on all four cylinders. New distributor with all new guts. Main relay is functioning and have gas flowing. Injectors are within resistance specs but it appears impossible to check for spray since there is no rail. Compression seems okay (blew 4 potatoes right out of the head). New fuel filter. All fuses look fine. ECU showed code 17 initially (vehicle speed sensor? ) but I can't believe that would prevent startup. ECU still flashes once for its "i'm alive" signal after clearing by pulling hazard fuse for 10 seconds or more.

I've read every forum around and can't find anything that fits my problems. Could the ECU be toast?

Thanks for any help...

The best thing I could propose is to find someone who has the same engine as you (D15B2) and ask him to try his ECU in your car. If it works - it's ECU. If it doesn't work - I have no bloody idea... :confused:

Do you think the O2 sensor could keep it from starting?

Or the ignition switch? I wonder if the ignition switch, which feels solid, could crank the engine but prevent it from running if faulty??

Ignition switch gives the signal to starter to crank... so, with a faulty ignition switch, starter wouldn't even crank.

O2 shouldn't stop the car from starting... it is used to control fuel mixture... if oxygen sensor reports that gasses exiting the combustion chamber are "lean" (too little gas), then ECU compensates that by adding extra gas. Similar if it reports "rich" (takes away some gas). But I don't think OXYGEN sensor is used while starting the car. It makes no sense anyway.

Ignition switch checked out fine.

I agree about the O2 sensor. You can't even check it without the engine running.

Checked airbox for dead animal obstructing air. No such luck...

After cranking for about 5-10 seconds the car acts like it wants to start. Is there a way to tell if the injectors are functioning outside of the throttle body (there's no fuel rail, so the injectors can't spray outside of the throttle body)? Will the car be sending 12 volts through the injector connectors?

Yeah, the ECU should be sending 12 volt pulses to the injectors.

If the timing belt was broken, I don't think you would have compression.

Try sloshing some gasoline into the air intake. If it fires any more than otherwise, the engine is not getting gas.

One last thing... fuel is delivered in a strange way in a DX. Because there is no fuel rail, you cannot just take the injectors out and expect them to squirt gas. However, fuel injectors are inserted into throttle body, which is held to the manifold by 4 screws. Try and see if it would be possible to unscrew the 4 screws and move the throttle body around with all the lines (vacuum and fuel lines) still attached to it. Fuel should squirt out of it when you crank the car. Well, in some way, you should use the whole throttle body as a fuel rail here... if you know what I mean.

I tried putting gas through the mesh top on the throttle body to no avail. I wonder if the gas just can't make it well enough into the head and cylinders to fire up.

That's an interesting idea about pulling off the throttle body as a whole. I smell gas when I crank, but who knows what the hell is happening in there with the injectors...

I'll give it a try, thank you...

for whatever it's worth, here's what happened.

the car has been sitting untouched for a couple days. I check the compression with a legit gauge. Compression wasn't so great, but not so bad that it shouldn't start. I was getting ready to pull off the throttle body as a whole to see if the injectors were indeed squirting. Got to the last nut and saw that it was very difficult to get to. Frustrated, I loosed the distributor, spun it all the way back (counter clockwise). I got in the car and starting cranking just for the hell of it.

the engine started acting like it wanted to start but didn't. I got out of the car and walked around to the engine and heard a funny electronic type sound. A little buzzing. I bend down to locate it and find the part and unplug it (prolly a bad idea in retrospect but who cares at this point). I get in the car and crank and it starts! It runs but can't hold idle very well. So I run it for a few minutes just to enjoy the sound of the engine.

I look at the LED display. 14 flashes = EACV or Electronic Air Control Valve = the item I unplugged. So I kill the motor and plug it back in. engine starts and now can idle normally.

I ran it for about 15-20 minutes staying within pushing distance from my house. It runs like nothing has ever happened.

so I pulled the hazard fuse to clear the ECU, and am going to let it sit until tonight when I'll try and start it again. Then tomorrow morning.

does this make any sense at all?? It's an intake side emissions control device??

Holy crap... EACV is a valve that keeps idle higher until the engine warms up, and gradually reduces it when it gets warm enough.

So you just disconnected the green connector and connected it back? Duh! Makes no sense, I must say :) Anyway, if it fixed your problem - great :)