Questions and Answers

Crazy Honda Civic Fuel Injectors Q. I have seen many people and had several look at my car with no resolve. I stumbled onto your web site and maybe you can help me. I have a 1999 Honda Civic DX Hatchback with a JDM Civic SIR II Engine in it. Everything ran well for the first six months, but now for the last month and a half my car has been running like crap on and off.

This is what I know: Number one injector stops working all together from time to time(don't know if its sticking open or closed). Number two goes crazy when number one stops working (injects out of order). Three and four are good.

I have replaced number one and still have the problem. When I remove the harness it runs well for a second and then bogs, when you plug it back in you can hear the injector open, then a cloud of gas filled smoke streams out of the tail pipe.

I read an article that you wrote about Honda Civic injector problems but didn't know if it was the same as my car. Can you help? I would like to know how to test everything to find out where the problem is.

Thank you for your time...

A. As you can see in the wiring diagram below, the injector electrical circuit is very simple. Power to the injector comes from the Main Relay and the ground is supplied by the PCM.

Since only one or two injectors are effected, and you replaced injector number one, I think it's safe to assume that the injectors and the injector wiring are all good. So that leaves the ground side.

What you need to do is check the brown wire for injector number 1 at the PCM connector. With the key ON and engine OFF, there should be power at the PCM. Do this for the red, blue and yellow wires for injectors number 2, 3 and 4 respectively.

If you have power, jiggle the wire harness at the injectors to see if the light flickers. If it does, you have a damaged connector.

Check the wiring from the injectors to the PCM very carefully for breaks and shorts. If the wiring is all good, then you have a bad PCM.