Code 16! Code 16!

[EJB EJ1]

Car is a 95 Civic EX coupe, turbo-charged. Engine only has ~14,000mi on it. Turbo has ~5,000mi.

So I'm driving to work yesterday morning, and it's especially foggy and there's LOT's of dew/condensation everywhere. I don't know if it rained or not but I'm going to assume it did because I just washed the car the day before! Got out to the car around 6:20am and started just like any other day. Drove about 7.5mi and as I was coming up to a stop light, the CEL came on and the engine idle got really rough. Freaked the F out of me. It felt like the idle was going to drop so low the engine would stall, but it didn't. First thing I thought was, "Shitake. Fuel pump is dead. Wait...no, that wouldn't make sense." Then my biggest fear - "Oh no...this feels a lot like when my 94 LX sedan lost compression on the #2 cyllinder. But there was no CEL for that..." Lots of possibilities started racing through my head, followed by a frustrated "WTF." It felt like the longest red light ever! Finally get the green and as I started to pull away, there was absolutely NO power and the car was shaking from the bad idle. It wasn't a really severe shaking but it certainly wasn't subtle either! I was able to pull into a gas station near where I get on the highway, and as soon as I did, the problem went away. Engine idle smoothed out, rev'ing sounded good and clean, but CEL stayed on. So I back up, pull out of the gas station - rough idle and no power again! I thought, "F it. I need to get to work." I was able to make it here just fine but the lack of power really concerned me, especially since it's turbo'd!

One thing I noticed was that my Tenzo-R air/fuel gauge wasn't working. Once I got off the highway and drove past a nearby high school, the idle returned to normal, power came back, and the Tenzo air/fuel gauge worked fine.

Now here’s where it gets really frustrating – I had a couple minutes around 11am yesterday to run out and see if I could get the code information and see if the car was still acting up. Car started up fine and idled fine, no CEL showing. Took a spirited drive around the parking lot - no problems. Frustrated, I ended up leaving work early to try and take care of the problem at home. Car started up fine but as soon as I got out onto the street, the CEL turned on and the rough idle/lack of power came back. Bravely (or stupidly) got it onto the highway and limped it a few miles, then suddenly it started working fine. Lots of power, smooth engine, no shaking. Then it gradually when back to no power/rough idle. When I got onto the surface streets, the car performed normally once more, then quickly went back to sh!t. It seriously feels like I'm driving a Geo Metro of Toyota Tercel.

A couple other things I noticed driving on the highway - When I would let off the throttle and coast a bit, everything seemed to smooth out. Still had a rough idle at stop lights though. I also noted that the Tenzo R air/fuel gauge does appear to be working the whole time, it’s just that the engine seems to be running really, really lean when it's acting up. If I hammer the throttle a bit, the gauge lights up. Take that FWIW.

Last night I was able to get the code, which was a Code 16 ‘fuel injectors’, and also ran the fuel pump relay through the checks outlined in the Haynes manual (page 4-3 for those following along!) When I get home today, I’m going to “borrow” the fuel pump relay from a friend’s ’99 Civic and see if that takes care of the problem. My POS RadioShack digital multimeter will only test continuity, so I wasn’t able to perform the fuel injector resistance checks or the checks on the P2 connectors. I’ll test those out today with a better multimeter.

A couple questions – what do I do after I try the different fuel pump relay and test the fuel injectors? What are the chances that it’s actually the ECU acting up? Could it merely be a sensor problem and nothing related to the fuel injectors, pump, or relay?

I know that’s a lot of detail but it’s better to have too much info than not enough. I’m really hoping it’s just the relay and not the fuel injectors – they’re freaking expensive!!! Thanks for your help!

[EJB EJ1]

I pulled the main relay again and checked all the soldering. No cracks or dry joints. Tested the fuel injector resistance with a Fluke meter and they came up all around 2.6ohms, which is fine for low resistance injectors. Completely reset the ECM - pulled the primary and backup fuses, disconnected the negative battery terminal. Car started up fine and idled fine. Took it for a quick drive down the street and back. No problems. Drove it around town for a half hour and still no problems. I just got back in from testing the injectors again and #2, 3 and 4 test 2.8omhs. #1 (far left) tested first at 20ohms, then droped to 19.5, then kept dropping. Last number I saw was around 17.5ohms. Almost seems like there is 3 low resistance peak/hold injectors and one high resistance saturated injector, but then the 2.6ohm readings I got when the engine was cold wouldn't have occurred.

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update

Just checked the #1 injector resistance again. 3.2ohms. This should be within the range of a low resistance injector but I'm not sure why the #1's resistance is getting so high.