1996 Civic EX with the D16Y8 engine. Fresh rebuild with bearings, rings, gaskets, and seals. Compression is good(as expected). Timing is set per the manual. Have good spark on all plugs and they appear to fire at the correct time(using a timing light to verify). Have good fuel pressure all the way to the injectors. No reason to believe there is an airflow problem. The first time I tried to start the engine it ran for about 8-10 seconds slowly. Since then it will occasionally fire but not consistently. The PGM-FI relay, and the relay circuit check ok per the manual. The manual indicates that the CKP/TDC/CYP sensors should read from 350-700 ohms but I'm only getting 335 on each sensor. Is that off enough to keep it from running? I'm not getting any error codes either. When I pull the plugs there is some oil on them but I don't smell any gas in the cylinders. Is there a way to tell if the injectors are firing? Any ideas or help would be appreciated.

 

Plug wires in wrong order? Valves adjusted too tight (was the compression checked with a gauge)? One bad cylinder makes these engines very hard to start.

Check for fuel flow by disconnecting the return hose (after the regulator) and direct into a container. Make sure the fuel is fresh.

You can check if the ECU is driving the injectors with a "noid light". Take a #194 bulb and bend the wires down to make pins. Unplug an injector and stick the pins of the bulb into the plug. The bulb should flash when you crank the engine.

 

Fuel flow checked and good. Plug wires in correct order. Made a "noid light"(nice simple test, I like that) and injectors are getting the signal to fire. The problem turns out to be compression I believe. #1-155, #2-150, #3-110, #4-140. A little oil in #3 and recheck = 180, which is what I expected to see across the board. My Bad. I trusted the advice at the machine shop who said honeing and new rings was all it needed. Won't make that mistake again. Thanks for the help mk378.

 

Take the valve cover off and make sure the rocker arms go slack when the respective valve is supposed to be closed. If not, back off the adjuster screw on that rocker. If the valves aren't closing fully you lose compression and it is hard to start.

Another thing that is not supposed to happen but sometimes it does is engaging the distributor shaft 180 degrees out of time. I don't think that's real likely in your case because it did run a little once.

Also check that the small ECU ground wires on the thermostat are secure. It is easy to forget those when swapping the engine.

 

I will check the rocker arms but oil in the piston doesn't usually bring up the compression unless the leak is through the rings. Ground wires are good and distributor is correct. I'm gonna go play in the snow for the next five days before I mess with this again. I will post what I find. Thanks.

 

So yesterday I checked all the intake and exhaust valves for proper clearance. They were a bit on the tight side so I adjusted them a bit. Checked my compression and it was significantly different. So I went through the valves again and made sure they were spot on. And the engine started and ran. A bit rough at first but after 30 minutes or so it was doing quite well. What I have learned is that these engines are VERY sensitive to valve clearance. I was getting 25-30 lbs difference just by minute valve adjustments. I will post my compression results after I have put some miles on the car and the rings have a chance to break in.

 

The valve adjustment is important. Follow the official procedure exactly.

If you're just guessing (NOT recommended), it is much better to have the valves too loose than too tight. If too loose they will make noise, but if too tight you will have loss of compression and possibly burn a valve.

 

After 750 miles I checked the valve settings and the compression. I have the valves set at the mid point of what the manual says the range is. The compression now is 1-180, 2-165, 3-160, 4-170. The motor has been using oil in varying amounts. At about 400 miles I only got 100 miles to a quart on one run. That seems to have settled down. When I did the compression check the #4 plug had a lot of residue on it like oil is being burned in that cylinder. Can the valve adjustment affect whether oil is burned? Just keeping an eye on it for now.