Jaynik

1996 Civic HB d16y7 Motor

Has no spark at coil

swapped in known working coil and ICM/igniter

still no spark

tested the engine grounds for continuity to the frame, all good

tested and found no voltage at yellow/green wire on distributor connector
however, the wire DOES have continuity between the distributor and the ECM

ECM bad?

Jjbaehr

Does it have power coming out of the Ecu if you back probe the connector?

Jjbaehr

I believe that's a signal wire does it show voltage while cranking? Also make sure it does not have continuity to ground.

Jaynik

Ok checked it.

Yes voltage at the connector when back probed, voltage steady with key on fluctuates when cranking

Negative on the continutity to ground

negative on voltage at dist when cranking

Jjbaehr

Ok well the only other connector to check is the distributor, have you back probed the connector on both sides? Engine harness side and distributor side?

Jaynik

No, will do

Jjbaehr

This is not adding, up continuity tests can be misleading, it only takes a single stran of copper wire to show good continuity, but not enough for voltage to flow through it. Although I would expect some voltage even if there was high resistance in the circuit.

Jaynik

ok it has continuity between the ecm and both side of the conectgor AND the wire at the igniter. It only has voltage at the ecm when back probed. I've never had a problem with voltage not being present when continuity was, its making me feel crazy!

Jaynik

the resitance is .5 at the dist

Jaynik

12 volts at the ecm, 0.00 at the dist. You're right this doesn't add up

Jjbaehr

Yea me too, well at this point I would run my own wire, snip it at the ECM and at the distributor and see if it fires. I know it's not the right way but you have some serious resistance in that wire somewhere. And there isn't any other connector to check.

Jaynik

I was afraid you'd say that. Welp, I'ma do it then.

Former User

I suspect that you may be probing the wrong ECU pin for voltage. Are you probing ECU pin A20? Is the pin attached to a Yel/Grn wire? Post pictures.

http://www.phearable.net/tech/wiring...schematics.gif

Does battery voltage reach the Blk/Yel wire attached to the coil and ICM when the key is in ON(II)?

Jaynik

Thank you for the input, ya'll! I feel very confident that I had the right wire probed. I used the schematic in the first place to back probe pin A20, yel/grn, at the ecu and verified continuity with the wire at the icm. I cant get you a image at this time, I'm afraid. I will double check the blk/yel wire this afternoon, but I think I remember it having voltage.

Jjbaehr

I was thinking the same RonJ at first.. I'm slightly baffled by this, did you try to run a wire yet?

Former User

There's something wrong with the OP's test.

• ECU D20 does not supply voltage, only ground.
  
• Voltage is suppled by the ICM and this voltage is grounded by the ECU.

All voltage tests should be redone. The OP should also post pictures of distributor and ECU wires that he is testing.

Jjbaehr

In the outputs section of the ETM it shows that A20 should have 12v with the key on.

Former User

10-12V, but the voltage comes from the ICM.

Jjbaehr

Ok so I'm super confused now, how is it that he has batt voltage at the Ecu and not the distributor then? I'm lost OP must be doing something wrong.

Former User

Exactly

Jaynik

Ron has to be correct, there is just no other way to explain my results other than error. All tests will be re done. Luckily I haven't done anything else yet.

Jaynik

Egg on my face! It passed all the icm tests. Back at square one.

Former User

List all tests you've done and the results.

Have you checked whether the timing belt snapped or stripped?

Jaynik

All righty. The car died while driving, started again and got to a safe spot. It wouldn't stay running longer than a few second. Towed her home, she has no spark. Tested coil resistance and it was good, I am going to re test this since my brain apparantly hasnt been working. No spark was verified with a test light that I verified was working on my other civic.

I got frustrated and put the coil and ICM my other, running, identical civic... no dice.

While screwing with the tests it randomly decided to start and ran for about a minute, which was long enough to test the ignition timing with a light, which was good. After that it quit starting again. I suppose I should call this an "intermittent no spark"

I removed the timing belt cover, the belt is good, it only has 20k miles on it. Verified mechanical timing mark at cam sprocket and at the crank pulley, all lined up perfect.

for good measure I verifed fuel pressure after the filter and at the rail.

The tests I just re did were from the honda manual ICM test section.

verified voltage at blk/yel wire at icm
verfied voltage at blu/wht wire at icm
verfied cont. between yellow green wire at ecu and icm
verified no cont. between yellow green wire and body ground
verfied cont. between tach test wire and icm blue wire
verified no cont between blue wire at icm and body ground

I am going to investigate the coil again now.

Former User

Definitely test the coil and have AutoZone test the ICM.

Have you checked whether the rotor screw is loose or missing?