No spark - Confirmed batt voltage at blk/yel wire. Intermittent spark at plugs. I took a test light and attached it to the pos batt terminal, then put the tip on the coil - terminal. Test light pulses with engine cranking, then fades away. I checked the ICU at Auto Zone. Bad. Replaced it, had good pulsing with test light at coil. Buttoned it up. No start. Pulled cap again. Checked with test light and spark faded away again. Had ICU checked again. Bad. Replaced entire dist. Car start. Ran for about 10seconds. Died and has intermittent spark again. Checked voltage at coil while cranking. Still full 11+ volts while cranking (batt charger attached). What now?

1996 Civic 1.6 A/T,

 

Hello,

I am stumped on this one so I hope I can get some help here.

My daughters Civic stalled while driving down the freeway a few days ago. I towed it home and checked:

Timing belt - Good
Bat voltage to + side of coil and ICU
Fuel pressure
Primary and secondary resistance on coil. .06 on primary 16.5 on secondary, two coils (original and wrecking yard dist) tested the same.

I tried a wrecking yard dist, no change.

I checked for spark at the coil and noticed that it was weak and intermittent.

I then checked to see if the coil was getting told to fire by hooking a test light to the + bat post and touching the - post on the coil while cranking. The test light pulsed, then faded away to nothing.

I pulled the ICU and had the wrecking yard one and the original tested a Auto Zone. Both tested bad. Bought a new one and had it tested before leaving the store.

I installed the ICU, checked at - coil for pulsing. Looked good. Buttoned up everything. No fire. Checked spark at the plugs. Intermittent. Usually, fire at first revolution. Less offer the more I crank.

I pulled the ICU and had it re-checked. BAD!

I bought a new complete dist. Installed and cranked car over. It fired right away, ran for 10 seconds, stumbled and died. I pulled a plug wire, plugged in an HEI spark tester. Intermittent and weak spark.

Could it be a bad ECM? Crank sensor. I'm out of ideas.

Thanks in advance for your help!

 

No CEL on either. Weather was cool and dry. Nothing out of the ordinary. She had only been running for about 10-15 minutes.

 

The primary reading is out of spec (10-fold too low).

After spark becomes weak, do you still read battery voltage at the Blk/Yel wire attached to the coil?

 

Thanks for the reply. That was a typo on my part. It was .6, not .06.
The battery voltage on the blk / yel wire drops from 13 to 11.5ish during cranking but it didn't appear to drop as the spark got weaker

 

Today, I swapped out the wrecking yard distributor for a Auto Zone distributor. It fired up and ran for about 10 minutes. While I was waiting for the fan to kick on to set the timing, it died and would not re-fire. This time, I noticed that the tach instantly dropped to zero like someone turned off the key before the engine died. That got me wondering I'd the main relay was the cause. I exchanged the dist at Auto Zone (just in case it was fried) and swapped out the Main relay with one from a known running car. Still won't run. It does stumble like it wants to run but will not stay running. Before it dies, the tack drops to zero every time.

Any ideas?

Thanks!

 

My 96 civic EX A/T has a P2P- A71. Would a P2E from a 98 Civic LX A/T work? My EX is a US made car and the LX is a Japanese car.

Thanks.

 

Anyone?

 

I let the car sit for the week. Now, when I attempt to start it, it will fire and run for 30 seconds or so. Then, the tach drops to zero and the engine immediately starts to stumble. If a attempt to give it any throttle, it will not rev. If I shut it off and restart it, it does the same thing. The warmer it gets, the less time it will run well (with the tach working). I cleaned all of the grounds I could find and hooked up my meter to the black/yel wire. I had 13.8 CDC while it was running well, no change when it began to stumble. I then checked the fuel pressure. 35-36 psi while running well. Same after the tach drops and it begins to stumble. I'm thinking ECM more and more but don't know if the ECM I found will work.

 

Darn autocorrect. 13.8 VDC, not CDC.

 

Is there anyone out there that I can send my computer to for diagnostics or do I take a chance on replacing it with a new one?

 

Have you Ohm tested the Grn/Yel wire that runs between the ICM and ECU (pin A20)?

 

I did attempt to check it but was by myself and wasn't really sure if I was making a good connection. When checking, should I be grounding one gnd to body and checking continuity to body on the other end or checking the distributor end for ground thru the ECU. Can you clarify for me?

 

This^ tests for a wire open. It's done with the wire disconnected from the ICM and the ECU connector unplugged.

Testing for a short is the same, except you don't ground either end of the wire.

 

Thanks for your help. I'll check it out tomorrow and re-post.

 

the ecu will not run your car correctly. you can open your main relay, check for burnt spots and resolder.

 

Okay. With the connectors at the ECU and at the dist disconnected, the wire has no continuity. With the ECU end connected to ground, the dist end read 3.6 ohms.

 

Looks fine. If you reconnect everything does the engine start and run?

 

Reconnected. Same symptoms. Starts and runs. After 30 seconds or so, tach drops to zero and engine runs like crap. Fuel pressure stays at 36 psi, voltage to dist stays good. No CEL.

 

I just checked the timing marks again. With cam gear marks lined up with top valve cover surface, yellow mark on crank pulley is lined up with pointer on belt cover.

 

Does the engine restart immediately after the engine stalls (I assume the latter happens)?

 

Yes it will refire. It seems like the more I mess with it (I'm assuming heat) the sooner the tach stops and it acts up.

 

Thanks for your help but I had already swapped out the Main Relay.

No change.

 

Does anyone know how to check the crank sensor? Will it always throw a CEL if it is not working properly? I have no codes.

 

it turns over but it wont start?