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Discussion Starter · #1 ·
Car just died going down the road. Checked for spark ....none. Checked for fuel pressure....yes. Opened the distributor to find small amout of oil, so I figured maybe shorted internal component. Bought remanufactured distrib.....no spark. Returned distrib. Further testing....solid CEL with service connector shorted...no codes. KOEO the CEL comes on for a couple of seconds along with the fuel pump and then goes off. I bench tested the main relay...ok. I was told I had a bad ecu because of solid CEL so I bought a "known" (?) good ecu. Still no spark. New rotor, cap, wires, plugs....no spark. I checked for voltage at coil and icm...ok (I think). I checked voltage to map sensor (5vdc & 3.5vdc @signal wire) Any advice would be appreciated.
thanks,
mike
(lowly 95 civic)
 

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How are you checking for spark?
You're getting 12V+ to the heavy blk/yel wire of the 2-pin distributor connector with the ignition switched on, right?
The thermostat ground connection is clean and tight? The valve cover and transmission grounds?
All the distributor sensors check out? (350-550 ohms each, no shorts to the distributor case)
Check that you have continuity on the ignition signal and distributor sensor wires between the distributor and ECU connectors.
 

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Discussion Starter · #3 ·
bobski,
Thanks for the reply. I checked spark by connecting a plug to a couple of different plug wires, grounding, cranking over and watching for spark.
Yes, I have 12.4 vdc at yel/blk, 2 pin connector. I checked tightness on the three grounds you mention and they are tight and appear to be clean connections, but I didn't clean them. I have checked the icm with wires disconnected I have battery voltage at the yel/blk and the blu/wht. I checked resistance at the coil. Between A & B I have almost 1 ohm and between A and output I have 13,600.
I don't know how to check "all distributor sensors" as you say. Please explain.
Further, I don't know which ecu pin numbers and distributor wires represent the ignition signal and distributor sensor wires. Please explain.
Thanks much for the help.
mike
 

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If you have a timing light with an inductive pickup (clips around the sparkplug wire), try using that to check for spark.
On the distributor's 7 pin connector you should have the following wires: yel/grn (ignition output), blu/grn and blu/yel (crank sensor), org/blu and wht/blu (TDC sensor), org and wht (CYL sensor).
Each of the sensors should have 350-700 ohms (since it's OBD-1... I was thinking OBD-0 earlier) of resistance across it's terminals and no connection to the distributor housing.
Here's the ECU pins:
yel/grn - A21 + A22
blu/grn - B15
blu/yel - B16
org/blu - B13
wht/blu - B14
org - B11
wht - B12
 

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Discussion Starter · #5 ·
I don't have a timing light ....yet. I do have an oscilloscope but I've never connected it to an auto engine. Not sure what leads I need to keep from blowing it up.
All of the sensor pairs at the distributor were about 375 -380 ohms.
None of them had continuity with the distributor case.
I had continuity from the distributor to the ecu on all the wires except A22, I believe....there was no wire there. I checked all these wires for continuity to the chassis also....none were common with chasiss ground.
I noticed that both coil leads (connected) were common with the distributor case / ground. Is that ok?
thanks,
mike
 

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I'm not sure how useful an oscilloscope would be in an automotive environment. I'm sure connecting it directly to the ignition output would screw it up, so you would still need some kind of pickup coil. You would probably be better off getting a timing light from an autoparts store or tool store such as Harbor Freight. There's no real hurry though.
zortmo said:
I noticed that both coil leads (connected) were common with the distributor case / ground. Is that ok?
I'm not sure... One lead should be connected to the ignition switch (via the heavy blk/yel wire) and the other should go to the ignitor unit. The ignitor unit may default to a ground connection when the power is off, causing the apparent short you're seeing. Either disconnect the leads from the coil (make sure you use the right size screwdriver or maybe a screwdriver bit for a ratchet - the heads of the terminal screws are easy to strip) or disconnect the 2 pin distributor connector from the engine harness and the wht/blu and blk/yel wires from the ignitor unit, then retest.
 

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Discussion Starter · #7 ·
Ok, with the coil leads disconnected there is no continuity to ground. I reconnected everything and then tested the output on the coil with a test light while cranking engine and it lights the test light. I also checked to see if I have 12 vdc (with test light) on the injectors, which I do.
mike
 

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Discussion Starter · #10 ·
Fixed it ...finally. The first distributor I bought was bad. Bought another one and it fired right up. I was able to rule out the ecu by using a logic probe to check the signal from ecu to ignitor. I couldn't see how it could be anything else but the distributor. Thanks for all the help.
 

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Discussion Starter · #12 ·
No can do...I had to turn it in for a core. I do know for sure that the coil was a little out of spec although it was functional. I think the ignitor was the main suspect because I saw the signal it was receiving. It had to be the ignitor or the pick-up coil ( I think that's what it's called).
Thanks again.
mike
 
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