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Compression test, now won't start

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  #1  
Old 03-18-2008, 09:35 PM
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Default Compression test, now won't start

Well I'm starting to learn more and more about cars, and my Accord in general. I ran a compression test today. My results were 182,183,189,190. These are good number correct?

However my problem is... my car won't start. I hear the fuel pump, but I'm thinking I'm not getting a spark. While doing the test, I disconnected the main relay under the dash that it describes in my haynes manual. (Brown connector, contains seven wires,blue,blue with whie stripe, blue with yellow stripe, green, black with white stripe, green with black stripe, and black, if that helps). I then removed hte distributor cover.I ran the test, put the plug back in, hooked the wires up in the right order, slip the distributor cap back over and screwed it in, and connected the relay. Tried to start the car 15 times and it just won't go. I tried resetting the ECU and still nothing. I'm a little lost, I read something about the igniter coil can go, is this true? And how much and how hard are htye to replace?
 
  #2  
Old 03-18-2008, 10:10 PM
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Default RE: Compression test, now won't start

Confirmed...no spark and there is fuel.
 
  #3  
Old 03-19-2008, 01:44 AM
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Default RE: Compression test, now won't start

How tight did you tighten the distributor cap screws? If you got them too tight you may have cracked the cap. If that happened, it won't start.
To see if it is the cap, check for spark coming out of the coil wire.
 
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Old 03-19-2008, 02:51 AM
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Default RE: Compression test, now won't start

If you were cranking the car with the distributor cap off, then you fried the coil. You should have unplugged the power wires that go to the distributor when doing the test or grounded the cylinder wire you were compression testing (while keeping the other three plugs/wires in place).

You basically charged the coil and the spark had nowhere to go, so it most likely grounded through the coil and shorted it out.
 
  #5  
Old 03-19-2008, 10:47 AM
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Default RE: Compression test, now won't start

Check the circuit drawing for '91 to confirm this, but...

I think with the main relay unplugged, the ECU was not powered. Therefore the ECU never sends an ignition trigger signal to the ignitor, so the ignitor doesn't try to fire the coil.

It shouldn't really matter that the distributor was powered if it was never getting a 'fire' signal from the ECU.
 
  #6  
Old 03-19-2008, 01:00 PM
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Default RE: Compression test, now won't start

I did unplug the right connector for the main relay right?
 
  #7  
Old 03-19-2008, 01:07 PM
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Default RE: Compression test, now won't start

I'll have to trust you on that one. I've never owned a '91 and I wasn't watching over your shoulder...

But your description sounds about right.
 
  #8  
Old 03-19-2008, 01:21 PM
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Default RE: Compression test, now won't start

If you read through the manual there should be directions for testing the coil with a volt meter (not 100% accurate but give a good idea) run through those procedures and see what comes of it.... did the car start before you did the compression test?
 
  #9  
Old 03-19-2008, 02:33 PM
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Default RE: Compression test, now won't start

Yes it ran fine, I tested it right after a good drive like the book said. BTW are the results good?
 
  #10  
Old 03-19-2008, 03:52 PM
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Default RE: Compression test, now won't start

The results are fine. You want the cylinders to be within 10% of each other (+/- 19). All of yours are close, so the engine is in good shape.

The main fuel relay does send power and provides a ground to the ECU, but that cirucuit deals with the injectors and the fuel pump. I have never read anything where the main fuel relay caused a no spark condition.

The ECU pin for the ignition system will get power when the ignition switch is turned on (with or without the main fuel relay plugged in). I am almost positive that the coil is shot, since the spark had nowhere to go when you were doing your compression test. Read the tegger.com site in the sticky above. There is picture where the coil was destroyed when cranking the engine with the cap off.

Read your manaual's instructions and see if you didn't skip a step where you were supposed to ground the coil tower, etc.
 


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