 Backfires while idling after checking compression |
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| ndtman |
 Sep 23 2012, 04:37 PM
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#1
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Newbie  Group: Members Posts: 5 Joined: 19-June 12 From: Moorhead, MN Member No.: 14,580 Region Association: Rocky Mountains  |
I have a 76 2.0 with the stock fuel injection that I am bring back to life. It ran fine, but I decided to check the compression. After doing this, the car now backfires a lot while idling (every 2-5 seconds), and even more so if I dare throttle up. With the dual exhaust mufler, I note that the backfiring is coming from cylinders 1 or 2. I swapped out both plugs and wires on 1 and 2, but the problem remains. All the spark plug wires are routed to the correct cylinder.
I found that if I disconnected the spark plug wire to cylinder 4, the car would not backfire, and ran smoothly. Replacing the #4 plug and wire didn't fix the problem. I plan to replace all the plugs, wires, distributor cap, etc, but was wondering why my testing is giving such confusing results. Bottom line - the only way I can fix the backfiring at idle is to disconnect the #4 plug wire. Any ideas? Thanks. |
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| 76-914 |
Sep 23 2012, 05:39 PM
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#2
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,700 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California 
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do you have a sticking valve?
Edit: you didn't cross the injector wires on 3 and 4 did you? |
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| Mike Bellis |
Sep 23 2012, 05:58 PM
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#3
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Resident Electrician Group: Members Posts: 8,347 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None 
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QUOTE(76-914 @ Sep 23 2012, 04:39 PM)  do you have a sticking valve? Edit: you didn't cross the injector wires on 3 and 4 did you? Crossing the injector wire would have little effect. The 914 uses a batch fire system and not sequential injection. You would loose 1/2hp maybe. If you could measure it on a dyno. My money is on a tight valve or carbon tracks in the distributor cap. |
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Posts in this topic
ndtman Backfires while idling after checking compression Sep 23 2012, 04:37 PM
ndtman I just checked and adjusted all the valves about a... Sep 23 2012, 08:23 PM bulitt An exhaust leak will cause a backfire as it introd... Sep 24 2012, 09:09 AM |
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