 Miss fire on cly 4, 73 d-jet |
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| rfinegan |
 Sep 24 2024, 07:51 AM
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#1
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Senior Member  Group: Members Posts: 1,067 Joined: 8-February 13 From: NC Member No.: 15,499 Region Association: MidAtlantic Region 
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I have been narrowing down the Root Cause on a misfire 73 2.0 D jet. Cold it hits on all 4 but as it warms up I have a miss. Compression a little low but may be washed down rings. 10% leak down/ seem to seal up ok.
When I disconnect the injector no change. Plug back in no change Noid light check for pulse PASS Spark getting to the plug PASS. Change plug anyhow as it was new and unknown state Gut tells me I have an injector acting odd Today I ran the same basic test: I had a good idle but fast, 1300-1500. Figured I has hitting on 4 now...I pulled the wire off the injector and the speed went UP.. plugged back in and the speed went back down. WTF NEXT STEP: 1) add fuel gage and confirm pressure ; adjust regulator as needed ( fuel Line kink has been fixed (was lean) pressure base line unknown 2) swap injectors 3/4 see if problem follows to Cly 3. (best) Or put a different injector in Cyl 4 and test for new behavior (lazy) Other: I borrowed my 123 Distribute and installed in the 73 2.0 to base line an ignition problem (jumping Tach) Root Cause was a Coil installed backwards. Smoke machine test shows no Vacuum leaks. Ever so slight leak at throttle shaft, but feels great Curious as to see if others feel that injector is off in the weeds? Sticking and now leaking? |
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| rfinegan |
Oct 19 2024, 06:25 AM
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Senior Member Group: Members Posts: 1,067 Joined: 8-February 13 From: NC Member No.: 15,499 Region Association: MidAtlantic Region
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update
I did stick to the plan and with swapping the 3/4 injectors. I did induce another variable by using injector cleaner and flushing and comparing the spray patterns with an injector pulser and a mock flow bench / fuel pump. This now hits on all cylinders and miss fire is gone..For now..we will see, and send them off to Mr injector if any issue persist |
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| Lockwodo |
Oct 19 2024, 06:59 AM
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#3
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Member Group: Members Posts: 213 Joined: 23-December 21 From: Santa Cruz, Californnia Member No.: 26,193 Region Association: Northern California
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QUOTE(rfinegan @ Oct 19 2024, 05:25 AM)  update I did stick to the plan and with swapping the 3/4 injectors. I did induce another variable by using injector cleaner and flushing and comparing the spray patterns with an injector pulser and a mock flow bench / fuel pump. This now hits on all cylinders and miss fire is gone..For now..we will see, and send them off to Mr injector if any issue persist (IMG:style_emoticons/default/beerchug.gif) |
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Posts in this topic
rfinegan Miss fire on cly 4 Sep 24 2024, 07:51 AM
Lockwodo You may be right about the problem being related t... Sep 25 2024, 01:57 PM
rfinegan YES, The 123 is in right now and clean things up t... Sep 26 2024, 04:54 AM emerygt350 Strange stuff indeed. Maybe swap injector with an... Sep 25 2024, 06:58 PM rfinegan Also the MPS is rebuilt from a 73 djet at auto Atl... Sep 26 2024, 05:00 AM rfinegan Cleaned injector is still running like a champ...C... Apr 25 2025, 09:42 AM Ron914 I used Mr Injector to test and clean my original B... Apr 25 2025, 10:30 AM |
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