 back fire, none under acceleration but ... |
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| jimkelly |
 Sep 5 2006, 09:58 AM
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#1
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Delaware USA  Group: Members Posts: 4,969 Joined: 5-August 04 From: Delaware, USA Member No.: 2,460 Region Association: MidAtlantic Region  |
as shortly after letting off gas - bang bang bang ?
We just installed a 1.8 with single carb and 050 distributor. Carb and dist appear to be working fine. What are the odds that the problem is due to valves needing adjustment as this is what we are gonna try next. |
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| tyler |
Sep 5 2006, 12:35 PM
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#2
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Member Group: Members Posts: 335 Joined: 24-September 03 From: southern california Member No.: 1,192 |
I always thouht the only cause of this could be timing but now I'm a believer that it's always more likely too much fuel that explodes in the tailpipes. My 350 did exactly what yours is doing after carb rebuid. Since the carbs were only supposed to have been cleaned and adjusted (and they seemed to be running lean), I went after the timing and valve adjustment, all to no avail. Later I found out the carb guy had put in bigger jets and didn't tell anyone. Put the old jets back in without touching anything esle and the backfire disappeared.
For what it's worth. ================================= QUOTE(jimkelly @ Sep 5 2006, 08:58 AM)  as shortly after letting off gas - bang bang bang ? We just installed a 1.8 with single carb and 050 distributor. Carb and dist appear to be working fine. What are the odds that the problem is due to valves needing adjustment as this is what we are gonna try next. |
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| ptravnic |
Sep 5 2006, 01:23 PM
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#3
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Senior Member Group: Members Posts: 1,231 Joined: 27-May 03 From: Chicago, IL Member No.: 747 Region Association: None 
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Mine did this b/c I was running it too lean...
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| smdubovsky |
Sep 5 2006, 01:28 PM
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#4
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Member Group: Members Posts: 331 Joined: 27-September 04 From: Silver Spring, MD Member No.: 2,837 Region Association: MidAtlantic Region |
If its in the exhaust, then you have an air leak in the exhaust. If its poping out of the carbs/intake Id bet its too lean (which is usually caused by a vacuum leak if the carbs are jetted even close to correct). Both my TWMs and Webers will pop in the intakes on the /6s when too lean (and BOTH are due to vacuum leaks).
Best, SMD |
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| ptravnic |
Sep 5 2006, 01:57 PM
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#5
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Senior Member Group: Members Posts: 1,231 Joined: 27-May 03 From: Chicago, IL Member No.: 747 Region Association: None
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My lean situation was due to a misadjussted FI system and poor engine build (too high of a CR). Both were completely my fault. O well, I'm in the process of rebuilding it now and will not make the same mistake(s) twice!
-pt |
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| jimkelly |
Sep 6 2006, 07:15 PM
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#6
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Delaware USA Group: Members Posts: 4,969 Joined: 5-August 04 From: Delaware, USA Member No.: 2,460 Region Association: MidAtlantic Region |
muffler is now on and back fire is gone - hum - simple solution : )
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| PORobinSCHE |
 Sep 6 2006, 07:26 PM
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#7
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Member Group: Members Posts: 421 Joined: 22-July 06 From: Orlando,Fl Member No.: 6,484 |
QUOTE(jimkelly @ Sep 6 2006, 09:15 PM) muffler is now on and back fire is gone - hum - simple solution : ) Gee, you left that 'lil' tidbit out (IMG:style_emoticons/default/rolleyes.gif) no wonder it popped. (IMG:style_emoticons/default/spank.gif) |
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| jimkelly |
Sep 6 2006, 07:52 PM
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#8
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Delaware USA Group: Members Posts: 4,969 Joined: 5-August 04 From: Delaware, USA Member No.: 2,460 Region Association: MidAtlantic Region |
hey - if I told you guys all the facts - I would not get such great replies : )
Thanks Jim |
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| PORobinSCHE |
Sep 6 2006, 08:17 PM
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#9
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Member Group: Members Posts: 421 Joined: 22-July 06 From: Orlando,Fl Member No.: 6,484 |
that's why i come here!!!
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