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|All Messages in Thread||Author||Date|
|Miss/ backfire issue||scott||3-28-05|
|1988 Holiday Rambler with 66000 miles on the 454 powerplant. Even after tune up it continues to miss and backfire. What would be the most likely problem, carb? timing issues? compression problem? My knowledge of the internal combustion engine is 0.|
|Re: miss/ backfire issue||Brent||3-28-05|
|I'm not an expert on these issues. My strategy would be to check all of the parts of the system until you find something not right. I'm having similar issues. Here is what I plan to do...|
-Double check the timing, and possibly the compression just to be sure everything is alright there.
- Make sure that the cap and rotor are in good shape.
- Same for the plugs and wires.
- On mine I would check the points and adjust the dwell. You probably don't have points.
- Check the vacuum lines for leaks. Replace any suspect ones.
If all that stuff checks out then I would start looking at the fuel system starting with the filter. From what I have been reading today it looks like a lean mixture can cause backfire when you decelerate so adjusting the mixture could help.
That's all I know. Good luck.
|Re: miss/ backfire issue||scott||3-29-05|
|Will do Brent, I appreciate your feedback.|
|Re: miss/ backfire issue||adam||6-14-05|
|I had a 1986 with a 454 with the same problem. After replacing part after part, with no luck, someone FINALLY told me what the problem was. It was the module in the bottom of the distributor. They explain that the circuit board in the module develops a small crack and causes the electricity to arc across the crack, and it gets worse with heat, which expands the crack. $12.00 later, I was back in business with no more backfiring!|
|Re: miss/ backfire issue||Chuck OConnor||6-18-05|
|Main Reason I have seen for Popping and misfires.|
AIR PUMP (smog) bad valve on AIR pump Very offten the issue if not lack of power)
TOO RICH and Firing in Exhuast manifold. (Bad Valves, WAY off LATE Timming,) Poor running
VAC Leak: at base of CARB, or at intake port. (Spray combustable starting fluid or carb cleaner and see if stops) Check vac guage for smooth pull or if it is bumping from 16-14 Like a shakey finger NOT good (bad valve)
Spark plug wire sending wrong firing order, IE If 7 jumps to 4 or you get the idea.
AIR Pump Valve (common)
Exhuast leak. (common)
Intake Leak (so so)
Vac Leak (common)
Heads cracked or broken valve springs (rare)
Broken Spark plug (more common then you might think)
Cracked Dist Cap. (common)
Inside Dist Cir board Less common but offten (say 15% of time maybe 20%)