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09-17-2024, 10:58 AM | #1 |
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Join Date: Jun 2017
Location: Painesville, OH
Posts: 173
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Re: Rough idle and takeoff 250 inline
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09-17-2024, 03:44 PM | #2 |
Post Whore
Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,247
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Re: Rough idle and takeoff 250 inline
I would break out my vacuum guage and see what it told me. If your not familiar with using one here is a basic primer. The vacuum guage should point you in the right direction in your troubleshooting.
There are numerous other articles as well as videos to help on the interweb. https://www.onallcylinders.com/2015/...gine-problems/ Good luck. I hope it turns out to be an easy fix.
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
09-17-2024, 08:41 PM | #3 |
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Join Date: Jun 2017
Location: Painesville, OH
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Re: Rough idle and takeoff 250 inline
I have changed the points, condenser and spark plugs. Point were set to. 019 gap according to the manual. Timing was off and is good now. Seems to be idling better but have yet to drive it. Hooked up a dwell meter and it is only reading 24. Should be 31-34 according to the manual. I keep reading that the dwell/ points should be set with the motor cranking, not with a feeler gauge. I have never done this. How do you do this by yourself? And how do you keep the motor cranking while adjusting the dwell / points?.... Help? Thanks!
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09-18-2024, 10:41 AM | #4 | |
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Join Date: Apr 2010
Location: So Cal
Posts: 1,452
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Re: Rough idle and takeoff 250 inline
Quote:
They mean with a dwell meter. You could check dwell cranking, but I always put the cap back on and start the engine to check dwell. Dwell angle is the period of time the points are CLOSED, point gap is checked when points are OPEN. When dwell reads low, it indicates you have gap set TOO wide. You can not be ham fisted when setting gap. It takes a delicate touch. The point spring is relatively soft and the feeler can act as a lever, prying the points apart, especially if you are using the entire pack of feeler strips. Separate the pack and use the single feeler strip.
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'67 GMC 2500, 292, 4spd, AC |
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09-18-2024, 11:18 AM | #5 | |
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Location: Painesville, OH
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Re: Rough idle and takeoff 250 inline
Quote:
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09-18-2024, 08:57 PM | #6 |
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Join Date: Jun 2017
Location: Painesville, OH
Posts: 173
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Re: Rough idle and takeoff 250 inline
Got the dwell adjusted to 33 (recommended range is 31-34). RPMs are where they should be and timing is dead on. It's idling great. Will take for a test drive tomorrow. Fingers crossed...
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09-20-2024, 02:32 PM | #7 |
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Join Date: Jun 2017
Location: Painesville, OH
Posts: 173
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Re: Rough idle and takeoff 250 inline
Took the truck for a ride. It idles fine and runs great when up to speed. It's still a little rich upon takeoff and under load with an occasional backfire. The timing is dead on, dwell is good, rpm's are good. I checked the vacuum lines and they are good. Replaced the points, condenser, spark plugs. What else would cause this?
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