Ive got a ford crate 302 when ever i rev it up quickly it wants to backfire though the intake. Ive tried the timing every where it would run, tuned the float levels and idle screws on the carb(holley 600). The only way I got it to stop was to take off the vacuum adv. and wire the choke most of the way closed- not what I want to do! Do yall have any Ideers?
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1984 CV tudor 351W, 4bbl, 5-speed best time in the 1/8 8.39 at 80 with 1.80 60ft time.
2006 P71, 1988 Bronco II, 1986 Baby LTD(5.0 & T5 swap in progress), 1976 16' Hobie Cat, 12' AquaFinn
http://www.cardomain.com/ride/2651997 UPDATED 20100826
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Do you know for a fact the carb is good? Its not some random used thing from a box o parts or something right? Fuel pressure OK? It sounds lean to me, either a vacuum leak, poor pressure, or some internal issue with the carb. Not enough / non-working acceleratir pump can also do this. Holleys have an adjustable pump shot, if thats way lean or if the linkage is not working somehow it would make it pop and splutter when revving.86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers -
I just rebuilt the carb yesterday, it was doing it before I did so it wasn't something I messed up. Ive ajusted the mixture screws and the linkage on the accelerator pump none of that seem to make a difference in the backfiring. Ill hook up a vacuum gauge tomorrow to see what it reads. Thanks for the idea.
Any others?1984 CV tudor 351W, 4bbl, 5-speed best time in the 1/8 8.39 at 80 with 1.80 60ft time.
2006 P71, 1988 Bronco II, 1986 Baby LTD(5.0 & T5 swap in progress), 1976 16' Hobie Cat, 12' AquaFinn
http://www.cardomain.com/ride/2651997 UPDATED 20100826
sigpicComment
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does the accel pump actually squirt fuel when you open the throttle blades up? There aren't any un-used vacuum ports on the carb right? Does the idle change if you spray carb cleaner or whatever around the base of the carb or along the edge of the intake near the head?86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousersComment
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Ok I check the compression on all cylinders and it was 150 +- 5 all the way around. The vacuum was around 15-18 at idle steady would drop to near zero when you blip the throttle and rise then steady out if you hold it at rpm. The carb does squirt fuel in when you hit the throttle. I tried spraying carb cleaner around and noticed no difference. I went ahead and change plugs/wires/points - no difference. It makes good power after it backfires a couple times. I'm so out of ideas you all have any others? I welcome and appreciate all input no matter how obvious it is.
Thank you!1984 CV tudor 351W, 4bbl, 5-speed best time in the 1/8 8.39 at 80 with 1.80 60ft time.
2006 P71, 1988 Bronco II, 1986 Baby LTD(5.0 & T5 swap in progress), 1976 16' Hobie Cat, 12' AquaFinn
http://www.cardomain.com/ride/2651997 UPDATED 20100826
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i'm really no carb guru, thats just the things that i could think of. The accel pump squirts as soon as you start to open the throttle right, no dead spots or anything? It sounds to me like it needs more pump but I'm not familiar enough with Holley carbs to tell you how to do that exactly. If it was an Edelbrock or Quadrajet, those use holes in the rocker arm, just change where the link goes. I dont think the Holley uses that setup though.86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousersComment
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Are you certain that you are using the correct firing order and that none of the wires are switched around ??Comment
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Yes I've triple checked the firing order I even tried the H.O. order for shits and giggles.1984 CV tudor 351W, 4bbl, 5-speed best time in the 1/8 8.39 at 80 with 1.80 60ft time.
2006 P71, 1988 Bronco II, 1986 Baby LTD(5.0 & T5 swap in progress), 1976 16' Hobie Cat, 12' AquaFinn
http://www.cardomain.com/ride/2651997 UPDATED 20100826
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It's running lean. It sounds like it needs to be either have a set of smaller primary rods in it, or you don't have enough accelerator pump shot.Comment
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A ford crate 302 should have the HO firing order.... I don't think anything they sell has had a lopo firing order in years.Builder/Owner of Badass Panther Wagons
Busy maintaining a fleet of FordsComment
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Its defiantly not the HO firing order it doesn't miss constantly enough and when I tried the ho order it ran like shit. Ive step up the shot in to the carb and it help but didn't eliminate the problem. What are the primary rods and how do I change them?1984 CV tudor 351W, 4bbl, 5-speed best time in the 1/8 8.39 at 80 with 1.80 60ft time.
2006 P71, 1988 Bronco II, 1986 Baby LTD(5.0 & T5 swap in progress), 1976 16' Hobie Cat, 12' AquaFinn
http://www.cardomain.com/ride/2651997 UPDATED 20100826
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