352 Backfires from tailpipe
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Logistics Pro
Joined: Oct 2005
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From: Mddl A MexCans
352 Backfires from tailpipe
Well it was bond to get worse, as the knock aint going no where. It's run ok other than the anoying knock at stoplights/signs. But on the way back from lunch, I let off the gas coming up on a light and POW! didnt realize it was me at first and started of from the light, she stumbled and POW! and again, I thought Holy shiat..and whipped a right to head back..pulled over and got out to see if puddle water had found it way up somewhere..all the top was dry.
I decided to accelerate her by hand, and noticed that at initial accel she almost cuts out then comes back if you let off or go ahead and gas it but want to backfire on initial rpm climb. ??
I know shoot it!!, LOL I guess the thing should be taken down but $$ aint there..I guess it's time to do a few test and find out the dirty on this thing and make a decision.. ;(
I decided to accelerate her by hand, and noticed that at initial accel she almost cuts out then comes back if you let off or go ahead and gas it but want to backfire on initial rpm climb. ??
I know shoot it!!, LOL I guess the thing should be taken down but $$ aint there..I guess it's time to do a few test and find out the dirty on this thing and make a decision.. ;(
Elder User
Joined: Nov 2002
Posts: 620
Likes: 8
From: USA
Have you done a compression check? I wonder if you have a valve thats not opening, or opening enough? The knock could be a bent or broken push rods.
A compression test could tell you a lot about the health of your motor.
Could be a carburetor issue or timing possibly?
A compression test could tell you a lot about the health of your motor.
Could be a carburetor issue or timing possibly?
Senior User
Joined: Jan 2003
Posts: 148
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From: Longmont, CO USA
What ignition system are you running?
If it is points I would check those. The gap on them might be almost closed due to wear. The points plate might also be worn down and when the vacuum advance moves it causes the ignition system to cut out for a second and then comes back on and creates a backfire. I had a truck along time ago that used to do what you are describing and I always carried an extra set of points in the glove box for it. My .02 cents.
If it is points I would check those. The gap on them might be almost closed due to wear. The points plate might also be worn down and when the vacuum advance moves it causes the ignition system to cut out for a second and then comes back on and creates a backfire. I had a truck along time ago that used to do what you are describing and I always carried an extra set of points in the glove box for it. My .02 cents.
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Logistics Pro
Joined: Oct 2005
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From: Mddl A MexCans
Well ten minutes and it's found but not resolved. Started by checking the lugs up front for signs of lean mix, they looked ok for 400 miles on them tanish a bit light but not bad so I richened it up a little. So I start it up and POW of the bat..never done this..let it idle to go have a look act like it wasn't me in front of the neighbors. While accelerating under the hood I notice the crane Xri lines going in the side of the dizzy are moving and when the engines begins to stall they stop, so I unplug the vac advance hose..and no more stutter.
I'm judging by the short turn just inside the whole to the back of the Xri is a tight one, and it was pretty cold here today. That the wires are somehow holdng the advance diaphram from pulling the plate normallly... I tried to push more wire through so it would have a little play on the inside and it works but the line eventually finds it way back out again..
Boy the Engineering heind this thing is top notch, I may just go back to points, heck it seemed to idle smoother then in my opinion..we'll see how it goes. I still need to get out there and do a comp test, maybe homeaide leak down if it looks bad..Taint 1 ting isa nudder!!!
I'm judging by the short turn just inside the whole to the back of the Xri is a tight one, and it was pretty cold here today. That the wires are somehow holdng the advance diaphram from pulling the plate normallly... I tried to push more wire through so it would have a little play on the inside and it works but the line eventually finds it way back out again..
Boy the Engineering heind this thing is top notch, I may just go back to points, heck it seemed to idle smoother then in my opinion..we'll see how it goes. I still need to get out there and do a comp test, maybe homeaide leak down if it looks bad..Taint 1 ting isa nudder!!!
Posting Guru
Joined: Jul 2003
Posts: 2,232
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From: Colville, Washington
Check the wires inside the distributor for cracking or a rubbed area. It sounds like when the plate moves under vacuum advance it is shorting out, backfire, no vacuum, then it runs after that initial movement. The wires should be free inside, but held at the hole in the dist. It might also be a poor ground from the point plate(XRi mounting) to the distributor body.
