BOGs down with WOT ??
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
BOGs down with WOT ??
I have checked EVERYTHING I know to check. I know that I am overlooking something. 
1974 454
Carb re-built.
Dwell / Timing set according to Tech articles on the forum.
Brand New EVERYTHING from the crank up.
Rocker arms adjusted properly.
EGR valve removed / blocked.
Camshaft "broke in" according to COMP Instructions.
New points and condensor.
This NEW motor idles perfect and accelerates AWSOME until 4000 RPM ... where it basicly "shuts off" ... sometimes with a slight backfire. When I let off the throttle.....rpm's drop....it comes back to life smooth as silk.
Feels like "electrical" to me....not fuel.
Can the LOBES on a distributor (that work the points) be worn out? I know this distributor is getting old. Just a hunch ... but it "feels" like the points are "floating" or just breaking down starting at about 4000. I was going to convert to the Crane Breakerless Module anyway.
Opinions ?????
1974 454
Carb re-built.
Dwell / Timing set according to Tech articles on the forum.
Brand New EVERYTHING from the crank up.
Rocker arms adjusted properly.
EGR valve removed / blocked.
Camshaft "broke in" according to COMP Instructions.
New points and condensor.
This NEW motor idles perfect and accelerates AWSOME until 4000 RPM ... where it basicly "shuts off" ... sometimes with a slight backfire. When I let off the throttle.....rpm's drop....it comes back to life smooth as silk.
Feels like "electrical" to me....not fuel.
Can the LOBES on a distributor (that work the points) be worn out? I know this distributor is getting old. Just a hunch ... but it "feels" like the points are "floating" or just breaking down starting at about 4000. I was going to convert to the Crane Breakerless Module anyway.
Opinions ?????
Last edited by fotyfobravo; Jul 22, 2007 at 10:59 PM.
Melting Slicks
Joined: Jul 2005
Posts: 2,060
Likes: 46
From: winter haven florida
St. Jude Donor '12
i had this happen to me a long time ago when i changed fuel lines. my fuel line was getting pinched off where it comes from the hard line to the fuel pump. it would idle great and run fine untill i ran it at wot. just something to check. good luck.
Melting Slicks
Joined: Mar 2006
Posts: 3,443
Likes: 2
From: McDonough Georgia
My 76 did the same thing.Ditched the quadrajunk-problem solved.I'm sure I will get flamed for saying that but I just don't like quadrajets.BUT I haven't had one Lars got his hands on yet either.
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Other than that...I seriously doubt I have a carb problem (built by Lars)
... know what I mean Vern ?Thanks............44B
Pro
Joined: Nov 2004
Posts: 575
Likes: 0
From: Nice Lake Ontario
I have what sounds like same problem with roughly same set-up.
I will be checking the fuel pump pressure later today.
Second option is maybe the old distributor has some sloppy bushing problems?
Anybody have any comments on how they act with sloppy dizzy bushing??
I will be checking the fuel pump pressure later today.
Second option is maybe the old distributor has some sloppy bushing problems?
Anybody have any comments on how they act with sloppy dizzy bushing??
CF Community Team
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From: Cape Cod, Mass.
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I had the same problem with my 68 427/390 last summer. It was the coil.
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Drifting
Joined: Apr 2003
Posts: 1,698
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From: Johnson City TN
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
Running out of fuel is my prognosis. Either a pinched line or some other restriction in the fuel delivery system. Have the fuel pump pressure and flow rate checked.
Melting Slicks
Joined: Oct 2005
Posts: 2,056
Likes: 8
From: Redruth Cornwall
What size main jets are you running? I know Lars has rebuilt it but as all engines are different that may be an issue....
Im guessing at it leaning out....
You could also check with Lars about secondary hanger height as I had/have a similar problem and he suggested going up on main jets and possibly altering the hanger height....
If you think its a dizzy problem, you could always get Lars to sort that for you as well!
Im guessing at it leaning out....
You could also check with Lars about secondary hanger height as I had/have a similar problem and he suggested going up on main jets and possibly altering the hanger height....
If you think its a dizzy problem, you could always get Lars to sort that for you as well!
Last edited by jotto; Jul 23, 2007 at 02:36 PM.
Safety Car
Joined: Aug 2000
Posts: 3,943
Likes: 44
From: Florham Park NJ Port Credit Ontario
I had the exact same prob with my Q-Jet. Turns out that the secondary wind-up spring was out of adjustment. Set the tension per Lars paper and voila! No mor probs. I chased this problem for a while too, swapped coils: same prob, new rubber fuel lines: same prob, checked timing: same as when Lars tuned it....turns out it was a 5 minute fix...
Good Luck!
Good Luck!
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
If I wasn't so "broke" from this 454 re-build, I would send you a PRIZE.
Look at the flattened fuel line in the pic below. You are a genius. At full flow, it would suck itself closed.I fixed this and it runs like a striped azz Ape ! Thanks ....
oh, and congrats!
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Thanks Y'all........
......44B
Melting Slicks
Joined: Jul 2005
Posts: 2,060
Likes: 46
From: winter haven florida
St. Jude Donor '12
good to see it's fixed. same thing happed to mine the last time i changed the fuel lines. it was easy to figure out because that is all i did to the car when it happened. with all the stuff you have just done to yours i can't imagine how many possible things you could have been thinking it could be. now for the fun part, post some video of that thing running.
same thing happed to mine the last time i changed the fuel lines. it was easy to figure out because that is all i did to the car when it happened. with all the stuff you have just done to yours i can't imagine how many possible things you could have been thinking it could be. now for the fun part, post some video of that thing running.
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Here's a poor quality video ... sounds pretty good when I put it into DRIVE. This was right after cam break in....it still needed some tuning. Don't be laughing at my bumper ... that's next!
http://uncutvideo.aol.com/search/rel...ue=454&index=0
http://uncutvideo.aol.com/search/rel...ue=454&index=0
Last edited by fotyfobravo; Jul 24, 2007 at 10:41 PM.