'70 L46 Cutting Out.
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,591
Likes: 53
From: Central MN
'70 L46 Cutting Out.
Under heavy acceleration and at high RPMs (>4K,) the engine seem to "cut out" or misfire. My mechanic says it's due to the carburetor - he's suggesting a carb. rebuild. To me, cutting out is an electrical problem. He's already replaced the distributor cap, rotor, points and spark plug wires. So, do you think a carb. rebuild will cure the "cut out" issue?
Drifting
Joined: May 2006
Posts: 1,425
Likes: 0
From: Seattle Wash.
What is your total timing set at? Should be 36* @ 2800 - 3000 RPM with the vacuum advance disconnected. Start with your timing first, and work you way out from there.
Last edited by 427-390; Jul 27, 2007 at 07:02 PM.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Sounds like a fuel supply problem to me. I'd change the fuel filter(s) first. Also, has the strainer in the tank ever been replaced? Do you have a crimp in a hard-line somewhere.
Other possibilities include malfunctioning mechanical advance (rust and crud can prevent the weights from opening properly),..or crummy fuel,...or broken valve spring(s).
Let us know what transpires and good luck!
Other possibilities include malfunctioning mechanical advance (rust and crud can prevent the weights from opening properly),..or crummy fuel,...or broken valve spring(s).
Let us know what transpires and good luck!
Advanced
Joined: Sep 2005
Posts: 89
Likes: 0
I had a similar problem on my 70 L-46, it was the fuel hose from pump to tank line. Mechanic used regular fuel line hose, made it too long and at high RPM would closeup. Replaced with the molded S fuel hose and vapor return hose, fixed problem. Good luck tracking down problem.
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Drifting
Joined: Sep 1999
Posts: 1,970
Likes: 91
Under heavy acceleration and at high RPMs (>4K,) the engine seem to "cut out" or misfire. My mechanic says it's due to the carburetor - he's suggesting a carb. rebuild. To me, cutting out is an electrical problem. He's already replaced the distributor cap, rotor, points and spark plug wires. So, do you think a carb. rebuild will cure the "cut out" issue?
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,591
Likes: 53
From: Central MN
Everybody...........Thanks for your replies and suggestions. My mechanic is rebuilding the carb. (Rochester) today. The previous owner removed the "in the carb." fuel filter and replaced it with a spliced in line filter. The mechanic will bring the fuel filter and line back to stock. Hopefully, the rebuild fixes the problem.
Instructor
Joined: Feb 2004
Posts: 210
Likes: 0
From: woodstock ga
Tach wire grounding out or finding a hot will cause that..... been there done that....
If the carb isnt the issue, watch the tach next time is does that... Does the needle drop to 0 or spiratically jump?
If so check the wire.... should be the brown one
If the carb isnt the issue, watch the tach next time is does that... Does the needle drop to 0 or spiratically jump?
If so check the wire.... should be the brown one
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,591
Likes: 53
From: Central MN
Well, as it turns out, the carb. was the problem. As mentioned earlier, the previous owner replaced the stock fuel filter with an inline filter that was very restrictive. Additionally, the carb. float bowel were stuck. The combination of the two was causing the carb. to starve the engine at high RPMs.
Aside from fixing the "cutting out" issue, the carb. rebuild fixed a roughness characteristic that I figured was normal for a 37 year old car. Finally, the car feels (as measured by my Butt-O-Meter) MUCH stronger. The gas mileage, however, is still terrible. Perhaps, I need to tighten the loose nut that holds on to the steering wheel
???? Nahhhhhhh!!!!!
Again, thanks for all your suggestions and advice
.
Aside from fixing the "cutting out" issue, the carb. rebuild fixed a roughness characteristic that I figured was normal for a 37 year old car. Finally, the car feels (as measured by my Butt-O-Meter) MUCH stronger. The gas mileage, however, is still terrible. Perhaps, I need to tighten the loose nut that holds on to the steering wheel
???? Nahhhhhhh!!!!!Again, thanks for all your suggestions and advice
.
Intermediate
Joined: Jul 2007
Posts: 40
Likes: 0
From: Springfield MO
Finally, the car feels (as measured by my Butt-O-Meter) MUCH stronger. The gas mileage, however, is still terrible. Perhaps, I need to tighten the loose nut that holds on to the steering wheel
It's a corvette.....ain't it cool!!!!!!!!!!!!!!!!!!!!!!!!!
It's a corvette.....ain't it cool!!!!!!!!!!!!!!!!!!!!!!!!!
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,591
Likes: 53
From: Central MN
Out of curiosity, at 70 mph (according to the inaccurate speedo,) how many RPMs are you turning?
Safety Car
Joined: May 2003
Posts: 3,814
Likes: 105
From: Dearborn Heights Michigan
FKING1.............I, too, have the 3.70 rear. My '05 has a 3.42 rear and gets 29 mpg. The '05, however, has an M6. Technology is wonderful, but nothing can replace tradition!!!!!
Out of curiosity, at 70 mph (according to the inaccurate speedo,) how many RPMs are you turning?
Out of curiosity, at 70 mph (according to the inaccurate speedo,) how many RPMs are you turning?