New Problem
Thread Starter
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
New Problem
My new stroker has about 250 miles on it. Wierd prob has developed and it's driving me nuts. When I run it to 5500 in low gear, and shift into second it bogs...for a second then catches up. This is not a gear issue ... it is an engine bog. Like it is running outta gas. But why would it do it only after the shift? When I get on it in first gear it moves right along, all the way up to 5500. When I put it in, I put a new fuel pump and new carb on it.
Suggestions appreciated.
Suggestions appreciated.
Le Mans Master
Joined: Mar 2002
Posts: 7,056
Likes: 40
From: Life is Messy, Bring a mop
Re: New Problem (SanDiegoPaul)
sounds like they need adjusting on the opening rate?
related thread
http://forums.corvetteforum.com/zerothread?id=462682
[Modified by 72rdstr, 11:37 PM 12/31/2002]
related thread
http://forums.corvetteforum.com/zerothread?id=462682
[Modified by 72rdstr, 11:37 PM 12/31/2002]
Thread Starter
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Re: New Problem (72rdstr)
sounds like they need adjusting on the opening rate?
That is a possibility. I still need to get it dyno tuned. So far, the carb is just as it came out of the box 250 miles ago. I'm sure it is in the carb. What is frustrating is that it's so darn healthy :cheers: in first gear and sounds soooo good til' I shift. :nonod:
That is a possibility. I still need to get it dyno tuned. So far, the carb is just as it came out of the box 250 miles ago. I'm sure it is in the carb. What is frustrating is that it's so darn healthy :cheers: in first gear and sounds soooo good til' I shift. :nonod:
Safety Car
Joined: Aug 2001
Posts: 3,683
Likes: 201
From: Waterford Mi
Re: New Problem (SanDiegoPaul)
I assume when you shift you are leting up on the gas pedal and then hitting it again. The problem could be in the accelerator pump shot. Not enough gas to handle the change in RPM's
Instructor
Joined: Dec 2002
Posts: 125
Likes: 0
From: Lebanon TN
Re: New Problem (SanDiegoPaul)
Sounds like a carb float level adjustment is in your future. You have plenty on one front end and as engine vacuum drops (at higher RPMS) you don't have enough ump for the bump to second gear. I hope you have a Holley. Float level is real easy to monitor on them. Adjust is easy. If its a jetting or power valve issue, it's still easy if it's a Holley. You should have got some literature with your carb. :smash: :smash: :smash: :steering:
Melting Slicks
Joined: Oct 2001
Posts: 2,064
Likes: 1,382
From: Halifax, Nova Scotia, Canada
Re: New Problem (SanDiegoPaul)
At 5500, the secondaries should be open and working great.
Then you shift.
If for some reason the secondaries are not closing fast enough, then after you have shifted and you are now at a lower rpm, the engine will bog due to the secondaries being open too far for that rpm.
Just something else to check.
Then you shift.
If for some reason the secondaries are not closing fast enough, then after you have shifted and you are now at a lower rpm, the engine will bog due to the secondaries being open too far for that rpm.
Just something else to check.
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Thread Starter
Race Director
Joined: Sep 2002
Posts: 10,362
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From: San Diego - Deep Within The State of CONFUSION!
Re: New Problem (Barry's70LT1)
Just something else to check.
Now, that does make sense. New carb ... maybe something is binding. I'm off today and I'll look at it.
Now, that does make sense. New carb ... maybe something is binding. I'm off today and I'll look at it.
Thread Starter
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Re: New Problem (BB wowbagger)
How about your fueldelivery system..Pressure??
The pump is new, installed with the engine. Of course that's no guarentee of it's integrity. When I get in, on the dyno, I'll check delivery and pressure.
The pump is new, installed with the engine. Of course that's no guarentee of it's integrity. When I get in, on the dyno, I'll check delivery and pressure.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Re: New Problem (SanDiegoPaul)
Sounds like an secoundary air-valve misbehaving Paul. Edelbrock may have set carb up for 350 cubic inches and 388 inches could require more air and /or different vacuum. This is interesting to me as I'm on the Q-jet learning curve too. It should be an easy adjustment without carb dissasembly - just remove the air cleaner and use small allen with small screw driver to tighten or loosen spring. Recommend you get the books out before any attemps. Try a small adjustment - one turn or 1/2 turn or whatever and please let us know results. Note where you started - just in case. :confused:
[Modified by cardo0, 3:56 AM 1/6/2003]
[Modified by cardo0, 3:58 AM 1/6/2003]
[Modified by cardo0, 3:56 AM 1/6/2003]
[Modified by cardo0, 3:58 AM 1/6/2003]