Noticeable miss at mid-throttle
I'm running a 350 with a MSD StreetFire distributor, Weiand dual plane intake and Holley 650 double pump carb. At idle the truck runs alright but there is a very slightmiss that you can hear if listening closely. I cant blip the throttle without it bogging hard and I don't believe its a problem with my advance. Im thinking a vacuum leak at the intake since i never retorqued the bolts after my break in period of the engine. The miss is very noticeable about 2500 rpm and there is a slight lurch that I can feel while driving. I've also seen fuel stains on the outside of the intake that would indicate a leak in the top of intake manifold but I've got the carb mounting nuts well torqued on top of a new gasket so I don't know why there would be fuel there.
|
Re: Noticeable miss at mid-throttle
The fuel stains may be gas boiling in the carb. You can try an insulator gasket under the carb if that's what it is.
How do you have the vacuum advance hooked up. Do you have the vacuum advance restrictor plate hooked up. If not you probably have too much timing advance. |
Re: Noticeable miss at mid-throttle
Newly rebuilt engine.... is the carb new ?
Posted via Mobile Device |
Re: Noticeable miss at mid-throttle
I'm a broken record with this, but most carb issues are ignition. Most likely you have a plug, a wire, the cap, maybe the rotor, etc. that is whacked. It's firing MOST of the time, or some of the time. But fix that and most likely (never say never, right?) your carb issues go away.
|
Re: Noticeable miss at mid-throttle
Quote:
|
Re: Noticeable miss at mid-throttle
Did you check your timing when you had the light on there?
|
Re: Noticeable miss at mid-throttle
check the exhaust manifold for temp. see if each exhaust manifold port is the same temp....
firing order is 18436572 check to make sure you do not have 5 and 7 swapped and/or on wrong....... I may have missed something here, but can anyone add to what has been done to this vehicle lately ? What work has been done lately ? my 2 cents...good luck !!! |
Re: Noticeable miss at mid-throttle
Quote:
|
Re: Noticeable miss at mid-throttle
We need to know what your initial timing is.
And pics of the fuel leakage on the intake will help. And what Cam? |
Re: Noticeable miss at mid-throttle
New engine that you just broke in ? No idea what you put the timing at and you think its a intake gasket leaking....
Good Luck !!!!! I do like the 5/7 plug wires swapped idea mentioned above. |
Re: Noticeable miss at mid-throttle
Try driving it with the vacuum hose to the dist. disconnected & pluged. Like Gary says, Sometimes too much advance can cause a surge at part throttle.
George |
Re: Noticeable miss at mid-throttle
What was the issue on this thread, so many of these threads go out to space and never resolved. Hate for someone doing a search and they read thru these threads and they go no where. i must be the only one that happens to.
|
Re: Noticeable miss at mid-throttle
Quote:
I've always encouraged everyone to please post a resolution whenever possible to help others with the same problem. Doesn't matter if there wasn't a resolution or if it was something simple. It's nice to know what happened. |
Re: Noticeable miss at mid-throttle
Quote:
|
Re: Noticeable miss at mid-throttle
Quote:
If you have an issue about something go to the specific site and at the very bottom there should be a member moderator. You could send them a private message. Correction... Not every forum has a moderator at the bottom. Best to click on Forums above and on the right is a column that shows the moderators. |
All times are GMT -4. The time now is 07:48 PM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com