Vacuum issues suck..or not
Thread Starter
Drifting
Joined: Aug 2007
Posts: 1,838
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From: Kingman AZ
Vacuum issues suck..or not
I put an Edelbrabock FI system on my 76 L48. The mech who installed it didnt do the vacuum right. Ive gone over the lines did some corrections and now lights are closing etc looking kinda normal. BUT, Im having stalling issues and I feel brake fade. Would an electric vacuum pump solve this? If so...Do I connect to master or connect elsewhere...
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Unless you are running a really big cam. You should not need a vacuum pump. On your screen, pull up guages and look at your vacuum reading at idle. What is it?
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From: Sunshine Coast, Queensland, Australia
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OK. Suggestions. Step one. You have a EFI setup. So. You must have a handheld screen. Plug it in. Select gauges. Find MAP reading and vacuum reading.
What are they at idle? You don't need a vacuum gauge. You can read it right on your screen.
Me I like to connect a vacuum gauge and confirm readings. But if your sensors are functioning properly you really don't need to.
How much vacuum do you have at idle?
What does your MAP sensor have to say?
It would have to be a huge vacuum leak to pull it down that much. You would have running problems.
Just how big is your cam?
L48? all stock? How about a lot more information and then maybe we can start to point you in the right direction.
Have you checked the vacuum check valve?
Have you checked the check valve at the brake booster? Do you have a leaking booster?
What are they at idle? You don't need a vacuum gauge. You can read it right on your screen.
Me I like to connect a vacuum gauge and confirm readings. But if your sensors are functioning properly you really don't need to.
How much vacuum do you have at idle?
What does your MAP sensor have to say?
It would have to be a huge vacuum leak to pull it down that much. You would have running problems.
Just how big is your cam?
L48? all stock? How about a lot more information and then maybe we can start to point you in the right direction.
Have you checked the vacuum check valve?
Have you checked the check valve at the brake booster? Do you have a leaking booster?
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In your first post you say that YOU put a (badly misspelled) Edlebrock EFI system on.
then you say a mechanic messed up your vacuum lines.
Totally not clear on who is working on this car.
NEVER LET ANYONE WORK ON YOUR PRIDE AND JOY!
No one loves your car as much as you do!
then you say a mechanic messed up your vacuum lines.
Totally not clear on who is working on this car.
NEVER LET ANYONE WORK ON YOUR PRIDE AND JOY!
No one loves your car as much as you do!
Le Mans Master
Joined: Nov 2004
Posts: 5,252
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From: Waterford WI
In your first post you say that YOU put a (badly misspelled) Edlebrock EFI system on.
then you say a mechanic messed up your vacuum lines.
Totally not clear on who is working on this car.
NEVER LET ANYONE WORK ON YOUR PRIDE AND JOY!
No one loves your car as much as you do!
then you say a mechanic messed up your vacuum lines.
Totally not clear on who is working on this car.
NEVER LET ANYONE WORK ON YOUR PRIDE AND JOY!
No one loves your car as much as you do!
Racer
Joined: Jan 2016
Posts: 290
Likes: 78
First thing to do would be to separate the vacuum system from the efi system, except for the map sensor.
This would help in letting you know if the running problem is engine/ efi related OR something else. This is how it should be tuned anyway to eliminate any variables in the tune. Plug all vacuum ports on the intake. If running problem is gone then you know you’re on the right track but if running problem is still there you’ll have to diag the efi/ engine.
This would help in letting you know if the running problem is engine/ efi related OR something else. This is how it should be tuned anyway to eliminate any variables in the tune. Plug all vacuum ports on the intake. If running problem is gone then you know you’re on the right track but if running problem is still there you’ll have to diag the efi/ engine.
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