vacuum oddities
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Junior User
Joined: May 2003
Posts: 79
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From: Rockwood TN
vacuum oddities
Hello Again,
Need some help understanding this one,
1985 f250
460 w heddmans, edelbrock 600cfm, comp cams 268 hi energy cam, all else is stock except that emmisions has been removed/disabled. Fresh rebuild has about 2 hours on it.
Problem(s)
1) no response from idle screws on carb until almost seated.
2) I was looking for a vacuum leak, when I unplugged a hose, she actually increased idle speed.
I would have figured her to slow down....
3)When I turn on the a/c (even with the clutch disconnected) she stutters real hard and will stall if stopped in gear.
I thought it might be exhaust leaking into the manifold from the egr plate, so removed and cleaned surfaces again and copper coated (was a little rough) reinstalled. no change.
Any ideas?
TIA
Dart
Need some help understanding this one,
1985 f250
460 w heddmans, edelbrock 600cfm, comp cams 268 hi energy cam, all else is stock except that emmisions has been removed/disabled. Fresh rebuild has about 2 hours on it.
Problem(s)
1) no response from idle screws on carb until almost seated.
2) I was looking for a vacuum leak, when I unplugged a hose, she actually increased idle speed.
I would have figured her to slow down....3)When I turn on the a/c (even with the clutch disconnected) she stutters real hard and will stall if stopped in gear.
I thought it might be exhaust leaking into the manifold from the egr plate, so removed and cleaned surfaces again and copper coated (was a little rough) reinstalled. no change.
Any ideas?
TIA
Dart
Moderator
Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
vacuum oddities
If the clutch is disconnected, I don't see how it could effect the idle. Do you have the step up solenoid on the carb? Have you checked the vacuun with a gauge to see how the mixture screws are actually working? It should start to die down as they get close to being closed.
What intake manifold are you running and what type of gaskets are under it?
Jimmy
What intake manifold are you running and what type of gaskets are under it?
Jimmy
Thread Starter
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Junior User
Joined: May 2003
Posts: 79
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From: Rockwood TN
vacuum oddities
Stock cast iron, with felpro blue gaskets. Installed on the stand, so I know they didn't get moved during.
I thought it might be an electric thing with the ac/vent fans but turning on the headlights does not cause the stutter. ( I know, seperate circuit, but it was just a seat of the pants quick test) So Ipulled the vacuum line that feeds the blend door system, which is when I discovered that she runs better with a vacuum leak. Air filter was off so it's not dirty filter. I just find that mind boggling.
To answer the question, no, I haven't put the vac guage on it yet, Nor does it have the step up solenoid.
Dart
I thought it might be an electric thing with the ac/vent fans but turning on the headlights does not cause the stutter. ( I know, seperate circuit, but it was just a seat of the pants quick test) So Ipulled the vacuum line that feeds the blend door system, which is when I discovered that she runs better with a vacuum leak. Air filter was off so it's not dirty filter. I just find that mind boggling.
To answer the question, no, I haven't put the vac guage on it yet, Nor does it have the step up solenoid.
Dart
Moderator
Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
vacuum oddities
I had to use the valleypan intake gasket on mine. It had a small vacuum leak at the bottom of the ports and would suck air and some oil under a load. I had used the felpro gaskets and had to go back to the valleypan.
Jimmy
Jimmy
Thread Starter
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Junior User
Joined: May 2003
Posts: 79
Likes: 0
From: Rockwood TN
vacuum oddities
It originally had that gasket when I tore it down, did the research on here and most posts said it was unessecary so I went with the ones in the gasket set. Didn't take time to mess with it today. Was to busy putting the front suspension back together replacing radius and pivot bushings.
Will follow up as info develops.
Dart
Will follow up as info develops.
Dart
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