Cruise Control 78
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Intermediate
Joined: Oct 2006
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From: Virginia
Cruise Control 78
I found out why my cruise control was unhokked from the throttle. When hooked up, it holds the throttle wide open. I noticed that the air bladder sucks all the way when the engine is running. What would cause this. Is it a vaccum problem, there seems to be plenty vaccum; or is it a mechanical problem?
Drifting
Joined: Jun 2004
Posts: 1,881
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From: staten island ny
Originally Posted by FireMedic5
I found out why my cruise control was unhokked from the throttle. When hooked up, it holds the throttle wide open. I noticed that the air bladder sucks all the way when the engine is running. What would cause this. Is it a vaccum problem, there seems to be plenty vaccum; or is it a mechanical problem?
ESU
Drifting
Joined: Jun 2004
Posts: 1,881
Likes: 9
From: staten island ny
Originally Posted by FireMedic5
Thanks, whats the best source for a vaccum diagram?
ESU
PS just re read your post, mine stuck at wot when engaged, are you saying the bladder sux in when engine is on at like idle without the cruise engaged? If so then its hooked up directly to a vac source.
Last edited by ESU; Oct 27, 2006 at 10:06 PM.
Instructor
Joined: Dec 2004
Posts: 198
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From: Newmarket Ontario
Inside the transducer there is a plate that engages when the cruise is activated. The plate when engaged should have clearance between it and a another plate under it.(very primative design but hi tech in its day) A common problem is the shaft that is joined to the plate becomes worn allowing the two plates to come in contact with each other which causes the car to go flat out. Best thing to do is buy one rebuilt for around $100.00. Solved my problem.
Thread Starter
Intermediate
Joined: Oct 2006
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From: Virginia
Originally Posted by ESU
The AIM or the service manual, try reversing them, worked for me. The fact that it kept it at WOT means the transducer is probably good, just routing the hoses. There is only 2 on the transducer so its not hard to reverse,
ESU
PS just re read your post, mine stuck at wot when engaged, are you saying the bladder sux in when engine is on at like idle without the cruise engaged? If so then its hooked up directly to a vac source.
ESU
PS just re read your post, mine stuck at wot when engaged, are you saying the bladder sux in when engine is on at like idle without the cruise engaged? If so then its hooked up directly to a vac source.
Correct me if I'm wrong, but on my cruise "booster", there is only one vaccum line leading to it. I pulled it off with the car running and there is a pretty strong vaccum. I tried to see where the vaccum hose went, but it went back under the driver's side fender and I didn't have time to trace it the other day. I assume if the vaccum is hooked up wrong, it would be on the other end of that hose.
Thread Starter
Intermediate
Joined: Oct 2006
Posts: 32
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From: Virginia
Originally Posted by canucbuck
Inside the transducer there is a plate that engages when the cruise is activated. The plate when engaged should have clearance between it and a another plate under it.(very primative design but hi tech in its day) A common problem is the shaft that is joined to the plate becomes worn allowing the two plates to come in contact with each other which causes the car to go flat out. Best thing to do is buy one rebuilt for around $100.00. Solved my problem.
Forgive my ignornance, but what is the transducer, is that the unit that links directly to the throttle. I've always referred to that as the booster, probably incorrectly however. Thanks
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Drifting
Joined: Jun 2004
Posts: 1,881
Likes: 9
From: staten island ny
Originally Posted by FireMedic5
Yes it sucks all the way in at idle.
Correct me if I'm wrong, but on my cruise "booster", there is only one vaccum line leading to it. I pulled it off with the car running and there is a pretty strong vaccum. I tried to see where the vaccum hose went, but it went back under the driver's side fender and I didn't have time to trace it the other day. I assume if the vaccum is hooked up wrong, it would be on the other end of that hose.
Correct me if I'm wrong, but on my cruise "booster", there is only one vaccum line leading to it. I pulled it off with the car running and there is a pretty strong vaccum. I tried to see where the vaccum hose went, but it went back under the driver's side fender and I didn't have time to trace it the other day. I assume if the vaccum is hooked up wrong, it would be on the other end of that hose.
ESU
Drifting
Joined: Jun 2004
Posts: 1,881
Likes: 9
From: staten island ny
Originally Posted by FireMedic5
Forgive my ignornance, but what is the transducer, is that the unit that links directly to the throttle. I've always referred to that as the booster, probably incorrectly however. Thanks
ESU
Thread Starter
Intermediate
Joined: Oct 2006
Posts: 32
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From: Virginia
The part that I was looking at has the rubber bladder that connects to the throttle linkage and has one large vaccum tube coming out of the back, right from the center. There may be another line from the bottom, but just one from the back. The one from the back causes the bladder to suck all the way in, when disconnected, the bladder is inflated, just as when the car is not running.
Drifting
Joined: Jun 2004
Posts: 1,881
Likes: 9
From: staten island ny
Originally Posted by FireMedic5
The part that I was looking at has the rubber bladder that connects to the throttle linkage and has one large vaccum tube coming out of the back, right from the center. There may be another line from the bottom, but just one from the back. The one from the back causes the bladder to suck all the way in, when disconnected, the bladder is inflated, just as when the car is not running.
ESU
Drifting
Joined: Jun 2004
Posts: 1,881
Likes: 9
From: staten island ny
Originally Posted by FireMedic5
Thanks for the diagram. I'll try switching those hoses and see if that fixes it.
ESU
PS and look for a pink wire that goes into the fuseblock, mine was unplugged and wrapped up in the dash for some reason. At least on my car it was pink. I think the prior owner was looking to free up a slot in the fuseblock
Thread Starter
Intermediate
Joined: Oct 2006
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From: Virginia
According to the diagram, it looks like all the vaccum hoses are hooked up correctly. The two on the front can't be switched because they are different sizes and the larger one switched to the smaller one won't seal. Does that sound more like the transducer would be bad?
