Vacuum routing, high idle, carb questions

[steve8691]

Hi. I have an 87 bronco with 351, 4bbl. Not a mechanic by any stretch. Friend and I pulled the trans (C6) and had it rebuilt.. I reinstalled it with the help of different friend. Now I have several questions and a few problems. Cant afford to stick any more $$ in it, wife will **** me.

First, the linkage fromthe neutral safety switch to the carb lacks about 1" to connect and rubs on the throtle cable bracket. I've tried to reposition the lever on the neurtal safety switch but no better. Not sure if it is even in the correct position now. What is next?

Everytime I put my hand on something under the hood, it breaks. On the passenger side of the carb is an electrical connection with 6" of wire on it. where does it go? There are 2 ports under the carb that are missing connection (vac line?). The vac line from the distributor is not connected but not the hose is not large enough to fit on the carb port the vac diagram indicates it should be connected to. what is attached to the other port? Any body with a good diagram/picture of where things are supposed to go?

Do you think this has a lot to do with my high idle?

I have a lot of questions but these are the first important ones.

Thanks for any help I can get. Steve

 

[BroncoJoe19]

Hi Steve,

I can't help you, and a lot of the guys start checking the threads after dinner, and later into the night. IF you could get a couple of pictures up before then that would be helpful for you to get answers sooner rather than later.

Good luck

joe

 

[Seabronc]

Hi. I have an 87 bronco with 351, 4bbl. Not a mechanic by any stretch. Friend and I pulled the trans (C6) and had it rebuilt.. I reinstalled it with the help of different friend. Now I have several questions and a few problems. Cant afford to stick any more $$ in it, wife will **** me.
First, the linkage from the neutral safety switch to the carb lacks about 1" to connect and rubs on the throttle cable bracket. I've tried to reposition the lever on the neurtal safety switch but no better. Not sure if it is even in the correct position now. What is next?

Every time I put my hand on something under the hood, it breaks. On the passenger side of the carb is an electrical connection with 6" of wire on it. where does it go? There are 2 ports under the carb that are missing connection (vac line?). The vac line from the distributor is not connected but not the hose is not large enough to fit on the carb port the vac diagram indicates it should be connected to. what is attached to the other port? Any body with a good diagram/picture of where things are supposed to go?

Do you think this has a lot to do with my high idle?

I have a lot of questions but these are the first important ones.

Thanks for any help I can get. Steve

That is the kick down rod, did you do anything with the intake like change from a stock to a performance intake. If so, that usually requires an longer kick down rod. It should be connected so that pushing it toward the fire wall it will cause the link on the transmission to move toward the rear of the truck.

The wire on the carb go to a switched voltage suppply. If it is the stock Foprd carb it connects to a wire of the same size comming from the alternator. If it is an aftermarket carb it needs to be connected to a seitched 12V source. It is for the electric choke heater.

The two ports under the carb my or may not be used depending on what other vacuum components ar still on the engine. Do you have any loose vacuum lines?

Post a picture of your vacuum diagram. They are specific to where the truck was originally shipped and components vary.

Good luck,

>-

 

[steve8691]

To the best of my knowledge, everything is stock. The kick down rod fell off whil removing the trans. nothing else has changed. The carb is stock also. The only loose vacuum line is the one off the distributor. 2 ports below the carb are open. From the front, the one one the right is capped (labeled AL T), the center (small one) is open(labeled BV), and the next one (large and labeled S) is open. It shows to go to the dist but it is too large for the vent line that is connected to the dist. There are lots of plugged vacuum lines on this vehicle. The airpump is there but not used. Cant a lot of this stuff be removed and make it run better? The chiltons book says holley but the tag on the carb says motorcraft

I'll look at the kickdown rod again. It was attached before the trans removal. The tranny guy told me he felt that the kick down was dragging when he checked it out (before removal) and could have been binding then. If you have pics it may help me.

I had the alternator replaced a few months bvack after the elec shop said there was a short in the alt. the other end of the missing wire may be inside the wire loom they have taped up. I'll check.

I will try to attach a few pics. Dont know what I am doing with this but trying.

Thanks for your help.

Steve

That is the kick down rod, did you do anything with the intake like change from a stock to a performance intake. If so, that usually requires an longer kick down rod. It should be connected so that pushing it toward the fire wall it will cause the link on the transmission to move toward the rear of the truck.
The wire on the carb go to a switched voltage suppply. If it is the stock Foprd carb it connects to a wire of the same size comming from the alternator. If it is an aftermarket carb it needs to be connected to a seitched 12V source. It is for the electric choke heater.

The two ports under the carb my or may not be used depending on what other vacuum components ar still on the engine. Do you have any loose vacuum lines?

Post a picture of your vacuum diagram. They are specific to where the truck was originally shipped and components vary.

Good luck,

>-

 

[steve8691]

did you see the pics? any ideas? sorry for the poor photography. How about bending the kickdown linkage? should I connect the dist vac tube to the port where it will fit? checked the alternator for a bare/loose wire and there is none. what now? Help! Steve

To the best of my knowledge, everything is stock. The kick down rod fell off whil removing the trans. nothing else has changed. The carb is stock also. The only loose vacuum line is the one off the distributor. 2 ports below the carb are open. From the front, the one one the right is capped (labeled AL T), the center (small one) is open(labeled BV), and the next one (large and labeled S) is open. It shows to go to the dist but it is too large for the vent line that is connected to the dist. There are lots of plugged vacuum lines on this vehicle. The airpump is there but not used. Cant a lot of this stuff be removed and make it run better? The chiltons book says holley but the tag on the carb says motorcraft
I'll look at the kickdown rod again. It was attached before the trans removal. The tranny guy told me he felt that the kick down was dragging when he checked it out (before removal) and could have been binding then. If you have pics it may help me.

I had the alternator replaced a few months bvack after the elec shop said there was a short in the alt. the other end of the missing wire may be inside the wire loom they have taped up. I'll check.

I will try to attach a few pics. Dont know what I am doing with this but trying.

Thanks for your help.

Steve

 

[BroncoJoe19]

There are 2 ports under the carb that are missing connection (vac line?). The vac line from the distributor is not connected but not the hose is not large enough to fit on the carb port the vac diagram indicates it should be connected to. what is attached to the other port? Any body with a good diagram/picture of where things are supposed to go?
Do you think this has a lot to do with my high idle?

Hi Steve,

Again... I am not the master here, but any time that you have a vacuum leak, you may have a surging, or high idle. So you want to at least cap off any obvious vacuum leaks.

SeaBronc really knows his stuff, there are others too, but be patient, I am sure that he will follow up. When he asks questions, please do your best to answer them, often they are asked to help him go down one diagnostic path or another. You have done a great job explaining what is going on, I just wanted to bring that point to your attention.

Hang in there buddy.

joe

 

[Broncobill78]

did you see the pics? any ideas? sorry for the poor photography. How about bending the kickdown linkage? should I connect the dist vac tube to the port where it will fit? checked the alternator for a bare/loose wire and there is none. what now? Help! Steve

Steve,

How you making out with this ? As a rule bending the kickdown won't solve the problem unless you're bending it *back* into shape. You need to play with at unti you see howw it was originally installed, it it simply fell off & nothing else has changed then either it bent somewhere along the line or things aren't where they were before & you need to figure out which it is. The distributor needs to be connected to vacuum, that's the vacuum advance. It's a bit late right now but I have an 88' in the driveway & I'll try to take a look at it in the morning & see just where the vac advance connects to.

Now, what I'm wondering here is what's the deal w/the engine ? An 87' *should" be an EFI truck. By 88' ALL Bronco's were injected and most of the 87's were. 86'+ 302's were injected but that leaves your 351 somewhere in no-man's land. I'm wondering if yours in a factory carb or not. Being 21yrs old it's not inconcievable that someone swapped in a carb'd engine somewhere along the line.

Regardless, open vacuum ports on the carb will generally result in poor performance & effect the idle. IF you can't figure out where the lines are then at least block them off with caps & see if things improve. Ck all the other vacuum sources, follow the lines and see if any are loose or unattached.

 

[steve8691]

Thanks! After letting the bronco sit for a day, I went out turned the kidkdown lever another way and it hooked right up. thought I ahd tried every position...it was like magic. I did hook up the dist vac to the only port where it would fit. Aslo plugged every line that was loose...still no change in the idle. If i push the butterfly valve(?) all the way closed, the idle goes down to a managable level but it smokes like the mixture is off. As soon as I release it, high idle again.

As far as I know everything is stock. The chiltons book shows a few figures of 87 with a 4bbl. They call it a holley but mine is tagged motorcraft. I assume its the same thing.

Now free wire on the alternator fot the choke heater, but there are 2 large black wires, one small white, green and yellow. Which should I spice in to?

Tried to drive it yesterday in the drive. Just had the trans rebuilt and reinstalled. Reverse is strong but no forward gears with weight on the wheels. On jackstands, the wheels did go forward.

I am about ready to reverse it off the cliff!

Again thanks for your time and effort

Steve

Hi Steve,Again... I am not the master here, but any time that you have a vacuum leak, you may have a surging, or high idle. So you want to at least cap off any obvious vacuum leaks.

SeaBronc really knows his stuff, there are others too, but be patient, I am sure that he will follow up. When he asks questions, please do your best to answer them, often they are asked to help him go down one diagnostic path or another. You have done a great job explaining what is going on, I just wanted to bring that point to your attention.

Hang in there buddy.

joe