24in of vacuum at idle too high for the 2.8L?

[SgtDan94]

Yeah, I use LocTite red for throttle plate screws.

If you think the throttle plates have been removed check them very carefully. The original screws are swedged to keep them from backing out and falling into the engine.If you remove the crews to center the plates in the bores I'd recommend a drop of locktite on each one when you assemble it. The base idle screw is not a throttle stop, it's one of the tune up adjustments. If the screw is backed out of contact with the throttle lever and it still runs, there's a problem. The idle control isn't a stepper motor, it's just an actuator but some have one position controlled electrically and one by vacuum.

OK... so it does work... and it's a stepper motor... not just an actuator.

Gotta be alignment of the throttle plates or the throttle shaft is twisted. Is the throttle shaft tight in the bore?

I think if it runs a drives good... I would turn the idle stop screw out until it barely touches the throttle lever... and just drive it... SMOG it and see what you have.

Is there only one way to install the plates? In other words... will I know for sure just by looking if the plates are not sitting correctly? I will include pictures when i take it apart later today.

 

[8thTon]

Is there only one way to install the plates? In other words... will I know for sure just by looking if the plates are not sitting correctly? I will include pictures when i take it apart later today.

The plates are clamped in a slot in the throttle shaft and usually have oversized holes for the screws, so they can float around until the screws are tight. First back off the hard stop completely. You install the screws just lose enough that the plates will move (do one plate at a time), and then close the throttle and shift the plate around until it is seated as well as possible - use the bore to align the plate. Then tighten the screws and then do the other one. You'll have to set the hard stop up again.

 

[SgtDan94]

@8thTon @Uncle Gump @19Walt93

Im going to be replacing the thermostat in the bronco as well tonight... is their only one thermostat in the 1984? Is it in the upper housing? Is it supposed to be a 195 degree thermostat? Thank you. After 20 minutes of idling the temp gauge barely moves. . . I already replaced the temp sensor so i can only assume it is a thermostat issue.

 

[Uncle Gump]

Yes... only one thermostat. 195 is typical...

 

[19Walt93]

If I remember right you may find it in the lower water outlet, I'd take off the easiest one first. While you have it drained try back flushing the heater core then flushing it in the normal flow direction. I've seen Rangers run cold because of restricted heater cores, not sure why they did it.

 

[SgtDan94]

If I remember right you may find it in the lower water outlet, I'd take off the easiest one first. While you have it drained try back flushing the heater core then flushing it in the normal flow direction. I've seen Rangers run cold because of restricted heater cores, not sure why they did it.

@8thTon

The heater works great so i can assume its not clogged, i will still flush it.. i hear refilling the system can be pretty tricky on these broncos.. many people end up having to pre fill the heater core and engine partially before reattaching the hoses.

It took me near 4 hours yesterday to install a new mechanical fuel pump.. now i know why people throw away the hard fuel line and replace it with a hose.

 

[sheep herder]

If the heater works great, I don't think there is a problem with your thermostat. Sounds more like a gauge problem.

 

[SgtDan94]

If the heater works great, I don't think there is a problem with your thermostat. Sounds more like a gauge problem.

You're probably right... I didnt think of that.

 

[alwaysFlOoReD]

It took me near 4 hours yesterday to install a new mechanical fuel pump.. now i know why people throw away the hard fuel line and replace it with a hose.

Yeah, that lower bolt is a bitch to get at. IIRC I used 2 universals connected together to get at that bolt. And that was on a parts truck with nothing in the way.

 

[SgtDan94]

Yeah, that lower bolt is a bitch to get at. IIRC I used 2 universals connected together to get at that bolt. And that was on a parts truck with nothing in the way.

I also replaced the oil sending unit at the same time. Removing both the sending unit and the extension for it made the fuel pump removal ALOT easier... i was able to get a standard 10mm wrench right on the lower bolt, while laying underneath the truck. I personally had a very hard time with the top bolt of the fuel pump, since all i had was a 10mm wrench, there was very little wrenching room. The worst part was trying to tighten the hard fuel line fitting onto the new pump once it was installed. I shouldve replaced it with a rubber fuel line...

as a matter of fact, if that connection ends up leaking, im going to remove that hard line and put a hose in its place.

 

[19Walt93]

If the line leaks please bend up a new one and don't put a hose on it. It's still worth flushing the heater core- after back flushing it first- to make sure it's clean. Your location says NorCal, I assume that's Northern California and you don't get extreme cold weather. You could have a few clogged passages and still get warm air, in sub zero weather those clogged tubes would be letting outside air in and you'd notice it quick. With the engine fully warm and the defroster on high you should see 140 degrees or darn close at the vents.

 

[franklin2]

I have been ignoring this thread because of the title. I saw it was getting larger and larger and thought I would see what is going on in here.

I can tell you that idle solenoid thing on the carb is a little DC motor. It controls the idle speed via the computer. I found the Ford adjustment procedure somewhere in my books, I can try to dig it up again, but I can tell you it is very complex. You have what you would call the idle stop and it has a certain adjustment, and then you have to mess with the computer and do a procedure so the computer sets the idle speed to 2000 rpm,, and then you adjust that little motor till the engine is running at 2000 rpm. There is more to it than that, but that is the jist of it.

I also had high idle problems when I first got my 1984 with the 2.8 and all this junk on it. It would idle beautifully, and then all of a sudden the idle would go up and it would start having a miss-fire to it. I found out for some reason the computer would suddenly advance the timing and cause the high idle and the miss-fire. I pulled the computer codes, I had so many I said the heck with it, and converted to the duraspark II distributor. I am still using the original computerized carb. It runs so good now and idles so smooth.

The only real problem I have now is with the choke. These carbs have a full electric choke, I am getting power from the white/black wire off the alternator. That works great also. But, this carb only has one high idle step for the choke. All the other high idle steps where done away with, the little idle motor did all that with the computer and the temperature sensor. So at first start everything is fine, I get a nice high idle. But soon after when the choke starts opening, the idle drops down too low, there are no steps on the fast idle cam and it wants to run a little rough and stall till it fully warms up.

 

[SgtDan94]

I have been ignoring this thread because of the title. I saw it was getting larger and larger and thought I would see what is going on in here.

I can tell you that idle solenoid thing on the carb is a little DC motor. It controls the idle speed via the computer. I found the Ford adjustment procedure somewhere in my books, I can try to dig it up again, but I can tell you it is very complex. You have what you would call the idle stop and it has a certain adjustment, and then you have to mess with the computer and do a procedure so the computer sets the idle speed to 2000 rpm,, and then you adjust that little motor till the engine is running at 2000 rpm. There is more to it than that, but that is the jist of it.

I also had high idle problems when I first got my 1984 with the 2.8 and all this junk on it. It would idle beautifully, and then all of a sudden the idle would go up and it would start having a miss-fire to it. I found out for some reason the computer would suddenly advance the timing and cause the high idle and the miss-fire. I pulled the computer codes, I had so many I said the heck with it, and converted to the duraspark II distributor. I am still using the original computerized carb. It runs so good now and idles so smooth.

The only real problem I have now is with the choke. These carbs have a full electric choke, I am getting power from the white/black wire off the alternator. That works great also. But, this carb only has one high idle step for the choke. All the other high idle steps where done away with, the little idle motor did all that with the computer and the temperature sensor. So at first start everything is fine, I get a nice high idle. But soon after when the choke starts opening, the idle drops down too low, there are no steps on the fast idle cam and it wants to run a little rough and stall till it fully warms up.

thanks for joining In. What I really don’t understand is why my bronco idles normally with the “idle solenoid” completely removed and unplugged. With this solenoid completely
Removed and unplugged, the throttle still does not make contact with the stopper. I know in the pictures I posted the solenoid is touching the throttle.. and it’s giving everyone the idea that this is the reason the throttle is not closing all the way.. that’s not the case.

I understand that the Duraspark conversion requires the removal of some emissions equipment. I live in an area in California where SMOG is required and is very strict. If anyone knows a way to do the conversion and keep all the emissions equipment, please let me know.

 

[SgtDan94]

@19Walt93 @8thTon @Uncle Gump

Does anyone know if I can lube the shaft that runs into the clutch cylinder from the clutch pedal?? The clutch does not roll out smooth, not as smooth as the gas pedal goes in, it sort of comes out in steps. which makes for a jerky take off... again, if you take your foot off it will come right out I have a full pedal

I don’t think the clutch needs to be bled.. if you push it in and let it go it comes right back out.. also it shifts into all gears just fine...

I noticed there’s a little rubber grommet that this shaft slides in and out of.. I was wondering if I could just slide that back and put some type of grease inside.

Im open to suggestions

 

[sgtsandman]

To be safe, you could try some silicone brake grease. It tends to be pretty friendly to rubber seals. I think white lithium grease might be ok too but I'm not 100% sure on that one.