I picked up a 1984 Bronco II from a buddy a couple weeks ago for a couple hundred dollars with the intention of using it as a small work truck. It's a 2.8L carburated V6 4x4 5 speed manual.

Most of the problems are obvious. The inner and outer tie rod joints need to be replaced (is there a trick to unscrewing the outer tie rod ball studs? We've got one off, but the other one just isn't unscrewing... I plan on taking a pair of pipe wrenches to it tomorrow). That's a simple fix for the most part. The whole truck will get a basic tune-up:

New fluids everywhere (what weight do you use for the transfer case lubricant?)
New Tires
New Oil Filter
New fuel filter
New plugs
New plugwires
New distributor cap
New rotor
New air filter
New PCV valve
Get the timing right
Check all the belts and their tension
Thought about adjusting the valves
blah,blah,blah...

Anyhow, the motor runs pretty rough. A lot of that will probably ease up after the tune-up. The one question I have though is in regards to this. While idling the engine will fairly quickly begin to increase it's RPM. It will continue to do that until its running pretty hard. Once you let up on the clutch and give it some gas it will immediately drop back down to regular RPM the gear starts at. You can get it to stop for a while by taking the air cleaner off of the carburator and opening the carburator up while reving the engine. That causes the engine to backfire and then the high reving in idle drops down.

My best guess is a vacuum leak. The evap can is shot. Both ends are completely rusted out/through. The inside of it looks an aweful lot like an old coffee can in fact. So that is a gaping hole in the vacuum lines. I also found another vacuum line that was disconnected from the air cleaner. I popped that back on, but that isn't making a noticeable difference. Regardless, I didn't/don't expect to see much of a difference until the evap system is replaced. I haven't mapped the entire vacuum lines out yet, so there may be more.

So... my question is... has anyone else run into this problem? And if so, what was the solution? Is it just the vacuum line? I've thought about rebuilding the entire carburator, but I would love to not have to do that if I don't have to. Could it be a problem with the carb? Anyhow, any advice would be appreciated.

Be gentle with your terms and descriptions. I'm only a backyard mechanic... Most everything I know came from a Haynes manual or some buddy of mine. Thanks in advance for any advice.

Mark

 

Everything you've posted about speaks of vacuum and/or carb problems. I went through all of this with my 84. I finally purchased a rebuilt carb ($394) and that solved the problem.

What your dealing with is Fords earliest computer control. It sux. The computer controls your fuel mixture and spark timing. If any item is off, the whole system is off as the computer tries to compensate for the problem.

What I finally ended up doing with mine is converting to the Duraspark Ignition System

BTW, I have all of the old computer stuff including the carb. If you need anything I'll give most of it to ya' and sell the rest cheap. Just ask.

 

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What can I expect to pay to upgrade to a Duraspark Ignition System? From what I've hear it's a fairly easy upgrade in the carburated 2.8L V6. Is there a good tech page anyone could recommend to me that outlines this as well?

Thanks!

 

It is simple and inexpensive. If you want to PM me an email addy I can send you some info on the subject including part numbers.

 

IndyBroncoII,

I agree with KcOrey about the vacuum leak, I had simular problems with rough idle and after replacing ALL of the vacuums lines and assorted hardware it smothed right out. Untill you get the vacuum leaks under control you're fighting a lossing battle with that engine. Another problem with the Idle might be the Idle Speed Control Servo, mine went bad once and caused simular problems, it's worth a look. But then again the first place to start is the vacuum system.

Also a carb rebuild would be a good idea, if you can't go the bucks for a store bought rebuilt, then you might give it a try yourself, the kits are cheap and if you take your time and be read the instructions it's not all that hard.

P.S. I agree, Duraspark is definatly the way to go!!

 

Where did you get all the vacuum lines and everything, and did you have manuals? I keep asking, and I've researched it, but I can't find anything.

 

I gave the truck a basic tune-up yesterday. While doing so I found some obvious vacuum leaks. Unfortunately, right now I have them plugged because I can't find replacement parts. With the lines plugged the engine runs quite a bit smoother. Whoever owned the truck previously must have tried to solve the high reving problem by adjusting the idle speed. Once the lines were plugged the motor would stall in idle almost instantly. That was easy to take care of.

The tune-up has brought up a few questions/concerns though. First off, the evap canister is shot(??? - at least that's what I believe it to be/be called - it looks like a coffee can with a duel vacuum plug nipple on one end). It's rusted all the way through and needs to be replaced. The guy at Autozone was clueless about what I meant and told me to look in junkyards. My concern is that most of the ones I find will be shot also. Does anyone know the technical term for this item and where I can find a replacement?

Next... the smog system on the motor is also shot. They don't do emmisions testing in Indiana luckily. This is kind of hard to describe, so bear with me...

The air filtration system has a piece that runs directly from the exhaust/heat shield and then runs to the smog pump and another hose runs out for fresh air. It also has a small vacuum line attached to it. The line from the exhaust looks to be solid metal tubing that attaches on both sides of the engine where the exhaust pipes attach and then runs up the left side (if your facing the engine) to attach to the air filtration assembly(I think that's it's name). It's right there that I found another problem. The metal tubing looks like at one point it attached directly to the assembly, however the line is broken off right there. I'm sure I can get the new parts at a parts store, but how do I get that line that runs to the exhaust off? It appears to be trapped back in there pretty well. Can I take it to an exhaust/muffler place and have them do it? Or is it easier than it looks?

The last obvious problem I found is that the wiring for the coolant temperature sensor has come off. The plug from the wiring harness is still on the sensor, however the wires have snapped off it. It looks like it takes a green wire and a red wire. Does anyone know where I can find that plug that goes with the wiring harness? I'm sure if it comes to it I could snip one off a truck at the junkyard and splice it into the wiring harness. Is there a better solution though?

Altogether the motor runs -ok- as it stands. It's still pretty rough and I don't feel like I have full power yet though. My hope is that solving the vacuum leaks rather than plugging them will make the computer feel all sorts of better and improve the timing on the truck. Until I have these few things done, I'm not sure I'm up for doing the duraspark conversion. If I can get it running pretty well stock, that's the way I'd like to go for now. I don't want to dump tons of cash into a $300 truck.

I apologize if I've mixed up some terms, I'm not the best mechanic there ever was. I kind of learn as I go...

Thanks again!

Mark

 

Just a side-note - I also replaced the inner and outer tie-rod ends on both sides yesterday. Don't try to be stupid like me and re-use the tie-rod sleeves... it just doesn't work. It's worth paying the $30 to have them. =P

I only wish I knew right away that the inner tie-rods were shot too... I unscrewed both of the outer tie-rods from the sleeves before realizing I really needed to replace the whole mess. I can't describe how frustrated I was that I wasted all of that time rather than just popping out the three joints and walking away from it...

If you do only have to replace the outer tie rods, two pipe wrenches is the way to go to get those suckers off. Or at least, that's the only way I could get em off.

Anyhow, just sharing my pain....

 

I've been there! When I first got my BII the engine was a mess, after making the decision to replace the motor I started the search for all the other peices parts that went with it. I replaced almost every part of the emmissions system, fuel system and the complete vacuum system, along with a new carb, alternator, etc..


I found that a trip to the local auto parts strore was a waste of time because they either had no clue to what I needed or said it was impossible to get and pointed me to the junk yard. I did'nt want to put 20-year old parts back in my truck, so I turned to the internet.

I got my engine from S&S rebuilder, and after spending alot of time on google, I was able to track down a bunch of places that still sell parts for the older BII's, Rock Auto is one of them and I'll dig up all the packing slips I saved and post some of the other's in the next day or so.

IndyBroncoII: I know exactly what part it is you're describing, Mine was in the same condition, after I figured out what it was called, I was able to find a new one on. I don't remember off the top of head what they called it, But I will find the papers that I saved and get you a part number and a place to order it from. I'm running late for work this morning but will have it posted this evening when I get home.

RomerB2: I just got a 50' coil of vacuum hose and an assortment of fittings at the auto parts store, I have a factory engine manual that had some pretty good diagrams. I'll find those and PM you so we can work out a way to get it to you.

The "Coffee Can" you're talking about is the Vacuum Reservoir, not the Evap Canister.

I'll get back to everyone with all my info as soon as I can, I got enough part numbers to replace almost everything under the hood of a 2.8L .

Never once had to hit the junk yard, just waited for the UPS guy!

 

Got home and found my file of reciepts from my engine rework. The two places I found that stocked just about everything I needed was Parts America, their website is setup really nice and even shows pictures of most of the parts, Thats how I figured out most of them. The other one that had quite a few was Rock Auto.

IndyBroncoII, I think the part your looking for is the Air Check Valve. GP/Sorensen Part # 7792947 (Ford Part #E3TZ-9A449B) costs right around $60.00 from parts america.

I've looked around to see if anyone has a Vacuum Reservior listed but have'nt had any luck finding one, mine was in perfect shape so I did'nt need to replace it, it really is nothing more than a empty coffee can with a couple of places to hook up vacuum lines. I guess if you had to you might come up with a way to make a replacement.

I also found my vacuum diagrams and engine and tranny manuals (the real Ford factory ones). If anybody wants copies I'll be happy to get them to you.

 

On the vacuum diagrams which engine is that for, or do you have one for like the 90 2.9L? I would be super happy if you could send me those.

 

Most of the suff I have is for the 83-87 2.8L, but I do have a few things on some of the later 2.9's, one of my HoneyDo's today is to clean-up/clear out all of the papers, maunals and misc. stuff I got piled up on the workbench. I'll see what I have and get back to you later today.

 

I found all the goodies I collected during my rebuild project. Here's a list of what I've got, if anyone can use any of this stuff I'll be happy to get it to you.

1983-1987

2.8 Engine Manual
2.8 Engine Training Manual
2.8 Vacuum Hose Diagram
2.8 Cylinder Head Cooling Modification
2.8 Hydraulic Lifter Guide
2.8 Rocker Arm Modification Guide
2.8 Aerostar Headers
2.8 Offenhauser Intake

2150 Carb Rebuild Guide
Bodylift Instructions
Clutch, Driveshaft and Tranny Manuals
Plus lots of other good info and Diagrams
Duraspark Conversion Guide

2.9 Engine Shop Manual
2.9 Homemade Manifoid Guide

I've also got a good CD that cover's the rebuild and modifications on the Ford 60 degree V-6 Engines (2.6,2.8,2.9 and 4.0 Liter)

RomerB2: It does'nt look like I've got a Vacuum Diagram for the 2.9, It's not included in the shop manual, but if I stuble across one I'll let you know.

I've got all this stuff on a CD that is about 500MB worth of data, it's a little rough to E-mail that much stuff, so if anybody wants it, PM me and I will drop a copy in the mail to you or for those that are computer geeks I can FTP you the files.

 

Thanks so much LikenewBroncoII! I'll check out those websites and see what I can dig up. As far as the Vacuum Resevoir goes, I'll probably just weld the two vacuum nipples to a coffee can and call it a day. I still have the nipples that went on the original and I'm pretty sure I can weld them on without much difficulty.

As far as the vacuum and engine manuals go I would love to have them. The carb rebuild manual will probably come in handy also. Do you have them digitally or on paper? Let me know and I'll send the appropriate information.

Thanks again!!

Mark