Beware Of The Bronco 2 Curse!!!!!

BRONCO 2 CURSE!!!!!!!

Well if anyone ever comes up with a resolve for this problem, and it is apparently a very common problem. Please let me know. It appears that the 86 and 87 Bronco 2's with a 2.9 were plagued with this problem, and as I have found no-one has ever been able to resolved the problem once it starts. I've read numerious forums and they all say the same thing. Runs great when cold, reaches normal tempertature and it starts missing and bucking like a, well for lack of a better word "BRONCO". At first when you start it up and it runs great till it reaches normal opperating temperature and then it all starts going down hill. Black smoke, missing shaking, no power. You can cut the switch off and right back on and it will smooth out instanly and run great for a few of miles and then it happens all over again.

I give up. I've now parked this 87 Bronco 2 parked right beside my other 87 Bronco 2, Both have the same identical problem I might add. Yep they both have the exact same problem and they both have all new sensors, fuel pumps and filters, new ECM, new vacuum lines, lots of new wireing. Both have 20lbs vacuum and around 35 lbs fuel preasure. Both have new fuel regulaters, new air filters, new distributer caps and rotors, new plugs and wires, new temperature sensor.

Heck, now this one even has a brand new, complete distributer, and oxygen sensor. Everything that I can find that could be a possiblility, has been replaced. still no resolve. Oh yes I failed to mention I took the plentium off and cleaned it and the intake. re-installed it with new gaskets.

Last ditch effort! Took it to FORD and they couldn't find the problem either. They said it could be the ECM, but that was not a gurantee. Well I didn't go that route as the ECM had already been replaced.

Any body want a good deal on either of my Bronco 2's, both with lots of new parts? Can't say they are very dependable, but they both look good, just setting there! I've resolved now that it is an uncureable curse!

WARNING!!!! Beware of the Bronco 2 curse!! It sneaks in, ruins an otherwise great little ride, then it proceeds to drain the life right out of your billfold. I would really feel bad if I wasn't "Spreading the wealth around a bit"!!!:rofl:

(UPDATE)

Well a friend said that it was probably the wiring harness and not wanting to be out done I replaced the wires from the ECM to the module on the distributer ( new SPOUT connector and all). Results, still the same. Still got the 18 code also. :banghead: Surely some one else has run across this problem????
Any ideas???

I just spent 4 days of a 14 day vacation hunting the same issue. After several "TESTS", I decided that the computer had issues. Not so!! I found that the out put voltage to my fuel pump relays was less than 11.25 volts (my battery had a full charge and is nearly new). Having found this I started checking for loose connections, broken wires etc.etc.etc. What I found was that the ground wire that comes directly off the battery has a "quick connect" near the battery. It took some efforf to disconnect this connection, when I did I found severe corrision. I removed the bad connector, did a butt splice and applied heat shrink. Bingo, the issue disapeared. I guess that the computer will not work properly with less than a perfrct ground.

Hey martyylephew;
Thanks for the input here. Heck I'll check my input voltage. I've already checked the ground circuits and nothing. I did replace the computer and that did nothing. Heck I've replaced everything I've had an notion it could be and absolutlely nothing has helped. Were you getting a trouble code 18?
Ron



I just spent 4 days of a 14 day vacation hunting the same issue. After several "TESTS", I decided that the computer had issues. Not so!! I found that the out put voltage to my fuel pump relays was less than 11.25 volts (my battery had a full charge and is nearly new). Having found this I started checking for loose connections, broken wires etc.etc.etc. What I found was that the ground wire that comes directly off the battery has a "quick connect" near the battery. It took some efforf to disconnect this connection, when I did I found severe corrision. I removed the bad connector, did a butt splice and applied heat shrink. Bingo, the issue disapeared. I guess that the computer will not work properly with less than a perfrct ground.

I did not get the "18" code, but, I was getting everythibg else. The thinking behind the corroded wire is this: If you measure any voltage on a vehicle, you connect the ground lead of your meter to ground (reference). Now, if you have a bad ground, every voltage you measure will be "off" by the amount of resistance that any corrision may cause. What this means is this:
The EEC (computer) is continously checking voltages that return from the "input" devices, and is sending voltages out to the different relays, valves and pumps. If the ground is bad it would appear to the computer that the voltages comming back from the devices like throttle position, O2 sensors will be "low" because they are measured against the ground. Having said this, the computer will generate error codes because it is not recieving a "GOOD" signal back from the devices. It also means that the voltages going out will be low also, which in turn makes the computer think that the world is comming to an end as far as the engine is concerned.

Well I have checked the ground connector you spoke of and mine was clean and in good condition. I did try bypassing it and I loosened the connection at the battery (for the second time) and cleaned the connection there also. I also tried replacing the 3 relays on the fender well. Still nothing changed. I've got over 12 volts at the relays.

I believe that what is happening is, when the vehicle shifts over to the computer to control the timing, something is sending ironious information causing the EEC to go haywire and throw the timing or fuel amount all out of whack. What ever it is, it comes and goes, and is disabled when you re-start the engine for just a short period, then it kicks back in. It is a timing issue, or too much fuel issue, because the fuel is present, and fire is present. This is evidenced by the black smoke and rich gas smell from the exhaust.

I have replaced the SPOUT connector and even replaced the SPOUT wire all the way back to the EEC and no change. The question is, (What can cause a code 18 other than the connector not working or the wire not being grounded or open. Everything at the distributer is new. EEC is new. New wire all the way from distributer to EEC. Why does it still show an open or grounded SPOUT connection?





I did not get the "18" code, but, I was getting everythibg else. The thinking behind the corroded wire is this: If you measure any voltage on a vehicle, you connect the ground lead of your meter to ground (reference). Now, if you have a bad ground, every voltage you measure will be "off" by the amount of resistance that any corrision may cause. What this means is this:
The EEC (computer) is continously checking voltages that return from the "input" devices, and is sending voltages out to the different relays, valves and pumps. If the ground is bad it would appear to the computer that the voltages comming back from the devices like throttle position, O2 sensors will be "low" because they are measured against the ground. Having said this, the computer will generate error codes because it is not recieving a "GOOD" signal back from the devices. It also means that the voltages going out will be low also, which in turn makes the computer think that the world is comming to an end as far as the engine is concerned.

I found an article @ therangerstation that may raise your eyebrows. Please look at http://www.therangerstation.com/tech_library/remote_tfi.htm

This site explains how to move the TFI away from the distributor to a cooler location, (worth a look??)

Good artricle. I've read it before. I have replaced the TFI, along with replacing the complete distributer. My problem is not that the engine dies, It only starts missing and running very rich, black exhaust smoke and rich gasoline smell. It surges and shakes and runs real crappy after warm up, but continues to run. If the TFI goes bad it will generally lose fire and die and most times will not start again till the TFI cools down. Mine does not do that. It loses power and seems to be flooding out but never shuts off.
Thanks
Ron


I found an article @ therangerstation that may raise your eyebrows. Please look at http://www.therangerstation.com/tech_library/remote_tfi.htm

This site explains how to move the TFI away from the distributor to a cooler location, (worth a look??)

Sounds strange but my sons 86 was doing the same thing. We kept reading on the subject and found that the 88 and 89 coputer would plug right in, and unluckly we had an 89 one that he rolled still sitting there. We swapped the computer out and put a plate between the EGR valve and the intake. And it runs fine now. If your state tests then it was mentioned that you can have the test station update your bronc to the 88 standards.

Hello, we had one we have been trying to figure out for a good year now. The first part we changed out was the low pressure pump in the tank. That didn't fix it. Even the Ford mechanics couldn't figure it out. Every conceivable part was changed out with new, down to the ECM unit. It would run fine for up to 4 hours and then just die. Sometimes it would run only 5 minutes. You just couldn't trust it to go to town in. My dad got a wild hair and decided it just had to be the new pump he had put in the tank. Guess what, that fixed the problem. Just goes to show that even new parts can be defective right out of the box. Been running great for a couple of months now. Hope this saves somebody a lot of money and head scratching.

Im in the same boat, my 2.9 - '87 has all but been rebuilt, as in new everything.
I have recently been experiencing the same issues. Have a few friends that are ASE mechanics and after running over the issues with them, the only 2 things theyve suggested are the Mass airflow sensor,the MAP sensor, or possibly the Throttle posistion sensor (TPS).
All the info ive found on the TPS points to it being the culprit...the surging, stalling, and poor performance all the way down to the rpms bouncing from 0-red and it dying while on the highway doing 60.
My boys tell me that if that doesnt solve the issue then im pretty much up the creek, because theyre at a loss from there.

This has been a decent link for the info: http://www.buzzle.com/articles/symptoms-of-a-bad-throttle-position-sensor.html

Im going to test out these issue as I type, so if its a fix, ya'll will be the first to know!

i AM ALSO HAVING SAME ISSUES:runaround:.
1986 bRONCO II 2.9 AUTOMATIC
RUNS FINE WHEN COLD AND THEN STARTS BUCKING,SPUTTERS,
RUNNING REALLY RICH.
fRESH TUNE UP, NEW CAP AND WIRES TOO
PLEASE HELP
THANK YOU

From: http://www.thorssell.net/hbook/intro.html


Sometimes it helps if you try to think like a computer. A computer is just a set of circuits that can switch one way or the other. It makes "this" or "that" decisions based on data it is receiving.

Fuel system control is a good example of how this works.
Say the oxygen sensor (O2S) signal line was grounded. The PCM says "the O2S is lean (0.0V) , so I'll richen the mixture". The O2S line is still grounded so the PCM keeps on richening. After a bit of this the vehicle is blowing black smoke.

The Manifold Absolute Pressure (MAP) sensor which reads manifold vacuum is another example: When the driver accelerates, the vacuum to the MAP drops off and the frequency it outputs starts going higher. The PCM says "MAP frequency up = acceleration = richen mixture" and richens the mixture for acceleration.
Now suppose the MAP line develops a leak and the vacuum drops to the MAP. The PCM again says "MAP frequency up = acceleration = richen mixture" and richens the mixture. Now you have a vehicle with a vacuum leak blowing black smoke.

This is why, when the customer complains about fuel mileage and black smoke you may get a lean code, or no code. In the case of the lean code, the rich mixture is just the PCM trying to compensate. In the case of the MAP problem, the PCM didn't see a problem. It saw what it thought was acceleration and it acted correctly according to its rules.

Keep this in mind when you are trying to figure out a tough problem.
Try to put yourself in the place of the PCM and figure out what type of INPUT would give you the REACTION you are getting.

try this please, i had problems similur to this and after spending LOTS of money found this solution, i changed the temp sending unit in the midst of all this and found that the b2 NEEDS A METAL/BRASS base sending unit. the one i got was plastic base. i put on a metal base sending unit and ran the b2, aaaaaahhhhhhhhh, like the best sex i ever had. problem solved, $5 dollar fix. hope this helps you all, remember, METAL base...:grinyes::grinyes::grinyes:

I've read all the posts and I was just wondering has anybody changed there alternator

This sounds like what happened to my 87 Bronco II about 15 years ago. I would be driving down the highway after the engine was fully warmed up and it would sputter and cut-out until it would come to a complete stall. Would turn on engine after several minutes and start the whole process over again. It was the ignition module!! When I had that changed out it never did that again and has been running great ever since, 380,000 miles later.

Hey everyone, so I had a similar issue with my 86 Bronco 2, the way I fixed my truck was by bypassed a fuel filter underneath the driver seat. I think there was a loss of fuel pressure and after this repair, I have not had this issue since (5 months).

Yea i got a 1986 broco 2 2.9 and its been sittin in a garge for 10 Years and i got it for 300$ and starts and runs but it pours white smoke i don't no y? can any one give me some tips

white smoke is usually water, is oil milky looking or bottom side of oil fill cap white? might also want to run a compression test. think the 2.8 and 2.9 had head gasket and head cracking issues

No the oil has no water in it don't know if the valves are stuck or rings it smell s like its burning oil

Mine was blowing black smoke changed a lot of emission parts. didnt work. Ened up being the catalytic converter.

DEFECTIVE EGR VALVE IS THE PROBLEM : )
I have an 87 Bronco II with 2.9 V6. Was having same warm up and stammer and sputter with loss of power. I did everything - plugs, wires, IACV, TPS, etc.

Had hunch it was a defective EFR valve. Tested the problem by placing a metal plate (made from cutting up an aluminum pop can) between EGR valve and intake. This prevented any exhaust gas being able to be recirculated back into the intake improperly. VIOLA!! FIXED PROBLEM!!

Stupid EGR was stuck open and choking car with too much recirculated exhaust gas. This was making the car sputter due to lack of oxygen and the car' s computer was doing its best to compensate the proper fuel air mixture but just ended up running way too rich and stinky.

Good luck.

Has anyone checked. The fuel reg. It has a rubber diophram in it that can go bad and srrart to dry up and leak fuel. Iit happened to me. It spit out black smoke and raw fuel ran like crap. Had it towed into my mechanic and he knew what it was right of the bat. It toasted the cat. Converter but that was an easy fix. Im not sayin this is your problem but it is the only problem i had with my 86.

Shot gunning pArts and sensors to a problem is amateur at best. Bronco 2 tfi ignition systems were notorious for multiple problems ranging from over heating to losing ground. Another problem was the pins I. The plastic fuel pump connector had plastic melted contacts these contacts were prone to breaking especially 86 and 87 with dual pump set ups. The pins would push down into the tanks and not plug into the connector.

After replacing everything electrical on my 88 b2 I realized AutoZone sold me an incorrect icm. I was about to go nuts before I found it. Compare new and old parts inside and out.

This is my first post ever. I ran across this post several years ago and just feel I need to chime in given my experience with my '87 Bronco II. I too had the "curse" where it would run fine in open loop but stumble and sputter once it warmed up and went to closed loop mode. Switching the key momentarily off then back on would give me a few seconds of normalcy then back to the sputtering again. I must credit this fix to an old post I ran across by Richard McCuistian of "Ask a Mechanic" fame.
In days of old, with three wire O2 sensors, the ground for the 1 volt signal has to travel up the exhaust pipe, through the manifold and bolts into the head, where the orange wire is fastened that leads to the PCM. Its a long way for that 1 volt signal to travel and the message to the PCM gets corrupted. In my case after fighting this for two years, I fastened a hose clamp around the base of the O2 sensor then attached a wire from the clamp up to that orange wire via a Scotch Bloc thpe connector. Worked like a charm for me. Give it a try. Hope this helps someone.
Just an aside, it gets hot down there so I attached my wire to the 'excess" end of the hose clamp with a screw and nut. Its a little cooler an inch or so from the sensor itself. Thank goodness for 4 wire O2 sensors nowadays.