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Charlie don't surf..
'92 Ford Bronco XLT
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16,429 Posts
Discussion Starter · #1 ·
Yesterday after work I was leaving the house to go running, figured I would take the Bronco since I hadn't driven it in a couple of days. Fired it up and it's idling funny, almost as if it's missing. I notice a really rich smell coming from the exhaust and some black smoke. It continues to idle rough and then dies. I restart it, it cranks right up but still is idling rough. I try hitting the gas a few times to see if that does anything but there is no improvement.

Now I will tell you that a couple of weeks ago, I was driving around in this:



but I had not had any problems until yesterday. I checked the plug wires and they seemed fine, I'm going to go through and check the following, if you guys have any other suggestions, please let me know. Thanks.

Spark plugs
fuel pressure
coil
compression

The engine has less than 2000 miles on so I'm doubting that it's anything major.
 

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Charlie don't surf..
'92 Ford Bronco XLT
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16,429 Posts
Discussion Starter · #3 ·
A fried TPS could explain the rough idle, not sure about the miss though. Your list looks like a good place to start.
Can't hurt to check that. Thanks for the suggestion.
 

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3,373 Posts
black smoke is from to much fuel.
i bet your not firing on all cyl.
with the motor running, pull off plug wires from the cap one by one.
if it stalls, or runs worse, then you know that cyl is firing.
if you pull one off and there is no change, then you found one thats not firing.
use insulated or plastic pliers unless you want a nice jolt.
 

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maybe an injector, sticking open, hook up a fuel pres gauge. turn KOEO check fuel pressure, if it drops fast, you either have a leak, a bad check valve in the pump or probably an injector, it will drop slowly tho, thats kinda normal. i would do the spark plug thing as well, just dont get jolted..
 

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Satyr of the Midwest
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17,747 Posts
After looking at that picture, I'd bet on a bad PIP, or water/dirt intrusion on the wiring harness connectors; specifically, the ones to do with the PIP/TFI.
 

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Charlie don't surf..
'92 Ford Bronco XLT
Joined
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16,429 Posts
Discussion Starter · #11 ·
Last night I checked the cap, rotor, coil and pulled all of the plugs. Plugs looked good, cap and rotor had a little wear but nothing major, and I swapped the coil for one that I knew worked, and nothing changed.

Thanks Alan, I figured it was rich, just hoping I didn't lose a cylinder or something. I didn't try pulling the plug wire off with it running, but I'll put that on the to do list.

black smoke is from to much fuel.
i bet your not firing on all cyl.
with the motor running, pull off plug wires from the cap one by one.
if it stalls, or runs worse, then you know that cyl is firing.
if you pull one off and there is no change, then you found one thats not firing.
use insulated or plastic pliers unless you want a nice jolt.

No water in the oil, everything looked good.

If it was the TPS, wouldn't it shift roughly from 1st to 2nd gear in limp mode? I know mine did that.

Did you check your oil to see if there was water in there?
Could be an injector, I'm going to check the fuel pressure this weekend.

maybe an injector, sticking open, hook up a fuel pres gauge. turn KOEO check fuel pressure, if it drops fast, you either have a leak, a bad check valve in the pump or probably an injector, it will drop slowly tho, thats kinda normal. i would do the spark plug thing as well, just dont get jolted..
SigEP, you mean the pick up in the distributor right? Handn't thought about the dirt or water getting into the wiring harness since it had been running fine for the last two weeks and then this just happened all of a sudder. Guess it's better to just eliminate any possiblities. Thanks for all of the suggestions.

After looking at that picture, I'd bet on a bad PIP, or water/dirt intrusion on the wiring harness connectors; specifically, the ones to do with the PIP/TFI.
 

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Charlie don't surf..
'92 Ford Bronco XLT
Joined
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16,429 Posts
Discussion Starter · #12 ·
Ok, so the compression is good, fuel pressure is good, injectors are operating properly. Cleaned the plugs off since they were pretty nasty from running so rich, and my buddy noticed that the # 4 plug boot was soft. It's the one that sits the closest to the header. Sure enough the boot was bad and there was quite a bit of resistance. Essentially # 4 cylinder wasnt firing, going to replace the wires today to see if that solves the problem.

Anyone with headers have any recommendations for plug wires, or some type of insulation to keep this from happening again. I had the 9 mm Ford Motorsport wires on there and never had a problem with the old stock manifolds, but I guess the heat from the headers ruined this set. Thanks.
 

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Same thing happened to my 9mm FMS wire boots. I have the 45 degree boots pointed away from the headers but they seem to still get soft. The rubber insulator gets so pliable I could feel the metal terminal thing inside. I've had to replace 2 boots on the FMS wires already. I know alot of people have had great success with the FMS wires, but I won't buy them again.
 

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3,373 Posts
those are pretty good wires. i'd run them again.
look at the auto parts store, summit or jegs, for insulated covers.
they are fiberglass, asbestos or some similar material. they are 4" to 6"
long and protect the boot and first few inches of plug wire from heat.
this will solve the problem.
 

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Charlie don't surf..
'92 Ford Bronco XLT
Joined
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16,429 Posts
Discussion Starter · #15 ·
those are pretty good wires. i'd run them again.
look at the auto parts store, summit or jegs, for insulated covers.
they are fiberglass, asbestos or some similar material. they are 4" to 6"
long and protect the boot and first few inches of plug wire from heat.
this will solve the problem.
Thanks man. I'll check those out.:thumbup
 

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Charlie don't surf..
'92 Ford Bronco XLT
Joined
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16,429 Posts
Discussion Starter · #17 ·
Thanks FG, that plug wiring diagram is very helpful.
 

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Charlie don't surf..
'92 Ford Bronco XLT
Joined
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16,429 Posts
Discussion Starter · #18 ·
Latest update, after replacing the plug wires, got a new set of 9mm motorsports, the engine smoothed out and was running great. I even bought a set of the plug boot protectors, to keep from having the same problem.

Took it for a test drive down the road and the engine just stops all of a sudden, was able to get it started and it did it a couple of more times before I got back to the shop, going to replace the pick up in the dizzy today and see if that's the culprit, so Sig, you may have been right after all.
 

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Charlie don't surf..
'92 Ford Bronco XLT
Joined
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16,429 Posts
Discussion Starter · #19 ·
Worked on this over the weekend, but have not gotten any farther. We pulled the dizzy out and there was all kinds of dirt and sh*t down inside. I'm guessing that is probably what is causing the problem, since the spark from the coil is good and everything else seem to be functioning properly. Let me tell you pulling the gear from the distributor shaft was a major PITA. I'm swapping in a spare PIP I have from my old distributor and keeping my fingers crossed.
 

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Charlie don't surf..
'92 Ford Bronco XLT
Joined
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16,429 Posts
Discussion Starter · #20 ·
My rig is still running like dog sh*t, got the new PIP in, and replaced the IAC, it was shot. Set the timing and now I'm getting a really rich condition. Fuel pressure is right about 35, and the spark is good, so I had my buddy hook it up to his snap on scanner. It pulled 20 codes that were in memory, we cleared them out and ran it in diagnostic mode, the MAP is reading out of range, the ECT is not working properly and it won't get out of open loop so it is running insanely rich. I'm thinking at this point that the EEC might be shot. One other thing to mention when it was hooked to the scanner it wasn't reading any voltages of the sensors, maybe a bad ground?? Any suggetions or other ideas??
 
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