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Discussion Starter #1
My bronco has been running worse now than before my tune up..:banghead

Tune Up:
Seafoam (vacuum line/gas tank)
Air Filter
Plugs
Wires
Cap/Rotor
Ign. Coil

It's missing somewhere.. i ran the codes last night

111
173
P0172 after a diagnostic scan...

It's saying i'm leaning out my bank 1..

I'm figuring this could be an injector problem or a cat. converter problem...?

Anyone have any other ideas to check out?
 

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are your o2 senors original? new?

I would get the 02 sensor bank lean CEL every once in a awhile even with a fresh tune up. replaced the 02 sensor and it fixed my problem....no CEL for about 2k miles now.

I have 2 upstream 02 sensors on the 96 and i replaced them both as they do most of the work...i had 80k miles on the original ones.
 

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Discussion Starter #4
yeah.. they might be original.. what i'm trying to figure out is if that would lean out my ratio enough to give me a miss?

obviously i will end up changing them out anyways if it's possible to fix my missing.
 

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ok...sorry missed the part about it missing........double ck your new wires, maybe burn through 1?

I had a plug wire that was partially burned thru....it was a intermittent miss and would trip the CEL
 

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Satyr of the Midwest
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Do the regular diagnostics first: check for vacuum leaks, make sure the PCV system is functioning properly, proper fuel pressure, etc. Note that exhaust leaks will cause a problem with HO2S readings.
 

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Did you set up the spark plug wires correctly ie: numerically from cap to plugs? Double check..

In many previous threads I've read where spark plug wires routed to close together can cause "cross-over" a possible problem or you may possibly have a vacuum leak in the emission system changing the EGR "air stream" from up to down going out the CAT.. starving the cylinder of oxygen...causing it to miss....

Injectors are redundant so as long as they're getting voltage they work but doubtfull they would cause a miss as they just spray fuel so they would really have to be nasty to fail but do check voltage....www.fordfuelinjecton.com has a section on rebuilding & cleaning them inexpensively..

Does the 95 BKO have the "Thermactor Air System" with the cross -over tube attached to the cylinders heads on the back of the engine?....if so look at the "check valve" on top of the C/O tube for rust/burn thru....check valve costs around $20.00 ...

Otherwise you may have to trace down any plastic vacumm lines in the system and definately replace the O2 sensor/s if there is 30k or more on them, over time from extreme heat and cooling they tend not to read accurately telling the system to go rich vs. lean...?

Check the FI Plenum and Lower Intake Manifolds for possible gasket leaks...

Good Luck ~ :thumbup
 

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Discussion Starter #8
wow. thanks for all of the information. i'll be checking these things this weekend.

it's been driving me nuts really.. it ran smooth prior to the tune-up, but the previous owner told me he had just replaced the drivers side plugs because the passenger side bank was too difficult to get to. so i wanted to go through and replace everything.. put all new stuff in and WHAM.. miss... the wires are properly routed so it's not a firing order issue.
 

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Check all the ceramic center cores of the plugs, some time ago I put in a set of Bosch Platinums and after a few weeks it was missing badly and turned out 3 of the center cores had gone away entirely.....? AND I found 3 bad wires, check the boot ends for burn thru from arcing.....PITA....

Now I only use 9 mm FMSR wires, MSD ignition parts and Autolite plugs............:rofl:

Get a Haynes Manual if don't already have one....other BKO help/tech sources are: www.fordfuelinjection.com and www.broncolinks.com ~


Good Luck ~ :thumbup
 

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Discussion Starter #10
it's getting the once over by a friend that builds drag cars and other toys to determine the cause of it.. i'm too annoyed with it at this point to pull the plugs again.. they've been out 3 times now in a little over a week. if these wires are behind it i'm buying 9mm ford racing wires... if my buddy can't figure this thing out, i'm hitting it with my muzzle loader.
 

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Have your buddy do a wet/dry compression test if necessary.

Being annoyed...:banghead lol lol...is part of the game keeping older rigs on the road, you can't let it get to you so keep diagnosing to learn, gain experience to figure out what it is, there's only so many possibilities it can be......:doh0715:

Hang in there Brother ~ :thumbup
 

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Satyr of the Midwest
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:stupid

Just go through things STEP BY STEP. There's no reason in driving yourself needlessly crazy chasing several different things at once; take time, have patience, drink a beer, look at it later.

Make sure the fuel pressure is tested. If you want a quick test to see whether the catalysts are plugged, drop the Y-pipe temporarily, and run the engine with a vacuum gauge attached to the intake manifold. If the vacuum reading increases dramatically after dropping the Y-pipe, then you probably did have a clogged exhaust system (not necessarily the catalysts, as I've found a decent number of plugged mufflers in my day). The vacuum gauge should show 18-22 in-Hg @ idle, and maintain a steady needle. Rev it up to ~2500 rpm, hold it steady, and you should see the needle drop, then slowly increase to a level close to the idle reading (though slightly lower is normal).
 

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Discussion Starter #13
i dropped it off to a friend yesterday and he started working on the broken rear shackle and found that the miss is being caused by the gasket between the lower plenum and the upper intake manifold.... he's charging me a bunch for labor, but it's still half what the shop wanted just to do my shackle, so i don't care at this point. now all i have to do is swap out tranny filters.
 

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Discussion Starter #14
Engine Still Missing... Injector help!

Alright... my engine is still missing even after fixing what was the biggest vacuum leak i've ever had in my intake gasket...

it dies when stopping too fast, it still studders off of the line. my only other option is replacing the injectors.. i figured i'd find answers to my questions on google or something but that turned up negative.. so...

what pound injectors are in there 19 or 24?

anyone have a beat on a good cheap place to pick up a set of 8? i've been checking ebay, but no one posts the lbs. that theirs push.
 

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gone fish'n
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Stop making new threads on the same subject.

you have 19lb injectors.
 

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gone fish'n
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it's been driving me nuts really.. it ran smooth prior to the tune-up, but the previous owner told me he had just replaced the drivers side plugs because the passenger side bank was too difficult to get to. so i wanted to go through and replace everything.. put all new stuff in and WHAM.. miss... the wires are properly routed so it's not a firing order issue.
I am thinking it is something you done with the tune up.

did you put the cheapest wires on you could buy?

There is a ford TSB out there for plug wire routing because of cross firing. search for it on fsb.


Alright... my engine is still missing even after fixing what was the biggest vacuum leak i've ever had in my intake gasket...

it dies when stopping too fast, it still studders off of the line. my only other option is replacing the injectors.. i figured i'd find answers to my questions on google or something but that turned up negative.. so...

what pound injectors are in there 19 or 24?

anyone have a beat on a good cheap place to pick up a set of 8? i've been checking ebay, but no one posts the lbs. that theirs push.
fsb vendor for injectors

injector testing
 

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Discussion Starter #17
i apologize for the multiple threads. but the issue has changed multiple times and i'm looking for input from all different points of view... the wires i put in are accel spiral wound 8mm.. i searched on here as well as google but the powers that be, trying to make a buck as they might, haven't listed a lbs/hr rating for any of their "bronco 351w injectors" so i came here looking for an "end all" answer so i can stop spending money on getting this 3-ton beast moving properly and start spending money on getting it riding right.

i'm sorry if i offended anyone with my multiple posts. the greater search for knowledge led me to post different threads as the challenge has changed with each piece i have altered/exchanged/upgraded...

i'm just looking to see if anyone knows the stock poundage (19lbs. as i've been quoted) and if there's a good cheap place to pick up such parts.
 

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Discussion Starter #18
checked all of the injectors.. their power levels were fine.. we were bashing our heads around the complete wiring diagram for the truck and decided to check out the MAP.. unhooked the vacuum line going to it and the truck jumped from a loapy 550-650rpm idle to 1100 and completely smooth.. we noticed that there was some moisture on the end of the vacuum line.. i'm guessing that when i seafoamed the intake that some of it got sucked through another vacuum line and into the little black box (map) and screwed it all up.

the truck is getting hooked up to a proper diagnostic laptop tonight to double check, but my problems may be over for now and i can finally get my 33's on there and some new rims.
 

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Satyr of the Midwest
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Would be easier to just test the MAP sensor, but hey, whatever works. :thumbup
 
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