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1988 FSB, 351W, Towing Package
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Discussion Starter #1
Guys help me out here, I know this is probably just an exhaust leak but just wanna hear from you guys. It only smells in the cabin when AC is on, doesn’t smell too strong under the hood. Doesn’t sound too exhaust leaky either.. if the gif doesn’t work, I’m seeing smoke coming out from the back left corner of the block. Somewhere underneath the PCV valve
Leak.gif



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Did you make sure the PCV didn't pop out of place?
 

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Mine poped out and caused a smell once so thats why I asked.
 

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1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
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Your safest bet is to climb up there with a flashlight & a mirror and take a look.

As for smelling gas, that tells me it is more likely internal engine gases, so PCV tube or crossover pipe, or the steel tube to your EGR valve broke, the one thing that is certian is that the seal to the evaporator box of your hvac unit is shot if its sucking in the fumes into the cabin. Not sure on a 5.8L as I have a 5.0L but most of those systems are similar.
 

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Rear corner of the valve cover is Leaking. Clean and replace the gasket
 

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Charlie don't surf..
'92 Ford Bronco XLT
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I agree with @Rob_64-365 it's most likely the crossover tube at back of the heads..they rust out over time..
 

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Discussion Starter #8
I agree with @Rob_64-365 it's most likely the crossover tube at back of the heads..they rust out over time..
I’ve deleted the EGR and replaced the headers, both about 4 months ago. does that change what you think at all?


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Charlie don't surf..
'92 Ford Bronco XLT
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you may have deleted the EGR, but that's not hooked to the crossover tube..The crossover is part of the air diverter system..see the pic below.

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1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
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The image above shows the many palces it "could" be coming from, but we are all just guessing. We could guess all day if you like, or you could remove the guess work by hopping up on top of the engine & looking, feeling, listening, using a mirror, whatever you gotta do & tell us which guess was correct when you find the culprit.

Check when the engine is cold, see if you can feel any obvious rust holes thru the crossover pipe (if the 5.8L has one) or if one of the plastic check valves or air diverter housings cracked because it's old and brittle after decades of hot air beating it to death. The PCV intake port could be off or a hole in that hose going to the PCV valve... how did you cap off your metal heat tube when you capped off your EGR during the delete??

You gotta commit, and you're gonna get lots of scrapes on your arms digging in there. Let us know what you find.
 

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Discussion Starter #11
The image above shows the many palces it "could" be coming from, but we are all just guessing. We could guess all day if you like, or you could remove the guess work by hopping up on top of the engine & looking, feeling, listening, using a mirror, whatever you gotta do & tell us which guess was correct when you find the culprit.

Check when the engine is cold, see if you can feel any obvious rust holes thru the crossover pipe (if the 5.8L has one) or if one of the plastic check valves or air diverter housings cracked because it's old and brittle after decades of hot air beating it to death. The PCV intake port could be off or a hole in that hose going to the PCV valve... how did you cap off your metal heat tube when you capped off your EGR during the delete??

You gotta commit, and you're gonna get lots of scrapes on your arms digging in there. Let us know what you find.
Thanks for the message man, I’ve been arms deep in there all morning, haha. I promise I’m usually fairly scratched on the arms. I couldn’t find a dang thing wrong, but I did notice my black vacuum line coming from the rear of the passengers side wasn’t connected to the black disk-like 3 way vacuum tree. I reconnected it and the AC didn’t smell gas like anymore. What is connected to that vacuum line?


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Thanks for the message man, I’ve been arms deep in there all morning, haha. I promise I’m usually fairly scratched on the arms. I couldn’t find a dang thing wrong, but I did notice my black vacuum line coming from the rear of the passengers side wasn’t connected to the black disk-like 3 way vacuum tree. I reconnected it and the AC didn’t smell gas like anymore. What is connected to that vacuum line?


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Do yourself a favor and pull the upper intake manifold. It may seem like a pain in the ass now, but if you do need to replace anything back there you'll need to pull it anyway to get reasonable access.
 

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Is it still smoking like that, or did re-attaching the vacuum line cure that as well?
 

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Discussion Starter #14
Is it still smoking like that, or did re-attaching the vacuum line cure that as well?
Reattaching the vacuum line seems to have fixed that, I see no smoke. I just can’t believe a vacuum line was causing that.. it doesn’t seem to me like that could be a cure for it. What do you think?


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I would have to know more about what line you hooked back up. A pic would help.

It sounds like that is vacuum to a diverter and without the vacuum line hooked up, it opens something to let exhaust gas or intake fumes vent to the atmosphere from something that is not supposed to me open to the atmosphere, under your hood somewhere. Could be part of your egr system or TAD/TAB for the air feed air to your catalytic converter. My fear is that something is unhooked & while it may not be doing it now, there may be times when the computer tells that valve to open, and causing this same issue, or getting your underhood oily, maybe cause an engine fire if it gets oily & hot enough...

Again, I am more framiliar with the older Bronco's, when I had a 96, it was brand new, & I never did anything but drive it, but on my 86, I've gone thru just about every system.

My advice is to get yourself very framilar with how your 95 systems work. It will make sense what it's doing, once you know exactly how its supposed to work. My guess is its related to how you bypassed your EGR.


On my 86 302EFI was working on hooking up my EGR system, as the previous owner had no clue what he was doing & unhooked everything & added full length headers. Headers are fine & no emissions here, but I had an EGR code, so my OCD made me investigste!! I replaced the EGR Valve & proximity switch & hooked a full manifold vacuum line to the egr valve as a test to see if it opened & yep, it opened for the first time in who knows how many years & I noticed the pipe from the intake to the EGR was loose & it started smoking and got hot. I tightened the pipe & it stopped the smoking. In my case, my EGR code was from a bad EGR control solenoid, which was only $25, but I gotta say, once i got the EGR system all working as it should, my Bronco has never ran better. So not sure why you would delete the EGR, but that is my experience with un-deleting the EGR.
 

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Discussion Starter #16
I would have to know more about what line you hooked back up. A pic would help.

It sounds like that is vacuum to a diverter and without the vacuum line hooked up, it opens something to let exhaust gas or intake fumes vent to the atmosphere from something that is not supposed to me open to the atmosphere, under your hood somewhere. Could be part of your egr system or TAD/TAB for the air feed air to your catalytic converter. My fear is that something is unhooked & while it may not be doing it now, there may be times when the computer tells that valve to open, and causing this same issue, or getting your underhood oily, maybe cause an engine fire if it gets oily & hot enough...

Again, I am more framiliar with the older Bronco's, when I had a 96, it was brand new, & I never did anything but drive it, but on my 86, I've gone thru just about every system.

My advice is to get yourself very framilar with how your 95 systems work. It will make sense what it's doing, once you know exactly how its supposed to work. My guess is its related to how you bypassed your EGR.


On my 86 302EFI was working on hooking up my EGR system, as the previous owner had no clue what he was doing & unhooked everything & added full length headers. Headers are fine & no emissions here, but I had an EGR code, so my OCD made me investigste!! I replaced the EGR Valve & proximity switch & hooked a full manifold vacuum line to the egr valve as a test to see if it opened & yep, it opened for the first time in who knows how many years & I noticed the pipe from the intake to the EGR was loose & it started smoking and got hot. I tightened the pipe & it stopped the smoking. In my case, my EGR code was from a bad EGR control solenoid, which was only $25, but I gotta say, once i got the EGR system all working as it should, my Bronco has never ran better. So not sure why you would delete the EGR, but that is my experience with un-deleting the EGR.
So I’ve finally found the issue I believe, stupid me. I felt a hole on top of my valve cover, I believe the PCV hole. The hose coming off of my PCV valve isn’t connected to anything, I believe I need to get a PCV elbow and grommet to reattach that onto the valve cover. Should hopefully fix this


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Ahhh, It happens... the only bad part was you had to admit it to us!! At least the problem is solved!
 
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