stxlt

Steve83,
Are NEW parts available for TAD & TAB, EGRs, and Catalytic Converters? How about the V8 crossover tube?
I agree with your advice about not replacing working parts; as I check these systems over, I want to replace any defective parts found. I am trying to improve efficiency and the proper venting of my engine. I have the oily intake and pre-filter sludge evidence as described in your article on the PCV system. When accelerating quickly/hard from a stop, I get the good ol' CEL, which leads me to want to inspect the EGR and the catalytic converter, both are original. (The CEL stays on for maybe 15 seconds after an 'aggressive' launch) Is the oil separator serviceable?
I have a question that came up as I read: You referenced "old" designs/systems/parts before certain improvements were made to create more efficient Ceramic composition, fuel vapor systems, sealed Charcoal canisters...I have 2 1993 XLT V8 trucks (see signature). Where does this old vs improved time frame come to bear?

HockeyFan999

So my problem is, I have no vacuum connection near my smog pump. I have replaced all of my vacuum lines. The one on the TAD that is supposed to connect
to the smog pump TAD broke off and I have no idea where it ran to. I am thinking somewhere on the read of the motor, which I have no way of seeing. Is there
something else on the rear of the engine that would take vacuum from the top connection of the TAD? The bottom connection is currently connected to the
vacuum canister (coffee can). All the diagrams I have seen only show the diverter valve on the back of the motor and some diaphrams near the smog pump
which I do not have on my truck (as the picture in my previous post shows) Please help, I don't know if I can drive it without the TAD connected.

Thanks

HockeyFan999

BLDtruth, was that smog crap you showed in your photo on the rear of the motor?

HockeyFan999

OK so the post I was reading on how to change all the vacuum lines was misleading. It said all the stuff in the above photo was near the smog pump. I didn't realize it was
on the back of the motor. I have the exact same set up behind my motor so now I know where to connect that hose from the TAD. Now for a test drive, hopefully this will
put an end to my smog failure and CEL issues, Thanks for all your great advice.

BLDTruth

LOL, I thought I had said it was on the back of the engine near the firewall, but who knows - all that matters is you got it sorted. Let us know how it all turns out in the end.

HockeyFan999

I meant the post on the fullsizebronco forum that you shared and I had already followed. It is a great post but the last connection was a little
fuzzy on where it actually went.... lol

Steve83

Not that I'm aware of, whether you mean the solenoid valves or the air valves. But they never go bad - they only get damaged, so it's pretty easy to find good ones in the JYs.Yes.I'm not sure what you mean.Are you saying you've gotten fault codes that refer to those parts? Post each code number AND its complete definition (in your own thread).So are the ones on my truck's engine - they have nearly a million miles, and still work perfectly. If they just went bad over time, they'd be listed in the maintenance schedule - they're not, because they only fail due to other problems.On these trucks, it's just a baffle welded inside the valve cover. To "service" it, wash it out thoroughly with solvent to remove all the sludge. They're visible here:


(phone app link)There's not a line. It's different for each system, and also varies by brand/model/option. Catalysts are constantly being improved, since they were first required (in 1975), and continuing now - both new OE, and aftermarket replacements for older vehicles. By '93, they were already VERY efficient, but still required 2ndry air. The only significant changes to the vapor system were the VMV in '95 which replaced the CANP, and the advanced EVAPS system a few years later, adding an isolation valve near the charcoal canister.You're not paying close enough attention to the diagrams I posted & their captions. All these trucks (except '96) have a smog pump with intake filter/muffler, TAB (solenoid & air), & a check valve to the cat. Most also have TAD (the air TAD is usually combined with the air TAB) & a check valve to the tube going to the head(s). The later ones also have a TAD muffler on top of the intake filter/muffler, and VERY few have a resonator immediately after the pump.Yes. The 2ndry air system is called "secondary" because it's AFTER the engine - it has nothing to do with how the engine runs.