Replace or remove smog pump?

[Ranger Kim]

Howdy y'all,

Was taking my dogs out for a hike in my 90 GW yesterday when the smog pump starting making a weird noise. When I fired her up last evening the belt seized and sounded like a cat got caught sleeping on the manifold. After 29 years guess it's time to replace or remove the pump. They're $128 locally and they don't carry my 8mm bolt style, only the 6mm. Is it worth the hassle or should I remove the whole pump unit? I've heard both sides of the aisle weigh in but trust the FSJ pundits for direction on this one. Thanks!

Ranger Kim

[Cecil14]

If you don't need emissions, the smog pump really serves no purpose anymore. Its original job was to dump fresh air into the exhaust to help the catalytic converter work, but modern cats function without that. If you're concerned about emissions output, swap your ancient cat (assuming you still have one) with a modern universal style and you'll be way ahead of the 1990 emissions standards.


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[Ranger Kim]

Replace or remove smog pump?

Thanks Anthony,

Seein's how I'm just down the road from you in Douglas County the emission thing isn't any big deal. (Yet!) I'm sure I still have the original cat on her as I am the second owner and purchased the vehicle with 52K. Guess no one wants to argue your point so think I'll save my $128 and retire the pump assembly.

[joe]

Agreed. If you don't have smogs regs/tests to deal with save the money. W/o the pump you will plug up the cat quicker and notice the performance loss when it does. Then you can move onto plan B. Replace or remove the cat.

[rang-a-stang]

Yep. When you pull the pump, follow the rubber tube that's attached to it up to the diverter valve it is hooked into, remove that hose and the diverter valve, plug the small vacuum line that was plugged into the diverter valve. Then follow those tubes over to the check valves on top of your intake manifolds. Remove the rubber hoses there, too. That should just leave the air injection tubes on your exhaust manifolds. You might was well leave those because removing them can be a serious pain and all it buys you is a slightly de-cluttered engine compartment. Removing the hoses/diverter valve/smog pump is easy and is worth the declutter you just did.

[Ranger Kim]

Replace or remove smog pump?

Rang-a-stang...

Thanks for the info...I feel like I'm cheating by removing that stuff. Back in the day up at Tahoe if your rig wouldn't pass smog you had to buy the gas station tech a case of beer to get it through. I guess those days are over but I still remember it cuz he drank Corona and it was high priced in the tourist town! There are a lot of old tubes and rubber on that 360 so it will be nice to "declutter" it a mite.

[Cecil14]

Greetings from Carson! ha I just moved out here last year from Michigan, what a change.

I'm all for a clean running rig. I'll be the first one to argue FOR a cat all day long, but the way everyone runs emissions testing now is utterly stupid. There's no reason my rig should meet emissions levels from 35-40 years ago. If I put a modern FI and cat system on a 35 year old rig, it's going to blow those numbers away and run considerably cleaner...why can't I do that? :P I refuse to live anywhere near Reno largely for that reason.


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[Ranger Kim]

Replace or remove smog pump?

Anthony,

Good for you. I'm a Hawkeye originally and I think it's supposed to be -27 below there tonight.

I've hesitated messing with dismantling the smog on the Wag since there always seemed to be some discord in the conversation over the years. She's all original so I've tried to keep it simple. I'll let you all know how the operation goes...and thanks to all for the input!

[rang-a-stang]

Most of the discord you will read on this forum looks like this:
Newb: I want to rip all this smog crap off my rig! Its sucks and by taking it off I'll get 50HP, 10MPG improvement, and my truck will run 12's in the quarter mile. Where do I start?
Forum: It won't give you that drastic of an improvement, in fact often times if you remove things like EGR, it will run worse.
Newb: yeah but I hate smog stuff and it all has to come off now!
Forum: If you remove the smog pump, you will not feel a difference in performance, if you remove the EGR your carb tune will be off, If you remove the AIR Injection tubes, you're going to regret it
Newb: I tried to remove the air injection bolts and they all broke off in the manifold. How do I fix those? I removed my smog pump and couldn't tell a difference. Now that I removed my EGR, it seems like it has a hallow spot at part throttle...

Your reasons are different; Your smog pump is dead/dying and it's not worth fixing. Taking it off is easy and the declutter from removing the smog pump and it's hosing is pretty drastic. Then again, there is NOTHING wrong with leaving it there, but removing the belt.

I am not a huge fan of removing a perfectly good cat on a mostly stock rig like yours. I don't even hate the idea of having a cat on my rig. If California would be OK with me installing two high flow 3" cats in a true dual exhaust on my rig, I would do that but CA says we have to have one (and only one) 2.5" cat. Don't touch your cat; if it ain't broke, don't fix it.

[ZackN920]

If your cat is original, most likely its not doing a thing. I read somewhere that they lose their effectiveness after 7-10 years. I believe it with my Burban. Its got an old one on it that when takin off, looks good inside. Nice looking honeycomb inside, light passes through it if shined in... But that is the most rotten smelling exhaust that comes out of that vehicle. Smells like rotten eggs that makes yours eyes water.


Putting a new one on compared to the old will actually be cleaner coming out and probably be higher flowing.



As to the smog pump... Yea, same opinion as everyone else. The one that was in my Wagon was long since all removed by the time I bought it. PO had it in a box when he sold me the Jeep, and it was seized tight. The system was all disconnected like these guys above all say... Other than that I found some odd vacuum line routing that I fixed when I rebuilt/tuned the carb and engine.
I wonder how much longer the one on my Dakota will last. Its stock from 1987 and its humming loud enough to hear above the engine running!

Hey Rango, on my Jeep EGR actually makes it run worse, so the vaccum line was plugged. With EGR I always had a hesitation, no matter how I tried to tune the engine. Without, it runs perfect.

[acct21]

Some day you may want to upgrade to fuel injection. Since the only really viable landing spot for a wide-band O2 sensor is just in front of the cat, the air pump can actually screw up a fuel injection install (in theory). Pull the air pump, and have your muffler shop tack weld the hole in the cat when they install your WBO2 sensor bung.

[Cecil14]

Hey Rango, on my Jeep EGR actually makes it run worse, so the vaccum line was plugged. With EGR I always had a hesitation, no matter how I tried to tune the engine. Without, it runs perfect.

Ruptured EGR valve? Carb out of tune? If EGR causes poor performance, something is wrong. Off topic, so don't want to get into troubleshooting, just something to note.


aa

[FSJunkie]

A bog that happens when the EGR valve opens is usually caused by having the wrong EGR orifice size or by a fuel mixture that is already too lean.

I hate the air pumps. The tubes invite exhaust leaks which are already a pain to prevent and the pumps seize up every couple of years. The original pumps lasted a long time when they were new, but the new pumps that you can buy today are all remanufactured old ones by A1 Cardone, and they do a terrible job of rebuilding them. Their pumps make a ton of noise that gets worse and worse until they simply seize up. I get about one year out of them, which is of course longer than the warranty, and I'm not interested in buying a new pump and a new belt every year considering what they cost. Nope, not doing it.

So I remove them. The good news about the air pump system is the engines run exactly the same without the pumps as they did with. No tuning is required after the pump is removed.

[ZackN920]

Hmm, I would think they may need tuning but...idk.

don't want to derail but just thinking out loud. Hmm, I may have the carb on the lean side. Not uncommon for me to pull a solid 15mpg on mostly highway driving, and if only highway going a solid 45-60mph I can average 16.5mpg.

[Ranger Kim]

Replace or remove smog pump?

So I pulled the belt on the old smog pump and that took care of that issue. Still need to yank out all of the leftovers and install some plugs. And FS I know what you mean about some of the new parts. I purchased new wiper motors for an old CJ-5 and couldn't get a year out of them. Also throttle cables for my 67 Jeepster that snapped in a matter of months. Once drove it home with my bootlace through the firewall!

But you guys got me thinking about the EGR...another part which I've neglected. Where do you get those? I see $114 at Team Grand Wag and nothing at local joints. She still runs a little rough even after tune-ups. Thanks again for the help!