The difference between a 30 year old smog pump and a new one is wild

I was working on a 90s Ford Ranger last week, the guy brought it in saying it was running rough. I pulled the air injection pump off, and man, I have never seen one that clogged up. It was from a 1993 model, so about 30 years of gunk and carbon buildup just baked inside it. The bearings were so dry they sounded like gravel in a blender when I spun it by hand. I put a brand new Duralast unit on there and fired it up, and the change was immediate. The idle smoothed out completely, no more ticking noise, and the check engine light even cleared after a couple drive cycles. What causes that kind of buildup anyway? Is it mostly from short trips where the pump never really gets hot enough to burn off the carbon, or is it just age no matter what?

2 comments

2 Comments

aaronclark13d ago

@bettyfox that coffee maker comparison is actually pretty spot on. Same deal with the carbon buildup, it's like sludge that never gets a chance to burn off if you're just doing short trips. I had a buddy with a 94 Ranger and his smog pump looked like it had been packed with mud, bearings were completely shot. Replacing it made a night and day difference on his truck too, idle went from shaky to smooth in seconds.

bettyfox13d ago

lol that's kind of like how my old coffee maker was. I used it for like 8 years with barely cleaning it and one day the water just stopped flowing through right. It was all clogged up with mineral deposits and old coffee oils. Same principle I guess, just built up junk over time. Short trips definitely make it worse though, that pump never gets hot enough to burn off the carbon like you said. Same way a slow commute makes your engine sludge up faster than highway miles would.