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Smog equipment delete questions

J

Jester1

1/2 ton status
Joined
May 8, 2011
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Location
Belgrade, MT
Ok I got a new to me 86 k30 454 with utility boxes and 22,000 original miles on it and i want to clean up the engine bay. I have been doing a lot of po clean up on it because it was a wildland medic/fire truck out of utah. It blew the radiator (impact unknown) the other day and as i was changing out for a new radiator I decided to start cleaning up the bay. Also this thing was showing need of new hoses, water pump and while i was there a new t stat. This thing literally had all the bells and whistles on it. Pre sale they removed all the lights and sirens but left the switches and most of the wiring behind.

On to the questions about the smog crap removal. This thing has 2 air pumps and all the hosing. I pulled the belt from the top one a couple weeks ago with no ill effect. Well i started removing the hoses from the pumps feeds and some of the vacuum lines. I have full intention of removing it all but i need to keep this thing running as it is my work/tool truck. So i just got rid of what was in the way for the cooling repairs for now. When i fired it back up the only odd thing was the sucking sound coming from the exhaust manifold where the rubber hose connected. Ran the truck at idle to come to temp, check for leaks all good. Ran the the gas station filled up, drove back all good. Shut it down cleaned up put tools away 20min or so, then restarted it. It went into a high idle, pulled it out of driveway went around the block and high idle didn't go away. Any thoughts?

As of now i am going to throw the top air pump back on and vacuum lines until i have time for full delete. I have read on other sites that the 86 has one of the most jacked AIR systems on them and it was just before tbi. I also read that on the k30 they had no ESC distributors or controlled q-jet. I figure for now putting most back on will at least keep me rolling for work until i get time and parts for full delete.

Any help and info is fully appreciated.
 
Also another thing that changed I just thought of. It has idiot lights only and the oil pressure unit is bad. At some point they put in an actual gauge down on the dash that reads fine but the light is always on. I got a new sender but wrong one and left the plug off for now could this be what is causing high idle? I unplugged it when i got back from the gas station. I will plug it back in first but wanted to throw it out there.
 
Also forgot. This is Montana. No inspections at all, no smog certs, nada. And if the rig is over 11 years old 200 bucks gets lifetime registration as long as you own it.
 
High idle MIGHT be from the oil pressure switch, as that helped control the choke, assuming this is electronic choke. I don't know what would happen if the switch was disconnected or broken, but it would probably affect idle, at least for awhile. Obviously check for vacuum leaks as well.

Many of the trucks didn't have any sort of computer control, as a matter of fact I believe ONLY CA trucks received the full CCC treatment, while 305 trucks from 1981(?)-1986 would have had ESC, but not CCC. Everything else was "computer free", short of some other weird stuff GM did for altitude, etc., but not controlled by any ECM.

Since high idle just started after removing some of this stuff, look at the choke linkage/wiring,

Removing AIR shoudl really have no bearing on how the truck runs, it's just to help combust whats left as the chamber evacuates. More tailpipe emissions of hydrocarbons, that's it. Can hurt catalytic converter (if present).
 
I don't know about two AIR pumps, as my experience is with my '74 which is (1) older and (2) a 1/2 ton. Mine had the one "air injection reaction" pump, to put "fresh" air into the exhaust, allegedly to more completely burn the gas & reduce emissions.

On mine, the pump fed into hard pipes into the exhaust manifolds. When I removed that stuff, I plugged those connections with appropriately sized pipe plugs.

The fast idle sounds distinctly like a vacuum leak.

Also note that your carb may be mistuned once you remove the AIR plumbing, as it will be set to be richer or leaner (I can never remember which) to make the exhaust Just Right with the extra crap.

I solved this by switching to TBI. :deal:

-- A
 
So pulled the famous Greg "might as well" move in working on the truck.

When I when to replace water pump I had to remove pump and alternator brackets. Well it was greasy/dirty, so i got out the pressure washer. Then while I am here lets delete some or this more greasy/dirty. So might as well pressure wash some more. Might as well get rid of these hoses more grease more pressure washing. On and on, well I must have cleaned well enough to make whatever was lubing the throttle cable and spring not to allow it to return all the way.

So relube the cable, cleaned up the springs plugged up the succubus opening on the manifold and all is right in the world. Now I can get the new front tires and alignment, then take some more off when i have time.

Might as well right???
 
Oh and no cats don't know if it ever had them of the old firefighters had them removed. Does have dual exhaust and from some homework stainless manifolds that have the AIR system attached. I will be plugging these when I remove it. They are bigger then ones I've done in the past but I read someplace that it is the same as the drain plug on an np208:dunno:
 
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