Runs weird without emissions junk - The 1947 - Present Chevrolet & GMC Truck Message Board Network

alextreme76 · 09-04-2007, 01:33 AM

So the worn out '86 305 that will be short lived in the engine bay has to stay in while the pennies collect in the bank. After tuning it up at home and at the mechanics we decided to yank what we could of the smog junk. The air pump hasnt had a belt for years and there are no cats, so the pump hit the trash and we started pulling vacuum lines. From what we could piece together, we left only the essentials...but apparently we screwed up somewhere.

So it runs great, best it ever has for like 15-20 min, then it starts to feel doggish. Still better than when it was leaking fluids of every kind so there is that improvement, but just not like it does those first few moments.

Any idea on what gives?

Srubydo1986 · 09-04-2007, 10:53 PM

well with all the junk off (emissions) it need to be adjusted and timed for it. but except for that that i have unless a vaccum line is un hooked somewere.

alextreme76 · 09-05-2007, 05:38 PM

i dont think timing and tune are it, otherwise it would run the same from start up... my guess is we took off something we needed or did something wrong that is messing with something else

Mickey_D · 09-05-2007, 05:52 PM

If it runs fine for 15 minutes then starts to run like crap, it sounds like something temperature related. You know that orange or green vacuum tree right by the thermostat housing? That's where I'd start.

jimfulco · 09-06-2007, 03:58 AM

EGR removal >>> knocking once it warms up >>> knock sensor retards timing???

09-04-2007, 01:33 AM	#1
alextreme76 Registered User Join Date: Apr 2007 Location: Arizona Posts: 45	Runs weird without emissions junk So the worn out '86 305 that will be short lived in the engine bay has to stay in while the pennies collect in the bank. After tuning it up at home and at the mechanics we decided to yank what we could of the smog junk. The air pump hasnt had a belt for years and there are no cats, so the pump hit the trash and we started pulling vacuum lines. From what we could piece together, we left only the essentials...but apparently we screwed up somewhere. So it runs great, best it ever has for like 15-20 min, then it starts to feel doggish. Still better than when it was leaking fluids of every kind so there is that improvement, but just not like it does those first few moments. Any idea on what gives? __________________ '86 Longbed 305 quasi-rat-rod father/son project Last edited by alextreme76; 09-04-2007 at 01:35 AM.

09-04-2007, 10:53 PM	#2
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: Runs weird without emissions junk well with all the junk off (emissions) it need to be adjusted and timed for it. but except for that that i have unless a vaccum line is un hooked somewere. __________________ 1986 Sliverado longbed 400 small block mean as hell, 700r4 trans (5 speed coming one day) 1970 chevelle 2dr sedan Latest update June 24 2007. *1957 4 door stationwagon - pink all original needing a good restore (body great, floors bad) newest additions 1965 shortbed fleet great granddads. Been told im nuts to bring it back from the dead (still going to happen) plans-all stock with a turbo 292 inline 3 speed column shift. and thats it big block 427 and 5 speed trans and ford 9 inch theyhave no home yet thinking what to put them in and a 79 c60 trash truck um no idea i have one

09-05-2007, 05:38 PM	#3
alextreme76 Registered User Join Date: Apr 2007 Location: Arizona Posts: 45	Re: Runs weird without emissions junk i dont think timing and tune are it, otherwise it would run the same from start up... my guess is we took off something we needed or did something wrong that is messing with something else __________________ '86 Longbed 305 quasi-rat-rod father/son project

09-05-2007, 05:52 PM	#4
Mickey_D Dirteh Kitteh Join Date: Nov 2006 Location: Mormon country Posts: 2,484	Re: Runs weird without emissions junk If it runs fine for 15 minutes then starts to run like crap, it sounds like something temperature related. You know that orange or green vacuum tree right by the thermostat housing? That's where I'd start. __________________ Darrin 1955 Willys CJ-5 all original and the oldest CJ-5 on the road. 2001 Dodge Neon (wife's car) 1995 Jeep Grand Cherokee Limited Edition SOLD 1981 K15 Custom Deluxe 4X4, rusty but trusty wood hauler. SOLD 1993 S-10 4X4 Tahoe SOLD Sign up with the Contact List RIP ESLL

09-06-2007, 03:58 AM	#5
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Re: Runs weird without emissions junk EGR removal >>> knocking once it warms up >>> knock sensor retards timing???



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