1986 gmc C2500 smog control deletion.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

wheelchair04

Junior Member
Joined
Nov 29, 2023
Posts
2
Reaction score
0
Location
sc
First Name
roy
Truck Year
1985
Truck Model
c1500
Engine Size
305
I just removed the smog control off my c2500 now I have a check engine light on and can't find the aldl to check the codes. where do I need to look? It also is idling high and hesitant to go when first start out but runs fine when under power since smog control system was removed.
 

RustyPile

Full Access Member
Joined
Oct 7, 2017
Posts
901
Reaction score
1,118
Location
Elkhart, TX
First Name
Nick
Truck Year
1983 GMC
Truck Model
1500
Engine Size
350 SBC
You can't just remove smog items and expect everything to be OK.. The reason you have a check engine light is because the computer isn't receiving feedback signals from whatever you removed.. The ALDL is located at the bottom of the dash near the steering column..
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
1,629
Reaction score
2,207
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
Huge mistake, hope the parts have been saved, they will need to go back on. When parts are removed that are controlled by the ECM or provide data, the ECM reverts to an internal algorithm. Engine will be rich, have poor performance and drivability issues. Exactly what is occurring.

May I ask what propelled you to make this decision?
 

RustyPile

Full Access Member
Joined
Oct 7, 2017
Posts
901
Reaction score
1,118
Location
Elkhart, TX
First Name
Nick
Truck Year
1983 GMC
Truck Model
1500
Engine Size
350 SBC
Huge mistake, hope the parts have been saved, they will need to go back on. When parts are removed that are controlled by the ECM or provide data, the ECM reverts to an internal algorithm. Engine will be rich, have poor performance and drivability issues. Exactly what is occurring.

May I ask what propelled you to make this decision?
We'll probably never know.. The OP posted the same question on the introduction forum the same day he posted here.. Hasn't been back since, probably wasn't satisfied or happy with our responses.
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
1,629
Reaction score
2,207
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
We'll probably never know.. The OP posted the same question on the introduction forum the same day he posted here.. Hasn't been back since, probably wasn't satisfied or happy with our responses.
Sometimes people don't appreciate the answers. They will find out we were right after wasting time and money but probably never admit it.

There was another post on the same subject today. Wasn't in the mood to explain it again when it would have been an easy search.
 

RustyPile

Full Access Member
Joined
Oct 7, 2017
Posts
901
Reaction score
1,118
Location
Elkhart, TX
First Name
Nick
Truck Year
1983 GMC
Truck Model
1500
Engine Size
350 SBC
Sometimes people don't appreciate the answers. They will find out we were right after wasting time and money but probably never admit it.

There was another post on the same subject today. Wasn't in the mood to explain it again when it would have been an easy search.
Yep, I saw that one too...
 

Forum statistics

Threads
42,136
Posts
909,959
Members
33,637
Latest member
Mistafishe
Top