What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Frustrating o2 sensor issue

4x4blaze

4x4blaze

That's not going to work
 Premium
GMOTM Winner
Joined
Jan 10, 2014
Posts
306
Reaction score
171
Location
Missouri
Whats up guys, I have been dealing with a very troublesome issue with my o2 sensor on my 87 k5 tbi:mad1:. After I had owned the truck for about year, I decided to put a nice set of headers on it and run a good exhaust setup. Well, as all of us know, the stock single wire o2 sensors do not like to be ran with headers since they cannot maintain the proper heat. The truck would run fine in the city, but whenever I would hit overdrive on the highway and cruise for a bit, the check engine would turn on. Well, after reading quite a bit on here, I decided to convert my single wire o2 sensor to a three wire heated sensor. it is run off of an ignition accessory and is receiving 12 volts when the truck is running(has been tested with voltmeter) Well after going on a short cruise down the highway, there was that annoying orange light on shining back in my face again...:dunno: When the key is turned forward, the sensor will get somewhat warm to the touch after a few minutes, but never really hot. The sensor is also a brand new ac delco that I had purchased off of amazon. Could this sensor just possibly be a dud..?

Thanks in advance for the replies!

Shane
 
How far down is the sensor? You may need to have it tuned to compensate for the new O2 voltage temp wise.
 
It is in the collector right after the header
 
have you actually checked the code?

highway cruise CEL tend to be EGR faults...
 
ryoken said:
have you actually checked the code?

highway cruise CEL tend to be EGR faults...
Click to expand...

I have yet to find a store that has a code reader for these types of trucks. I will go out and get the code read asap though. I'll post it on here as soon as I do.
 
bigblock72 said:
You can do that yourself with a paper clip.

Here is a guide. http://coloradok5.com/forums/showthread.php?t=240425
Click to expand...

ryoken said:
all you need is a paper clip...


http://www.obd-codes.com/faq/read-gm-2-digit-obd-codes-free.php


edit - doh! too slow satchmo!
Click to expand...



Woah....:eek1: I would have never guessed that! I love how simple pretty much everything is with these older squarebodies..:bow: Well anyways, I tried the trick on my truck, but it just kept flashing the 12 code. The starter had gone out on it and It has been sitting for about a week with the battery unhooked, so it must have cleared itself. But the new starter arrived from summit earlier today, so that's tonight's project.:doah: As soon as I get it out of the garage again and get the code to pop up, I'll post it on here..

Thanks a lot guys!:waytogo:
 
If it's coming on only during highway, it's a pretty good *guess* that it's an EGR function. I can't recall if these store codes even after the light goes off or not. You'll just have to check.

I can't comment on others results with unheated O2 sensors, but on *my* setup with long tube headers, and the unheated sensor installed beyond the collector, at idle it would go open loop, but any throttle would instantly (and I mean as fast as the computer could react) put it into closed loop.
 
ryoken said:
all you need is a paper clip...


http://www.obd-codes.com/faq/read-gm-2-digit-obd-codes-free.php


edit - doh! too slow satchmo!
Click to expand...
bigblock72 said:
You can do that yourself with a paper clip.

Here is a guide. http://coloradok5.com/forums/showthread.php?t=240425
Click to expand...

dyeager535 said:
If it's coming on only during highway, it's a pretty good *guess* that it's an EGR function. I can't recall if these store codes even after the light goes off or not. You'll just have to check.

I can't comment on others results with unheated O2 sensors, but on *my* setup with long tube headers, and the unheated sensor installed beyond the collector, at idle it would go open loop, but any throttle would instantly (and I mean as fast as the computer could react) put it into closed loop.
Click to expand...


Sorry for replying so late guys!:doah: I have been really busy and haven't had a chance to get on here lately. But anyways, I did the paper clip trick and it was displaying code 32 which quote on quote means "fault in exhaust gas recirculation valve diagnostic switch":confused: Do any of you guys know of a solution to eliminating this issue?

Thanks!:bow:
 
Thanks for posting that reply bigblock72. Ill definitely have to give it a try here shortly. Do any of you guys know of any way to bypass this though?(besides ripping all of the efi stuff off and sticking on a brand new double pumper:rolleyes:) Im sort of afraid because alot of my egr stuff got torn off and thrown around while putting my exhaust on I believe.
 
4x4blaze said:
Thanks for posting that reply bigblock72. Ill definitely have to give it a try here shortly. Do any of you guys know of any way to bypass this though?(besides ripping all of the efi stuff off and sticking on a brand new double pumper:rolleyes:) Im sort of afraid because alot of my egr stuff got torn off and thrown around while putting my exhaust on I believe.
Click to expand...

The way to bypass EGR is to have it programmed out of the chip.

I do not like check engine lights, but at least it's not hurting anything. There is a routine run after certain conditions are met, that's why your getting this code when you do.

What do you mean got torn off and thrown around? Other than some wires and vacuum hoses that are nowhere near the exhaust, there isn't anything to be harmed. If you think you might have hurt the EGR solenoid wiring, solenoid, or the hoses associated with it, check them out good. The flowcharts are good, but a GOOD visual inspection is the first place to start, before even getting into the flowcharts. Things like bad electrical connections are left off the flowchart sometimes because the technician is just supposed to know that is something to look for initially.

EGR is pretty simple...ECM commands it on, solenoid lets vacuum get to the EGR which opens it (in most setups), which creates essentially a metered vacuum leak in the intake, where exhaust gas is fed into the engine. The ECM "tests" for EGR operation by looking for the MAP sensor reading to change when EGR is commanded. The test the ECM runs is no more complex than that. If no reduction in vacuum when the EGR is supposed to open, code is thrown. Obviously anything that prevents the EGR from opening (vacuum hose leak, etc) is going to trigger that code. ECM has no clue what part of the EGR circuit has an issue, just that there is one.
 
You must log in or register to reply here.

Latest Posts

Top Bottom