drove the blazer home today to swap my 31 dick cepeck mud country over from my toyota. the tired would swap over to the blazer bot not to the toyota oh well and also the blazer tires seemed larger than my 31's. also when driving I keep getting a check engine light but goes away after restarting the truck, i havent pulled the code yet. and also have a broken stud on the header so i got a nice ticking sound ugh more money into this truck lol.

what did the muffler shop do about the Cat? or did you remove it? or was it replaced? because you mentioned that you were throwing a code, but it would reset everytime you shut the truck off, i first thought of my situation, of no cat, and 02 sensor code comming up everyonce in a while.. and it reset everytime i shut the truck off. if the cat was removed, you will have this check engine light come on... now you mentioned headers with the exhaust leak i was curious if it was headers or the manifolds, and where abouts is your 02 sensor... if headers were put in place of the manifolds they should have a weldbung on them.. and not down on the crossover pipe.. or somewhere like that.. if they are not on the header they will give false information.. seeing there not getting the heat they normally would.. if this is true you might have to look into a heated 02 sensor.. i personally have never used them before but i have heard others having luck with them.. i believe that they have a extra wire in them.. but should still hook up to your stock harness.. the extra wire i believe is to run the internal heater in them to bring the temps up to normal while its running. but if it has the weld bung in the stock location, you dont need anything there, and i am rambling on lol..
depending on where the studd is broken, you might have to remove the header/manifold and try to use a ez-out.. or weld a nut onto it, and remove it.. or you can upgrade the radio and pretend your not hearing the ticking sound lmao...

like i said if you get tired of this truck.. let me know :) hehehe

hope this helps, and keep us posted

Ck1500

ok I got the stock exhaust manifolds and the O2 sensor is in the stock location on the Y pipe. the stud is broken on the driver side closest to the fire wall and you can tell because you can see the white residue build up. The check engine light only comes on when I get on the gas hard I am going to see if I can pull a code thinking maybe the O2 sensor but also a miss fire of some sort and yes I deleted the CAT. Going to have to update with some pictures as me and the neighbor swapped over my Dick cepeck tires from my Toyota last night.

hmm i wonder if they changed the location? because on my stock 87 the weld bung is in the manifold before the donut gaskets, and Y-pipe.. as for the misfire.. it could be the 02 sensor... but what makes it interesting is that the 02 isnt monitoring the system at full WOT "wide open throttle"
if you can get some pics of the 02 sensor location. and the truck it might help diagnostics on the truck... not to mention i need to drool over some more K5 pics :)

Ck1500

pulled a code 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194� F or the knock signal was present for 5 seconds or more during normal engine operation.

could this be because of exhaust manifold leak?

and now for some updated pictures.

knock sensor arent normally affected by exhaust leaks, thats mainly the 02's i would check the knock sensor on the engine block.. its down by the starter normally right behind it. its not the easiest to get to.. but im wondering if someone has unhooked or broken the connecting wire from the knock sensor or possibly the sensor is bad.. which the last one i bought from autozone was like 30 bucks... if you do by chance change it ... DO NOT USE Silicone Tape.. or Teflon Tape on it... its best to install with a water based caulk.. that way the sealant will not insulate the sensor from the engine block..

hope this helps..


Ck1500

thanks, yeah the guy I let borrow the truck replaced the starter as he said it wouldnt stop spinning. he must have hit something on the knock sensor.

hope you like the pics.

looks like the wire to the knock sensor has been melted a bit and is bare in a spot would this make the the check engine light to come off.

there is a good chance it will do it.. if there is any hint of a poor connection due to it being melted... i would try repairing the wire.. and give it a test run..

Ck1500

seems as I had a slight leak in the heatercore and had leaked some antifreeze, I topped the truck off and didnt get the check engine light to come back now my only problem is that I am only getting roughly 8 miles per gallon lol but the truck runs good. I am going to pull the battery to reset the code in my computer to see it will better my gas mileage.