first off i just want to say hi to everyone,

I just came across what I thought was a great deal on a 89 K5, the truck was in mint condition and when I say mint I am talking about a 21 year old truck in NY state with no rust on its body and it had a brand new crate motor dropped in 500 miles ago or so.

So I went and looked at the truck and the owner told me the truck would stall out after warming up, no bigge I said probably just the coolant sensor. I check for the coolant sensor and it was never hooked up on the new motor. I was also told the brake line had been busted, also no big deal 30 min and ill have that fixed.

So today I had bought all the parts and headed an hour away with my good friend, we fixed the brake line and hooked up the coolant sensor then topped the truck off with coolant started it up and bleed the fuel line. The truck ran great and much longer than it previously had with out the coolant sensor so we both thought the truck would make the hour drive home.....


Drive the truck out of the guys driveway and head down a long mountain road that is roughly 3-4 miles long, the truck feels a bit rough but it was low on gas and figured i would just top her off at the first gas station. We get to the bottom of the hill and she stalls right out like she would without the coolant sensor. I keep trying to fire her back up but she wont even spark, I poop the hood and disconnected the left fuel injector and she would spring to life but run really rough, hooked it back up and kept trying to get her to fire up on two injectors and would get nothing but a cloud of smoke out the tail pipe.

I am looking under the hood as my friend is cranking, we did this probably for a good 15 min and I yell the truck is on fire. Sure enough she caught on fire right between the cat and muffler, I knew I didnt have an extinguisher and was pretty sure my friend didnt either so I attempt to blow out the fire which i did successfully. I couldnt see any damage to the tuck but crawled underneath to get a closer look that is when i seen the O2 sensor being broken off half in the header and other piece hanging by the connector.


Would the O2 sensor make it run really rich or am I overlooking something else as well.



cliffs:
bought a new truck with minor problems.
fixed problems and attempted to drive truck home.
truck stalls out and wont start.
tried to start truck and it caught fire between cat and muffler.
found broken O2 sensor.
assume the O2 sensor is responsible for the flooding of gasoline in the exhaust.

i am stumped if it isnt the O2 sensor.
need help.


sorry fir the first long post, I did lurk but could not find anything on the subject.

 

An O2 sensor can definitely cause a rich condition. An exhaust leak head of the O2 sensor can cause a rich condition as well.

 

So do you think I will be ok once I swap out the O2 sensor, would it be anything else that could cause the motor running rich and could the motor running rich have done damage to the Cat or anything else in the motor?

 

a 02 sensor if not properly working will tell the computer that it needs more fuel... so yes, not having it connected or in your case busted, the computer is going to keep pouring on the gas.. i had a similar problem with my 87 K5, the weld bung was cracked, and it was giving false readings, after fixing the problem i unhooked the battery for a couple minutes, and fired it up. been going strong for a couple years now.

as for anything else, that can cause the overfueling, a vacuum leak or something like that. your truck should be okay, it is however possible, that depending on how long the truck has been in the current state, that the cat might be somewhat clogged. and the plugs might not be in the best shape. i would try to get it home, and address those areas.

hope this helps...

Ck1500

 

Ck1500 thank you much for your assistance.

drove an hour to try and remove the broken O2 sensor, I brought PB blaster with mebut could not budge the sensor for the live of me. I tried warming the truck up and see if that would make it any easier but it didnt help either.

I pulled the code by jumping slot A and B, first I got 12 three times then I got 15 three times then 2 three times and back to 12 three times. what would this be?


edit: ok 15 seems to be the coolant sensor, I connected the coolant sensor and had the battery disconnected. are there any other coolant sensor other than the one on the driver side block? not sure what the 2 code is doesnt seem to exist.

 

Are you sure that it was '2' and not '22'. They should go in order with '12' at the beginning and end. '22' would be a TPS code.

 

there is only 1 coolant sensor on those trucks. but i have been fooled before, but i am 99% sure there is only 1 on them.... to get the 02 sensor out i have used a propane or mapp gas handheld torch and get the weld bung nice and hot... then i applied the wrench. you may have to repeat this process, and be CAREFULL if you have put penetrant oils and what not on the threads.. highly FLAMMABLE!!!! and as for the codes 12 is "No Engine Speed Reference" probable cause is No Engine Speed Sensor reference pulses to the ECM which is a normal code for the vehice when the ignition is turned on but not started. code 15 is coolant sensor which you already figured out. code 21 is TPS signal to HIGH! and 22 is TPS signal to LOW and if you have cleared codes you will have to run the engine for 30 seconds at idle minimum to clear the TPS high or lows..

let us know whatcha find..

hope this helps

Ck1500

 

I am going to head out once again tonight, I think i put in the coolant sensor that goes to the gauge inside the cab and not the computer which would explain why she is still running so rich. I pulled up a picture of the engine and it shows the ECT located infront of the engine the sensor i put in was on the driver side halfway down on the block. Also picking up a new TPS for $40.00 at autozone on my way home tonight. If the CAT is plugged up I have my metal sawzall with a spare battery, it might be loud but should run good enough to get home. I dont think the O2 sensor would cause the flooding of fuel so I will remove that once i get the vehicle home as the vehicle is on uneven ground and in dirt right now and I dont have all the tools out there that I want. Going to Ft Drum tommorrow so I just want to get the truck home. will keep you posted on what the issue is.

 

There may actually be two temperature reading devices (sending unit for gauges & sensor for ECU). If there is, the 2nd one will be up near the thermostat housing.

 

Ok UPDATE:

drove an hour once again to try to bring the truck to life, brought one of the guys from my job that has some mechanical knowledge and brought a 5 gallon bucket of wrenches and sockets.

The truck has 2 coolant sensors, the one I hooked up goes to the gauge inside the cab and I completely over looked the one right in the front that sends the data to the computer. changed out the coolant sensor first then attacked the TPS and finally tried the O2 sensor. finally got the o2 sensor after heating it up good enough and using a socket wrench along with fixed wrench to pry the socket wrench and it popped loose.

I looked over the sensors making sure they where all hooked up and connected the battery, I was still unsure the TPS was on correctly but fired up the truck. Still the truck wouldnt respond correct to the throttle and the check engine light came back on within seconds. Turned the truck off pulled the code and got 22 (TPS) pulled the battery cable off and inspected the TPS, my friend hooked it up just like the old one was on there but whoever tried to fix this truck had it on wrong because it would not move with the throttle so we reinstalled it and truck responded great and no codes.

Let the truck warm up a bit and kept checking the throttle response after she got warmed up and it was perfect, until it bogged down just like previous. I pulled the intake off to check the injectors even thought there still was no code, injectors seemed to be dribbling fuel instead of shooting a nice cone shaped mist. Now I was getting pissed but I also knew that the truck was somewhat low on gas and had bought a 5 gallon jug of gas that I brought up last night.

We topped off the 5 gallon jug and she fired right back up and throttle response was still great, dove her to the nearest gas station topped her off for $75.00 and had my friend drive her home to his house an hour away with out a problem.

Thank you everyone for your help as I am new to the Chevy coming from a Toyota Tacoma, this is my first V8. So far so good, I enjoyed getting the truck fixed even though I had my moments getting pissed but wasnt going to give up. Figuring the truck was listed for $2500. I got it for $1500 I am still up a few bucks right.