Running super rich

[RiceEater]

Ok so my 92 TY has been running richer and richer so I stopped driving it for a few months till I could figure it out, and now this is what I have. In the last 2 weeks it has started throwing code 45 rich while driving, and starting to run like crap. This went on for about a week and now it shows code 15 for coolent temp low. I just did a DM run and it shows -37.8F as my engine temp! I removed the 160 thermo the truck came with and put in the stock 190 and replaced the temp sensor but it is still the same. The dash shows 190 but DM shows -37.8 no matter what. I checked the new sensor and it seems to ohm good but I put my leads on the connector for the sensor and got 10 ohm, now is that the problem? If I jump it like that shouldn't it be 0 with the ohms comming from the sensor? I can't follow the wire back very far to see if it is broken and it is wrapped but I just wanted to ask and see if I was in the ball park. The truck is almost all stock, I just did the IC upgrade and put a motes 2.0 in running the starter bin. I wasn't sure if it could be the bin doing this, but I loaded a few and they all do it. Any ideas would help. Thanks!

 

[berzerker]

Re: Running super rich

you are talking about the sensor located at the front of the lower intake manifold . That is the sensor that sends the signal to the ecm for coolant temp . If so i would bet you've got an bad connection at the sensor or a broken wire in the harness. I would try a new harness connector for the sensor first . carquest or napa will have them . only a few dollars . good luck .

 

[RiceEater]

Re: Running super rich

Ok so after some testing, even if I unplug the temp sensor with the motor warm it says -37.8. I tested the wires after the connector and it still shows 10 ohm. with the sensor on (not in the motor) it drops to 2 ohm. Is any of this right/wrong? I'm about to dive into the harness to try and find a cut/broken wire and just want to make sure that is what I should be looking for. Does the wire from the sensor run all the way to the ecm?

 

[ziembic]

Re: Running super rich

this may be a dumb question but there are two temp sensors and I just want to make sure you are looking at the right one. As bezerker said the one you need is on the front of the lower intake. The other one on the driver side head is for the gauge in the cluster.

 

[Quickstop [UK]]

Re: Running super rich

Have you got the manual? Sounds like your sensor may have gone out. There is a test for it.

Disconnect it while the engine is running and look at DM. Get a paper clip and short the terminals on the connector and watch in DM. Should give you a really high reading.

I had a bad sensor right out the box and it did exactly what you're saying. Maybe you got a bad one.

If when you short the connector you get a high DM Reading then the sensor is the problem. There is a test procedure in the manual as well.

To double check the sensors the ECM feed has two wires and is next to the heater hose feed on the lower intake, the gauge feed has only one and it should be green at the back of the dvr side near the headers.

 

[RiceEater]

Re: Running super rich

Yes I'm on the right one, the one next to the heater hose and the 2 wires. I shorted the wire with a paperclip and the temp stayed the same.

 

[RiceEater]

Re: Running super rich

Ok well got the temp fixed. I dropped down the ecm and found a loose wire. Now I have the problem that my 02 mv in open loop drop all the way to 0 then spike to 860 then drop to 0 over and over. I think my 02 sensor is fried. I wanted to pull it out and check it out, i'm sure its covered in crap, but now i can't get it out. My 02 socket rounded it right off.

 

[Don W.]

Re: Running super rich

Well what I would do is pull the fender well to really have access then apply some PB Blaster, tap on the thing to allow better penetration then apply some heat to the pipe around the bung.

HTH

 

[RiceEater]

Re: Running super rich

Ok I got the O2 sensor changed, I did like someone else said and bashed off the top of the sensor and then just put a regular socket on it and it came right off. My TY seems !00% better now. I still have a RPM flux, but now it is much smoother only about 600 to 750 no 850 to 400. Now I just think my tune is a little rich. I just got autotune but I'm not really sure how to use it.

 

[Quickstop [UK]]

Re: Running super rich

Nice work, glad it's as easy as it is so far.

Is it stock tune? If so, the idle may be due to the IAC and passages being fouled. How does that look in DM?