I have a fresh build 355 ci 1990 tpi al heads,mild proformance increase 350hp 400 tork. It does not go closed loop the engine doesn't go over 192 deg. I'm getting error codes 13 and 42. I'm not seeing any BLM changes? I'm using Datamaster. Also I have a broken off sensor on passenger side of engine inline with header flange does anybody know what it should be ???? please help need direction THANK YOU Mike

 

Closed loop is determined by the O2 sensor .
DTC 13 says the computer is not seeing the O2 sensor/ wire is broken / or it is not working
Have you got one?
Is it connected ?
Can you see O2 voltage changing in Datamaster?
Should range from 100 - 900Mv constantly when working

 

yes I have two O2 I took a 4 wire GM out of the wreacking yard, need heated for headers. and no voltage change stays at 447 all the time. I'll have to check my wiring and look for an open. I have a wide band in the dash.

 

Maybe the heater element is not working so the sensor is not getting up to correct operating temp in the headers.
When I had a single wire O2 in my headers it would come online when engine was driven or reved up, but drop out again at idle when the headers cooled off

 

This is a normal condition.

 

I realise that but maybe that is the situation he is in IF the heater in his O2 is not working
The fact that DM is showing O2 volts @ 447 would indicate that he at least has a path through the sensor and circuit is not open or dead short to ground ?

 

Being that you already said the O2 came from a wrecked car that you dont know the history of, I would buy a new O2.

 

I bought a new AC deco 3 wire ,check my connection from the ECM to the O2 sensor it's good. took another Datamaster log got it to go closed loop for about a min. I'm going to try the ANHT.BIN . I had 12 volts at the O2 connector with the key in on,but have not checked for 12v when running will do today.

 

There are a couple things that have to happen for closed loop to engage. One is the O2 sensor must be hot. The second is the coolant temperature must be at or over a certain threshold. And there is a couple timers that must run down to zero before closed loop is enabled. There should be one for various O2 temps. Cold,Warm,Hot...etc. There is most likely a timer for when the coolant temp hits the pre-programmed threshold. Its generally only about 30 seconds or so. But if you have a bad or malfunctioning O2 sensor, it does not matter if all the other conditions are met. If the ECM does not receive a signal from the O2 sensor that it is up to temp and ready, it will never enable closed loop.

 

found the problem the ecm was not grounded on the O2 curcuirt . I checked the ground connection at the 32 pin connector and it was not connected to anything. O2 working. Now it time to tune? Thanks for you help Mike

 

you can edit your first post and change the title n put solved in it, so folks know.

 

http://www.gmtuners.com/OBD1_DTC.htm Check out that link. I hope you didn't break off the connector for your knock sensor. Then it will barely accelerate.LOL

 

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