Hi Folks,

First let me say that I am very impressed with this sight. I am new to this sight. This winter I replaced a new Jasper rebuilt 5.7L 350 TBI into my sons truck k1500 1989. Everything is going well except I can't seem to get it to pass inspection. Edelbrock intake manifold and Edelbrock headers. Universal football type CAT.

The problem I have is the SES light comes on and then the ECM decides that it needs more fuel and bad things happen. I can make this happen without much effort.

I am running WinALDL and can watch it happen...

Here is how I can reproduce it.

1) Start the truck and let it idle in Park until it goes into Closed Loop
In fact the car can sit and idle all day long in park and everything is cool.
2) After the truck is warmed up to normal operating temp placing the truck in Drive causes the O2 sensor to read 1 volt. I can put the truck back in Park and watch the O2 sensor go back down and the truck settles out.

I haven't actually driven the truck down the road because it doesn't have an inspection sticker on it... Too many police cars in the local area.

WinALDL did help me figure out that I had a bad MAP sensor, which I replaced. All of the other sensors look like they are in spec.

Here is a rather interesting data point.

If I remove the CAT and the "Y" pipe and run straight headers, although LOUD I can not reproduce the SES light and the O2 sensor going wild on me.....

I am really scratching my head.. I came on line today and found this sight.
Any help would be accrpted.

Thanks
-Marc

 

sounds like a restriction somewhere............

 

Huh ? A restriction would cause no flow to occur.

 

you said :If I remove the CAT and the "Y" pipe and run straight headers, although LOUD I can not reproduce the SES light and the O2 sensor going wild on me.....
maybe 2 much backpressure