Code 13

[Unofficial]

Hey guys, I'm having some problems with my '87. It's a 350 TBI with not even 800 miles on the new motor. I put headers on a long time ago, so I had to modify my oxygen sensor setup. With the factory exhaust, the sensor was after the y-pipe in the manifolds, but with the headers, I have the sensor in bung on the the driver's side header only, I no longer have a y-pipe. The oxygen sensor is fairly new, but I keep getting codes for it. First I was getting code 44, which is a lean condition. Thinking it had something to do with my adjustable fuel pressure regulator, I put the old non-adjustable regulator in. I reset the ECM to clear the codes, and now I'm getting code 13 again.  This has happened before, so I put a new wire in, thinking that may have been the problem. I'm only getting about 12-13 mpg, and that's driving it REALLY easy. I didn't take it over 2,000rpms for a week and I still ended up with 12 or 13 mpg. This seems awfully low considering I have throttle body injection, a 700r4, and 2.73 gears. I drive for roughly ten minutes on the highway to school cruising at about 1800rpms. Any ideas on how to solve this? Code 13 is open circuit for oxygen sensor by the way.

Thanks in advance

[jaredts]

Just a stab in the dark, but if you're sure the wire to the sensor is not the problem maybe you're not getting a good ground to the header.  Its hard to imagine that, but I've seen stranger things.  Are they coated headers?

[VileZambonie]

There are two identical connectors that will fit the O2 sensor. Do you have it connected to the right one?

[Unofficial]

I'm positive it's the right connection. The headers are not coated. The light usually comes on if I run it hard or go highway speeds for a long period of time.

[topp]

I wish I got 12mpg with my '87 tbi 350 and TH700....

[Irish_Alley]

Did you use the sensor that you splice into the plug or the type that you plug into the plug

[Unofficial]

If I remember right, it was a plug-type. The wire was too short though so i clipped off the two plugs and put a new wire in to make it reach.

[TexasRed]

Are you sure the fuel pump is good? It may not be blowing fuses but it may be too weak to keep up with engine load.

[Unofficial]

Well I guess the fuel pump may be possible, but I don't think that would have anything to do with an open circuit code for the oxygen sensor

[Irish_Alley]

I would double check the wires to make sure

[Unofficial]

Hey, I'm bumping this thread because I ran a new wire from the oxygen sensor to it's plug, and I'm still getting code 13 after resetting the ECM. I'm still getting around 11 to 12 mpg. I remember seeing a way to test the oxygen sensor circuit on ALLDATA, but I no longer have access to it.

Does anyone know how I can figure this out? Read first post for more info on my truck. Thanks for any help.

[VileZambonie]

If I remember right, it was a plug-type. The wire was too short though so i clipped off the two plugs and put a new wire in to make it reach.

Wait you cut the O2 sensor wire on the sensor side or the harness side?

[Unofficial]

If I remember right, it was a plug-type. The wire was too short though so i clipped off the two plugs and put a new wire in to make it reach.

Wait you cut the O2 sensor wire on the sensor side or the harness side?

Oh yeah I forgot to mention that...When I looked at it again I guess I was wrong, I never clipped that plug off. So I cut it on the sensor side.

[Irish_Alley]

but you still cut the wires. it could be a bad connection not letting the o2 sensor send the right signal

[Unofficial]

Cutting the wire has nothing to do with getting the code, it was throwing code 13 with the oxygen sensor before the one with the longer wire that I made. The connection is fine anyway.