GM Truck Club Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
I recently replaced the engine in my 99 K1500 sub with a gm performance HT383E. It starts up great in the morning but after running for a little while it takes a while to start back up. Also it is seriously lacking power. I had the guys from GM reset my timing to factory and that is when all of the problems started. Also I am getting a code saying that bank 1 is running lean. Need some Help! Any Ideas would be great!!
 

·
Moderator
Joined
·
1,536 Posts
What was the actual code number? Any indication (spark plug condition or similar) if that bank is actually running lean as indicated or if it's running rich instead? If you switch the pre-cat O2 sensors, does the code follow the sensor?
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
P0171 Fuel Trim System Lean (Bank 1). Brand New O2 Sensors (4). New Cats, new Computer, new engine, new transmission. Had it programed at the dealership and that is when things started going wrong. it is hard to start back up after letting it cool off a little after driving a couple of miles, hesitates, and has a serious lack of power. Tried changing the plugs, wires, distributor, dist cap, rotor, coil, and the ignition amplifier. Plugs looked good, not fouled but looked like some slight carbon build up on the #8 cyl. Also replaced the fuel injection spider when I replaced the motor. I am stumped!! Thing should run like a new truck and did until I took it to the dealership.
 

·
Moderator
Joined
·
1,536 Posts
What did they reprogram for, and would they admit to anything in the reprogram that might have triggered the problem?

Normally, with new O2 sensors, that usually means the problem is somewhere else. Problem is, the PCM's principle function is mixture control, so there are a lot of things that can trigger a P0171. A typical 1st check would be fuel pressure (I got a P0171 when my fuel pump went out, causing low fuel pressure). Also check for vacuum leaks and exhaust leaks.

Check those things, but I'd also check into the reprogram. Your description says that the problems all started then, and it may be worth the effort to see if something in the reprogram could have triggered this.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #5
The reprogramming was to to set the timing after installing a new distributor and crankshaft position sensor. I have a new fuel pump so I will try that. I already sprayed the top of the engine with ether to see if I had any leaks and didn't find any. There is a small exhaust leak, I'll fix that too. Thanks
 
1 - 5 of 5 Posts
Top