Rough Idle

[waderain]

after I put in the new engine the idle is really rough, almost like it wants to die but it feels fine when I'm driving it.

I figure its an air sensor problem. Either the 02 Sensor or the MAP sensor.

I had a test done and here are the error codes, any ideas.
P0171: SYSTEM TO LEAN (BANK 1)
P0106: MANIFOLD ABSOULTE PRESSURE
P015B: 02 SENSOR DELAYED
P1101: INTAKE AIR FLOW SYSTEM PERFROMANCE

 

[skurtov]

MAF? P0171 is also symptomatic of the dreaded PCV issue.

 

[waderain]

I don't hear any leaks from the PCV valve and if I pull the MAF sensor out the car completely dies. The old engine overheated really bad before it blew up so I figure the 02 sensor got ruined when it overheated.

I'm just not in the mood to keep experimenting with this car. At this time the only reason I'm keeping it is because I can't afford a new car right now. So I have to keep this one running as cheap as I can

 

[mja]

Exhaust leak, vacuum leak, broken harness, faulty MAP, MAF, or air temp sensor. Could also be ECM issue or throttle body. Maybe O2 sensor. I'd start with tightening up exhaust/intake fittings and test resistance of the sensors and harness.

If it feels good under boost but just idles rough, may not be PCV. Could check the orange poppet valve through the PCV outlet line.

If you have a friend in the area with a sonic, swapping out their good sensors with yours will clear up the sensor issues real quick.

....
Here's another rough idle fix, yours sounds like a different issue but GM does recommend changing purge solenoid as a regular maintenance routine.
http://www.sonicownersforum.com/for...22240-low-idle-shutoff-after-you-put-gas.html

 

[Maddmatts]

Check the cam cover's pressure regulator. It's the circular bit under the "ecotec" cover. If air is being sucked into the square hole at idle, you need a new cam cover and possibly a new intake manifold.

 

[waderain]

Went through and tightened up everything. unpluged and repluged. The engine light shut off for a while but came back, idle is still bad. Going to have a different mechanic look at it this weekend. Really if I can't get it fixed this weekend then I'm going to get rid of it. I'm tired of its problems. this is the second Chevy I had that started giving me problems at low mileage. it's the last Chevy I will buy. In contrast I have a 2001 Nissan Xterra that's just about to hit 300,000 miles and its hardly given me any trouble over the years.

Thanks for all the advice everyone. It was a fun car while it worked.

 

[mja]

I've never had an engine swap go 100% smoothly the first time. Something is always unbuttoned here or there even with a blueprinted and tested motor. Yours is a junkyard motor, with all the (not)fun problems that come with it.

Check common fail points as maddmatts said valve cover, and also orange pcv poppet in intake manifold. Pull the O2 sensor or downpipe and check for cracked turbo/manifold casting around the wastegate.

I once rebuilt an Olds 455 three times and the machine shop couldn't figure out where a head was leaking. I ended up selling it in the end, but didn't hold it against the car, just at that time the engine work didn't fit my budget and the headache didn't fit my lifestyle.

If you think you have problems now, go buy a 6 year old Nissan Versa

 

[Gobinator98]

after I put in the new engine the idle is really rough, almost like it wants to die but it feels fine when I'm driving it.

I figure its an air sensor problem. Either the 02 Sensor or the MAP sensor.

I had a test done and here are the error codes, any ideas.
P0171: SYSTEM TO LEAN (BANK 1)
P0106: MANIFOLD ABSOULTE PRESSURE
P015B: 02 SENSOR DELAYED
P1101: INTAKE AIR FLOW SYSTEM PERFROMANCE

I know the thread is old but do you know what caused this issue? I got a P015B, P0171 and P2270 recently and I had a new engine put in around October 2018. I know it's not a vacuum leak or an Evap/fuel system problem. What could it be?