V1 LSJ rough Idle

[jcdman]

2005 SS/SC

Hey everyone, I've got a rough idle right now, looking for some help to brainstorm what might be the issue. Here's link to my google drive of the idle.

https://drive.google.com/file/d/1ACNhimnVnaUGCCFp540-SJt3md3Mv6QY/view?usp=sharing

I let it idle for about 30 seconds and it does not improve. I attempted to blip the throttle and the idle got worse and then the car stalled. I attempted to hold the throttle at about 2k rpms and after coming off it did not fix it. Boost gauge is showing good vacuum (although not sure if that gauge is reliable, doesn't move at all after starting). I currently do not have a hose running from my valve cover to my intake, although I don't believe that could be causing a vacuum leak? I have disabled the EVAP system in HP tuners. I've also disabled O2 sensor Bank B since there is only one O2 sensor on the exhaust manifold; possible that I have the wrong connector on the engine harness loom connected? Not sure if an O2 sensor could cause this idle.

I'm out of town right now, but I'm planning on getting a vacuum gauge to see what's going on with the hoses for the supercharger and boost control solenoid. From my research the boost actuator on the supercharger should remain open on idle, but mine fluctuates between open and closed as you can see in the video.

 

[baustin]

Things I'd check:
Are you sure your MAF sensor is the correct direction?
How does it run if you unplug the MAF sensor?
No hose from valve cover to intake but did you cap the intake hole for that line?

 

[Gtstorey]

Any other codes?

 

[Rauq]

Not having the hose on the valve cover could conceivably cause a vacuum leak, as the PCV valve is between the intake manifold and head, so you're essentially pulling air through that port and into the intake manifold. I just have a breather filter on mine for now so I wouldn't expect that to be the cause, unless your PCV system is way cleaner and more free flowing than mine. You could try plugging that port with your finger and seeing if that changes anything.

It sounds like a vacuum leak to me, though. Try spraying brake clean around the entirety of the intake system to see if you get a surge anywhere. That would indicate if and where you're getting excess unmetered air into the system.

I believe the first and second O2 sensors were wired opposite each other between male and female plugs and connectors, so the only way you'd have the wrong O2 sensor is if you cut the wrong one out while doing your harness work. I don't have a great picture on my phone but I think the first O2 sensor is a female connector on the harness, and on my car has pink/black, purple, tan, and dark green wires.

I also second double checking that the MAF is completely connected and facing in the right direction. If it is facing the right direction (it should have an arrow on it in the direction of airflow) and correctly wired, unplugging it should produce a drastic change in idle.

 

[Dale E]

In your video, was your vacuum boost opening and closing? It should be rock solid at idle and move only under acceleration and vacuum changes to provide boost and no boost. Does your boost valve have a leak? or a hose to it not connected?

 

[Gtstorey]

I can't get the video to play but is this a new issue on a running car, first startup, motor at operating temp, etc? Have you logged it HP Tuners to see what fuel trims, fuel pressure, etc are doing?

 

[jcdman]

Lots of helpful tips, thanks everyone. I've been out of town for work but hopefully can put in some time tonight to troubleshoot. I'll let you all know if any of these help fix the issue!

 

[Corgithulhu]

I just have a breather filter on mine for now so I wouldn't expect that to be the cause, unless your PCV system is way cleaner and more free flowing than mine. Mine is also breathing to atmosphere with no idle issues.

I don't have a great picture on my phone but I think the first O2 sensor is a female connector on the harness, and on my car has pink/black, purple, tan, and dark green wires. This is correct on my car. Female pins with the rubber seal on the harness side of the connector.

I also second double checking that the MAF is completely connected and facing in the right direction. If it is facing the right direction (it should have an arrow on it in the direction of airflow) and correctly wired, unplugging it should produce a drastic change in idle. I forgot to plug my MAF wire connector in when I first tried starting, and it wouldn't even run more than a few revolutions of firing before cutting out.

Just editing yours as a quote with my experiences/observations in bold.

 

[jcdman]

In your video, was your vacuum boost opening and closing? It should be rock solid at idle and move only under acceleration and vacuum changes to provide boost and no boost. Does your boost valve have a leak? or a hose to it not connected?

Vaccum boost is opening and closing on idle. All the hoses look good and the boost valve was changed out by Category V Port worx during a rebuild of the supercharger. I'm doubtful that's an issue but I won't rule it out. Do you know a way I can test the actuator?

 

[jcdman]

I can't get the video to play but is this a new issue on a running car, first startup, motor at operating temp, etc? Have you logged it HP Tuners to see what fuel trims, fuel pressure, etc are doing?

Issue on first startup. Motor hasn't been at operating temperature yet. Just got a digital gauge so I can monitor water temp cause I think there are still big air pockets I'm my coolant system.

Never logged anything with HP tuners yet, haven't played with the software enough to try that out.

 

[Gtstorey]

Really hard to do anything but wildly guess at this point.

Are you getting any other Pcodes other than the obvious for removed systems?

I assume the donor was running good before disassembly?

Could be wiring. A lot of the wiring issues will throw codes but not all of them.

Could be a vacuum leak after the MAF.

HP Tuners would have shown engine coolant temps if the 2005 wouldn't give you a readout on the instrument cluster.

 

[jcdman]

Got some codes pulled down and looks like I have 2 significant codes that would be causing my issue. P0017 (Crank/Cam Position Correlation – Bank 1 Sensor “B”) and P0230 (fuel pump primary circuit).

Fuel pump seems to operate correctly, so not sure why that code pops. I have wired black/black, purple/purple, gray/gray, and orange/tan.

It's likely my timing is off a tooth, I did rebuild this engine and installed a new harmonic balancer, but triple checked the timing marks. Looks like the correct terminal is on the crank position sensor, alldata says it's a purple in pin A and yellow in pin B.

I might try swapping that sensor for a new one.

 

[Joebob]

I don't know anything about the LSJ particulars but it does look like your grounds there may not be great. The bottom nut looks loose and the ground lugs all look rusty. I had some gremlins and I think these sensors are very sensitive to ground resistance over a simple +12V supply voltage.

Joe

 

[Gtstorey]

(1) P0016 and P0017 (cleared/solved) | DF Kit Car Forum

 

[Gtstorey]

I doubt it's a sensor that is bad since it seems to be reading but if so it could be just as easily be the cam positioner sensor.

 

[Rttoys]

I don't know anything about the LSJ particulars but it does look like your grounds there may not be great. The bottom nut looks loose and the ground lugs all look rusty. I had some gremlins and I think these sensors are very sensitive to ground resistance over a simple +12V supply voltage.

Joe

I can’t get your picture to pop up, but you are probably talking about this? It does look loose.

 

[Gtstorey]

If not loose, sure looks rusty.

 

[jcdman]

I doubt it's a sensor that is bad since it seems to be reading but if so it could be just as easily be the cam positioner sensor.

Think I found the problem! I don't believe my cam sensor was aligned properly when I rebuilt the motor. The last 4 cylinder I worked on was out of a Mazdaspeed protege, and the cam sensor on that operated differently and didn't need to be oriented a certain way. I assumed this one was the same but I was wrong. Picture off what it should look like vs mine.

Corrected the issue, I'll fire it up in the morning (don't wanna annoy the neighbors) and see if this fixed it.

 

[jcdman]

Am I using the wrong O2 sensor? Saw on another thread that the one with the purple/white stripe is sensor number one and manages fuel. I'm also throwing a P0141 code.

 

[Rttoys]

It only goes one way.

The pre cat o2 (upstream) is a female connector on sensor side and male on car side.

The post cat (downstream) O2 is male on the sensor and felmale on the car.

The sensors are technically the same, but the connectors are swapped depending on location.