Running poorly after starting

Posts specific to the 2.0 litre Turbo engine

Re: Running poorly after starting

Postby dmcke5 » Sun Jan 19, 2020 7:31 pm

bigBADbenny wrote:Are you on the original fuel pump and in tank fuel filter? At what km is the car?

Also you can do some logs with per cylinder misfire count, just select the parameters for each cylinder, log it around the block, just to see if any results...


Yeah I believe it's still the original pump and filter, car is at 215k at the moment. I considered the filter but I checked the fuel pressure and the pump was maintaining pressure well so I didn't think that could be the cause.

Yeah I should be able to log that if it's an option, I'll see if I can get it done tonight.
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Re: Running poorly after starting

Postby dmcke5 » Mon Jan 20, 2020 9:43 pm

No luck on the test drive yet, haven't had the time or energy unfortunately.
I did play around a bit tonight and started probing wires with my multimeter. Checked all the connections between the front 02 sensor and the ecu. Signals were within the correct ranges but I am getting about 0.35v on the shield which obviously isn't right. There's also about 24k of resistance between the sensor ground pin and the battery negative. I'm yet to look at where that wire goes but that doesn't sound right either.
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Re: Running poorly after starting

Postby bigBADbenny » Tue Jan 21, 2020 4:31 am

A jdm FSM of the correct year will have all the diagnostic info or try the adm entries in the SLI link at the top of my FSM links page.

My06 adm : http://www.mediafire.com/download/2t85o ... ML_version).zip
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Re: Running poorly after starting

Postby dmcke5 » Tue Jan 21, 2020 7:03 am

bigBADbenny wrote:A jdm FSM of the correct year will have all the diagnostic info or try the adm entries in the SLI link at the top of my FSM links page.

My06 adm : http://www.mediafire.com/download/2t85o ... ML_version).zip


Yeah that's what I was using to even know which pins go where.

I've got 0.35v on the Front oxygen (A/F) sensor shield (B134, pin 25) when compared to battery ground. That reading should be 0v according to the FSM. To me that says there must some broken insulation on one of the signal wires, and its leaking to the shield slightly. Only happens with the sensor connected and the ignition on. Signal values were still within the range specified but I suppose the vibration/temperature change could make the short worse or better depending on the conditions.
Looking again at the FSM this morning, I suspect the wire I thought was ground on the 02 sensor end of the loom may have actually been one of the signal wires (I'm blaming lack of sleep on that one!). If that was the case, that's probably where my leak to the shield is since I should have got nothing between that pin and ground if it was working properly.

No idea if that's a big enough problem to cause what I'm seeing, but it seems like a reasonable place to start I guess?
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Re: Running poorly after starting

Postby dmcke5 » Tue Jan 21, 2020 9:16 pm

Just confirmed. I've got 24k ohms of resistance between the shield and one of the 02 sensor signal wires. Will run some wires to test and report back.
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Re: Running poorly after starting

Postby dmcke5 » Fri Jan 24, 2020 6:55 am

dmcke5 wrote:Just confirmed. I've got 24k ohms of resistance between the shield and one of the 02 sensor signal wires. Will run some wires to test and report back.


I did some more testing and realised that the resistance I was seeing is coming from the ECU, not the wiring. I decided there wasn't much I could easily do about that so instead I ended up swapping back to my old 02 sensor and it seems to have fixed the problem, even though the new one was only a few months old.

Anyway, thanks for the help. Shame it was something so stupid in the end, I'm just glad my car is running again.
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Re: Running poorly after starting

Postby bigBADbenny » Fri Jan 24, 2020 7:28 am

That’s great, and all the little checks contribute to your confidence in the car.

Was the new sensor oem, correct part number?

Was it installed with non sensor safe rtv?
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Re: Running poorly after starting

Postby dmcke5 » Wed Jan 29, 2020 6:10 am

bigBADbenny wrote:That’s great, and all the little checks contribute to your confidence in the car.

Was the new sensor oem, correct part number?

Was it installed with non sensor safe rtv?


Nah, it was definitely an aftermarket brand. Came from Repco in a plain white cardboard box, no sign of a brand name on it.

Didn't use RTV, is that something I should be doing? The sensor had anti-seize on the threads from new but that's about it. Was extremely careful when I installed it to make sure nothing got on the end of it and it didn't receive any bumps in the process.

The car is definitely running better than it was prior to the sensor failing, so fixing that little vacuum leak and the new coil packs definitely feels like it made a positive difference as well. Thanks for the help, sorry it was something so stupid. I'm frustrated that I didn't pick up on it earlier but I think its because I had been chasing driveability issues for a little while before this and it just felt like a progression of the problem I was having, rather than a new separate problem. I had only just checked 02 readings with the gas analyzer a few weeks prior and they were all looking good at the time which is why I ended up checking everything else first.
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Re: Running poorly after starting

Postby bigBADbenny » Wed Jan 29, 2020 6:51 am

Well, chalk up another one for oem sensors only!

As per rtv, I’m referring to some types not being sensor safe, being used on or upstream of the sensor and ruining it.
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