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Author Topic: Can't connect to running car  (Read 1657 times)
Leafy
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« on: November 08, 2020, 07:27:14 AM »

So I've got a bit of a weird problem judging by the fact that I get no search results. On my 01 allroad with m-box flash I can connect read the rom(with chinses fidi cable and mpps), connect with me7loggger, connect with vcds, connect with obdii reader with the key on but engine not running. Once the engine is running I get none of that except for my elm 237 bluetooth. Also I have a very low rate of success flashing in the car, I basically just have to bench flash. Additionally but maybe unrelated I randomly get codes for the sensors driven off the fuel pump relay(egt, n80, o2 high internal resistance), I just replaced it even though the contacts (inside) looked brand new and it made no change.
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nyet
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« Reply #1 on: November 08, 2020, 12:35:17 PM »

You'll likely need to wire a dedicated kline from cable to ecu for flashing/logging in obd.

You can also try a variety of different inits, i don't recall which one you might need for that car (there are suggestions spread throughout the site).

maybe somebody else can chime in with one they know works but if this is the 8D0 and not the 4z7 551M the default init should work. If it doesn't, you definitely will need a dedicated kline, or there is a problem with your harness.
« Last Edit: November 08, 2020, 12:41:45 PM by nyet » Logged

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Leafy
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« Reply #2 on: November 08, 2020, 02:54:26 PM »

Yeah I was already half considering running my own kline wire and putting a ferrite choke on it.
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dal
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« Reply #3 on: November 09, 2020, 07:36:04 AM »

In my car this same  thing happens. What I do is open nefmoto flasher, connect to the ECU, close connection, and then use me7logger normally.
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Leafy
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« Reply #4 on: December 12, 2020, 06:32:23 AM »

My weirdness continues. Hooked my scope up to the power leads to the ecu with the car running, 0.34v of noise in the DC voltage that shouldn't cause a problem. And I can finally get intermittent connection to the ecu with the engine running with obdeleven, enough to discover that the ecu always thinks the throttle angle and load are 0, it also commands 0 duty cycle for the n75. Maf reading is like 5g/sec cruising and 20g/sec at WOT and maf voltage barely crests 1v. Unplugging the maf doesnt change the throttle plate angle always being zero issue. I guess this explains why I never got codes for boat deviation while only seeing 4psi on gauge since it's never commanding more than that. I confirmed that the car has a Hitachi maf and that the previous owner didn't do something dumb.
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nyet
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« Reply #5 on: December 12, 2020, 11:17:50 AM »

None of that makes sense. You should be throwing a ton of codes.
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ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
Leafy
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« Reply #6 on: December 12, 2020, 11:22:54 AM »

Right?! The only thing on my tune is rs6 egts, soft launch rev limiter, left foot braking, and raised top speed limiter. It's otherwise a completely stock 551M-0001 tune. I'm going to try flashing the original allroad tune back on it and see if I get everything back except the egt being pissed off.

*Edit, no joy with the factory flash either. I did confirm that the ecu is reading different voltage than the maf sensor is outputting. With on scope on pin 4 of the maf I had 0.7v idling and got it to like 1.5v holding the revs in neutral, at the same time measuring block 39 reported 0.4v and 0.7v respectively. Also still only 0% load and 0* throttle angle in like measuring block 3. But like obviously it drive like it drives fine, just like you unplugged the N75. I confirmed that the maf is getting 14v and 5v and the sensor ground is grounded, not amazing though, its 4 ohms to the battery terminal from the maf connector.

I can hear the throttle plate stroke out both directions when the car is off. I'm pretty much out of ideas here and very confused why the only codes in the whole car are in the cluster for missing communication to the air ride module (because delete) and no radio communication.
« Last Edit: December 12, 2020, 01:28:14 PM by Leafy » Logged
Leafy
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« Reply #7 on: December 13, 2020, 09:26:04 AM »

This truely makes no sense. My mass flow is way off but my ltfts are 0 and stfts are +3ish on both banks. And it runs fine with the maf unplugged but also always reads the throttle angle as zero even when I visually confirmed with the tbb of that it does move. All 6 throttle body connector wires have continuity to the ecu connector.

I also confirmed that my body gauge hose doesn't collapse under vacuum so my 10mmHg at idle on the gauge is real. Which is odd that I can't find a vac leak and it runs fine. It also only ever hits like 12inHg in overrun, and the engine braking is kind of weak.

I'm just going to drive it and see if I ever get some codes out of it.
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Leafy
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« Reply #8 on: December 01, 2021, 04:37:09 AM »

To bump this back up I have an update. I fixed the cat being slow, it achieves target boost now. The 4 pin temperature sensor connector was broken by the PO and I finally replaced it, that's all I changed. What's weird is that with the broken connector completely unplugged it would throw a code, but with the broken shit jammed into the sensor no code, no weird temperature readings on obd11. Now I need to attempt to log with me7logger to see if this somehow fixed that issue and my flashing in thy car issue too.
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adam-
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« Reply #9 on: December 01, 2021, 06:09:46 AM »

You're relying on OBD11 parsing the data correctly.  What does VCDS say?
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Leafy
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« Reply #10 on: December 01, 2021, 06:27:50 AM »

You're relying on OBD11 parsing the data correctly.  What does VCDS say?

I've got to try connecting it again now that I've replaced the connector, but before VCDS refused to connect to the car when the engine was running.
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