2001 V70XC - struggles to idle when coming to stop light Topic is solved

[xHeart]

Westgate holds vacuum.

The last things to check are the wastegate adjustment (https://www.matthewsvolvosite.com/adjus ... wastegate/) and whether MAP sensor is faulty/lying. If everything is fine, it all points to the ETM, I think.

Do I check for vacuum at MAP sensor riding on the hose to ETM? Probe for opening and closing?

[vtl]

Do I check for vacuum at MAP sensor riding on the hose to ETM? Probe for opening and closing?

Unfortunately you can only reliably test it by swapping with a known good one and driving through the pattern which was causing problems previously.

[xHeart]

Do I check for vacuum at MAP sensor riding on the hose to ETM? Probe for opening and closing?

Unfortunately you can only reliably test it by swapping with a known good one and driving through the pattern which was causing problems previously.

Very helpful vtl.

I'll see if O'Rielly's have the gauge in the rental tools list, like the one in IPD's video. HFT do not show such tool, but can the A/C manifold be jigged for wastegate application?

[vtl]

Gauge for the wastegate adjustment? A/C gauges are for hundreds of PSI, you need like 5.

[xHeart]

Gauge for the wastegate adjustment? A/C gauges are for hundreds of PSI, you need like 5.

Yes, unless there are other DIY ways. O'Reilly does not have such tool.

I wonder if my MityVac 8000 can be configured, here is the manual: https://manuals.harborfreight.com/manua ... /39522.pdf

[vtl]

It's gauge is for negative pressure, wastegate needs positive.

Otherwise it's a very nice little brakes bleeder, I have one

[XC70Rider]

Don't know if yours has the same feature but my MityVac 8500 can perform both vacuum or pressure. The gauge has a neg vacuum and a pos pressure reading. You need to turn the knob on the left down to get pressure.

[xHeart]

After removing engine brackets, heat shield, and various hoses around the turbo, the task for the wastegate and bypass valve becomes visible but physically stretching.

Since both wastegate and bypass valve hold vacuum, I'll thoroughly clean and put is back together for a drive with new MAP this weekend. This drive may firm my next steps...

A turbo service and exhaust seals appears to be the next.

[abscate]

I have the IPD wastegate pressure tool in my instruments box, would fit in the smallest USPS ship box nicely.

[xHeart]

I have the IPD wastegate pressure tool in my instruments box, would fit in the smallest USPS ship box nicely.

Wastegate would be my next step, before taking up ETM.

SO, a 10 miles test drive did not show any hesitation when coming to stop and idle.

Thus far, I've replaced large hose between MAF and turbo, MAF, TCV, MAP, and replaced the green, yellow, red, and blue vacuum lines. The wastegate (yellow line)) and bypass valve (green line) hold vacuum.

In the following description ECM-6806 and MAF appear in same sentence for signal too high.

Code: ECM-6806

Definition: Turbocharger (TC) Control System, Flow Fault Too High Or Too Low

Description: If engine speed (RPM) is above 3500 rpm and the engine is operating at a high load, the control signal to the turbocharger (TC) control valve is at maximum and the boost pressure (from boost pressure sensor) is lower than a designated value (approximately 20 kPa (2.9 psi) under normal boost pressure - signal too low). If the air mass (from mass air flow (MAF) sensor) is higher than a desired value (signal too high) it is interpreted as a fault and diagnostic trouble code (DTC) ECM-6806 is stored.

Cause:
Signal too high:
Air leakage after turbocharger (TC)
Signal too low:
Hoses between turbocharger (TC) and turbocharger (TC) control valve respectively Turbocharger (TC) control valve and pressure servo are loose or are blocked/damaged
Faulty turbocharger (TC) control valve
Faulty boost pressure control (BPC) valve pressure servo
Sticking boost pressure control (BPC) valve