2007 XC90 Sputtering and won't go above 1600 RPM [Solution, shorted wires]

[MRSCOTTPERRY]

UPDATE - Problem resolved - 12v wire was shorted to 5v wire. Wire bundle rubbing on top of engine wore off insulation on several wires. 5 wires needed to be spliced.

UPDATE - Pics added. Seems every time I pounded down the engine cover caught up to me https://photos.app.goo.gl/Lq2icanKbynya9mM8

XC90 with 230k miles. Was pretty much fine and then wouldn't start at the grocery store and had to have towed home. Cranked - fired - and died. So far, I have replaced/swapped cam sensors, cleaned MAAF, replaced MAF, replaced fuel filter, replaced throttle body.

After all this, the car will start and with some finesse on gas pedal, I can keep running but can't get RPMs above 1600. Seems just starved of fuel.

Have Carsoft reader for VOLVO. Codes seem to point to throttle position sensor. Live reading says rail pressure is 70-90 PSI (high?).

Ordered Fuel Pump but dreading doing that job and then finding out it wasn't fuel pump.

Have reviewed well over 100 posts on this and many point to MAF - others to vacumme leak (I can't seem to find vac hoses).

Anyone have an idea what could be causing this condition and/or how to diagnose? If it was my 70 Camaro, I'd just open throttle on carb or adjust an air screw. Ready to sell to junkyard.


Thanks,
Scott

[Vova585]

Icarsoft will not help you here IMHO. It is a great easy to use tool during maintenance and code read/erase but when it comes to more serious work it is not good. You need to decide what is of priority here. If you need car to be operational asap-call "volvo towing" for free 25miles and bring it to the dealer for diagnostic. Pay for usual rate 1hr diagnostic fee and then decide based on report if you can easily do it yourself at home(towing price back) or you want to pay dealer. If you can afford this car sitting around while you play with it, I would invest Into either vida($100 plus headache to install and use) vs midrange topdon, autel, thinktool for about 300-400(might be cheaper this way given possible partscannon). For now if you want to gamble: check info on temp sensor with icarsoft, buy bosch fuel pressure sensor for $40 and install(90psi is too high). Most likely it will be fuel sensor if I would be betting. Also would be great to see duty cycle info of the fuel pump and what fuel trims are showing. If not, then without scanner it will be hard to do anything.

[MRSCOTTPERRY]

Good intel - thanks. I did replace fuel (rail) sensor with amazon cheapo as well as an old one I had laying around from last parts cannon fix (forgot to list that one). Paid 3600 for car 4 years ago - have about $300 into this latest fix attempt so not looking to throw too much more $$$ at it at this point - but THANKS

[Vova585]

Please no electronic equipment from ebay or Amazon. Quality sucks and can do you more harm than good. You might think(I put new tmps that were sold as oem and they came in oem looking box and outside they had similar writing, but why car drops them after 4min..)ask me how I know. If your previous sensor was also from questionable source and was laying somewhere between screwdrivers in the toolbox. I would not rely on it. You are in Chicago area. Put on craiglist "volvo enthusiast with Vida or capable scanner needed". Chances are someone might come and loan you their tool or be happy to scan it for you with graphs on coolant temp, rail pressure, fuel pump duty cycle, maf sensor read, etc.
Also you didn't mentioned what engine you have in this car(sorry I am not xc90 fan) 2.9, 3.0, 3.2, 2.5? What are the codes icarsoft is reading? Have you tried to erase all codes. Restart it again and reread for what codes are coming back?

[abscate]

Is that a fuel pressure measurement on the rail with a gauge or reported in software ?

For diagnostics, gauge is needed. Software is dependent on wires , voltage, sensors, grounds, battery voltages… all failurepoints

[MRSCOTTPERRY]

Is that a fuel pressure measurement on the rail with a gauge or reported in software ?

For diagnostics, gauge is needed. Software is dependent on wires , voltage, sensors, grounds, battery voltages… all failurepoints

My fuel measurement is reported in software - no schrader valve on my rail - I did notice one before the fuel filter.

[MRSCOTTPERRY]

This is a 3.2 engine. After clearing codes and then restarting I get 5 codes:

1 - P064300 Sensor Reference Voltage A Circuit High General Failure
2 - P061B64 Internal Control Module Torque Calculation Performance. Algorithm Based Failures. Signal Plausibility failure
3 - P022023 Throttle/Pedal Position Switch B Circuit. General Signal Failures. Signal stuck low.
4 - P177100 Throttle Position Sensor Circuit High Input.
5 - P157300 Throttle Position Not Available

[ggleavitt]

See what this gets you (cut/paste from VIDA):

ECM-P064300
Engine control module motor (ECM) checks the internal end-stage for 5 volt feed.
If voltage becomes too high or too low, the diagnostic trouble code is generated.
The diagnostic trouble code can be diagnosed when the ignition is on.
Substitute value
Nothing
Possible source
Signal cable for connected component short-circuited to voltage
Open circuit on signal cable for connected component.
Signal cable for connected component short-circuited to ground.
Damaged engine control module (ECM).
Fault symptom
Uneven idle.
High emissions
Poor performance.
Engine stops while driving.

ECM-P061B64
Engine Control Module (ECM) monitors the torque in the engine by reading and interpreting signals from mass air flow sensor, electronic throttle unit and air pressure sensor in the inlet manifold.
Torque is calculated according to two separate methods. The control module checks and compares both results of the calculation.
The diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects that both results of the calculations deviate too much from each other.
The diagnostic trouble code (DTC) can be diagnosed in specific driving conditions.
Substitute value
The engine torque is limited by the throttle position (maximum permitted torque depends on accelerator pedal position).
Possible source
Air leakage in the intake manifold (downstream of the mass air flow (MAF) sensor and electronic throttle unit).
Damaged throttle unit.
Damaged mass air flow (MAF) sensor.
Damaged engine coolant temperature (ECT) sensor.
Damaged flywheel sensor.
Damaged air pressure sensor in the inlet manifold.
Damaged camshaft reset valve.
Damaged VVT-unit.
Damaged engine control module (ECM).
Fault symptom
Message in information display

ECM-P022023
The engine control module (ECM) checks the pulse width modulation (PWM) signal and the analog signal from the accelerator pedal (AP) position sensor. The analog signal is directly connected to the Central electronic module (CEM) and the signal is transmitted via CAN communication to the Engine control module (ECM). The pulse width modulation (PWM) signal is directly connected to the engine control module (ECM).
The PWM signal is used to determine the current accelerator pedal position in a fault free system.
The Engine control module (ECM) checks the analog signal (via CAN).
The diagnostic trouble code (DTC) is stored if the control module detects that:
Analog signal (via CAN) is too low.
Incorrect value lasts longer than 16 seconds.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
Ignition switch position II.

ECM-P177100
The engine control module (ECM) checks the pulse width modulation (PWM) signal and the analog signal from the accelerator pedal (AP) position sensor. The analog signal is directly connected to the Central electronic module (CEM) and the signal is transmitted via CAN communication to the Engine control module (ECM). The pulse width modulation (PWM) signal is directly connected to the engine control module (ECM).
The PWM signal is used to determine the current accelerator pedal position in a fault free system.
The Engine control module (ECM) checks the analog signal (via CAN).
The diagnostic trouble code (DTC) is stored if the control module detects that:
Analog signal (via CAN) is too low.
Incorrect value lasts longer than 16 seconds.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
Ignition switch position II.

ECM-P157300
Engine control module (ECM) checks the signals from the electronic throttle unit's two position sensors.
The diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects a fault in both sensors.
The diagnostic trouble code can be diagnosed when the ignition is on.
Substitute value
Supply to the damper motor for the electronic throttle unit is shut off. The throttle will set itself in the return position.
Cruise control turned off when malfunction is active.
Possible source
Fault-trace through another stored diagnostic trouble code (DTC) for throttle position (TP) sensor in the engine control module (ECM).

[MRSCOTTPERRY]

Thank you for this - WAY MUCH more info than I was able to gather by myself (long live the tribe!). Still have to digest but at first pass - looks like the only course forward is to start sticking pins in wires that are not easy to get to or determine how to read=HOURS and HOURS ? . Engine is solid - change the oil with the good stuff often -make sure coolant is good - until now, the car has been solid. Hopefully, the answer is in there somewhere. Now I just gotta find it.

[ggleavitt]

Something's wonky with the electronic throttle unit I think, both outputs (CAN and analog) seem affected and the 5volts plus the position sensors suggest on the surface that there's no connectivity or it's dead. Might be something else but sure seems like the module is unhappy.

See attached for the ECM functions, section under throttle control is decently descriptive.

ECM B6324S.pdf

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