2004 XC70 no start - faulty fuel pump and/or electrical connections? Topic is solved

[jonesg]

Get a cheap $3 tire pressure gauge, the long one with the plastic piece that extends out, use it to read fuel pressure at the rail,
if you see 50+ psi the pump is good. Throw the pressure gauge away.

[enotslim]

Get a cheap $3 tire pressure gauge, the long one with the plastic piece that extends out, use it to read fuel pressure at the rail,
if you see 50+ psi the pump is good. Throw the pressure gauge away.

Thanks, I do plan to do this regardless of how this episode turns out. I expect it will deliver adequate fuel pressure when it is running. It's been all or nothing, not stuttering or bucking. In 2017 this car did have a short period that felt like intermittent failure of fuel delivery while driving. But that resolved "on its own" with normal behavior for over two years until the current episodes.

[enotslim]

The other clicks when cranking are the delay relay, it shuts off power to all acc's and headlights during cranking so the start system gets full clean power.

I opened up a dead volvo pump and found the motor brushes completely melted in their holder, the solder connections melted off, lots of brown black burn marks, theres no mistaking it. The elec motor is made by AC Delco in korea, I bought a new motor from autozone and soldered it into the original pump housing, $65.

Get that vida running so you can use the bi-directional controls and look at the duty cycle. And try to keep the tank above half full.

I thought you replaced the relay with new up thread? I think you have narrowed it down to relay , wiring, or pump with the lack of fuel at the valve diagnostic on no-start. Vida won’t tell you much if the pump or relay are dying, it’s good for missing signals more that intermittent

Your car will have an FPR built into fuel delivery back at the tank, not on the fuel rail.

I tested and swapped the fuel pump relay when the car would not start. Still no start. Did not replace the relay.

Current thought is to puncture-probe the fuel pump leads, multimeter-verify 12V on start/run, leave probes in place, and drive until the no-start condition recurs (hopefully in my driveway). Then document the voltage that is delivered to the pump on failed start and go from there. VIDA/DICE would likely be best to monitor duty cycle rather than simply mean voltage. Would a simple oscilloscope app on android tell me essentially the same thing?

By simply replacing the motor I will never know what failed and will have no confidence that it won’t happen again (until it does).

Fuel tank is ~1/4 full so I don’t spill too much assuming I eventually do open the tank. I am concerned about overheating the pump, but I'm not driving very much so ....
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Other thoughts:

I read that fuel pressure regulation can be achieved “solely by the pump.” This could be an actual in-line, in-tank regulator or a pulse-width-modulated fuel pump in a non-return system that does not have a separate physical regulator located anywhere in the vehicle. In this case fuel pressure, or a surrogate parameter, must still be monitored to provide the data used to modulate the pump, right? I did not see a FPS on the rail or anywhere nearby. Did I miss it? The FPSs I’ve seen in photos seem too obvious to miss. What, then, performs this pressure sensing function and where is it (if I actually have a PWM fuel pump)?

[XC70Rider]

The FPS is attached to the far right of the fuel rail. I just replaced it on a 2007 XC70. It's mounted with a torx screw.

[enotslim]

Thanks for this suggestion but this car does not have a FPS in that location (or at the other end of the fuel rail or anywhere else that I've looked). See discussion and photo in the original post in this topic.

FWIW I also haven't found a PEM in any of the usual locations, also covered above and in a previous topic linked above.

[Vova585]

So as far as I see this we are down to 3 possibilities-1) pump itself, which is slightly questionable at this time since the car is working good when it works and you didn't report any abnormal sounds. 2) wiring to the pump- question if this is the case since wiring to the pump was found to be ok as per your review. 3) periodical loss of command side of the fuel pump relay.
I would try to get more data on what is going on. Car is not starting- check the voltage at fuel pump. If you have 10.5-12v at pump while cranking and there was no start-replace pump. No detected voltage at pump- remove the fuel pump relay and check the voltages. You will have 12v permanent on post 31. So install Bridge wire between 31 and 87 posts and check if you have 12v at the pump (but if your pump started to work and you can start the car, you now wiring and pump is good). So it will leave you with control side of fuel pump relay.
I think on one side you should likely have 12v permanently and other side should be controlled by ecm by supplying "-" ground upon cranking and idling,etc. You can take a test light and put it in between control side posts and crank the car. No light- either no control or no 12v.
In order to properly diagnose it you will likely need 2-3 channel scope to see what is dropping first-control side of the pump, 12v of control side, 12v supply to the post 31. But unless you want to invest into good diagnostic and oscilloscope with several channels and learn how to play with all that equipment...simple multimeter and control light should be enough to find where is the problem.

[enotslim]

Three issues before I actually drive this car.

1. Assuming I do drive till it won’t start what do you suggest about fuel in the tank? Currently 1/4 full. I’ve read that anything over 1/8-1/4 full leads to spillage into the interior when the ring that secures the pump housing is removed. That seems like a pretty bad design so I question if it is true. On the other hand, low fuel risks overheating the pump. Would elevating the front or rear of the car on ramps or jack stands prevent (or worsen) spillage?

2. The no-start conditions for this car occurred after driving down two floors into a parking garage and after driving the front end onto ramps. Could there be some relationship to fuel level in the tank and/or fuel level sensors (see codes below).

3. Below are the codes found during this recent no-start period (). Any insight about why this car sometimes doesn’t start? Any of these relate to a problem with the command side of the fuel pump relay (as suggested previously)?

Several relate to the fuel system, which of course is suggestive with respect to a fuel-related no-start condition. However, although all were present when I scanned during the first no-start episode, most did not recur during the second no-start episode (after I cleared all codes, was able to drive the car a short while, and the second no-start episode occurred). I haven’t driven more than 2 miles total during this time. I know that some codes require more driving than others to be set and found. However, the fact that these codes were not found during the second no-start episode should indicate that they are not "required” for a failed start.
* indicates codes that have been found on every scan
# indicates codes that were inconsistently found after all codes were cleared. (Also, these actually were not found on the initial scan.)
I’m not showing the air bag error that resulted from connecting the battery with the rear seat unplugged.

*ECM-928C Cruise Control Lever, Signal Faulty
ECM-4050 Fuel Level sensor. Faulty Signal

CEM-6F71 Switch, Fuel Tank Filler Cover. Signal Too Low
CEM-6C48 Transponder Type. Faulty Signal
CEM-8F21 Windshield Wiper. Faulty Signal
CEM-8F2C Windshield Wiper. Signal Too High
CEM-8F2E Windshield Wiper. Signal Too Low

*REM-8F10 Position Sensor Xenon Lamp. Signal Too High
REM-4A37 Fuel Level Sensor. Signal Too High Or Signal Missing
REM-4A33 Fuel Level Sensor. Signal Too High Or Signal Missing

*SWM-000A Communication With Steering Wheel Switches. No Signal
#SWM-0008 Communication With Steering Wheel Buttons. Signal Too Low
#SWM-0009 Communication With Steering Wheel Buttons. Signal Too High

CCM-0021 Evaporator Temperature Sensor, ECC, MCC. Signal Too Low
SRS-007C Rear Center Seat Belt Tensioner. Resistance Too High
SRS-0084 Rear Right Seat Belt Tensioner. Resistance Too High

[Vova585]

1) unfortunately around 1/4 of the tank will be max to remove the pump without spills.
2) dount there is relationship with ramp driving.

Based on the quick look at your codes the only one that is of particular interest is cem-6748 which possibly can cause the no start. As far as I understand it is a code of immobilizer system. If you have a spare key which is original to the car and was not used much before, try using it. Maybe the immobilizer chip inside of the key or immobilizer antena are at fault. So I would start with key.
Other codes-looks like your clock spring is on the way out. Codes for fuel level-most likely contact element of the fuel level sensors are worn(metal wire gliding on top of a special plate. Overtime metal eats through that plates coating. )solution-replace pump assembly and fuel level sensor in the other side of tank.
Your srs light should be on as well with those codes for rear seat. Likely something with igniter at pretensions mechanism. Solution- if noone drives there install $8 ballast in place of connecting to the tensioner mechanism. If you want it perfect-salvage yard and let's hope you will find a good part.

So you added immobilizer system into the list of possibilities. Try the different key or go to junk and pick up different antena ring(or buy a new one for around $70)

[jonesg]

Three issues before I actually drive this car.

you need to read fuel pressure.

[maraschino]

have the same car with crank no start (after sitting for 5 months)
Is there a way to check the fuel pressure line without VIDA and without being able to start the car? (ie: at the schrader valve)

I only have a foxwell 301 and to add some more fun facts i live in the yukon and car is parked outside (still -10C)

I checked the fuses and swap the pump relay with the fog light. New battery, no codes. Checked ECM, cleaned it with stabilant 22a.
Just ordered a new fuel filter which I'll change as soon as it arrives.

Following here see if I can find some answers! RobertDIY and Peppermint have shown some options but still no start...