XC90 V8 Intermittent fuel pressure cutout (kinked fuel pump line) Topic is solved

[SHOCKWAVE]

Pictures of intake area:

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xc90_cabling_.jpg (138.54 KiB) Viewed 2786 times

XC90_Throttle_boot-2.jpg (108.73 KiB) Viewed 2786 times

VIDEOS:
1) COLD START:

1a) Close up of serpentine area after cold start

2) Inside cabin showing "Rev delay" (taken shortly after a cold start)

3) This was taken after I got home after the last incident, I did not shut it off and took video. I believe there is a slight hissing coming from somewhere... Loudest at the end of the video.

[SHOCKWAVE]

So after the PEM replacement and the subsequent hiccup (Feb 8, noted earlier in thread) at about 28 miles...

I drove the car this weekend without any (apparent) issues. I did not baby it and drove about 30 miles. I also drove it into work this morning (15 miles).

I contacted Volvo and another shop last week with my data and they said I had to bring it in to make an assessment (even with gobs of data supplied). I understand they don't want to give free evaluations. However, if they ignore my data, and if it is running fine they aren't going to be able to find any issues (most likely). Volvo was able to schedule an appointment on at the end of March..???? They said they are really busy, lol. I was expecting one of them to at least say the data is worthwhile to look at.

There's one more shop that specializes in Volvos (Pennas Volvo), and I'll see if they are willing to work with me.

[SHOCKWAVE]

So drove to work and back conservatively. On the last few blocks home I increased rpma 3k-4K. Then I parked at home and idled for about 15 minutes getting VIDA hooked up and playing around with parameters. It proceeded to die, but didn’t throw codes. I restarted and after 5 minutes, same thing but with MIL and codes..here is the video:

I’ll post up some more info hopefully but I noticed cylinder 1 and 7 have misfire counts of 256 each...interesting

XC90V8_CylinderOrder.JPG (31.46 KiB) Viewed 2724 times

[precopster]

Do these V8s run a Bosch ECM? Though rare they do fail and cause similar (intermittent) faults

With enough time on your hands this may end up being a diagnosis going straight back to the ECM.

[SHOCKWAVE]

The ECM is a Denso. Are you saying the ECM just dies out with no signs of physical ingress/corrosion? Does the Denso/Bosch brand make a difference? How is a failed ECM diagnosed?

[precopster]

Denso also fail but it seems I have more Bosch ones being cloned of late probably more due to the popularity of the turbo five cylinder.

One thing a car can't do well is diagnose it's own ECM when intermittently faulty. If you're lucky you'll get a failed communication code on Vida ECM-003 I think it is. My own XC70 2002 just had ECM cloned. Engine was shutting down in the middle of driving usually more than 20 minutes of operation. Then it would start straight back up and drive another 20 minutes.

First step is to clean ECM edge connector before stepping out to replace. There is a forum member that can clone if you have Dice.

[SHOCKWAVE]

I’m not familiar with cloning...are these the steps...
1) Diagnose ECM as bad
2) Procure used ECM assumed to be working
3) Download current ECM image
4) Install used ECM in place of original
5) install “old” ECM image onto used ECM

Mind you this is a SoCal car spending it’s life in 0-5% humidity, .5 in water/ year, and 70 degree weather...a used ECM from a different area is going to have gone through much harsher conditions...

[abscate]

I still want to see the CEM to PEM voltage. That's the test of the fuel pump relay which is hard soldered onto the CEM

I'm in Irvine this week, might have time Sunday !

[SHOCKWAVE]

</s>
No electrical testing yet...Haven't done much of this on an auto so I'll be learning a new skill here. I need to get some backprobes first...However, the CEM would generate a code if the voltage is too low from what I understand of the description I posted ...<B><s></s>"From 372: CEM-3F90 Fuel pump relay. Open circuit or short circuit to ground."<e></e></B><br/>
(B+ = BL ?)
Test like this?
<e>

I didn't want to jump into that until I was certain of what I was doing. Any chance you can confirm my questions above? Basically, back probe the blue wire from the CEM and I should be getting +-.1V? Also, Amazon won't ship cheap back probe kits to CA, so I'm having a difficult time finding some. I'll probably just get T-pins. I'll send you a PM for Sunday. That would be awesome if you could stop by. I'm around IRVINE BLVD/SAND CANYON AVE. I'm taking into Pennas Volvo on Monday.

Further testing at idle and I was getting some weird/interesting things. The individual misfire counters were all zero, but the average was increasing. I kept taking readings and sometimes the value would be listed (per cylinder = 0), and sometimes it was blank...I did this multiple times to see if it was a computer/DICE glitch, but got the same results. The fuel pressure never changed from 480kpa.

It seems the date is off or the codes were set before the day I let the engine die which did turn on the MIL. The MIL turned off on the third drive cycle, I believe. It wasn't turned on yesterday.

Weird thing this morning...I went out and the parking lights were on. I checked to see if I somehow turned the knob, but the light switch was in the "0" automatic position. The security light / alarm was not triggered.

[SHOCKWAVE]

We did some testing today. Much thanks to @abscate for his help:

The voltage from the CEM remained relatively constant at 14.00 +/- .05 V. The voltage from the ECM remained at 7.00 +/-.5V. The fuel pump duty cycle was at 40-50% during this test. The car proceeded to die after 10 min of hard driving and +40min at idle. The voltage from the ECM dropped intermittently around 3.0V to full signal (7.00 +/-.5V) while revving and it was starting to die.

The ECM signal is suspect at this point. Does anyone know the acceptable value range? Revving the engine created a dying condition and the signal bounced from 3.00 to 7.5V. Once it died, both signals (CEM and ECM) were 2.0V +/-.2V.

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Considering hooking up an oscilloscope to check the PWM signal...

After hooking up battery...

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After driving...Instantaneous MPG seemed to be improved...

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ECM edge connector looked brand new. Maybe a cleaning would help regardless...