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

[Vova585]

Any updates enotslim?

[enotslim]

Any updates enotslim?

Car still starts but I'm not driving due to a blown exhaust gasket (cat/muffler). Hopefully replacing tomorrow with split flange and gasket. Then we'll see. I wish it would fail to start.

[enotslim]

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...

Prop open the Schrader fitting at the fuel rail, crank engine and catch any fuel in a container. No fuel means no pressure. Or use a real fuel pressure gauge. Test plug sparking during crank/no start? Then test 12V delivery to the fuel pump harness as discussed up-thread here. 12V was very short-lived when I did this but it was observable.

[enotslim]

Quick update (but no progress). Starting finally failed again. I was working on an exhaust gasket leak (I fear to soon to be a separate MVS topic) with several successful starts when the car began to fire, faltered and failed to start x 3. Then failed to fire at all. Battery 12.32V. The only change during this time was a light rain beginning to fall. I planned to test voltage to the starter as discussed above the next day because the rain soon became a torrential downpour . However, next day the car started fine and still does. I missed my chance.

It's ironic that the underlying reason I cannot drive this car is because it does not fail to start.

I expect to post updates if anything useful or enlightening ever happens.

[jonesg]

get this,

https://www.amazon.com/Gorgeri-Exhaust- ... _rp_0_67_t

and this,

https://www.amazon.com/Fel-Pro-61451-Ex ... _rp_0_21_t

[enotslim]

get this,

https://www.amazon.com/Gorgeri-Exhaust- ... _rp_0_67_t

and this,

https://www.amazon.com/Fel-Pro-61451-Ex ... _rp_0_21_t

I used the same split flange (from a different Amazon reseller but looks identical) but the size required is 3 inches (not the 2.5 inches in the link). I used a different gasket. I'll try this one. Thanks.

[abscate]

Bear River converters in LA for really excellent exhaust solutions. Thank Firefox31 for the find

[enotslim]

Update: Codes read five days after the last failure to start episode - that lasted less than one day. Found:

* 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-0009 Communication With Steering Wheel Buttons. Signal Too High
* SRS-007C Rear Center Seat Belt Tensioner. Resistance Too High
* SRS-0084 Rear Right Seat Belt Tensioner. Resistance Too High

Did not find the code below that was seen in the past.

* CEM-6C48 Transponder Type. Faulty Signal

Does not seeing CEM-6C48 eliminate the immobilizer system (key chips and/or antenna) as the source of the intermittent failure to start?

[goldxc70]

I had a fuel pump issue which only happened when the tank was 1/4 or 3/8 full. It turned out that it was the fuel pickup assembly that was faulty. Replacing the whole fuel pump and fuel pickup assembly resolved the problem. Like OP my 2004 has no sensor on the fuel rack and not module on/near the fuel tank.

[enotslim]

I had a fuel pump issue which only happened when the tank was 1/4 or 3/8 full. It turned out that it was the fuel pickup assembly that was faulty. Replacing the whole fuel pump and fuel pickup assembly resolved the problem. Like OP my 2004 has no sensor on the fuel rack and not module on/near the fuel tank.

What were the symptoms when your fuel pickup assembly was faulty? No-start?

I find that the relevant error codes I see (REM-4A33, REM-4A37 and REM-4A38) are reported by others to be associated with inaccurate fuel level sensing but not with a no-start condition (unless the fuel tank becomes entirely empty, of course). I'm not sure that these DTC are related to my no-start condition. My tank reading in the instrument cluster always seems to be accurate. At least it never drops to zero or pins at full. Currently about 1/4 full. These codes are also intermittent, not permanent. I don't know if they became permanent ahead of the no-start condition.

The car has not failed to start since my last post ~ one month ago. I also rarely drive it and never stop anywhere when I do. I haven't filled the tank since the last no-start episode for fear of being stranded at the pump. It's essentially a short trip touring vehicle - not very useful because it will not fail to start.

The only change from previous conditions is that I now always use a quick-disconnect battery switch when the engine is not running to interrupt the parasitic leak I detected but have not yet tracked down to fix. Is it possible that a low battery is causing squirrely behavior of some sensor that then interrupts the starting process? Jump starting with a known good battery doesn't work immediately after a failed start. That would make it easy - just travel with a portable jump starter until I figure this out.

FWIW the no-start condition is exactly mimicked by pulling the starter relay under the driver-side dash.