2006.5 BRM DSG - New harness, more problemss

2006.5 BRM DSG - New engine harness, more problems

After my 2006.5 BRM DSG Jetta died for a second time in 2 weeks, slow down, engine stall, no start until engine cools off.

I check the harness found no chaffing, no broken wires, replaced ESS, rewrapped with friction tape after the first stall.

Bought a new harness after second stall.

Installed, long crank and rough start, low oil pressure warning comes on, flashing glow plug.
ABS, steering, MIL on.

Pulled codes-

01 Engine-
000802 - Engine Speed Sensor (G28)
P0322 - 000 - No Signal - MIL ON

02 Auto Trans-
18256 - Please check DTC Memory of Engine Controller
P1848 - 000 - - Intermittent

03 ABS-
01314 - Engine Control Module
013 - Check DTC Memory - Intermittent

17 Instruments-
00446 - Function Limitation due to Under-Voltage
002 - Lower Limit Exceeded - Intermittent

65 Tire Pressure-
00625 - Vehicle Speed Signal
008 - Implausible Signal - Intermittent

When I erase codes, start or drive, all codes come back.

I left the new harness in and installed the old harness laying it on top of motor, I used a new coolant temp sensor because it sux to get at, same codes, erase, drive codes come back.

Left the battery unplugged and bat terminals shorted all night, started right up.

Took it for a couple mile drive, worked perfectly, no codes, no lights.

Got home, 10 minutes later, started back up when hot, low oil warning, all codes back.

Replaced both 460 relays with known good, no change.

Any ideas?

Have you checked the ground connections next to the battery and under the air cleaner? Take the connections apart and clean. Don't just wipe clean, but lightly sand to get clean metal on both the terminals and the posts. How old is the battery?

New harness, crank sensor, same stall and no start

I did find the main ground was already relocated 1 1/2" forward from the original due to corrosion.
Cleaned all under hood grounds, I also added additional grounds between bat, main, and left frame.
Everything seemed perfect.
Car was already warm.
This afternoon drove 1 mile to Post Office, 90 degrees, AC on, coming back car stumbled for a few seconds, 1/4 mile later when slowing to turn car dies, roll into exact same spot as last time.
New engine harness and ESS since, starts cold instantly.
The car 2x lightly stumbles for a few seconds (new added - 5-1-15 - at 50-60 mph when hot) before stalling in a 1/4 mile when slowing for a right turn.
VCDS no new codes while dead (dr door harness needs replacing, unplugged when dead this time, still no start), + remove and reseat all fuses, + replace underhood relay in e-box.
No start until 2 hours later with long crank, running rough for a few seconds, with hood open,windows down, in shade, same as last time.
Waiting on new cam sensor.

Hopefully Monday I can get it to stall and tow it home while dead.
Then I can test:
ASV
EGR
Fuel Pump / pressure / relay
ECU - I have one but immo is still on, but should start anyhow.
Temp Sensors

Have to figure out what to log in VCDS when driving.

Today I hooked up a adapter and fuel gauge to the tandem pump port today, 0 psi when I turn on the key, running bounces between 45-60psi, starts instantly engine cold, @ 80+ f degrees, later checked 2-3k rpm 80-100+ psi.
Last night I bought the last new OE lift pump from a NE VW dealer, $98 shipped.

TDI Lift Pump Activation with VCDS

Ran VCDS Engine> basic settings> group 035> click start for lift pump activation.
Confirmed 12.5v to pump, dead pump.
This test is also great for priming after replacing fuel pumps, filters, hoses and injectors, runs for 30 seconds each click - search youtube for video.

Waited until hot today, 85+ degrees. AC on..
Have tow hook in, buddy was home a block away ready for my tow strap, so I can test when car is dead and hot.
Let it warm up 1/2 hour before driving 2 miles up to 60mph.
Made a couple stops for shopping.
Last stop back to full throttle up to 60/65, felt the sputter before dying.
Pulled onto side street back to my house, dies.
Check FP volts again 12+, VCDS was hooked up, 298 cranking RPM - no codes.
Replaced FP, can hear now, also 10lbs cranking fuel pressure (had test gauge still on engine).
Ran FP 30 second run test on VCDS a couple times, no start. (VCDS Engine> basic settings> group 035> click start for 30 second lift pump activation)
10 minutes later sputter, give throttle, starts up. (started the same as the last 2 times when it died, but not 2 hours later! started in 15 -20 minutes + multiple 30 second FP primes on VCDS , checked ASV was open)
Thinking pulling air in fuel line, bad tandem pump, fuel temp sensor?
Ironically same corner but opposite way, let it heat soak for 15-20 min at my house and hit the road again, back to the Post Office, sit 5 min while inside.
Come back out full throttle, no slight stumble, no stall like the last couple times on same corner.
Run it up and down the to 65/70 on 55mph highway5 times, let sit, run it, no stumble or stall.
Had to wait until it was near 90 air temp + air on, let it sit hot 30 minutes+ , full throttle, stumble , then slowing for corner dies seconds later.
Fuel temp / heat / vacuum leak tandem pump problem, I'm guessing.
Definately has more top end power too.
Keeping old FP assembly in part kit in trunk - will replace internal pump inside for spare, I do like having one that will run when dead.

I also had a spare ebay ECU with me, I bypassed the IMMO on yesterday.
(Starts and runs great on just a key, no chip)
Didn't need to try it today.

Drove to Miami 400 miles RT Thursday no problems, smoother running, more top end.
Will be in the 90's at least for a week.
Will be testing locally, stop and go traffic, hot restart, full throttle then slow down before I'm sure it's fixed.
I do need to:
Adjust zip tie mod.
Remove old harness that is laid on top of engine.
Check / change fuel filter, possible add one of my large CAT filters.
Replace dr door harness and latch.
Then delete ASV, EGR, CAT and turbo w/rebuild BMM from europe and tune.

I don't get it. You had a fuel problem that could easily been checked but decided to replace the wiring harness first even though you could not find anything wrong with it.

That was a painful gut feel diagnostic.

Just drove 2100 miles RT in 4 days, solid 40mpg @ 75-80 mph, no problems.
Changed to Mobil 1 15w 50 oil, 5qt less than $11 AR, ends 5-31-16.
Change dr door latch, hopefully battery drain and fault is gone, didn't check VCDS.
Getting sluggish when kicking down at higher RPM, probably change fuel filter today.
>>> ALSO, bought a new USA made fuel pump, with volume, pressure and diesel compatible, will be installing in old FP can soon.

James & Son said:

I don't get it. You had a fuel problem that could easily been checked but decided to replace the wiring harness first even though you could not find anything wrong with it.

That was a painful gut feel diagnostic.

Click to expand...

The harness is a known problem, and wires can break internally but still ohm out.
I'm keeping the car for 5+ years so $300 is cheap for peace of mind.
The old harness had repairs on temp sensor and cam sensor, glow plug harness was deteriorated.
I frequently drive long trips and do not want any problems, I have never been stranded on the side of the road.
Luckily the Jetta would stall on way to the local waterfront Grill, and rolled into my parking spot for happy hour.

Can @badgator1 or anyone else please clarify what the actual problem and solution was here? For some reason I find this thread impossible to decode.

I get that some relays, the wiring harness and the lift pump were replaced, but that didn't solve the issue. What did?