VW T6 CXBG won't start after replacing injectors and CR pump

[seba65310]

Hello,
I have a problem with my T6 CXGB 102HP. Unfortunately, the pump started to flake and unfortunately due to the shavings the entire fuel system had to be replaced.

New pump and injectors (regenerated), fuel pump, lines, filters etc. Additionally, the timing belt was replaced at the same time.

After assembling the car, it started, it worked for 30 minutes, I turned it off and it won't start... it can only run on auto start (spray). No errors in the ECU.
The pressure on the rail is good.

What could have happened?

(timing belt adjusted? , camshafts etc. )

 

[Dellmassive]

if it starts with starter fluid - then its lack of fuel issue.

sounds like either the HPFP or injector/s or both have failed?

can you get any VCDS data to measure the fuel rail pressure?

......


was the fuel system completely flushed out properly, fuel filter replaced, fuel tank flushed etc etc . .

any old contaminants from the old pump will will destroy the new pump and injectors.

this is one of the reason VW main dealers want to fully replace the tank and lines to 100% make sure that no contaminants are left in the system.

+++

 

[seba65310]

The entire system was replaced, including the pumps in the tank, metal pipes, filters, etc.

I read here on the forum that if there is a problem with the camshaft setting, the computer does not open the injectors, but mine worked for 30 minutes and did not want to start.

We checked the injectors again and they are ok. We did not check the pump.

 

[bluezie]

I'd start with double checking the cam and pump timings, in case it's slipped or wasn't quite right to start with. I'm assuming it was done with locking pins, not Tipex marks?
Also unplug all connectors that were disconnected, and check them for corrosion, contamination and proper insertion.
Also read in the measuring blocks the crank and cam sensor outputs.
If the injectors are getting no injection pulses, it sound like the ECU isn't happy with the sensors input data, really hope the new pump and injectors haven't gone again!

 

[seba65310]

 

[mmi]

Picture 1: There is no fuel pressure (IDE07818 = 0...1 bar) even though ECU asks for 320 bars (IDE07820) - assuming the snippet was made while cranking the engine.

Picture 3: The engine is cranked quite well (IDE00021 = 236...254 RPM) but the injectors do not fire (IDE00352 = remains at 0 µs) - obviously because there is no fuel pressure (IDE00589 = 0 kPa)

 

[seba65310]

Yes, exactly.
The fuel goes to the injection rail 100%, but it seems like it doesn't go any further.
I'm going to buy a new injection rail because I have no other idea.

 

[bluezie]

I'm struggling to interpret due to not being able to copy and paste and translate from what looks like possibly Polish?
But if the ECU thinks there is no pressure, it won't fire the injectors. What have you used to determine whether you actually have rail pressure or not, ie an external gauge? If that's reading good very high pressure, then there is probably a fault with the rail pressure sensor. If the regulator is shot, it should still run, although badly, but you could try disconnecting the regulator wiring plug, and see if it will start, or get any rail pressure.
If there is no actual rail pressure, then it's a fuel supply issue, or the new pump is faulty.

 

[seba65310]

Unfortunately, I did not check the pressure coming from the pump with a manometer, but the mechanic said that the pressure coming from the pump is 100% because he disconnected the line and fuel is flowing.

linki to log:
https://drive.google.com/file/d/1DYXY5zhPBv9z3YFLmJL63TFlwGAfzkDf/view?usp=sharing,
https://drive.google.com/file/d/1dI1AGemDhD46fZP8d0XPGe21R2pK-chg/view?usp=sharing,

https://drive.google.com/file/d/1iqN0IJBr2nB7A1n5DPArtS9eohF2m4Gg/view?usp=sharing

I will translate the table and send it to you

 

[bluezie]

Unfortunately, I did not check the pressure coming from the pump with a manometer, but the mechanic said that the pressure coming from the pump is 100% because he disconnected the line and fuel is flowing.

There's a massive difference between 'fuel flowing' and 300 BAR , (or 4260 PSI) on the rail! The only way to know for certain is an external gauge, I've no idea what the ECU's programmed cut off point of requested vs actual fuel pressure is before it refuses to fire the injectors? It may be if it's requesting 300 BAR, and getting less than 100 BAR it shuts down, but cracking off a union will still show very high pressure, but not how much.
Undoing unions can very dangerous on a CR engine, proper rail pressures can cut you open and inject diesel into the bloodstream, or damage your eyes etc!

 

[mmi]

the mechanic said that the pressure coming from the pump is 100% because he disconnected the line and fuel is flowing.

Hmmm... while cranking the lift pump in fuel tank (IDE07824 on the logs) creates some pressure (a few bars) to make fuel flow...

linki to log:
https://drive.google.com/file/d/1DYXY5zhPBv9z3YFLmJL63TFlwGAfzkDf/view?usp=sharing,
https://drive.google.com/file/d/1dI1AGemDhD46fZP8d0XPGe21R2pK-chg/view?usp=sharing,
https://drive.google.com/file/d/1iqN0IJBr2nB7A1n5DPArtS9eohF2m4Gg/view?usp=sharing

Can't access any of them.

 

[seba65310]

LOG-01-IDE01378_&3 - Google Drive

docs.google.com

LOG-01-IDE00178_&11 - Google Drive

docs.google.com

 

[bluezie]

Ah, thanks for the translation!
Those logs are showing a requested pressure of 200bar to 320bar, and an actual pressure of 0 to 1 bar, so as good as zero. As said above, the 1 bar is probably the lift pump.
So, it looks like there is a fuel supply issue, the new pump has packed up, or the pressure sensor is faulty.

 

[seba65310]

Hello, I bought a new complete strip, but it didn't help. We also checked the pump pressure and it is there.

We will look for electrical problems.

 

[Arpski762]

I might ask here as well.
Got multivan for repair, it was running before without issue. Stripped the engine, got new one from VW with 4 new injectors. Rebuild everything, out inside the car, primed fuel few time with vcds, engine then started for like 6-7 seconds, went down as if there was no fuel and since then won't start anymore. I've already tried to put old injectors, still no run at all. With startspray it can run without issue. I've checked timing belt few times (although through my carrier never made error there). Fuel is there, rpms too, everything electrically looks perfect to me. Yet engine won't start and run in it's own. This is a big mystery as I rebuild like 6 of these engines and never ever had any problem with starting. Ofcourse it's giving me no errors.

Log #861538

log.tunezilla.com

IT seems like even if it shows that injectors are opening electronically, they are phisically not. I don't know what to think about this anymore.