Pump starts then stops within a second. MKVI GTI - HFS-4 - Page 6

Richard L · #51 30-03-2015, 01:46 PM

Cutting the white wire will minimise the interference, one of the cause of interference.

The white wire transmits raw pulses from the flow sensor to the controller and external device. If you are not using a third party ECU, you don't need it. No negative effect

maskari_gti · #52 06-04-2015, 04:10 PM

So, I can now say that my problem is solved. Big thanks to Richard for assisting me here first of all. You did a great job walking me through various steps of diagnosing the issue. With that, I've learned more about my Aquamist setup. Special thanks to Tensai Tuning in Abu Dhabi for scheduling me in even though they were fully booked.

Things done during the fix in order:

- Visual check for any leaks in general.

Two leaks on the tank. (Fixed)
Jet leaking in the TBP. (Replaced with a new 0.8mm Jet)

- Replaced the in tank filter.
- Did a spraying test and found out that the pump is actually pumping.
- Checked spraying after the FAV and turned out to be clogged. So with the aid of air pressure, we managed to free it out. It then sprayed meth from there.
- Checked the soldered wires going to the ECU. All were looking good and in place.

After this, we took the car for a test drive and all worked well. But on my way from the workshop, the same issue came back! So I drove back the following day and had it checked with the following:

- Got a new FAV to check if the problem was there. Issue still exist.
- Finally, started checking the pump and found out the pressure wasn't 160PSI. So, the pressure was then adjusted accordingly.
- Cut the white wire from the USER harness to eliminate false flow. It works 100% now.

Took the car for the final test drive and all is working on well now. Even better than before. No more hiccups. And I mean by that, FS activates from time to time for no obvious reasons.

I'm really happy that the issue is now gone. I can now drive my car happily

Richard L · #53 08-04-2015, 07:49 AM

Thank for update, happen ending. There was quite a bit of effort on your side. well done. I think a full service every three years should prevent this from happening again.

Juts need to fine tune the WL and WH. Make sure the bars on the gauge does not exceed 6 bars... this stops the WH from triggering.

maskari_gti · #54 08-04-2015, 08:46 AM

Quote:

Originally Posted by Richard L

Thank for update, happen ending. There was quite a bit of effort on your side. well done. I think a full service every three years should prevent this from happening again.

Juts need to fine tune the WL and WH. Make sure the bars on the gauge does not exceed 6 bars... this stops the WH from triggering.

I really appreciate your swift responses and time spent to get this sorted Richard. I shall do regular servicing every now and then to prevent anything similar from happening.

Just one more question, it's strange what happened to the pump, is this a sign of it dying? I never adjusted it before but how come the pressure was low.

Richard L · #55 09-04-2015, 10:33 PM

The pump should last for many years. The drop in pressure could be due to the spring ageing other the years. 1/4 to 1/2T clockwise should address that.

Richard

maskari_gti · #56 30-04-2015, 07:56 AM

So, the system runs just fine. I logged the car and I can see drop in temperature. I still have timing retardation but that's just -1 to -2 which is acceptable.

Only thing Ive noticed is, the failsafe triggers on the first spraying. But then it runs normally.