Vems making restart/startup loops

Mr.E · August 11, 2016, 08:23:38 AM

I have Audi 1.8t AEB,
Everithing was ok, but i installed WI injection and needed to remove vems, now ..

What could cause this symptom: if ignition is on, vems keep making restart/startup loops (turning FP on and off and making priming pulse), if cranked then all ok and vems & car runs normally. Issue seems to be related with VR (primary trigger) sensor input, if vr disconnected than no restart/startup loops but ofcourse no rpm signal. if i connect ~1kohm resistor in parallel with vr sensor then also no restart loops but this resistor causes weaker vr signal therefore rpm sync issues over 2..3k rpm. question then: what parts of schematic could cause thiskind of restart anomalies for vems?

VR sensor is usual ~500ohm iductive sensor, one side grounded and other side connected to primari trigger input

B.R
Erik

MWfire · August 11, 2016, 10:06:04 AM

bad cable for vr sensor(not shielded as shoud be).

Mr.E · August 11, 2016, 10:13:37 AM

Cabel and shield ok, checkd.

Mr.E · August 11, 2016, 11:12:24 AM

When i remove fuelpump relay, there is silence. Ofcourse the car won't start and allso thers no on/off switching.

fphil · August 11, 2016, 05:15:03 PM

You may have a pulse coming through the ground which then triggers the VR chip
Have you tested with the FP side disconnected from the relay?
Have you tried with another relay?
I would also test with a diode in line on the return to ecu

Mr.E · August 11, 2016, 10:18:36 PM

Removeing fp fuse/relay , everithing seems to be okay, but the car wont start because thers no power on fuelpump. When i reconnect fuse and relay error comes, but when i start the car again all is ok.

Error came afther MAP change.... Maybe its connected somehow???

Crazzy???

Kamuto · August 12, 2016, 05:16:30 AM

how wired is your map?

Mr.E · August 12, 2016, 05:57:56 AM

Exactly like original,

Old electric plate removed - > MAP sensor remove -> new MAP installed > electric plate install.
( Map settings is changed via vemstune and working )

MWfire · August 12, 2016, 10:11:06 AM

Quote from: Mr.E on August 11, 2016, 10:13:37 AM
Cabel and shield ok, checkd.

Is you shield connected to ground in engine bay? If yes, that is a problem.

Mr.E · August 12, 2016, 10:16:04 AM

Dont know, i didnt do wiring, but before it worked and i havent changed wire locations. Only added meth injection to injector + and ground. At the moment WI is dissconected.

Mr.E · August 12, 2016, 02:48:13 PM

Quote from: MWfire on August 12, 2016, 10:11:06 AM
Quote from: Mr.E on August 11, 2016, 10:13:37 AM
Cabel and shield ok, checkd.
Is you shield connected to ground in engine bay? If yes, that is a problem.

Shield isn't connected in engine bay. - checked

Mr.E · August 12, 2016, 03:43:55 PM

We measured output from lm1815 during this restart/startup loop and its in silence, no pulses sent to cpu.

fphil · August 12, 2016, 04:59:36 PM

If you got a oscilloscope, you are saved. I would first scope the signal FPrelay/Vems to the relay. btw have you tried with another relay?

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Vems making restart/startup loops