Starts then stops

   #1  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
2001 beetle 18.T 5 valve.
Died on the road.
No codes
Fuel system = good
VCDS see's rpm while cranking. Does this clear the G28? Mass air also reads.
Diode test light on injector pulses while engine almost starts then stops blinking.
Spark is always present.
Curious, is that a period of time needs to elapse before it will try to start again. Is this from the ecu going to sleep then waking?
 
Last edited:
   #2  

FandaTDI

Verified VCDS User
Verified
Joined
Feb 24, 2018
Messages
108
Reaction score
37
Location
Czech Republic
VCDS Serial number
C?ID=204559
Sounds almost like immo, but if no DTC present, power supply (/voltage drops) of ecu could be one of possible causes, what about sparks/plugs(/coils...)? Engine ground?... For sure(even without faults) would check also communication status to other units in mvb ... And as I am reading it again and thinking of it, synchronization check or compression test might be good start also ;-)
Btw. how long period and what is almost starts(rpm)?
 
   #3  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
Wednesday,07,April,2021,12:34:27:34163
VCDS Version: Release 21.3.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 25: Immobilizer Labels: None
Control Module Part Number: Bitte Adress
Component and/or Version: e 17 eingeben
Software Coding:
Work Shop Code:
VCID: 5ABBB239C69A0A5BED-4B00
No Faults Found

or DTCs not supported by controller
or a communication error occurred

Does this look legit?
And how would one disable the immobilizer?
 
Last edited by a moderator:
   #4  

Uwe

Benevolent Dictator
Staff member
Joined
Jan 29, 2014
Messages
33,668
Reaction score
24,024
Location
USA
VCDS Serial number
HC100001
Does this look legit?
Yes. "Bitte Adresse 17 eingeben" means "Please use Address 17". In other words, 17-Instruments is where you will find immobilizer functions.

-Uwe-
 
   #5  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
Replaced the ecu. The original had a GIAC chip. Requested an ECU w. no Immo.
VCDS does not read an IMMO present. Starts for 2 sec.
Question, does a bad cluster or Immo coil still have the ability cause this?
 
   #6  

Uwe

Benevolent Dictator
Staff member
Joined
Jan 29, 2014
Messages
33,668
Reaction score
24,024
Location
USA
VCDS Serial number
HC100001
Question, does a bad cluster or Immo coil still have the ability cause this?
No. If the ECU is immo defeated, it should not care what the cluster/immo thinks.

-Uwe-
 
   #7  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
There is something fundamental wrong.
Question; does the timing for the injectors come from the same source as ignition? What does the camshaft signal do that the flywheel sensor doesn't?
Immo is definitely ECU removed. (Check adap. #91)
Spark is always there, injector pulse is not.
Won't run on starting fluid. Checked belt timing = OK Since this is an interference motor it would not run ever if it has jumped time?
 
   #8  

Uwe

Benevolent Dictator
Staff member
Joined
Jan 29, 2014
Messages
33,668
Reaction score
24,024
Location
USA
VCDS Serial number
HC100001
Question; does the timing for the injectors come from the same source as ignition?
Yes, the ECU directly controls both.
What does the camshaft signal do that the flywheel sensor doesn't?
First and foremost, it provides phasing info. ECU can tell when cylinder 1 is at TDC from the flywheel & crank position sensor, but it doesn't initially know if that's the top of the compression stroke, with the power stroke about to start, or the top of the exhaust stroke, with the intake stroke about to start. ECUs have been smart enough to figure it out anyway for 20+ years, but it takes them several revolutions to do so, and the cam position sensor provides that info immediately. On newer engines, cam position sensors have gotten precise enough for the ECU to be able to notice things like ti chain stretch.
Spark is always there, injector pulse is not.
Won't run on starting fluid.
That's puzzling.
Since this is an interference motor it would not run ever if it has jumped time?
That would depend how much it jumped; one tooth probably isn't enough to cause valves to meet pistons, but it's certainly enough to cause a very poorly running engine.

-Uwe-
 
   #9  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
Yes, I'm still at it! I got two ECU's with imobilizer delete from the same outfit. VCDS affirms there is no Immo.


2001 Beetle 5 spd. ECU 06A 906 032 FD ME7.5

Here's where it stands.

New fuel filter

Cam timing ok Sounds fine when its running.

Spark is always present.

Injectors firing then stop. Visually verified.

Fuel pump still runs after its stopped running and is cranking

New crank position sensor. Tach needle moves when cranking with no start.

No error codes.

Per suggestion:

Tested with cam position sensor disconnected. No change. VCDS see's it missing.

Disconnect mass air , no change.

Disconnect air temp no change. VCDS see's it missing.

Look for damage on harness

Remove and clean ECU ground.

Disconnect cluster, no change.

Is there something I missed? Does this point to a bad ECU?

If it's permitted, please recommend a source for ECU w. immo delete
 
   #10  

Uwe

Benevolent Dictator
Staff member
Joined
Jan 29, 2014
Messages
33,668
Reaction score
24,024
Location
USA
VCDS Serial number
HC100001
   #11  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
The really curious thing is, only if it sits for about 30 - 45 min. will it start for a few seconds.
 
   #12  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
Looks like low side triggered?

 
Last edited:
   #13  

Uwe

Benevolent Dictator
Staff member
Joined
Jan 29, 2014
Messages
33,668
Reaction score
24,024
Location
USA
VCDS Serial number
HC100001
Looks like low side triggered?
That's what I would consider most probable. However, I have no idea where you got that "plate of spaghetti" type wiring diagram; it sure isn't an official one from VAG.

In any case, if they're low-side switched, put a meter on the high side and see if 12V on the high side doesn't go away the moment they stop spritzing fuel. If that 12V goes away at that point, then trace it backward using a wiring diagram to see what's interrupting it.

-Uwe-
 
   #14  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
That's what I would consider most probable. However, I have no idea where you got that "plate of spaghetti" type wiring diagram; it sure isn't an official one from VAG.

In any case, if they're low-side switched, put a meter on the high side and see if 12V on the high side doesn't go away the moment they stop spritzing fuel. If that 12V goes away at that point, then trace it backward using a wiring diagram to see what's interrupting it.

-Uwe-
The high side V. is always there. Running or cranking after motor stops.
 
Last edited:
   #16  

Uwe

Benevolent Dictator
Staff member
Joined
Jan 29, 2014
Messages
33,668
Reaction score
24,024
Location
USA
VCDS Serial number
HC100001
The high side V. is always there. Running or cranking.
If that's the case, then it kinda has to be the ECU that deciding to no longer fire the injectors. The question is: Why?

#191 GOES TO CLUSTER
Yeah, that's probably the W line; an extension of the K-line that the cluster can interrupt.

-Uwe-
 
   #17  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
here's a log of cranking no start.

Curious that there is a injection time.

 
   #18  

fredgilb

Verified VCDS User
Verified
Joined
Jul 3, 2018
Messages
27
Reaction score
6
Location
Rockland county, NY, USA
VCDS Serial number
C?ID=224483
The ECU's (2) that I used both had Immo disabled. Is it possible that they are not actually "fully" disabled?
 
   #19  

Uwe

Benevolent Dictator
Staff member
Joined
Jan 29, 2014
Messages
33,668
Reaction score
24,024
Location
USA
VCDS Serial number
HC100001
The ECU's (2) that I used both had Immo disabled. Is it possible that they are not actually "fully" disabled?
In that case, I would expect to see a DTC that indicates, "Engine start blocked by immobilizer" or something very similar.

-Uwe-
 
Top