Crank sensor reading double

   #1  

James07879

New Member
Joined
Sep 2, 2021
Messages
5
Reaction score
1
Location
England
Good evening all. Just want to clarify if something can be done using vcds or if anyone had any ideas. Basically I have a 2008 1.8 tfsi a4 which has a slight/major issue.
Bought the car a couple weeks ago with an eml on and with injector seals gone. Serviced injectors and car has p08800 fuel pressure to high. wanted to clarify timing was spot on so redone timing chain (which was fitted 100 miles ago) marks are within limits (125mm between cams at Tdc.
car has had new
Hpfp and sensor
Breather system and hoses
Fuel pressure sensor
New crank sensor
Breather system and fps and crank sensor are genuine but on the live data cam sensor is reading 340-350rpm and the crank sensor reads 1450-1500rpm at idle. Engine speed is at 740-780 and I’m hoping to get a vcds log from the car early next week and will post but wondered if a. Anyone has had anything similar and b. If crank sensor can be adapted using vcds?
mom just at a complete loss as what to do from this point on and any help would be very much appreciated.

many thanks
 
   #2  

Uwe

Benevolent Dictator
Administrator
Joined
Jan 29, 2014
Messages
48,902
Reaction score
33,621
Location
USA
VCDS Serial number
HC100001
If crank sensor can be adapted using vcds?
A crank sensor just produces pulses as the teeth on the flywheel pass by it. There's nothing to be "adapted".

-Uwe-
 
   #3  

James07879

New Member
Joined
Sep 2, 2021
Messages
5
Reaction score
1
Location
England
Oh ok excuse my ignorance I’m just a simple diy mechanic. Do you have any ideas what could cause the crank sensor to read so high?
 
   #4  

Uwe

Benevolent Dictator
Administrator
Joined
Jan 29, 2014
Messages
48,902
Reaction score
33,621
Location
USA
VCDS Serial number
HC100001
Cam turns at half the speed of the crank so that sounds good.
You say "Engine speed is at 740-780" and "crank sensor reads 1450-1500rpm".
Please explain where you're getting the latter value.

-Uwe-
 
   #5  

James07879

New Member
Joined
Sep 2, 2021
Messages
5
Reaction score
1
Location
England
That’s what Ive come to understand. Well not the best scan tool I know but have a snap on scanner. On live data gives a engine speed reading then a cam shaft sensor and crankshaft sensor rpm reading. Had a friend check it with vcds and checked the fuel pressure and crank sensor reading. Fp was at 162bar on idle at 90 degrees and crank sensor was reading same as snap on.
 
   #6  

Uwe

Benevolent Dictator
Administrator
Joined
Jan 29, 2014
Messages
48,902
Reaction score
33,621
Location
USA
VCDS Serial number
HC100001
Well not the best scan tool I know but have a snap on scanner.
G35InKi.gif


-Uwe-
 
   #8  

James07879

New Member
Joined
Sep 2, 2021
Messages
5
Reaction score
1
Location
England
Should be able to use the “correct scanner” today so will post some logs
 
Back
Top