Blue Temperature Sender...

[[steve]]

As some may know, I've been having an issue with my mk2 8v Digi bucking and jerking when going onto and coming off throttle (when cruising - no gear changes or clutch involved)...

I got the injectors cleaned, I have timed it up to 6BTDC @ 2250RPM with blue temp sender unplugged.

I replaced the sender last year (GSF one though!) and had the head gasket done after that - I only recall the issues emerging after the head gasket and I can't for the life of me remember if the sender was changed before or after the head gasket!

Anyway, I have been tweaking the idle screw and the CO adjustment screw in the MAF body to try and smooth out this jerking however, as smooth as i get the idle, it is still happening!

Now, this morning, I went out and adjusted the Throttle Closed Switch ever so slightly (moved it back about 1mm) to ensure it clicks at the exact moment the throttle arm starts to move as I was convinced the play there was causing this jerking but alas, took it for spin and NO CHANGE 

Anyway, my thoughts brought me back to the blue temp sender, so I unplugged it and took the car for a quick spin up the road... absolutely no jerking/bucking 

However, is it that simple to diagnose that the blue temp sender is at fault?

I have checked resistance on the GSF sender on the vehicle with engine up to temp and it read 200ohms... I think this is a little low as the stats I have found in the interwebz of things say it should be 375ohms @ 80 degrees...

I can't check the resistance in any more detail until the engine cools down and I can get it off the car.

I checked the original VW one I took off last year and the resistance went to just over 3000ohms when put into boiling water out of a kettle and then in a cup of cold water with an ice cube it only got down to about 500ohms...

Can anyone tell me if the original one is any good, or if I should just go to VW and get a new sender?

I suspect the GSF one is not great so I may just swap it out for the genuine VW one to see what happens..

I just don't want to order in a new sender and fit it to find that the issue is still there!

Any advice appreciated.

Thanks.

Steve

[lemski]

It seems like the sender.
As its unplugged the problems gone and the resistance is down from whats specified and what the original is readimg

[[steve]]

It seems like the sender.
As its unplugged the problems gone and the resistance is down from whats specified and what the original is readimg

Cheers dude.

Engine should be warm enough in the next hour to go out and swap back to the original for testing.

If still no joy will order a new Gen one from VW on Tuesday and fit it next week.

Appreciate the reply. Just wanted to make sure I was on the right track with my thinking.

Steve.

[lemski]

Trust your gut feeling. Normally right.

[theclash]

Check the wiring to the throttle body not the wiring between the 2 switches but the wiring on top right of tb looking from front of car coming from under scuttle physically check it as this goes brittle and snappes in its sleeve and will give you the exact same symptoms you are experiencing