Anyone ever had a problem with a 7638B autosampler when injecting?

One thing to try is take the syringe completely out and see if it stops again.

It doesnt stop when there is no needle, so its either the spring of the syringe motor or its a problem with the septum/little spring by the injector..?

Yes could be the resistance of the syringe which causes it, i tried to find a spring to replace and maybe see if that was the case but unfortunately could not find one :( So yes Agilent should be the next step

You said your septum is 5mm thick, the ones we use are 3mm thick maybe that's it.

It sounds like you're injection into a cool on-column inlet since they use 5mm septa.  I saw the same issue when removable needle was not installed correctly onto the syringe barrel.  See pages 107-108 of the 7683B manual: Agilent 7683B Automatic Liquid Sampler Installation, Operation and Maintenance

This is how my syringe is installed, so maybe we are missing the PTFE disk? but our other autosampler looks the same and works, but im not sure which septum that one has. Ive been at this job for one week, so not sure what was happening before that :P 

The syringe looks like it has a fixed needle, not a removable needle.  What is the syringe part number?  Is it injecting into a cool on-column inlet?  If so, please remove the syringe from the injector and make sure it will go through the septum nut and insert into the column.  Don't try to force it - it may break or bend the syringe.

its the G4513-80226 5ul agilent syringe. Ive tried manual injection and its indeed stuck at one point. Its on-column injection. Ill take a look today at the septum again and the inlet, the septum we checked and the needle should go trough the 5mm septum 

its the G4513-80226 5ul agilent syringe. Ive tried manual injection and its indeed stuck at one point. Its on-column injection. Ill take a look today at the septum again and the inlet, the septum we checked and the needle should go trough the 5mm septum 

Check to make sure the syringe can go through the insert into the column.  You will need to remove the insert from the inlet.  The insert is dependent on column inner diameter also.  See pages 110-111 of the 7890 Maintenance Guide: 7890 Series GC Maintenance (agilent.com).

It looks like your GC is a 6890, but the most of the procedures and consumables are the same for the cool on-column inlet between the 6890 and 7890.

Yes thats what i checked and its not going through the insert, unfortunately we dont have other inserts now so ill order them and hope this fixes it. Thank u for your help

You said it's your first week there, was nobody using it before? 

oh yeah but the GC specialist been gone since september and I started november so no one to consult on this issue

Ok sounds like most labs... a skeleton crew. :)

yes