Advice on Injectors

I'd appreciate some help to clarify what injectors are required for my EV series Mk2 1.8l engine.  When I removed the injectors, I noticed that the #4 cylinder one is different to the other three.  However they all carry the same part # 049133551A.
Is it simply that the "end cap" has been removed from one of them accidentally or is one a later version?  Which is correct?  See later post for image.

There is 2 types of injectors as you can see, it seems some one has replaced one for the wrong type. Do you have a air/rubber hose attached to the head at the back between cyinders 3 and 4?

mark1gls said

There is 2 types of injectors as you can see, it seems some one has replaced one for the wrong type. Do you have a air/rubber hose attached to the head at the back between cyinders 3 and 4?

Indeed there is and I was wondering about its purpose.

You have the later air shroud injectors, info on different injectors here but ignore the info in the picture to which engines they are fitted to as it's wrong I have a 1988 DX engine with the air shroud injectors.
http://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=technical%2Ffuel-systems-and_3%2Fare-these-suitable-o&kfs86=30
 

mark1gls said

You have the later air shroud injectors, info on different injectors here but ignore the info in the picture to which engines they are fitted to as it's wrong I have a 1988 DX engine with the air shroud injectors.
http://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=technical%2Ffuel-systems-and_3%2Fare-these-suitable-o&kfs86=30
 

Many thanks for that!  So 3 of the injectors are correct, but I'll be replacing all of them anyway.
What is the purpose of the pipe you mentioned connected between 3 and 4 cylinders.

To be honest I have no idea... I guess it feeds air in but have no idea how it all works, I just know I have air shroud injectors because when I replaced mine I found out there was 2 types when I order them so guess they need air in there to work.

the idea is to help the fuel atomise better but ive used both types in my 16v lump and i found there was no noticeable difference. it looks liek the top hat used to be there but has fallen off as you can see witness marks on the end where it used to be, have a look inside the head to make sure its not stuck in there!

you can use either type when rebuilding just note the non-shrouded type have a different thread so you have to change the lines too if you swap. you can get mercedes brass non-shrouded type much cheaper than the normal vw injectors but bear in mind the cost of replacing the lines too

if you dont go with shrouded injectors you ca njust blank off the nipple on the rear of the head to disable the system

rubjonny said

the idea is to help the fuel atomise better but ive used both types in my 16v lump and i found there was no noticeable difference. it looks liek the top hat used to be there but has fallen off as you can see witness marks on the end where it used to be, have a look inside the head to make sure its not stuck in there!

you can use either type when rebuilding just note the non-shrouded type have a different thread so you have to change the lines too if you swap. you can get mercedes brass non-shrouded type much cheaper than the normal vw injectors but bear in mind the cost of replacing the lines too

if you dont go with shrouded injectors you ca njust blank off the nipple on the rear of the head to disable the system

Thanks again, John.  I've already ordered and received new shrouded types as I'm pretty sure all of these are very old so better to replace them. Thanks for confirmation that either type is suitable.

coolio, If you do want the shrouded system to work make sure the plastic insert tube  things are ok and the seals underneath are good