doing a UIM off overhaul (vacuum and fuel hoses, deleting things that do not need to be there and cleaning up some hack work from previous mechanic etc...) on a customers S4 TII.

He is getting rtek 1.8 and four brand new Siemens low imp. 750cc injectors (purchased by him). Everything is all gravy except on the secondary rail. Seems like the injectors are too tall. I can get pictures if need be. I searched and could not find anything relavent. Any information or simular occurances would be greatly appreciated. Thanks guys!

 

are you using the little plastic spacers?
are the injectors the same size as the ones you took out?
some injectors have different plastic castings around the body that need to be trimmed to make them work in our fuel rails.

youre going to have to show pictures for anyone to see what you really need.

 

Are the pintle caps the same style as the factory ones? post side-by-side pics of the original injectors and the 740's. Are these Siemens injectors modeled after the OEM Denso Japanese style or the Bosch style? Denso style has different dimensions and has a lower grommet and pintle cap. Bosch style has a lower o ring built into the injector.

 

i recall sizing them together and they were pretty close to identical (550s VS 750s). only diff. that was noticeable was that the 750s had two smaller o-rings as apposed to one larger o-ring (inlet side). and connector styles were also identical.

I wont be up there again untill tom. night so I will get pictures up then. Thanks for the help so far guys.

 

If they look identical to the Siemans shown in my attachment, then the HARD plastic ring I point to in this jpg needs to be turned down so it will be smaller than the bore in the rails for the injector to work.

They came with the large o'rings which do not fit so I used two o'rings off the stock injectors to make it work. Works fine in two seperate cars. I've no idea how you could have made these work in any of the stock series four rails. Can't work unless modified.