MK1 Kjet pump with MK3 AGG engine?

hi guys,

My camper van currently has a Mk1 Gti kjet engine that uses a high pressure pump and accumulator. Would it be possible to use the same setup with an AGG engine I am going to upgrade to?

Would the pressure be too high from my existing pump? Would the accumulator cause issues by maintaining high pressure?

Thanks

 

Presumably the agg is electronic fuel injection, and has the 3 bar or whatever it actually is fuel pressure regulator and a fuel return line to the tank, so it wont matter as I see it what the original pump puts out. As for the accumulator why not remove it as its not required, one less thing to leak..

 

Hi abf, Ideally I would like to keep the current fuel setup mainly as its working well and plumbed in with metal pipes etc. Removing the accumulator or replacing fuel pump would mean having to research and install different unions etc to get the fuel to the engine bay. I will do this if needed but had hoped I could run my current Pierburg MK1 gti pump with the AGG setup.

I know the AGG has a fuel regulator but wondered if 6.5 bar over the usual 3 it is designed for might cause issues, as well as the constant pressure of the accumulator after engine shutdown.

Has anyone here ran an AGG with a MK1 inline type fuel pump before?

 

Hi Johnny, that is music to my ears! But isn’t the mk2 digi pump lower pressure than the kjet?

Will I be ok going from the metal pipe on the high pressure side to some kind of rubber hose I assume the AGG will accept for the fuel? Will that pressure cause easy leaks?

Thanks Johnny, amazes me how much you know about all the different golfs!

 

What did you do for a fuel filter Johnny?

 

So I am inching every more to the engine swap. On a bit of an ordering mission now so just want to check a few things if that’s ok and anyone has time to help with some advice.

Firstly I am a bit paranoid about the higher fuel pressure I will be delivering. Can the FPR really bring the 6bar my kjet pump gives down to the 3 needed?

Also what fuel hoses would you recommend to go from the output side of an existing kjet fuel filter in my engine bay to the fuel rail? Am I ok to go to rubber fuel hose using a banjo and fuel clips, or is it likely to leak / burst off due to the high pressure?

Next is an issue with the rocker cover breather. Due to having to use a non standard airbox I will not have the spigot for the top breather hose. I was considering running this to a catch can with a small filter so it releases to air with no return to the inlet side. Will I have issues doing this? I read about oil leaks due to disturbing crank pressure or some such but have seen other conversions fine this method. I cannot think how I can splice back to the inlet side and keep it airtight.

Lastly out of interest does anyone know how the AGG will compare to my existing DX engine in terms of power / torque curve?

Thanks for all the help so far

 

I ran my efi converted mk2 16v on k-jet pump without issue.

The pump only produces fuel flow/ volume, it's the Fuel Pressure Regulator that governs the pressure and you'll be using the one on the end of your new fuel rail .

The k-jet FPR is in the metering head that will be in the shed!.

 

That's 2 people who have said it will be fine here so I am happy with that )

Regarding fixings, will fuel hose with banjos and fuel clips be OK in this application? I aim to leave the current metal fuel line going to the kjet filter and use a banjo on the output of the filter to then carry fuel to the rail. Not entirely sure of the best fixings. Ideally I would like to avoid banjo as I worry it might come off, paranoid I know. However I cant think how else I can get fuel to the rail as it will have to go to rubber hose eventually to fit over the rail inlet and outlet.

Also any advice regarding the catch can to air solution for my breather hose issue?

 

A banjo to barbed fitting with good quality fuel hose and screwed hose clips will be absolutely fine.

Have you any pictures, is the filter in the engine bay?.

 

At the moment I actually have the MK1 K-jet installed and so the filter is attached to the rear of the metering / air filter assembly. I am hoping to mount this same filter on the bulkhead with a bracket and have the current metal fuel line and fixing still going to it. I will then fix a banjo to the outlet side and run the fuel across engine bay to the AGG fuel rail.

Catch can I am not sure yet if having it breath to air will be an issue.

 

That will be fine, my GTO came with banjo fittings from the factory so no worries there.

Just make sure you get decent quality hose.

I run a catch can, it may smell open vent unless you can pipe it down. Could try open first (filter over it) and see how you get on.

Maybe fit an oil separator?, depends on how heavy it breaths I suppose!.

 

I am getting a lot of concern on the VW T25 facebook group about using such a higher pressure pump but trust all your opinions as you guys must know these engines like the back of your hands

Rather than starting a new thread I may as well ask here as it is related. I am looking at ways to best join the AGG rubber fuel hoses to my current hard fuel line setup.

My van currently has a solid fuel hose to and from the fuel tank and I would like to connect this fuel return line to the 8mm rubber hose that will be leaving the AGG fuel rail.



The fuel is returning to the tank from right to left.

It seems you can get straight barbed connections with thread on one end but not sure firstly if suitable for this use, and secondly what the diameter and thread size would be needed for a female to barbed fitting?

Is it 3/16" or is it metric?

Unfortunately I cant measure mine at moment as on the road soon.

Thanks again for your help.

 

There is a barb under that plasic return pipe (rhs of fitting) by the look of it (there was on my MK2 k-jet). Worste (or best!) case you can use that barb for the return pipe with no issues.

The pump has no pressue, only flow. If you ran it with no FPR into a bucket it would have next to 0 pressure in the lines.

 

Ah I had not noticed that. Is there any DIY way to use that heat shrink pipe plastic fuel line or is it added to the barb at factory? What method would you use to connect up the engine to the fuel lines like I have?

Thanks

 

I think whoever did the current MK1 Gti conversion way back in the early 90's used all sorts of parts not standard on a T25. The solid fuel lines are not T25 standard so thought maybe they are more specific to the GTI engine hence asking here. I assumed they might be brake connectors but looking closer they look different.



I have no idea how they work without cracking them open. Do these look familiar to you GTI guys? Are the metal line connectors male or female?