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Hi all, I was wondering: On what models did Porsche use the fuel distributors that have the fine tuning adjusters on them just outside of the banjo bolts, as seen in the picture below? (Was it just on Euro S 4.7 liter cars?) I have three of these, one off a 79, 80 Euro S and 84 Euro S.
From what I can see, the 1978 band 79 cars seemed to not have the added adjusters, as seen below. I borrowed this pic from a Rennlist member who rebuilt one off a 1978 928 4.5 liter
However, the 1979 4.5 liter I have does have the adjusters on the top. I recall that the guy I bought the car from had changed out the fuel distributor. I don't think the new one is from a 79. Thanks a lot!
As far as I know Mercedes had the adjustable ones not the 928. My car had one on it when I got it and I messed around trying to get it to work for a long time. I finally replaced it with the fuel distributor the car was supposed to come with and it fixed all the problems I was having trying to get it to put down smooth power.
All 928 CIS Fuel Distributors are the same - 78 to 82 4.5L & 80 to 83 4.7L
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Thanks a lot, guys, this helps. I tried to find out as much as I could online on these fuel distributors. I also looked in my shop manual, but could not seem to find what I was looking for. So what are the round things outside the banjo bolts? Are these fine tuning adjusters to allow individual cylinders to receive more fuel, or do they serve another purpose? Thanks again.
I’m pretty sure they adjust the fuel flow but it is almost impossible to get that kind of distributor to work smoothly. Based on my futile attempt. Messed with it for over a year
Thanks a lot, guys, this helps. I tried to find out as much as I could online on these fuel distributors. I also looked in my shop manual, but could not seem to find what I was looking for. So what are the round things outside the banjo bolts? Are these fine tuning adjusters to allow individual cylinders to receive more fuel, or do they serve another purpose? Thanks again.
I have an aluminium one from a Mercedes on my 80 S which look the same as yours. What you see is only a plug. If you open the plug there will be an adjustment screw inside (see pict).
It's possible to adjust but tricky. If you adjust one it effect all. Need to make some kind of test rig to measure the fuel on all 8 injector at same time. Took be about a day for me to get them all balanced within a few percent.
The 4.7 Euro S, did have a steel or iron unit with adjusters. I have a Euro S top end on the my cab with one such. As others have mentioned, probably more trouble than its worth, and I am considering changing to a normal FD. Before I do that, though I will try to use a IR heat gun to see if I can get individual cylinder temperatures and try to adjust it that way. Before I do that I need to smoke test to make sure I don't have any air leaks. Before I do that I have to make the plate to block off the intake. Before I do that... (sigh)
Best thing (easiest) to do is to get a new set of new injectors flow matched and then install them into a car with a standard FD.
They will already be dialed in and wont need their fuel supply individually adjusted to get within a few percent.
The adjustable FDs have their advantages, but for most of us without the proper testing rig it is a major hassle and complication to get it working right.
Thank you for the reply. I thought that the Euro must have some kind of adjusters, since the top looks different than the US type. I think I will NOT mess with these adjusters, it sounds like I would be opening up a can of worms.
Honestly, I am not sure what I want to do just yet, but now I know what my options are. The guy I bought the 79 US car from swapped in a Euro FD on the 4.5 for some reason. He may have had it professionally adjusted with a test rig, not sure. I already have a rebuild kit for it, so I may just run it for now. I will swap it for a US FD later if the car doesn't run well, money is kind of short right now. Thanks a lot for your help.
Honestly, I am not sure what I want to do just yet, but now I know what my options are. The guy I bought the 79 US car from swapped in a Euro FD on the 4.5 for some reason. He may have had it professionally adjusted with a test rig, not sure. I already have a rebuild kit for it, so I may just run it for now. I will swap it for a US FD later if the car doesn't run well, money is kind of short right now. Thanks a lot for your help.
These guys are saying Porsche 928 fuel distributors are all the same. If it’s different it’s one that was not original. That’s the way I am interpreting it. Roger sells 928 parts for a living
08-21-2019, 11:59 PM
K Jetronic Fuel Distributor Questions
George Layton March 2014
