Note: Everything described here is based on my own experiences. I will not be responsible for any potential damage of
you or your car. I also assume a certain level of experience - if you've never done any major work before on your Pug,
think about getting a professional to do it for you, or to teach you how to do it.

Bosch K-Jetronic
One day my STI lost power above 4000 rpm. This got worse everyday until the car was barely driveable. I checked and tested everything, from ignition to fuel pressure, but every component was just fine. It turned out that the fuel flow was much to low, this is measured by disconnecting the fuel return line and should be 750 ccm in 30 sec.

505 STI main fuel filter

Hollow bolt at left side of filter must
be shortened, (F) is flow direction
The restriction of fuel flow was caused by a too long hollow bolt at the main fuel filter input, in combination with a slightly plugged filter. The bolt must be 23,5 mm instead of 26 mm, so I shortened this one and had full power again. This problem may occur, according to a PEUGEOT service information, on cars until chassis no. 1.247.000 - just like mine...

plug for adjuster on airflow meter
When I checked the K-Jetronic for correct operation, I found the plug (P) for the adjustment screw missing on the airflow device. This is missing on almost every early 505 and allows dirt to be sucked in. I made a new one myself.

Adjusting valve clearances ZEJ and ZN3J engine
When I bought the STI, it had a very rough idle. So I checked the valve clearances, and found 3 exhaust valves to have almost zero play. The clearances defined by PEUGEOT for the ZEJ engine are (cold):

  •   Inlet: 0.10 mm
  •   Exhaust: 0.25 mm
  • To have a smoother idle, and more grunt from low revs, of course in expense of a little bit less max power at high revs and a bit more valve noise, I set the valves 3/100 mm greater (0.13 inlet / 0.28 exhaust), resulting in a "tamer" timing.

    The procedure for setting the valves on the 4 cyl ZEJ is simple (remember though that PEUGEOT defines cyl no 1 as the closest to the firewall):

  •   Ex No 1 fully open: Adjust In 3 / Ex 4

  •   Ex No 2 fully open: Adjust In 4 / Ex 2

  •   Ex No 3 fully open: Adjust In 2 / Ex 1

  •   Ex No 4 fully open: Adjust In 1 / Ex 3

  • In contrast, my ZN3J engined 505 V6 was very noisy when bought. Removing the valve covers takes some time here. Note that the V6 with the casted valve covers has different cover seals as the tin-covered versions. Valve clearances are the same as with the ZEJ engine. I also adjusted the valves to Inlet: 0.13 mm / Exhaust: 0.28 mm. Absolutely worth it!

    There are two procedures for setting the valves on a ZN3J:

  •   Procedure 1:

  • No 1 firing TDC, No 5 rocking: Adjust In 1 2 4 / Adjust Ex 1 3 6 No 1 rocking, No 5 firing TDC: Adjust In 3 5 6 / Adjust Ex 2 4 5

  •   Procedure 2:
  • Adjust only one side of the engine at a time:

    Left cylinder bank:

    No 1 rocking: Adjust In 3 / Ex 2
    No 2 rocking: Adjust In 1 / Ex 3
    No 3 rocking: Adjust In 2 / Ex 1

    Right cylinder bank:

    No 4 rocking: Adjust In 6 / Ex 5
    No 5 rocking: Adjust In 4 / Ex 6
    No 6 rocking: Adjust In 5 / Ex 4

    Procedure for setting the valves on ZEJ engine

    my 1981 505 STI
    ZEJ valve train, after removing injectors and valve cover

    Procedure 1 for setting the valves on ZN3J

    my 1989 505 V6
    ZN3J valve train right cylinder bank (cyl 4 - 6)

    ZF 3HP22 / 4HP22 automatic gearbox
    If you have an automatic gearbox, change the oilfilter-mesh right under the oilpan as these get clogged up with age. The mesh is so fine that it's impossible to clean. Buy one from a ZF dealership, and you'll get away with about € 20. Just tell them the type no. and serial no. (production plate on left side of the gearbox).

    I did the job on my ZF 3HP22 equipped STI, and also on the V6 which has the "famous" 4HP22 'box. Since then especially the old 3-speed box shifts much smoother and reacts quicker. Change the ATF every 30.000 km, as recommended by ZF. When changing oil & filter about every 90.000 km, you'll need

  •   3.0 to 3.5 litres ATF (to old DEXRON II spec)
  • Don't forget give the oilpan a good clean inside, including the two small magnets. The oil-pan rubber seal can be reused if in good condition. Sounds too easy ? Ok, you'll need a 27 TORX bit to unscrew the filter.

    Cleaned oilpan of ZF4HP22, new filter and gasket
    (here for 1987 PEUGEOT 505 GTI)

    On pre-82 models, the printed circuits in the fuse and relay-box (on the left strut tower) suffer from high electrical resistance due to bad connections and oxidation:.

  •   Plugs and board can get so hot that the plastic is melting

  • I broke down twice with my STI because the printed circuit separated from the board just under the plug which also feeds the fuel pump (with 16 A!). I purchased a new board and cleaned all connections, but this did last for only one year when the electrics started to play up again.

    PEUGEOT recommends changing board and plugs with the later type, but instead I took a new board and soldered new cables directly on this. The new cables are then connected via new BOSCH plugs with the old harness. This repair should be durable and is invisible when you open the fuse box.

    Actually, the pre-82 design of the fuse box is the cause for many inexplicable electrical faults...


    Modifications to pre-82 fuse board
    first part of board modification, old melted plug is shown right
    Getting things done on the STI
    Arrgh! I HATE those electrics !!!

    Much has been said and written about how to get the sunroof to work properly. When I purchased the STI, the sunroof was badly corroded and had to be replaced with a good used one. I then installed new slide-shoes and also a new rubber seal.

    The cable was pulled out and lubricated with a combination of graphite grease and silicone spray. The rails received the same treatment. Since then I can enjoy a sunny day with a working sunroof, although it took some time to align the roof properly, because a bad alignment causes jamming.

    On some cars the sunroof stops functioning because of the cable guide breaking where it's attached to the motor. There are quite a number of fixes around, here's the official factory solution for that problem (picture top right):

    Use 2mm sheet metal, best would be stainless steel. The hose clamp is soldered or welded on the stiffening plate. Mount according to the picture right.

    Most sunroof problems - apart from rust - are related to the cable guide: On my 505 V6, the platic cable guide separated from the bushing, which is attached to the roof cross-beam and from where the metal rail begins. It was realativly easy to undo the right C-pillar trim and the passenger handle and to lower the rear of the headlining. I glued the guide back into the bushing after degreasing it, and the sunroof works faultless now.

    stiffening plate for sunroff cable guide, thickness 2mm
    Bracket made from 2mm sheet metal...

    ...and how to fix it

    ...and how it's installed

    505 spare parts
    Spares are quite easy to get here in Europe from your local PEUGEOT dealer or any motor-factor for something like oil filters, brake parts or dampers - as long as it's not for the interior or an early 505 (like my STI, you've guessed it) and you don't care about your wallet...

    garage24 action pic

    4 years ago: Stephan Sontag parting out a 505 SR at the local breakers yard.
    Seldom sight below is 604 V6 SL
    . Wish I'd bought some parts back then...
    this used to be a 505 GL

    Second hand parts are really scarce over here, same thing in France, so I was happy when I found the unlucky 505s pictured left and above. They'll help to keep my 505s on the road for many years to come... if I will ever find a good ZEJ (829) engine as a worst-case backup for the STI.
    he 505 GL pictured above for example still yielded some useful parts as heater unit, wiper motor and tail lights.
    Some days later I found another parts car, a swiss 1984 505 GTI, with heated seats and like-new rear brake calipers...