SRDT

This ECU does not keep error codes if you cut the power. As for the 52 error code it could mean your ECU has a chip.

A temp sensor should be fully sealed so it's probably simply the washer.

Sometimes ABS drive shafts can also be stronger than the regular ones but again that shouldn't be a problem for your car.

Take a look here: Also codes 31/32 aren't major falts (no * on the chart) so no light on for them.

Dou you have the check engine light on? Even if not minor problems don't keep the light on so it's worth checking, and at least you will know what isn't malfunctioning.

No ABS on a Mi16? Well it doesn't really matter as the ABS drive shaft should fit all the same.

It's still better thant the L-Jetronic using ony one channel. Also the spray pattern isn't optimised for two intake valves, the XU9JA 8v engine is using the exact same injectors.

Yes, these engines have mechanical pumps so there is no engine ECU to control boost or even share usefull information with a boost controller. The Fiat one was the first diesel car with a VNT turbo (and before that it was also the first car to have a direct injection diesel engine). A former coworker of mine had been working at PSA prototype department aroud the time the Fiat engine was launched and he said that it caused quite a stir...

Variable geometry can also work without any controller, just some actuator using boost pressure. The Fiat Croma TDid and the Renault espace 2.1 dtv had this kind of setup, too bad that the turbos are on the small side for a XD3T (92/94hp for these smaller engines).

There is no sequential injection on this engine. The ECU has only two pins for four injectors so even if you swap the wrong injectors it can't be that bad. You can also check if the HT leads are properly connected to the distributor cap, I had a problem with that just yesterday and the engine actually managed to ran better with the lead completely disconnected. That beign said my car has no lambda, yours probably doesn't react the same way if they are misfires.

I don't know how it is for the 405 but the 309 has the big blue double switch for the fans on the inlet side of the radiator.

I have the same information: EQ is for the 11x35 final drive, U should be about gear cutting but i don't know anything much and B means LSD but again i don't know if it's the Torsen or the older one. Here is all i have about final drives: A: 6x37 B : 6x43 G : 8x37 F : 8x39 C : 8x45 L : 9x34 K : 9x35 J : 9x37 H : 9x38 M : 10x37 Q : 11x35 N : 12x43 S : 13x40 R : 13x43 P : 13x45 T : 15x43

The first BMW 8 series had a V12 with a 6 speed manual gearbox but they are way too expensive, most V12 are from the 7 series and those are all mated with automatic transmission.

The 505 has a 90° V6 so a compact V8 like the one from Audi should fit. Also do not forget that the diesel engine is not exactly small so a small bore V8 could be even shorter. The easy way to swap a new engine should be to keep the same engine family, mosty the Renault variants like the 2.0 turbo or 2.0 12v from the R21, 2.2 12v from the Safrane or 2.1 turbo diesel.

You can order a XD2S from l'aventure Peugeot but it's not exactly cheap.

The two manufacturers should be Veglia and Jaeger but the gauge itself could be the same. I have seen parts with Jaeger printed on the back inside Veglia clusters.

It's not only about the pump head diameter, you should also check the cam plate lift. If the engine output is roughly the same then the big head pump probably has a smaller cam.

It's not really fun to tension the belt on this engine: You need to do it on both sides with the cams and crank locked in place then you rotate the engine for two crank turns (in the running direction) and check if the tension is still good and the crank and cams can still be locked in place. If not you have to do it all over again.

Instead of boiled linseed oil or this red spray I would use Loctite 5923, it's a sticky and ugly thing made out of pine resin or maybe pine tar but it's really good at sealing a leaky head gasket. US equivalent may be Permatex Super “300” Form-A-Gasket or maybe some shellac compound.

First try to check the wiring, sadly I don't have any 405 wiring diagram but looking at the 309 diagram you may have many things that can go wrong between the sensor and the cluster: Anyway removing the cluster doesn't look too hard: http://xrms.free.fr/phpwebgallery/category.php?cat=12&start=0 Sure you need to take the top of the dashboard off but after that you got plenty of space. For having done the exact same fix than this guy on a 309 I can tell you that it's not as fun when you need to put back the cluster.

You can "fix" many engine problems with a rich mixture so maybe after reading the workshop manual they tried this instead of setting the pump.

How long does the oil still inside the drum last?

The wastegate is indeed a problem, I think the only K24/K26 with internal wastegate are for diesel engines. You need to weld a V-Band flange on the brand new housing or on the manifold.

The SEDIS belt was ahead of it's time, and also very hard to find for a long time. "Wet" timing belts are now much more common.

The valve cover is made out of magnesium, not anyone can powdercoat it. You also need to paint or clearcoat the "16V", sanding it won't do as raw magnesium won't stay shiny for long. On top of that the plug cover is made out of plastic so it may be hard to have the same aspect on both parts. Also before doing any work on the valve cover look for stripped treads, you may need some M6 helicoils if lucky and if not a M8 tap.