DS EFI system

ajaxvte

ajaxvte

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Fellow Frogger
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Dear brains trust

Over time I have seen various views on the DS Bosch EFI system. The predominant view seems that these systems are now old and fragile, and difficult to maintain and keep well adjusted etc.

Are there alternatives to trying to keep what is now a 45 year old (at least) set-up? Like a replacement system? At what degree of difficulty and cost?

AM
 
Touch wood. I have now owned my DS23 EFI for over 10 years. Whist I have renewed many parts (fuel pump,fuel pressure regulator, fuel lines, starter, battery, plugs, filters etc..., water pump (thanks Greenblood), belts ,recon auto box, reocon steering rack etc..etc..).
The ONE thing that has proven the MOST reliable is the fuel injection! I recall having a few issues early in my ownership with the cold start injector but that's all.
You mention "keeping well adjusted", I can't think of any adjustment that are needed. You may mean in conjunction with a BVH maybe?
As I said above I replaced parts which I thought may impact on the system like fuel pump, fuel pressure regulator, many electrical parts, but it was just a matter of fitting, and then the system became quite a lot happier but never required other adjustment.

If the EFI is keeping you from buying an otherwise decent and working DS, don't let it worry you, I think when you buy a car in which the system is working fine, it will keep doing so.
I would keep away from a car that is partly dismantled and that you may have to put the system back together......that could be a bit of a challenge...and that maybe where adjustments need to be made, then God only knows who can help you.
 
Apart from some problems related to a dead ECU about 5 years ago when I first got the car, I've found the EFI system to be the least trouble prone part of my DS. Provided all the electrical connectors are clean and the fuel rail maintains 30 PSI with the tacho approaching the redline then you're good to go. There are only 3 adjustments in the whole system, the grey knob on the ecu for idle mixture, fuel pressure and the adjustment screw on the MAP. Never touch the MAP adjustment screw

Most of the age related problems come from cracked vacuum lines, leaking fuel hoses, old injector seals and dodgy past repairs. All easily sorted. If you need work done on it, go hunting for an old VW/Volvo/Merc mechanic. The system is largely the same no matter what vehicle it is fitted to.

Conversion to Megasquirt or one of it's variants is pretty straightforward as it uses the same principle as D-Jet. Fitting a lambda sensor is a good idea but not essential. The hard part is doing all the required reading to understand where to start with creating the fuel map. You're looking at around $1500 for the ECU, sensors and new injectors if you do it yourself. No idea who you would even take it to for installing a custom system but I'm sure there are people out there.
 
Someone here in the UK has just had their efi system replaced with a modern equivalent I believe. Pallas Auto (the DS one - not the other one in the UK with the similar name - Pallas Autos (plural)) did the work.
 
i run bosch L-Jetronic in my 46 year old vw-porsche 914. the system is very robust. the brains are built to military grade and over engineered to a ridiculous degree. its rare for a bosch D-Jetronic or L-Jetronic brain to die. very rare, even at this age. some of the injectors are getting hard to get. not sure what a DS would be running for injectors, but Bosch stopped making the injectors for the VW applications about 10 years ago. so its NOS or trying to find an injector reconditioner. the NOS stuff sells at a steep price. i have heard the air flow meter that is required with L-Jetronic can wear out. its basically a printed circuit the sweep flap in the air intake (part of the air cleaner and pre throttle) . there are specialist rebuilders of that part in the USA. but D-Jetronic does not use a air flow meter. personally i think D-Jetronic and L-Jectronic of that vintage is unbreakable. you can fly to the moon and back on it. its military grade stuff because they were very cautious with it as a new product. vacuum/air leaks are usually the thing that can set it off and make it run badly. make sure all vacuum hoses are new and not leaking air. a source of trouble in the VW applications was the crank-case ventilation hose which feeds back into the air cleaner and the oil re-fill cap that was part of it. making sure you had a good seal o-ring on the oil cap is essential. any air leak in the system upsets it. there are a couple of temp sensors/valves and other things which you need to make sure are operating properly. but thats about it. you have to ensure those valves and sensors are up to scratch. its basically unbreakable in my humble opinion. certainly the brain (ECU) is. its analogue and uses transistors (I think) and its basically pretty dumb and small minded as per the lunar module and its famous computer.

there are a few adjustments which i shall have to ask my mechanic about, mostly to do with setting the richness or leaness of the mixture.
in an L-Jet i think these are near or part of the air flow meter, but again that is not part of D-Jet. normally you do not touch these things.

I'd stick with the D-Jet which is what will be on the car? You can still get most of the things you need for them. And there is a big fan base for the system in the USA. all their VWs ran D-Jet and then L-Jet.

The L-jet is famous on the porsche 914 1.8, first application of the system in a production car. met californian emission standards without the need for smog pumps and other strangulation devices. made the american manufacturers sit up and take notice. SAAB were also on the ball along with VW in applying the system to all their cars. the USA market was very important and EFI was a necessity. here in australia those cars with EFI were more a novelty at that time. but its a great system in my view.
 
Folks, look at this web site that someone on AF found recently. It looks like a really up to date replacement system for DS and SM Djet systems.

https://www.efignition.com/c-3645270/citroen/

I have been living with an SM DJet system for the last 5 years and it is still not completely sorted. I will add some specific comments when I get get them straight in my head.

Cheers, Ken
 
Ken W said:
Folks, look at this web site that someone on AF found recently. It looks like a really up to date replacement system for DS and SM Djet systems.

https://www.efignition.com/c-3645270/citroen/

I have been living with an SM DJet system for the last 5 years and it is still not completely sorted. I will add some specific comments when I get get them straight in my head.

Cheers, Ken
Click to expand...
You can upgrade the CX with that injection system as well.... You'll fry your clutch as soon as you use the extra boost though ....... It seems very easy to bump the CX upto 200hp with no changes as its in such a low state of tune. You'd have to chat with Neil and see what he's done to upgrade the clutch!
 
The principal defect of the D-Jet system is it has no lambda sensor and, therefore it is an open loop system. I think of it as an electronic carburetor. Based on the current state of the sensors (MAP, coolant and air) the D-jet opens the injectors for a certain number of milliseconds each time the trigger points in the distributor open. Based on a fixed fuel pressure, a reasonably correct amount of fuel will flow through the injectors into the cylinders. If anything in the system is out of spec, the D-Jet will continue to operate the injectors based on the faulty sensor information until the faulty sensor information becomes bad enough to cause misfire, stalling, etc. Although most of us know what a lean misfire sounds like, unless you are paying close attention to the exhaust smell, there is nothing in the system to warn you that the mixture has gone rich until the plugs are fouled and the car won't start. A separate lambda meter would be a nice addition to any D-Jet system.
 
ajaxvte said:
Dear brains trust

Over time I have seen various views on the DS Bosch EFI system. The predominant view seems that these systems are now old and fragile, and difficult to maintain and keep well adjusted etc.

Are there alternatives to trying to keep what is now a 45 year old (at least) set-up? Like a replacement system? At what degree of difficulty and cost?

AM
Click to expand...
That's true. Before my 1969 DS21 EFI Hydraulique was drowned in 2013 I was considering installing a 2 litre Holden Barina EFI system. My biggest problem was the 2nd set of distributor points, unable to get new ones. Harness connectors and covers. I guess the throttle switch wipers were also problematical. Loved that car though. She always got me home on long runs..always with some irritation. Wonder if her restoration has proceeded?
 
wonkipop said:
i run bosch L-Jetronic in my 46 year old vw-porsche 914. the system is very robust. the brains are built to military grade and over engineered to a ridiculous degree. its rare for a bosch D-Jetronic or L-Jetronic brain to die. very rare, even at this age. some of the injectors are getting hard to get. not sure what a DS would be running for injectors, but Bosch stopped making the injectors for the VW applications about 10 years ago. so its NOS or trying to find an injector reconditioner. the NOS stuff sells at a steep price. i have heard the air flow meter that is required with L-Jetronic can wear out. its basically a printed circuit the sweep flap in the air intake (part of the air cleaner and pre throttle) . there are specialist rebuilders of that part in the USA. but D-Jetronic does not use a air flow meter. personally i think D-Jetronic and L-Jectronic of that vintage is unbreakable. you can fly to the moon and back on it. its military grade stuff because they were very cautious with it as a new product. vacuum/air leaks are usually the thing that can set it off and make it run badly. make sure all vacuum hoses are new and not leaking air. a source of trouble in the VW applications was the crank-case ventilation hose which feeds back into the air cleaner and the oil re-fill cap that was part of it. making sure you had a good seal o-ring on the oil cap is essential. any air leak in the system upsets it. there are a couple of temp sensors/valves and other things which you need to make sure are operating properly. but thats about it. you have to ensure those valves and sensors are up to scratch. its basically unbreakable in my humble opinion. certainly the brain (ECU) is. its analogue and uses transistors (I think) and its basically pretty dumb and small minded as per the lunar module and its famous computer.

there are a few adjustments which i shall have to ask my mechanic about, mostly to do with setting the richness or leaness of the mixture.
in an L-Jet i think these are near or part of the air flow meter, but again that is not part of D-Jet. normally you do not touch these things.

I'd stick with the D-Jet which is what will be on the car? You can still get most of the things you need for them. And there is a big fan base for the system in the USA. all their VWs ran D-Jet and then L-Jet.

The L-jet is famous on the porsche 914 1.8, first application of the system in a production car. met californian emission standards without the need for smog pumps and other strangulation devices. made the american manufacturers sit up and take notice. SAAB were also on the ball along with VW in applying the system to all their cars. the USA market was very important and EFI was a necessity. here in australia those cars with EFI were more a novelty at that time. but its a great system in my view.
Click to expand...
I replaced one of the injectors in my mum's 1972 DS21 with a Bosch injector out of a BMW. It had the same blue-collar and it worked. The only problem we had with the car was the fuel pump, one of the pump rollers had a flat spot.
 
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