The M110 D-Jet Manual
 

Last year or so, somebody reached out to me looking for the D-jet manual for the M110.

This version of the M110 book should have that section...
https://www.ebay.com/itm/1979-1980-Mercedes-Benz-280E-280CE-280SE-2-8L-M110-Engine-Service-Repair-Manual/373249993468

I would confirm that by asking the seller to see if it includes section 7.4.

-CTH

Hi,
I think this manual will not contain a D-Jet-section.
D-Jetronic wasn't installed anymore after 1975.

The manual will contain K-Jetronic-only.

Regards
Norbert

I believe the most important part of what you say is true, and this will probably really come across as splitting hairs, but I believe that the 280slc was manufactured with d-jet through February 1976. I believe that all the 1976 w114 were also d-jet too.

Most fun fact d-jet topic ever was an m130 ever coming with a d-jet or no? I can’t remember but think I remember falling out of my chair hearing that an m180 family sohc straight 6 came with d-jetronic. I can’t remember what model car that was.

The M114E, the 2.5l motor in the 250E and 250CE was d-jet.

The 1st versions of the US M110 book comes with the D-jet section.
Later versions won't have it.
I know this because my copies of it have it.

Like I said, if somebody needs it, confirm the section's existence with the buyer of that copy. Most buyer won't know what D-jet is. But they hopefully can read well enough to find section 7.4.

-CTH

D-Jet works the same way of all the cars it is installed on. Just the tuning specs are different.

There are several web site up that have the original Bosch repair manual in total.

I can remember when this system came out it was considered a magic thing that only elves could work on. I had an Opel Manta with the system and no one could figure out what was wrong.

So I dug into and found it is rather simple. If you have a volt meter and a vacuum tester you can figure out almost anything.

Helpful hint.... I have found that many times the problem is a vacuum leak that is solved by pulling the ends of a hose off of it's connection, cutting off the dried out rubber (which is cracked and leaking) and sticking the supple rubber hose back on.

Of course if you have the time it is wise to replace all of the vac lines. This is not expensive and usually needs doing anyway.

You might have to fabricate a fuel pressure gauge to see if you are getting 42 psi to the engine. This was my problem. A new fuel pump and everything was OK. Make sure to plumb the gauge in down stream of the fuel filter.

the wierdness of the M110 is the wiring pattern, how 6 injectors are mapped to the box. All the other doc I've seen shows 4 or 8 cylinder cars.
-CTH

Yup. If it's the brain then the only thing you can do is replace it. During the day Bosch sold a machine that would analyze the electronic brain. This machine cost a small fortune, but Bosch had a exclusive so PAY UP!

Then two Swiss guy hacked the machine and started producing one o their own for about two thousand dollars. Still not cheap since you could buy a nice house then for forty thousand, but far below the price Bosch was charging.

I had to always take the approach that after checking out everything else and finding no problem I had to troll the salvage yards for another brain. At that time the going price for a used brain was around $35. For me that was a lot cheaper than doing it right and buying a machine I would use about five times during my life.

@cth350: The M110 injects 3 cylinders at the same time. Two of them share an output of the ECU, the third is another output.
I will send you a plan to your email-adress

@idle: You write about your experience with an Opel Manta. The Manta wasn't equipped with D-Jetronic, but with L-Letronic. This is a different system with other problems.
The cars with D-Jetronic are quite different from each other.
Some car types had different components installed almost every year.
It's not true to say they only differ in the tuning specs.

Regards
Norbert

Thanks for the correction. I was doing this about 30y ears ago so my memory seems to have slipped a bit.

But the advice I gave about there being a Bosch manual posted on the internet is accurate. I was just using it a few weeks ago.

And the part about all you need is a voltmeter, a vacuum pump and a lot of time on your hands.... Yeah, that's still accurate, too.

Most of the FI troubleshooting I have done has been with the early electronic systems on Porsche's. Every 914 had one of these and I never liked switching over to carburetors.

I have all the benz manuals there are (paper, fiche, digital) to have, pretty much, from 1947 to 1999. My interest in their cars ends about there.

My original post was to point out the book for others. I get inquiries from 280E and 280CE owners from time to time looking for that wiring info.

Norbert reached out to me earlier today with a reminder of a great D-jet resource, www.jetronic.org/en. For reference for folks that need to know...


pin, color, Connection
3, green, output A (cylinders 1 & 3)
4, grey, output B (cylinder 5)
5, yellow, output A (cylinders 2 & 4)
6, white, output B (cylinder 6)

The system was designed for 4 & 8 cylinder engines Bosch shoe-horned those extra 2 cylinders in the system as above. One interesting thing to read on that D-jet site is how Lucas adapted the setup for the Jaguar v-12 engines and set up a trigger using a hall sensor and an adapter board. That's a technique that might have made a 450se with d-jet a more interesting car and maybe more djet cars would still be on the road.

-CTH