I've pretty much decided to go the Megasquirt route with my 4.5. According to the Megasquirt formulas, the 4.5 really only requires an injector capable of 16.9 lbs/hr. The OEM injectors as I understand are rated at 39 lbs per hour.
I would like to use a modern 19 lb/hr injector that fits into the head without modification if such an animal exists. Some have suggested the Mustang 5.0 injectors. Anyone have a definitive answer on this, or other alternatives?

Tom

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1972 280SE 4.5

The Ford injector fits in the M117. The arrangement of the o-ring and spacer on the nozzle end needs to be reversed.

When you build the fuel rail be sure to use the AN-6. I used the AN-8 on my M117 ('85 500SEL M117 and no, I'm not finished with it yet) and I ended up having to weld the ends to receive the fittings as the AN-8 rail walls were too thin to get a decent thread. Could have been the brand of fuel rail.

I did turn the injectors down just a touch. Chucked them in my drill press and used a bit of emery cloth. It probably isn't needed but they're pretty snug and I was concerned about heat expansion.

I would use higher than 19 lb/hr as you dont want them running above 80% duty cycle - shortens their life. I'd use 30 as a safe starting point for a standard 8:1 smogged 4.5 (I'd use 35 for an 8.8:1 pre-smog which yours may be).

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

19 lb.'ers will work fine. Tom's rationale makes sense IF you are using the D-jet controller. Using the MS, the 19's will be fine. They are used on the Ford 5.0 after all and that engine is a lot more fuel demanding than the M117.

If you feel you need more fuel flow then you can increase the pressure.

I still don't understand why different capacity injectors are used with MS. And, even with a Euro 3.5L M116 with about same BHP as the 4.5L M117 lower capacity injectors are used.

When I asked some time back why the 3.5L M116 has lower capacity (yellow) injectors for same BHP, someone said it was because of the higher displacement of the M117. This does not change when you go to MS.

What is it about MS that allows the lower capacity Ford injectors to be used?

Another question - Do the Ford injectors operate at the D-Jet pressure (28psig) or is the pressure increased? If it is increased, is the fuel supply system (pump, rails, connectors) upgraded to handle the higher pressure?

Another question. I have been told that the M117 engines were designed to run rich and that trying to run them close to stoichiometric could cause problems with valves/pistons burning. Has anyone long term experience with MS on a M117 engine?

I still kind of enjoy the challenge of keeping the D-jet working, but one of these days may want to go to MS or something similar.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

keeping d-jet working isn't a challenge.

1. you need money
2. You need a working brain
3. you need some instructions.

have fun with mega-crap. now, if you need to source a part, you can call advance auto parts and get it from china instead of having a benz or BOSCH WARRANTY BEHIND YOU.

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Pierre Hedary 1985 280SEL, 1970 111.026 in progress
Mercedes technical advice hotline: 407 765 2867
[servicing older Mercedes in the state of Florida with competence and passion].

From the standpoint of an honest MB technician, Vegetable oil is a threat to your diesel engine's mechanical integrity.

Ouch! That was bit harsh, don't you think? Changing to MS reminds me of the controversy years ago about changing the ignition points over to an electronic pick-up device.

What "made in China" parts are you referencing? Injectors and sensors used are all available in Bosch.

A properly working D-jet system is a fine thing. If it's working then keep it working. An abused system can be a total nightmare to restore.

Yes, the MS system uses 45 p.s.i. to operate the newer, more efficient injectors as opposed to the 28 p.s.i. used on the stock system. The standard fuel pump can easily handle up to 80 p.s.i. continuous service. The replacement fuel rail is rated at over 150 p.s.i. so no problem bumping the pressure.

I am using Nissan Z 280 turbo injectors. They are 260 or 280 cc if I remember well. If you feel they're too big you can use non turbo ones. They have several advantages:
- They are hose injectors and their shape is exactly the same as the original D-jet ones. So they fit straight, no need to fabricate fuel rails, you just reuse the D-jet ones.
- They are plenty around. I got mines by browsing on the Nissan Z forums
- they are cheap

I got mines cleaned and flow tested by "Cruzin' Performance" and he got them flowing within 1% of each other with a proper spray pattern. I sent him two sets of 6 though. Two were bad, and I have two spares.

I also have replaced the fuel pressure regulator by a vacuum actuated one. I got one from an L-jetronic Vanagon. You just fit it in place of the D-jet one, it fits straight. You have an additional port on top of it that you need to connect to the air plenum.

As you're going Megasquirt, you should also have it control the ignition. this is where you will really gain power and fuel efficiency. I went EDIS. Pictures here:
weekend Wrenching and here: weekend Wrenching

Thanks to all for their responses.

Mike D: Thanks for your solid, level headed info.


Pierre: I certainly respect your opinion and the fact that you are a professional MB Tech, which I am not. Please allow me respond to the points you have raised:

1) I am not taking a penny-wise pound-foolish approach to restoring this car. I know the difference between quality OEM parts and the alternatives and am not afraid to spend where necessary. I got into this project with my eyes open and having done extensive research on the 4.5 to know what I was in for. I am striving for the BEST way to solve the mechanical and cosmetic issues the car presents, while maintaining the spirit of the original car.

2) The lack of a reliable ECU is probably my biggest frustration with the Djet system. I now own four of them, one of which was sourced as a rebuild from Programma in Flordia. Upon receipt and installation of that one, the car would not even start. The car will run on the other 3. I called Programma for an explanation and was told that they cannot get the information they need from Bosch to properly test the circuit!!! They do the best rebuild they can do with what info that have, and basically hope it works. I could not find anyone else in this country or Canada who would supply a rebuilt ECU. HOW CAN YOU DIAGNOSE THIS SYSTEM WHEN THERE IS NO WAY THAT YOU CAN DETERMINE IF THE ECU IS OPERATING PROPERLY? I am not interested in an ECU that was pulled from a car with the statement "The car seemed to run OK". I already have 3 of those. If you know of a source that can supply me with an ECU that is GUARANTEED to meet specs according to BOSCH, please let me know and I will do the work to retain the Djet system because I will at least have a reliable starting point to work from.
Oh, and did I mention the MAP sensor? I have 3 of those as well. All meet the specs for the vacuum & electrical tests outlined in the service manual (because I have done those tests on each of the units) but even the manual admits that there can be internal anomalies that are not detectable by any test procedure. The solution: "Use a known good MAP sensor". Here we go again!! I believe the sensors are available NOS for over $1000.00, but it's still a 40 year old highly complex assembly that can't be tested definitively! Each of the 3 MAP sensors I have cause the car to run differently even though they are the same part# and meet the vacuum and electrical tests outlined in the manual!
Would you go to a doctor to be diagnosed for an illness knowing that the thermometer and blood pressure gauge were not properly calibrated, and that the results of blood and urine tests were coming from a lab that could not guarantee accuracy?

3) I own the MB Manuals that are relevant to my car:

Service Manual Passenger Cars starting August 1959
Service Manual Passenger Cars starting 1968
Service Manual Engines M 116 - 117
Maintenance Manual Passenger Cars - USA Version 1974

Plus I own aftermarket books on Bosch fuel injection and have accessed much good information on this Forum and on the Internet as well.

Pierre, my main issue is that the two most important parts of the system (ECU & MAP) are virtually un-testable. My time is too valuable to continue to try and diagnose problems under this scenario. And, even if everthing was working perfectly, you still have an open-loop system where the ECU has no idea what's coming out of the tailpipe!

I want the car to get the best possible fuel efficiency, to start and run reliably, and be capable of being diagnosed in the event of a problem. I don't believe that keeping the Djet system will accomplish those goals in 2010.


Graham: I have followed many of you comments on the forum, and appreciate learning from what you have done regarding Djet. I think the Nissan injectors are a great idea, do you have a part#?
I look forward to continued disscussion, thanks.

Tom

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1972 280SE 4.5

Regarding the MAP sensor, D-jet

If your motor has perfect vacuum, like the top/bot halves connectors and injector seals are good. good compression and cam chain alignment, even the voltage regulator can influence it, etc....

Then pop off that black cover of the MAP sensor and start adjusting it. unscrew (cclw) to lean, Clw to richen.

1/8-14 turn will affect the overall fuel settings, center the adjustment knob on the ECU first.

Check the mileage and plug colors to fine tune.

The system is good as-is (big IF) all parts are correct.

All the information to check these systems and FULL SCHEMATICS of the ECU are on the 'Web....

BTW, The D-Jet does not have a MAP sensor...

--It has an MPS. --Quite a different device and works Totally Differently.
Please, DONT Potch with the MPS unless you know what you're doing.--For a start, Under that cover, there are Two Adjustments, and its easy to total this VERY Expensive part!!

Here is a Porche Owner's page on the full operation of this amazing Injection-System, and a full description on the MPS and its operation that has informed good advice on its diagnosis and repair, including the diagrams, although you gotta search through his site...

http://members.rennlist.com/pbanders/djetfund.htm

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

The nissan Z 280 Turbo are brown top JEGS A46-00

If you want to stick with Bosh, you should look with the Volvo and VW crowds. They use 200cc high impedence yellow top hose injectors (Bosch ref 0280150204). They are easily available around and will be enough for the 200 hp of the 4.5, especially if you use a vacuum actuated fuel pressure regulator (the Vanagon one is also Bosch) which will increase fuel pressure up to around 40 psi (at least for the one I have) when you press on the gaz pedal. My stock D-jet fuel pump delivers over 50 psi, so is good enough.

BMW also used hose injectors with their L-jetronic systems but they do not seem so readily available.

I understand Pierre's concerns, but all depends on the type of car one has and the use made of it. Time ago I had a very nice 6.3 and was using only MB original parts, keeping it stock. I sold it via Kienle, which is a tribute to the quality and shape of that car. I sold it because my pleasure is to drive (a lot) in my older cars, and I also like to play around with them. And it would have been a crime to do so with that nearly perfect low mileage, unmolested original 6.3. So I now have a nice, but far from perfect, W111 Coupe. I took it for a coast to coast round trip last summer, and this is the type of things I like doing with my cars. So, at least for now, no low milage, unmolested cars for me, as I would be frustrated not being able to do what I like with them with full peace of mind. And yes, a well sorted Megasquirt controlled fuel & spark set-up is very easy on a D-jet system and is a progress in terms of reliability, budget, performance and ease of maintenance for someone who likes enjoying his car on the road. It's just one among so many other aproaches of enjoying our cars.

Here you go--

MPS---

http://members.rennlist.com/pbanders/manifold_pressure_sensor.htm

ECU description and Repair with Schematics---

http://members.rennlist.com/pbanders/ecu.htm

__________________
http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

Alastair,

I wish it were that simple. I've read through all of Mr. Anders excellent information. The problem is that the info provided is specific to the versions of the ECU and MAP that an air-cooled VW engine uses. In fact, the MAP for the VW has an inner AND outer adjustment screw. The MAP for the 117 Djet engine has only one adjustment screw. With all due respect, I don't have endless amounts of time to make suppositions about whether these parts are functioning properly or not.

Tom

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1972 280SE 4.5

Alistair,

I apologize for using the acronym MAP instead of MPS. I HAVE been referring to the manifold pressure sensor in all of my previous comments. On the M117 engine the MPS has only ONE adjusment screw. I have 3 of these identical parts, i ought to know. I have also researched this device quite extensively and have had the benefit of other's experience as to the adjustment of this device FOR THE M117 engine. If you are using the info on Mr. Anders site, it SPECIFICALLY refers to the VW versions of these parts, WHICH ARE VERY DIFFERENT!

In addition, I do not have the knowledge to test an ECU for proper circuit operation. I doubt if most MB techs have this knowledge. I am simply looking for a source for an ECU that meets spec for my car to even consider continuing with the Djet. Believe me, before I "potch" with any part of this car I do my homework. If you've read my above comments I've made it obvious that I understand the MPS is an expensive part.

By the way, my original intent with this post was not to debate the Djet vs. Megasquirt issue, but to get information about injectors with a smaller flow rate that could be used with as few modifications to existing setup as possible. I appreciate greatly those helpful responses I've received.

If you or anyone else wants to convince me that I should stay with the Djet system, then I need two pieces of information:

1) A source for an ECU that is warranted to meet Bosch specs FOR MY CAR

2) A source for an MPS that is warranted to meet Bosch specs FOR MY CAR

If this info can't be supplied, then it's just talk and I would then prefer to only hear from those who are interested in helping me meet my goals for the car, which I have made absolutely clear in my above posts.

Tom

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1972 280SE 4.5