megasquirting a D-Jet

[Takernz_30]

hi guys!

Just a thought, is it possible to convert an old D-Jet set-up to modern fuel injection system like Megasquirt, Accel,etc..... while retaining it's stock looks? I'm studying for changing from carb to D-jet.

[Mike D]

On what? D-jet control can be handled by the Megasquirt and there are a couple of write-ups here on the board. Why D-jet?

If it's carbed, I'd go with throttle body. Unless it's dual carbed 90% of the time you can hide the TBI under the existing air cleaner.

[Takernz_30]

Originally Posted by Mike D

On what? D-jet control can be handled by the Megasquirt and there are a couple of write-ups here on the board. Why D-jet?

If it's carbed, I'd go with throttle body. Unless it's dual carbed 90% of the time you can hide the TBI under the existing air cleaner.

On my '73 280S, If I can't get a replacement carb locally, I'm considering this route. Is there a throttle body in place of solex 4a1? I saw that when you're converting M115 into TBI using chevy throttle bodies (injectors on the throttle bodies rather than on the ports). Did you do that in your M110?

I got an idea on a magazine that there's such thing as throttle-bodied multi-port injection, I found the bosses just above each intake port on the carb intake manifold. And on my another magazine, the guy made his carb into a throttle-body (stripped and plug all fuel passages but only air is admitted) and placing injectors in each port and made fuel rail concealed for stock looks, I like that.

[Mike D]

Holley makes an adapter plate to change from a Rochester Quadrajet (our Solex'es are a licensed copy of the Qjets) to a GM TBI unit. The rear mounting holes need to be re-drilled on their adapter but other than that it is a straight bolt on unit.

Any GM 2bbl TBI bolts right on the adapter, slip the riser stack on the TBI unit and plop the stock air cleaner on the riser.

Somewhere, buried in one of my postings on FI conversion, I've listed the part number from Holley.

[Takernz_30]

ok mike, how much should I spent on these(estimate)? GM TBI on what type of vehicle?

[Mike D]

The converter plate was about $40 USD, I found a GM TBI at a pick'n'pull for $25 USD.

The GM TBI are rated by their venturi openings. There's a "small" one, I believe it's about 11/16" of an inch, used only on their 2.8L engines, very difficult to find. The "standard" one, 13/16" inch, used on almost every other engine and the "performance" TBI (7/8") used on their "muscle" cars and heavy duty truck engines.

They used the same injectors on the small, standard and most of the performance packages. Fuel requirements were adjusted by the Eproms in the ECU's.

I used an aftermarket inline fuel pump for a '85 Ford Econoline for fuel supply but any inline fuel pump capable of 15-20 psi will work.

The pricey part was the Megasquirt ECU. I think it was about $450 USD by the time I added on the cabling bundle and relay board (I highly recommend you to go that route as it makes wiring so much easier).

You can also use a GM ECU but it takes a bit more work figuring out the wiring. You can pick those up cheap from the pick'n'pulls.

I went MS because if I have/want to move the unit to a different engine I can simply reprogram it for the different engine with my laptop.

Wiring and fueling are exactly the same using the 2 bbl TBI as the 1 bbl TBI. They use the same sensors.

I'm also still driving my '74 280C M110 using an old Motorcraft 2 bbl from a '72 Ford pick-em-up (over a year now). Getting about 13 mpg in town and about 17 mpg on the road.

My M110 project got put on hold because I found a M117 which I am in the process of converting to MS. My wife says if something is running I'm not happy until either it's running better or not at all!

[Takernz_30]

we don't have pick-and-pull-a-part american cars here a lot japanese cars did, is Megasquirt is compatible to all jap engines? TPS, throttle bodies, but I can source German injectors,fuel pump,accumulator and mixed them all up, is it allright? also, I found a M104 engine from Euro S320(S320) but without it's ECU, can that be run by Megasquirt?

[Mike D]

Megasquirt will run any electronic fuel injection system. It takes the input signals from the sensors and adjust the fueling "squirts" to achieve a pre-set air to fuel ratio.

You could use any TBI set-up. If you have access to a machine shop you can have them manufacture a plate using the thick resin isolating gasket from your existing carb set-up as a template.

Center the TBI unit on the plate, scribe the required openings for the venturi and the mounting bolts, have the machine shop cut the bore holes and drill and tap the mounting holes. If you have the plate made of aluminum be sure to heli-coil the mount holes since the sheet aluminum is soft.

The bores should be tapered out towards the actual manifold but it's not really critical.

Choose a TBI unit which is closest to the original carb's throttle linkage if you have an automatic so you can retain the transmission shift linkage set-up.

[Takernz_30]

hey mike,

I've not been in for a week b/c I'm studying the TBI system (what's that, how it's works, etc..) and the MS(almost done). TBI with MS works great in my '73 280S but quite a lot of work to do when going this route, a 4.3L TBI would work.

I can solder electronic parts(I've been making DC regulated power supply and power amplifier in my teens), make connections, fabricate and of course turning wrenches. Lastly, I need a complete 4.3L throttle body (with 55lb/hr injectors,TPS,IAT attached) here in the Philippines, I really can't get one. 100-150 bucks would be fine.

[JMURiz]

Originally Posted by Mike D

My M110 project got put on hold because I found a M117 which I am in the process of converting to MS. My wife says if something is running I'm not happy until either it's running better or not at all!

Darn you all to heck! Haha, thanks for the info, good to know a megasquirt controller can work with the GM TBI systems. This may be the route to go...perhaps with a Pertronix ignition setup....hmmmm.

[Mike D]

Yeah, unfortunately my youngest son is driving my 280 and I refuse to drive the wife's 250C to where I work so that leaves me with my 280C "project" as my daily driver. So, the M110 got put on "hold". Have no fear for idle hands. I picked up the aforementioned M117 ('85 500SEL with fueling problems) for a song.

I'll check around at the pick'n'pulls and see what I can come up with. What would be the best way to ship to the Islands?

[GGR]

Mike, are you planning to fit that M117 in a W114 Chassis? I would be interested to know what injectors and fuel rails you will be using.

[Mike D]

Nah, the M117 is staying in the W126 or at least that is the plan for now. I don't figure the W114's driver train would hold up to the M117. It had crossed my mind but after laying out the bucks for the 280C's head rebuild it would be a long time in the future project.

I had rails made from fuel rail stock ($50 from Fuel Air Spark Technology) which I took over to a machine shop for the injector drilling ($115 for eight holes and the rails cut to length). It is AN-8 stock which I wasn't too happy about because I have to tap the ends out to 1/2" NPT as opposed to using "standard" AN-6 (3/8" NPT). No big deal and it may actually work out due to the larger interior diameter acting as a buffer, or dampener. But of course the machine shop didn't have a 1/2" NPT so I have to buy one and then either tap the rails myself or pay them $10 a hole. Frickity-frick! I'll bite the bullet and take it to them. Sigh.

I'm using standard Ford 19lbs. an hour injectors used in just about every Ford engine from 1996 til 2002 or so.

The fittings for the ends are $5 apiece but the 90 degree barbed fittings are $16 APIECE! Thank goodness I think I only need 2 (across the front, connecting the rails together). The rear holes will be used for supply/return and I'll have to get an adapter to the metric lines. They are available, just a matter of squeezing the old pocket book just a LITTLE harder.

Just received my MS relay board and cable yesterday so I might begin the wiring process this weekend.

Still futzing about with the TPS. Pumpish shows one which bolts right up, with a little grinding of the aluminum housing, so I might go that route.

[Takernz_30]

Originally Posted by Mike D

Yeah, unfortunately my youngest son is driving my 280 and I refuse to drive the wife's 250C to where I work so that leaves me with my 280C "project" as my daily driver. So, the M110 got put on "hold". Have no fear for idle hands. I picked up the aforementioned M117 ('85 500SEL with fueling problems) for a song.

I'll check around at the pick'n'pulls and see what I can come up with. What would be the best way to ship to the Islands?

thanks Mike! use US postal for shipping to the Philippines it's cheap compared with UPS,FEDEX or DHL, but it's a bit more waiting to arrive. I've done that when I bought used parts for my 1966 200 from Australia and I paid customs fees about a dollar! because it was used parts.

Mike, advise me on what would be the best suitable TBI for M110? Is 4.3L will do?

If you happen to find a used but very good condition with complete TBI with TPS, injectors, IAC, attached below 150 bucks, let me know

[GGR]

Mike, I'm asking this because I noted the fuel rails and stuff around them were usually a pain to do and not exactly cheap. I am fitting Megasquirt on a euro 5.0 M117 and have fitted the intake manifold out of a Djet 4.5 M117. It was designed as an EFI manifold to begin with, they are plenty and cheap, and injectors and rails are a straight fit. Throttle body is much more accessible and fitting a TPS is much easier. See pictures here: EFI vs CIS.

Fitting an M117 in a W114 has been done before ans seems to be an easy swap. The alloy V8 is lighter than the L6 and the W114 Chassis shares the same front subframe and other elements with the r107. So it's a matter of getting an oil sump, oil filter housing, exhaust manifolds and engine brackets out of a r107 560 SL. In such a trim your W126 5.0 engine would clear the W114 engine bay and bolt straight on the original front subframe. You can then upgrade rear diff, brakes etc. by using 450 or 560 SL parts which are plenty and be a direct bolt on to your car. You may even use your W126 first gen. diff and brakes, I think they also would be a direct fit.

A Megasquirted euro 5.0 V8 W114 Coupe: that would be a very nice car, and you could have it look as if Mercedes did it!