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D-Jet to Megasquirt conversion

Started by thysonsacclaim, 05 October 2010, 01:18 PM

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thysonsacclaim

05 October 2010, 01:18 PM
Hey everyone,

I am in the planning phase of converting the '74 D-Jet 450SEL to Megasquirt 3.0. I am currently acquiring the replacement Porsche Bosch TPS potentiometer, wide band heated O2 sensor, injectors and new Air and Coolant temperature sensors. The original TS1 and TS2 will work just fine, I am merely buying new ones. My TS2 is shot and the TS1 is in questionable condition.

I plan on keeping the stock fuel rail and fuel pump if possible. The stock pump throws out more pressure than the injectors actually require, which is sent back to the tank. However, the D-Jet injectors use about 39 pounds, whereas the recommended injectors use around 19.

The stock injectors *will* work, but efficiency will suffer. I am hoping the regulators will allow me to adjust downwards from 36-40 pounds to 19-20. If not, I will have to look into a different regulator or fuel pump.

I believe the entire project will cost ~$500. If I decide to go along with it, I will post the procedure here. I am currently working out the cost figures and will post that soon. It will include the cost for everything from the MS board (assembled) and the wires and injectors and so forth.

oscar

#1
05 October 2010, 05:30 PM
Go you good thing!!!!!!   8) 8) 8)

Noone on the net has posted a d-jet conversion before, AFAIK.  Searched many times and only one conversion springs to mind and it's this guy's k-jet 450 SLC which is very detailed, really good info.  I trust you've seen it, but if not
http://www.hitechengineering.net/DNN/MegaSquirted450slc/tabid/54/Default.aspx
I've always thought it would be easier to convert d-jet and in a sense that link confirms so far as integrating original equipment, fuel rail, injectors etc.  But more importantly, it shows k-jet can be done.

Anyway, looking forward to seeing this happen.  Good luck!
1973 350SE, my first & fave

thysonsacclaim

#2
05 October 2010, 05:48 PM Last Edit: 05 October 2010, 05:51 PM by thysonsacclaim
K-Jet can be done, but requires much more work.


On D-Jet, the only missing thing is the O2 sensor and a different TPS.

On K-Jet, I assume you may need a new TB or at least a new TPS (I'm not sure if it uses one?). Also, you'd need those sensors (TS1 & 2 on the D-Jet).

From what I have gathered, it should take about as long to install as a nice sound system. The harness and ECU comes out. The distributor can stay, but the points will no longer be used. I'm not sure about the Ignition Control Module. I have to look up how it functions, but I would imagine it stays in place.

I think the Air Slide would be defunct, as well, but could stay in place. The cold injector MAY also be a point that would be defunct. I think the MS software would regulate the cold air mixture, meaning the regular injectors would be used instead for initial crank firing of the '5th injector.'

On a side note, I found today when removing the valve covers that one of the 5 10mmx155mm allen bolts was missing its bolt head! Luckily, it was not jammed and come out with vice grips. Unfortunately, my compression test was poor.

The right side (if looking at the car) is in spec, but the left side is out of whack. The lowest measurement is 90 PSI and the highest is 210 PSI. We triple checked these readings, which didn't change much wet or dry.

However, the cylinder giving the low reading (#3) is located where that bolt head is missing. It was not screwed down tight. I imagine when the cam shaft is turning over, it would flex slightly in this place. The area with the busted bolt would flex upwards, towards the hood, while the areas on either side may deflect slightly downwards. This could be causing my compression problems.

That cylinder's spark plug was also very clean, but looked as though it is combusting. It just seemed lean compared to all the others, which all looked the same.

The other theory is that since that head bolt was not screwed in correctly, it was not properly sealing the head gasket. This creates a small seepage, which allows water into the combustion chamber. This is why the piston seems to be running leaner. With water, the combustion would be influenced. Also, when the cam shaft rotates, it is causing a minor deflection in that area, affecting compression on the culprit cylinder and those directly next to it.

The car does not smoke white and there is no noticeable oil in the coolant, but I am fairly certain when we take it apart we will know what was happening.

So far we are:

1) Replacing the fuel injection
2) Replacing the timing chain
3) Replacing the timing chain guides
4) Replacing the left side gaskets
5) Replacing the broken head bolt
6) Hoping that will fix it all

thysonsacclaim

#3
05 October 2010, 08:42 PM Last Edit: 06 October 2010, 01:36 PM by thysonsacclaim
Megasquirt Conversion Costs:

8 x Low impedance (14.4 ohm) Fuel injectors (19lb/hr) - $60
1 x Saab Bosch Throttle Position Sensor (POT) - $65 (new), ~$10 (used)
1 x Heated Wide Band Oxygen Sensor - $60
1 x Megasquirt 3 - $359
1 x MegaSquirt-II - $259
8 x Fuel Injector pigtails - $15
1 x TPS Pigtail - $5

Total: ~$344-$404

When I finish this, I will be selling the working MPS, ECU and injectors.

npk

#4
06 October 2010, 01:21 AM
Quote from: thysonsacclaim on 05 October 2010, 05:54 PM
Are you using the same injectors? What is EDIS? And what are you doing to get around the TPS?


I believe this is a better thread to discuss about MS conversion( we shall leave the other thread to discuss about the D-jet TWO fuel regulators)

Are you upgrading the ignition system too?

I done several conversion on KE jet(both Fuel and Ignition/Spark controlled by MS). I prefer to use the EDIS but require trigger wheel and sensor(I sent the main pulley to be tooth to 36...after setting the trigger sensor, I cut out one tooth, thus making 36-1)

MS ECU has a MAP sensor(to be connected to the inlet manifold)... MAP(manifold air pressure) tells us the engine load....thus, in the tuning bucket(RPM vs MAP), we can adjust the fuel required by the engine and the ignition advance(for the spark advance) 

I prefer MAP cos TPS can be a pain to built-in existing manifold and system may less reliable with TPS(esp using USED TPS).

npk

#5
06 October 2010, 01:27 AM Last Edit: 06 October 2010, 01:39 AM by npk
Quote from: thysonsacclaim on 05 October 2010, 01:18 PM

The stock injectors *will* work, but efficiency will suffer. I am hoping the regulators will allow me to adjust downwards from 36-40 pounds to 19-20. If not, I will have to look into a different regulator or fuel pump.



I am still studying this matter...since we are using back the stock injectors(D-jet), I think they will work better at 36-40 psi(since they are designed to operate under those condition).

Cutting down the pressure may reduce the performance of the stock injectors.

Does this make sense??

??? ???

npk

#6
06 October 2010, 01:36 AM
About Oxygen Sensor, all the conversions I done are without O2 sensor feedback...

Reasons :-

1. O2 sensor are expensive and require regular check that the power supply(to heat the sensor) to the sensor is adequate.

2. In the morning, the driver must turn on the ignition(without starting the car) for a good 3-4 mins to heatup the sensor  so that moisture doesn't kill the sensor prematurely.

3. If the sensor fails, the ECU can run the car WAY out from optimum point

I use Innovate AFR meter(with O2 sensor) for tuning...once tuning is done, I remove the sensor....any deviation from optimum point, will be very little/small.

For me, lesser sensors always better...I run my conversions on FOUR sensors(namely, trigger wheel, MAP, Inlet Air temp and Engine Coolant).....failure of any will be shown in the MegaTune Software

I love to keep them simple and reliable

(I also convert the belt driven fan to electrical fan.....in Malaysia, temp can really destroy a lot of things in the engine bay)

thysonsacclaim

#7
06 October 2010, 01:45 AM
Quote(I also convert the belt driven fan to electrical fan.....in Malaysia, temp can really destroy a lot of things in the engine bay)

I am planning on doing this as well. I will look for a suitable variable speed fan in the future.

QuoteAbout Oxygen Sensor, all the conversions I done are without O2 sensor feedback...

The O2 sensor isn't necessary by any means. I'm not sure it would even be worthwhile on an engine that is worn in well. I may let it slide for a while and see how it runs. However, it is good to note that a standard spark non-fouler perfectly fits most O2 sensors. Good to know, because you can is it for the oxygen sensor bung.

QuoteI am still studying this matter...since we are using back the stock injectors(D-jet), I think they will work better at 36-40 psi(since they are designed to operate under those condition).

Yes. Definitely keep the PSI high for the stock injectors. I meant if you went with lower pressure injectors, the regulator needs to be adjusted to allow less pressure.

QuoteMS ECU has a MAP sensor(to be connected to the inlet manifold)... MAP(manifold air pressure) tells us the engine load....thus, in the tuning bucket(RPM vs MAP), we can adjust the fuel required by the engine and the ignition advance(for the spark advance) 

The TPS isn't necessary either, but I thought it would better fine tune to acceleration mixture. I'm not sure if it would be much though. Where on the 116 are you connecting the MAP sensor, by the way?

npk

#8
06 October 2010, 01:54 AM

I am planning on doing this as well. I will look for a suitable variable speed fan in the future.


I usually run the fans on dual speed...Low when aircon compressor is energized.....High when engine temp is too high (adjustable by keying in the cut-in and cut-out temp in MS)


The O2 sensor isn't necessary by any means. I'm not sure it would even be worthwhile on an engine that is worn in well. I may let it slide for a while and see how it runs. However, it is good to note that a standard spark non-fouler perfectly fits most O2 sensors. Good to know, because you can is it for the oxygen sensor bung.

Yes...if the engine is not healthy and burning engine oil, soot can kill the O2 sensor in a few days!




Yes. Definitely keep the PSI high for the stock injectors. I meant if you went with lower pressure injectors, the regulator needs to be adjusted to allow less pressure.

In the KE Jet conversion, I use those non-adjustable regulator with a connection to manifold vacuum...once the vacuum is high(engine high load), the rail pressure increases



The TPS isn't necessary either, but I thought it would better fine tune to acceleration mixture. I'm not sure if it would be much though. Where on the 116 are you connecting the MAP sensor, by the way?


Acceleration mixture can adjusted thru MAP but may not be as accurate as TPS(but the TPS must be a high quality with high precision output).

Anyway on the inlet manifold(after the throttle body) will be fine(eg, near the brake booster/servo vacuum connection).

To make cold start easy and cold idling at higher RPM, I run a Toyota Vacuum Valve (adjustable) that allow more air into the inlet manifold when engine is cold....the valve will close when the engine is heated.

thysonsacclaim

#9
06 October 2010, 02:30 AM
Updated my price list up top based on NPKs responses and more in depth reading. I do not need MS3.0 because I am not doing sequential fuel injection and EDIS (distributorless ignition).

MS-II should be perfectly fine for D-Jets, unless you want to go with a better ignition system, like EDIS. Also, the Cold Start Injector and the Auxiliary Air Valve are absolutely defunct with MS. You could remove both, and stop the holes up.

MS software adjusts the cold starting mixture, so you do not need this initial fuel enrichment and ignition.

I will also not initially use an O2 sensor, but will probably install it at a later time, when I am sure the engine is running better. Using MS is partially a way for me to determine what actual problems do exist. D-Jet is very finicky and somewhat troublesome to troubleshoot. Even though all of my parts work, the aging electromechanics and resistance changes necessarily mean the system will not operate as it did in 1974.

npk

#10
06 October 2010, 03:27 AM
I been using MS1 029Y4...simple and proven.

I believe EDIS makes the conversion complete and accurate. I don't like the present ignition system using contact point and pre-resistors....used EDIS system are readily available in ebay and several sites...they don't cost much but the returns is great.

I would strongly recommend Innovate(or something similar) AFR meter...this will make tuning a lot easier and faster.

Without the meter, it's difficult to know if the car is running rich or lean(unless you can remove the sparkies repeatedly to look at the built-up at the electrodes).

I usually tune a car in less than 1 hr on the road...and tune the cold start in the next morning

thysonsacclaim

#12
06 October 2010, 01:01 PM Last Edit: 06 October 2010, 01:28 PM by thysonsacclaim
The mounting should be the same or very similar. Many use the soft hoses and clips the same way, but just look around for low impedance, 19lb/hr injectors. Then see how they are hooked up in other cars. I originally though you would need to change the fuel rail, but I cannot see why. The injectors will go in the same place. The only thing that could change would be the height of the injector and thus the relative length of the soft hose as well as the manifold fitting and fuel hose fitting. I am still looking for the best injectors.

Also, contrary to what I said earlier, do not change the line pressure with different injectors. It seems even new injectors use line pressures of up to 45 PSI, whereas the 39lb/hr or 19lb/hr thing is a different measurement. Therefore, regardless of whether you use the D-Jet 39lb/hr injectors or new 19lb/hr injectors, leave the fuel line pressure at 39 PSI.

QuoteI believe EDIS makes the conversion complete and accurate. I don't like the present ignition system using contact point and pre-resistors....used EDIS system are readily available in ebay and several sites...they don't cost much but the returns is great.

This is true. EDIS is better, but it requires the gear and induction sensor. I do not currently have anyone here who can fabricate the gear onto the shaft like that for me.

QuoteWithout the meter, it's difficult to know if the car is running rich or lean(unless you can remove the sparkies repeatedly to look at the built-up at the electrodes).

I was hoping an O2 sensor would help me with this. I may go with a narrow band sensor instead of the wide band type. I will look into an AFR meter.

thysonsacclaim

#13
06 October 2010, 01:35 PM
I believe I am going to use the stock injectors because I think they will actually be easier and better to use than trying to find another set that meets the lb/hr spec, impedance, and hose connections. I will clean them and re-do the connections. Edited the price list.

By the way, NPK, a good site: http://www.megamanual.com/v22manual/minj.htm#size

SELfor50

#14
07 October 2010, 07:00 AM
Looking forward to seeing pics of the progress!!  2 conversions at once.. the time is now people.  ;D

Personally I'll be going down the Autronic path, everything and everyone I've spoken to has pointed me to this.

I have heard of 1 person converting K-jet on a 6.9 (motec6.9 on here) to EFI using D-Jet parts.
I think his throttle body was swapped to d-jet.  d-jet injectors and sensors etc... and then just custom fuel rails and Haltech ECU.  Motec will be able to jump in here and confirm.
He's now using an M48 pro ECU i think.

Anyway, looking forward to seeing how you go.

You going to Dyno before / after to see the difference?

Cam.
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