D-jet MegaSquirt&Spark system, Show Stock MSII system in D-jet box Options

[kertwerks]

Hello Group,
My name is Kurt and I love 914's and older 912's.
I have a product I've made for my girlfriends Volvo 1800 that might interest some of the members of your list.
I can offer a Megasquirt&spark engine management systems the modifies the D-jet distributor and replaces the FI timing cam and points with a magnetic trigger wheel and hall effect sensor. it dupicate the D-jet system to Show Stock Quality.
An O2 sensor bung in the exhaust and a vacuum line are the only thing to be added to your car.
I've set up an album on my fliker page here is a link:
http://www.flickr.com/photos/kertwerks/set...157627511841022 You can e0mail me of list @ kertwerks@mindspring.com
Kurt

[JamesM]

Another thing i did was to wire the MS serial port to a 1/16 audio jack and use the Innovate serial cable for the MS tuning cable. This way the you dont have to cut the D-jet case for the 9-pin port, you can just drill a small hole for the audio jack.

[kertwerks]

James,

"To answer your questions though... The stock d-jet TPS is unuseable with MS. One of my goals was to eliminate the need for all the d-jet pieces that are getting expensive and harder to come by, TPS, trigger points, MPS, cold start injector. Initally for the TPS I did the same as you and gutted a stock one and replaced the innards. I realized a few things with this method though. First from a production standpoint this would be a pain to do for every build. Second, while the TPS is nice to have with Megasquirt it is unneeded. You can jumper the TPS circuit in MS with a resistor and run without it. You will lose Flood Clear mode and TPS in your datalogs but you can still have accel enrichment by running MAP based and leave the stock sensor in place for looks".

I don't totally agree with not using TPS input for the same reason I added MSII with closed loop system. The more inputs the EMS has the better&faster it can adjust and compensate for changing conditions. Why add a O2 input then remove one of the exsisting ones? Yes it's a bit of a pain to mod the stock TPS but the Volvo community was it to look totally stock for shows. I have an aluminum plate that just mounts a Accent TPS on it but doesn't look stock.

"As for the the Fuel pump circuit, the 914s fuel pump relay is activated by grounding the accoicated pin at the ECU. If you are not using the MS relay board then it is the same operation with MS".

I'll have to go and double check my notes I know it works but I added a fuse for it in the D-jet case, as well as fuses for injector outputs, O2 controller and Fast idle solenoid.
How did they handle fast idle on the 914?

"I dont trust PWM, seems most peoples failures with MS are related to it. I chose to go the same route as Bosch and run resistors in the circuit. I had initially used 10ohm 25W aluminum cased ones and in later builds switched to using the resistors in the injector circuit from the stock d-jet ECU as they were alreday mounted so nicely in the case. Think i will go back to the aluminum cased ones though as I have found there is a bit of variance in the stock resistors and i prefer consistancy".

I built 1 system with 7.3ohm 25w alumnium cases (this was the value the MS calculator came up with), I continueally had transiant noise issues in the TPS signal. After much searching w/o-scope I found the issue. There is a thread on the MSII forum about it from about 2 years ago. Seems in 100% output it feeds back noise into the TPS circuit, there are some circuit mods to resolve but the easiest solution was to remove the resistors and go back to 70% output.

"What are you doing with the dizzy sounds like a lot of work for what is still just a 4 point pickup, I was hopeing you found a way to get something more like a toothed wheel in there. In my auto-X car I just locked the advance weights and plates and run a pertronx with a pullup resistor, fuel only builds i use a totally stock dizzy. Some people have said that running ignition with a 4 point pickup can cause unstable timming but i have yet to encounter a problem. Ideally though, next time the engine comes out I think i will switch over to a trigger wheel on the crank that one of the guys here produces".

The next version will be a missing tooth trigger wheel w/optical sensor. Most hi-performance builders will agree that a Cam trigger is far more accurate then a crank trigger wheel but most use both. The crank is mearly for TDC ID.
The current version in my 1800 has a 8-1 magnetic wheel w/1/4" magnets so the missing magnet is at #1 fire position and a TDC sensor on the crank pulley. MSII extra code can use these inputs for Wasted Spark or COP applications and makes sequencial port injection of fuel possible with a minor amount of modification to the PCB (basically your just adding the additional 2 injector outputs and seperating the tied outputs for batch fire), I did this for these future mods.
Additionally, for COP or Wasted Spark you need to add 1 or 3 more coil drivers, DIY now offers the Bosch BIP 373 coil driver IC w/overheat protection for about $3 instead of the old unprotected transistor.
Modifying the dizzy isn't that much work. The advance plate is pressed onto a knurl on the shaft and can be knocked off with ease. I made a jig for drilling the wheel correctly and assambly is pretty stright forward after that, grinding off the points studs on the FI plate and mounting the Hall sensor.

"Another thing i did was to wire the MS serial port to a 1/16 audio jack and use the Innovate serial cable for the MS tuning cable. This way the you dont have to cut the D-jet case for the 9-pin port, you can just drill a small hole for the audio jack".

This is a good idea and may start implementing this. Still need a USB convertor for most late model laptops as they don't have com ports anymore.

My first MS system was a water-to-air intercooled supercharged Volvo B-20 bored .095 over w/ported head measured 2.42L. It had a DCOE Weber on the intake of the SC and was a major mess just cleaning the varnish out of the intercooler when we installed the FI system. I machined a plate and adapter for the w/gate and throttle body. Pre-detonation was a major issue with the boosted motor so we installed a J&S Spark retard system w/knock sensing, this was all prior to MS-Extra code 3.1 that now handles all of these systems as well as waste gate/boost control, 2 stage nitrous, trans lock controller and a host of other goodies.

What PCB ver running and what version of firmware are you using?
Are you using TunerStudio or MegaTune?

Feel free to e-mail me off list as the # of people using MS on former d-jet apps is small and having someone to bounce ideas and problems off of is priceless when working with AM systems.
The Track car is going to a Dyno shop in Carlsbad, CA who specializes in MS systems and should bring the last % of performance out of the system in the near future.

Kurt
kertwerks@mindspring.com