Desperate for some Help With Microsquirt, Beyond Frustrated Options

[Mblizzard]

I have been trying to get my conversion done in time for Okteenerfest. I have run up against a brick wall and just cant seem to figure out what i am doing wrong.

If anyone can help me by looking at my tune files or providing insight it will be very much appreciated.

I can get th car to idle but nothing beyond that. Any use of the throttle is less than impressive and almost useless. Meaning it bogs down and does not accelerate at all.

I have no clue what i am missing.

2056 with new low impeadance injectors. Bosch Wideband O2 sensor.

Really need some suggestions. Not sure if i can post the tune files here. But will try.

[JeffBowlsby]

Please do not misunderstand my question, I am an inquisitive person and only seek accurate information, not to start a heated debate. The question is purely rational and not subjective. When a bold claim like that is made it requires justification otherwise the myth that D-Jet is somehow problematic/flawed/inefficient/etc. continues without justification. I have always run D-Jet cars and find them to have no issues and terrific. No doubt other FI systems have their benefits. We have street cars here, not high performance, highly sensitive machines requiring the minutia to be exactly perfect.

From my perspective, any quality made, appropriate to the engine, properly adjusted FI system is as good as another in terms of how the engine performs and functions. With that understanding no FI system will perform significantly better/worse/differently than another, will not be more responsive/give more power/better mileage etc. The best FI system just feeds the engine what it needs and as long as it does that well, whats the difference?

Show us the justification of the above claim or qualify/recant the broad generalization. Its a fair question.

[JamesM]

Please do not misunderstand my question, I am an inquisitive person and only seek accurate information, not to start a heated debate. The question is purely rational and not subjective. When a bold claim like that is made it requires justification otherwise the myth that D-Jet is somehow problematic/flawed/inefficient/etc. continues without justification.

I totally understand as I am very data driven person myself. Much like the carbs vs d-jet discussions the Megasquirt vs anything discussions have a tendency to devolve hence my response and my reluctance to even post on the subject anymore.

That being said, and not having been the one to have made the statement here I can only comment on what I know about. I do know that the particular motor in question was not stock so I am going to assume the rest of the statement should have been "performs better than the stock system on my motor."

To be clear, I love a well running d-jet system on a bone stock motor. I have both a d-jet 1.7 and a d-jet 2.0 that amaze me every time i turn the key, they start on the first compression stroke and I am in awe that these 45 year old parts still perform so well.

My appreciation of Megasquirt has to do with it being a technical advancement that allows optimization and precision not possible with d-jet. Added bonus is that is is also tune-able to any modification you make to the motor.

From my perspective, any quality made, appropriate to the engine, properly adjusted FI system is as good as another in terms of how the engine performs and functions.

I do not believe this is an accurate assumption. If it were why are all Porsches today not running D-jet? Technological improvements have been made that result in real world benefits. At the most basic level, putting aside the massive feature set of Megasquirt and the documented shortcomings of D-jet wiring connectors and just comparing the two systems from a fueling standpoint there are still advantages to Megasquirt. Specifically I am referring to the accuracy of supplying fuel based on an analog curve vs a digital programmable fuel map. Yes under some conditions (specifically the points in the curve the d-jet system has been tuned to) the fueling of the two systems will be identical however outside of those very specific points the curve approximating fuel needs is just that, an approximation. It may be close, but a digital map will be closer if not dead on. In addition, the needs of an engine are not always on a perfect curve. The engine in my autocross car for example once the fuel map was completely dialed in for whatever reason has a noticeable dip in fuel needs at WOT around 3200-3600 rpm so looking at it on paper the fuel curve at WOT is not a curve but looks more like a 2 humped camel. A d-jet setup on this motor could be tuned to produce a perfect mixture at couple specific points but because of the shape of the fuel requirements it would always hit a rich spot around 3200 RPM at WOT unless it was tuned to be dead on at 3200 RPM in which case it would be lean everywhere else. Would it be noticed from the drivers seat? Who knows, but it can be seen in the data.

Add to that O2 closed loop operation and you just increase the real world accuracy of the system even more.

And that is just fueling. Megasquirt has a complete engine management feature set and the advantages that the accuracy of a digital system provides are multiplied as soon as you add ignition control which is really where i feel the most gains are. You can visibly see the difference with a timing light between a car running a stock distributor and one running a 36-1 tooth wheel with wasted spark. You can also again tune the ignition table in ways that are just not possible with analog advance weights and vacuum canisters.

I can go more in-depth but the bottom line is always accuracy improves performance and efficiency and Megasquirt can be tuned to a higher level of accuracy across all running conditions than d-jet, even on a stock motor. Nothing "wrong" with d-jet, its just the nature of the two systems. Points that can be made to the advantages of d-jet over carbs are similar to the ones that can be made about Megasquirt over d-jet. Its further refinement and less compromises.