Megasquirt owners thread

[jerrah]

I've just dropped some 320cc Supra injectors (green tops) into my NA6. I'm currently using a DIYPNP megasquirt to run the car.

I've scaled back my required fuel but the car idles like a tractor and feels really rough. What else should I be changing to get this to run right? I thought it would just be a case of telling the megasquirt that there was now bigger injectors.

[Steampunk]

Simplest and safest changes are in the VE table and spark value around idle.
Increase fuel first to see if it smooths things out.

Perhaps set base idle to 1,000RPM.

Sorry, it's been a while since I've played around with MegaTune, so can't help all that much. You know about miataturbo.net don't you?

Keep in mind that it may not be MegaSquirt related, ie. try opening/closing the idle-bypass screw on the TB.
oh... hang on... have you got your SC installed? if so, is there a manual adjustment for idle air?

Are the injectors clean and in good nick?

[Si.G]

Hi Guys,

I think I might have trashed my MS PNP. What is the best way to go about doing diagnostics on an MS?

Thanks.
Si.

[Si.G]

Hi Guys,

I think I might have trashed my MS PNP. What is the best way to go about doing diagnostics on an MS?

Thanks.
Si.

I have fixed the MSPNP - I had to reload the firmware using hyperterminal (never done this before) - so it must have gotten really messed up.

Si.

[timk]

Did it get trashed while you were trying to do an update or did it just randomly happen? If the latter, that sounds concerning.

[Si.G]

Did it get trashed while you were trying to do an update or did it just randomly happen? If the latter, that sounds concerning.

It got trashed while doing an update. Although I do get a miss match type error from time to time between megatune and the ecu. - Any idea what that is about.

Any way, I have had a very very frustrating day of tuning, but mainly because of my own ignorance

I thought moving from MAP to Alpha-N would be pretty straight forward, but it really is not. I thought I could just replace my MAP values with the corresponding TPS values. I got the car running and then found that the engine would die as soon as I touched the throttle. I found that I really need to have max resolution at the small throttle openings. My MAP VE table had more resolution at the oposite end, so that is how I set out with TPS.

After figuring out the resolution issue for myself, I did a bit more reading and found a couple of supporting articles on the web. It is interesting, because with Alpha-N at low rpm a 10% throttle opening right up to 100% all need the same fuel because at 10% (at low rpm) the engine my be pulling no vacum, hence whether the TPS is 10% or 100% the engine will still pull in the same amount of air. I still have my MAP hooked up so I can log MAP and figure out what TP is WOT at what rpm if you get what I mean

So the fuel and spark tables are going to be very different using Alpha-N. I am thinking that I might just go back to MAP, drive it to the dyno and then switch to TPS for the tuning. I was hoping to get this pretty close to save dyno time ($$$), but i think it is too risky, because of the spark setting. I might end up with a load of detonation.

FYI - I am going to alpha-n because I have ITBs and MAP signal is not stable enough.

Si

[Okibi]

Where are you getting it tuned Simon?

[timk]

Does the MAP stabilise at higher RPM? If so, maybe try hybrid Alpha-N mode?

[Si.G]

Does the MAP stabilise at higher RPM? If so, maybe try hybrid Alpha-N mode?

I did some more reading last night and saw the Hybrid Alpha-N stuff - I think I am going to give it a go next. thanks for the suggestion though, it validates my thinking!

[zossy1]

Just found this thread - I think that the experience you guys have with the MS may come in very handy for me in a couple of months' time!

Once my NA8 is back on the road, it will be turboed with the help of a DIYPNP I bought back with me from the USA. It was built by Braineack of the MT.net forum and his units have a good rep so here's to hoping it works! It cost me $580USD including the GM IAT, EBC, 4 bar MAP sensor and LC-1 hookup.

My plan is to go in the following order:

* Finish repairing car - blue slip and register;
* Install A/C - car currently has no A/C and I have bought an A/C system from another forum member's NA which is said to include all the bits I need including under-dash box and wiring... not looking forward to this but I *really* want A/C!
* Install DIYPNP, delete MAF for IAT, and tune with Tunerstudio;
* Install 420cc injectors and retune;
* Install turbo and retune.

Any thoughts or advice at this stage? I figure when the time comes i'll have plenty of questions

[Steampunk]

I would read up as much as I can on the AC side of things. Idle dashpot settings and AC circuits seem to be the most common bane in most aftermarket EMS'ses.

[jerrah]

I've been wondering... Is there any reason why people don't just wire an output to turn off their air conditioning compressor below 1500rpm and above 90% TPS?

It'd solve the air conditioning idle issue and retain the compressor off during acceleration like the stock ECU. Sounds heaps easier than trying to get the IAC to maintain idle with the compressor kicking on and off.

[geofiz]

Time for the questions to start

I now have a MS3, which I will hopefully get installed and runing in the next little while on my 99 NB.

The unit I purchased has the MS Extra module, so I guess I will use the sequential fuel options for now, and eventually get a COP set running as well.

Any tips on setting up the sequential injection would be greatly appreciated, along with some suggestions on which injectors to run. I have standard and SE injectors available, but don't know if there is any difference between them. Motor will probably end up FI (leaning toward supecharged at the moment), so a little future proofing at this stage is planned.

Thanks.

[gslender]

Decided to start a build blog relating to DIYPNP.

http://rednels.com/2011/09/diypnp-megasquirt-step-1/

G

[zossy1]

Phew - now I'm dealing with the most common problems faced by all Megasquirters - hot idle issues, and IAT heat soak (probably related to an extent).

Lots of reading and making progress... but getting there