I posted some time back with some Z31 ECU swap questions and recieved good advice, but once I got it together I was still plagued by electrical grimmlins and the heartache that comes with a 25 year old electrical system. The car would surge and lunge and it drove me crazy, and this I blamed on the ECU and wiring. That has changed now

I ordered the MegaSquirt-I Programmable EFI System PCB3.0 - Un-Assembled Kit and the recommended parts from DIYAutoTune. I got my parts in less than a week and within another three days had the kit assembled and began rewiring my engine bay. I chose to remove the original wiring harness and create a new one from the harness received with the kit. It took me about four more days to wire everything back up and it was off to the wrecking yard. I needed a new coolant temperature sensor from a GM vehicle and a throttle position sensor from a 90's model 240SX. Spent $30 bucks and was on my way back with the parts. The sensor is a direct replacement, no re-tapping or threading needed. I did have to modify the TPS and extend the bolt-down tabs, but that was easy enough. Once this was done it was time to fire it up.

The timing was the hardest part for me to grasp, but once I got it and the software configured, she started up and purred like a new car. I took some time and got my idle and low-speed settings done and today I took it out for my first drive after the install. Unbelievable.... The car runs unimaginably well. I wanted to right this up and let yall know. The project is definitely not for the timid, but if you have patients and a little skill it is well worth the effort.

 

Nice!!! Are you still using stock injectors?

 

that's great. i've forgotten your original problem from a while back. is this meant to be an upgrade on the stock system? it sounds like that has already been accomplished no?

 

glad to see another fan of ms on the board. yea timming is the biggest problem. something im still trying to fight.

 

Yes, I'm still using stock and utilizing the PWM circuit in MegaSquirt to limit the current to the injectors. So far so good...

 

KasbeKZ yes this is an upgrade over the stock system, it's good stuff.

 

I was having trouble with the wiring on the distributor. I went by the guide at DIYAutoTune for the 280ZX. After I got the wiring it correct, had trouble figuring out where the resistor went, it was just a matter of getting the crank set right and pluggin the numbers in. Took me about four tries to get everything correct.

 

Does this mean you have a z31 ecu mas for sale or donation? WINK WINK.

 

well that's great. i want to hear about fuel mileage as soon as you get a number

 

lamest request ever... lol a standalone performance turbo car and the guy want MPG.... im going to punch you square in the face over the internet, here it comes!

 

lol forgive me. i am still interested. we have already heard the performance aspect, i want efficiency!

 

Yes, his mpg will get better with MegaSquirt if he tunes it for maximum efficiency. I can tell you from experience, I've never run into ANYONE that did an MS&S installation that didn't tune for maximum PERFORMANCE and completely disregard fuel efficiency...

That being said, with a wide band O2 sensor, it still has the potential to get better MPG with a power tune than the stock system tuned for maximum fuel efficiency.

Cheers,
LWW

 

how much did the megasquirt all cost you? ive been thinking about the setup as the ecu is the last major upgrade the car needs to be tuneable.

 

My total order was $400.25 with shipping next day delivery. If your handy with a soldiering iron I would highly recommend the upgrade to MS.

As soon as I get a number I will post it.

Wide band 02 sensor will be my next purchase. The narrow band works ok for idle and slow speeds, but I really need a wide band for boost settings and higher loads. Will have to work a few side jobs....

 

I have two ECU's and a MAF available. PM me if your interested. Oh and I have the distributor wheel as well.

 

If you have something like MS&S that is tuneable, I don't see why you wouldn't work to tune for fuel mileage. Even when planning to tune for maximum performance there will be times when you will more than likely be just driving it regularly, you can load in a tune that will help provide better fuel mileage and go. I've read many a threads about people using these things to run leaner ratios at cruise to pull better mpg. Glad to hear about MS, I just got Nistune installed in mine, unfortunately haven't had time to mess with it.

 

duowing I agree 100%. The ease of changing the fuel ratio table and spark table should make it easy to tune for mpg's when daily driving and for performance when needed. With this car being more of a daily driver I will most likely tune for better mpg's than performance. So far I am very impressed with this system.

 

I'm going to be doing nearly the same thing, except I'm using Nistune. By the way have you gotten yourself a wideband? That's going to be the thing to really help you tune. After much debating I went ahead and got the Zeitronix ZT-2 with ZR-2 gauge, and their map sensor, came out to be like $470 total. It was either that or the Innovate LM-1 w/auxbox. Which really all it did was provide me with additional accelerometer, injector duty cycle(which nistune monitors anyway), and egt via K-thermocouplers. They even say in the instructions that an actual egt probe is more accurate and they recommend that. So really you get the same features from the ZT-2 for about $100 less.

 

I haven't purchased a wide band yet, but that is next on the list. I can't get a perfect tune without one. MS and a narrow band work ok for low load tuning, but once you add boost then it's anybody's guess. I had to leave the mixtures fairly rich in the higher RPM's and boost to compensate. I'm going to have to work a few side jobs so I can upgrade.

 

you think a wideband would be needed for an n/a? i'm looking into this now as its about the last thing i can do to the car

 

A wide band is always useful for tuning. Most especially on a dyno.

Other than that, for those that use one, a narrow band is all that's needed by your stock ECU.

If you're not running a stand alone ECU and some forced induction, it has limited value.

 

yeah was just looking at setting it up for fuel and spark.
what were the other add ons you bought? i'm looking at it and still confused to what exactly i need to get

 

For me I just bought the wideband and the map sensor with a gauge. I wanted the map so I could have an accurate measure of boost, and then this way via Nistune I could also log the map signal, so I could go over a log of boost vs. rpm vs. mixture, etc. I'd say for your N/A setup you'll be fine with just a simple wideband.

 

well after getting a devastating 15.7 at the drags i think i need to fix it up a bit. from what i was reading i really dont need the wideband for a basic n/a

so besides the MS2 PCB 3.0
DB9 tuning cable
and the 12' wiring harness

is there anything else i need?
all i want is mainly changing fuel setting to get a better power output then when it comes to track meets etc be able to advance the timing to change over to higher octane fuel

edit:after further reading realized i need ms2 for spark also

 

Just an update. The car is still running great, better than I could have expected. I haven't gotten a mpg reading yet, as this is not my sole daily driver, but so far it looks like a substantial increase from what I was getting. That was around 16 mpg. I will keep this updated.