New Zealand Datsun Club

Not sure if megasquirt can do it but you can also control cold start with ignition timing. In the new link G4s you can set up a table that gives a certain timing vs a given rpm level, can go into this a bit more detail later if you want
However Cold start is normally the very last thing done when tuning and is done dead cold. pref in coldest weather.
I would concentrate on mechanically getting it sorted. Set it up much like you would with side drafts. Set the idle speed, crack the throttles a touch, then balance each one. You could put a feeler gauge or something similar under each blade then they will all be the same, it will just be a guess to start with, you will need to reset it once its running. Make sure you have the TPS set correctly, IE the scale is correct, so it has the right resistance at opening and closed. Check it doesnt have any vacuum leaks, There will need to be NO open to atmosphere ports after the butterfly. Check your base timing is correct (your just running a points dizzy? so should be straight forward)
Once thats all sorted it 'should' be a case of cranking it and adjusting the master fuel value until it idles. You may find the revs will pick up once it fires if you have adjusted the idle to high, Probably better to be slightly on the higher side than the lower side

Thanks for comments guys.

The 4AGE ITB's have individual "closed" stops and also balancing screws between the linkages to individually tune. Yes I should check all this though, as custom manifold/flange, has altered geometry a fraction no doubt. Yeah Nick, I was thinking feeler gauge under the butterfly would suffice for balancing them at "closed" setpoint. Yes at this stage I am just running OEM ignition system, with 10° advance set (trying to get fuel sorted a bit better before I bring in the complexed iginiton programming as well!). I really need to get my O2 sensor fitted up and calibrated to give me realtime feed back of lamda, and additionally the temp sensor online as well.

The more I read this morning online, the more it seems that my application will be OK with mechanical idle setup, rather than fussing around with cold start valves and the likes. At the end of the day my side draught setup was the same, no cold choke setup, just crank it over, pump the pedal to get some fuel into it, bring it up on to cam once its firing, and then just manually rev it to warm it up for 3-5 minutes. its not a race car, but its not a daily driver either. I will have electric fan on thermostat switch, and able I guess to get some more fuel in with my temp controlled fuel settings to make it reasonably user freindly.

Reading up a bit also on some new code that MS offer for ITB setups, which seems to run a hybrid VE ouput using a combination of TPS & MAP signal tables to maximise performance throughout the rev range.

If possible I would like to get fuelling a bit better, so I can bring the new ignition system online, before I pull motor out for next stage of body repairs and initial painting later next month (hopefully) when I get motor back in, I will get exhaust system made, all sensors online, and start on the tuning process (car will basically be drivable so I can do back road tests..??) if I iron it out over next few months, means when it gets final paint in the summer, I know car is ready to hit the road.


Its a big steep learning curve, but when I eventually get it driving, I am going to reap the rewards of all the hard work.

those 2mm holes would be fine to adjust the idle if you want your butterfly's closed. you will be surprised how little air you need to get it to idle. my setup has no cold idle adjustment and no idle control valve its all just butterfly's and once set runs completely fine. i cant remember how many thou it was I have my butterfly's set to to make it idle but is naff all.

like you say you just warm it up with your foot. its only initial start anyway, once mine has been running for a minute or 2 its fine to just sit and idle away till its warm. runs a wee bit rough but as the MS dials the fuel out as it warms up it never fouls up or anything. i wouldnt worry about it to much.

biggest thing as bart and others have said is get your butterfly's all in sync, will save you so much mucking about trying to get a stable idle.

its a pitty you are so far away, i would just come over and give you a hand.

Hey Mark - thanks for the comments - great to have feedback from someone who has been through this and had success.
Will pull the ITB's off over weekend, and get them mechanically balanced, then try it all again.

Hard to get motivation to do much on these cold winter nights....

Small boring update....:
- Stripped off ITB's and have set all the closed stops again (cracked slightly open), and reset all the balancing/linkage screws etc, actually took quite a bit of adjustment, as was out by quite a bit I believe
- Will keep the manifold off till I get some new tabs welded on between my injector pockets, to "pull" up the fuel rail more effectively when I refit it all up
- Got a new custom throttle cable made up
- Going to fit my new alloy radiator and fan at weekend
- Made prototype Z seat bracket adaptors
(unsure what to do here, does anyone know much about cert spec for seat rails?
I want to use like 65x6 alloy bar's spreading across original rails, all using M8 8.8 grade bolts
but maybe I will have to use (heavy) 50x5 MS or the likes)
at least the seating position is sweet, not too high up thankfully, and goes back far enough for ample leg room
- Started sorting through all the parts in my second mancave, trying to suss out whats there, whats not, what needs
to be replaced or reconditioned etc...

Excellent dude!!!
In regards to cert question for the seats its best to go straight to your cert man and show him via rough sketch with specs of material your using and he will give you a straight answer. The cert rules are changing so often it pays to go to the man himself rahter than here say from other forum users. Thats what i did for the camber issue and he put me straight.

Personally i used 50x5 flat steel bar and 50x25x3 box for my seat brackets using 8.8 M8 bolts

Dattochriswagon wrote:The cert rules are changing so often it pays to go to the man himself rahter than here say from other forum users. Thats what i did for the camber issue and he put me straight.

What was the outcome there Chris in regards to camber?

Its still seems discretionary. I explained to him that my thoughts of my wagon with no camber with a 200hp engine where a 69hp used to live is unsafe. He agreed and didnt seem phased that i might have somewhere between -2 & -3 deg camber. He said i just need to provide a current wheel alignment printout stating the camber measurement.

Yeah good call Chris

I started draughting it up today at smoko time at work, figure its about
time I talked to the cert guy anyway, so will touch bases and show him
what I plan to do.

Did you 25x50 RHS need crush tubes or end caps, or is it OK to have open section?

I had crush tubes. Just a nice logical thing to do. End plates couldnt hurt either.