barf

thanks. i get 11.4v during cranking. most fuel injectors are +12v ground switched, that helps explain why cranking pulse widths are higher too. the megasquirt has a battery voltage correction factor for inj' duty cycle.

Why? Could you please explain that? How is the spark made more powerful durink cranking?

if while you're at it, you want a cheap spark upgrade, connect your spark plug receptacles to the battery negative. i think HKS sell some kit to do that. don't connect to painted stuff tho. ground is just as important as power supply.

do the nissan MAF sensors contain an air temperature sensor? if so, any ideas what wire into the sensor is the temperature? (i'm being lazy i could just note resistances and temperatures.)

ground your temp sensor better

i agree the code needs to be open, i'm sticking with MS2/Extra until they GPL or open it in some way. there's a growing clone market out there that they seem to be at odds with, when they really should just embrace it. that whole 6x6 table needs to be copied from Flash or RAM to the accumulator (=clock cycles) before each group of math functions is done on it, table lookups are expensive in low-memory systems like a microcontroller. MS2 is a freescale MC9S12 - 16-bit @ ~25 MHz http://en.wikipedia.org/wiki/Freescale_ ... erivatives MS3 is a newer MC9S12 (MC9S12XEP100MAL) still 16-bit but with improvements. i suspect it's mostly a code re-write(?). http://www.freescale.com/files/microcon ... 00RMV1.pdf

@Spencer - you say "only" 6x6 as if thats a bad thing, the value output is taken from an interpolation based on this table lookup, it is smooth, there is no sudden change between values - assuming the table is 'spaced-out' correctly across the desired range of operation. bigger is always better tho even a 16x16 VE or spark table could be 'too small' if the values on the axes were not placed in the area where the greatest transience is. hope that makes sense lol.

I've ordered mine as kitsets from diyautotune.com shipping was prompt (2 weeks) and they had good after-sales support and a facebook group, although I didn't need much help with all the great documentation and forums at msefi.com. you can buy preassembled ones at a slightly higher cost. the CPU module is preassembled always however, owing to being largely TSOPs and other SMT components. use MS2 at least, MS3 looks awesome. if you need help with them, ask. it's not a turn-key system like MoTeC or Link but the features certainly compare. maps and correction tables are in 7 or 8 dimensions if you do it right. I've installed a few, just for mates in Christchurch and we tuned them ourselves using Innovate LC-1 wideband controller with Bosch LSU 4.2 exhaust gas-oxygen sensors (although they actually detect the amount of nitrogen). we didn't have a dyno and tuning is a completely different matter to installation.

does it still go hard OK? if so idle control valve maybe? they can become fouled with oil from PCV, soaking in diesel worked for me

the 20v itb's vacuum signal isn't shit - it's application is different (they combine AFM and MAP - if am I correct?), actually it has a very precise vacuum sensor position but it is denied a MAP reading when the throttle is closed as noted, there is a small vacuum-sensor hole occluded by the butterflies when shut, if you look closely. will document how we got around this in a new project thread, hope to post that up soon as poss. basically you need idle control system plumbed into your itbs - got photos you can put up rob? In the case of Megasquirt 2 - TPS without MAP works OK using a speed-density algorithm but you'll likely miss out on features like acceleration enrichment, X-Tau (wall wetting compensation) and have no chance of electronic spark advance derived from manifold pressure. there are two main fuelling algorithms, speed-density (for throttle-body injection ie; V8 holley TBI manifolds) and alpha-N which is the multi-factor algo you want to get it nice and smooth. out of curiosity, how do you ppl achieve proper spark advance control when the vacuum signal has been neglected? does the Link have a simple RPM + TPS table? good luck with your project.

you can go sequential injection and 8-cyl COP with MS3 for well under $1000 - if you can solder. bank-fire fuelling algorithm in MS2 accounts for wall-wetting so it's a fine difference (don't bother with MS1). one project coming up is a 4k with twin-downdraught throttle body injection robbed from a 1S-iLU

whats best on valves?

thanks head is off but i don't have a valve spring compressor, just been turning the cam to open valves and clean it up :-\

I've seen kitsets by MSD to replace points, not cheap, I suggest address the ignition system as a whole. you're not just replacing a part here, you're moving from kettering points to electronic ignition systems. I like the megasquirt II (ignoring the fuel injection features) it works great in a 'spark-only' application and they're cheap and reliable. they work with almost any crank or cam-speed timing signal, the challenge here is getting a timing signal, use a sensor from a dizzy, install laser-cut disc (+pickup) onto front crank pulley,etc.

i lost compression in a cylinder because of loose coke interfering with the valve seat, whats a good/safe solvent to use on, or way to clean an alloy head to remove coking? basic question i know but, first rebuild here, she was burning a lot of oil before the rebuild. already had the acid dip and leak down test was OK but there was still lots of gunk on top of the valve when i got it back from the head shop. turning the engine over was enough to loosen it off when the valves moved and i don't want to burn that shit in clean cylinders!

so I'm frustrated and want some advice. trying to disassemble the oil pump on the 4G93 to de-coke it, the bolts are supposed to be torqued to 10NM but after 270,000kms they seem pretty stuck. they are a plus-head countersunk bolt and i'm not keen on mincing the bolt head if i can avoid it, theres no nut they just fasten into the oil pump. whos got the best pro-tips? do i reaaaaalllly have to drill and eziout these tings? would heating/cooling help?

i think you might not observe anything on that wire from the ignitor because it doesn't output a voltage but switches to ground instead, there was a 5v pull-up in the ECU on that diagram for this purpose.

well you might be lucky here, if the signal from the toyota ignitor was the same or similar enough (can't recall) then it could just wire straight up OK. the theory is the same in either case, a tacho identifies a revolution by observing a momentary break in the ignition circuit. logic level tachos may invert this signal and/or represent it by frequency of a square wave forgive the pbrush.exe diagram

looks like that ignitor outputs logic levels and my dash (CM5A) measures RPM as logic-level pulse from ignitor/ECU - not from coil. so that tacho output from the ignitor probably won't drive your tacho, that circuit with the zener is the ticket.

what sorta tacho are you hooking up? vehicle's original tacho? (what car?)

wasted spark FTW! I use a similar ignition module on my 4G93 turbo that 5v probably just indicates the ECU has a 5v pull-up to sense the tacho (ie you should see 5v relative to sensor ground on pin#109, when the circuit is open/unloaded). here is an example from megasquirt manual, you could implement it this way also, assuming the tacho is not looking for a logic-level pulse http://www.msextra.com/doc/ms2extra/MS2-Extra_Hardware.htm#tachoout

if wiring from scratch also a good idea to use a power diode on the positive of the field coil to prevent back emf destroying other devices, ie if you have electronic spark or fuel injection computer, head unit, et cetera

i already replaced them at once about 200,000 so these ones have done less than 80,000kms, they're not noisy either was just askin for advice. last time i had to mild race the engine for 30-60 secs to bleed air out of them

would it be wise to use assembly (Dry) lube on these? or better to just use typical lube oil?

can anyone share their tips for installing, bleeding air from and checking hydraulic lash adjusters? working on a 4g93 (1996 turbo one) and thanks in advance for any advice, my first rebuild here.