Megasquirt users thread to discuss all things Squirty

[knightrous]

Nice work nuk1ear, you should do a post over in the MR2 Australia MegaSquirt Thread
If you do a post on MS3X and I post up about my DIYPNP, there will be a good chunk more information over there on setting up MegaSquirts for MR2's with different configurations

[nuk1ear]

there u go bud, posted. Yeh easier to buy premade, but the wireharness still needs to basically be made haha.

[MWP]

Nice work on that loom.
Where did you get the cable sheath from?

[WDE_BDY]

Manifold is getting modified for the new throttle body.


Callum

[ballpencil]

Perhaps the fine gentlemen of Toymods could enlighten me with this problem i'm having. Engine is 4A-GE smallport setup for Turbo. Previously running great with the stock NA MAP Sensor. However, when i switched to 4A-GZE MAP Sensor, i had to shift the whole VE table by 30% to get a decent AFR reading (not too lean). I mean, the whole values on my VE table are now 30 points bigger than when it was on NA MAP Sensor.

I have altered the kpafactor.inc files and burn them to the CPU and i believe my mapping for the kpafactor is more less correct, like so:
1. For NA MAP Sensor, i altered the kpafactor4115. With the mapping i did, atmospheric pressure (MAP sensor reading at turn of ignition key) is at 101 kPa and idling at 35kPA
2. For 4A-GZE MAP sensor, i altered the kpafactor4250. Atmospheric is at 94 kPa and idling at around 28 kPa. Yes it's still off by about 6-7 kPa from the NA MAP sensor reading but this doesn't explain why i had to shift the whole VE table by 30%.

This is my VE Table on stock 4A-GE MAP Sensor, idling at 35 kPa at around 13.5 AFR.

and this is my VE table on 4A-GZE MAP Sensor, idle at 28 kPa at around 14 AFR (so still leaner than NA but decent).


My problem is that i'm under the impression that as long as they're reading the same kPa value, changing MAP sensors shouldn't require me to alter the VE table. Why do i have to shift the table by so many just to achieve similar AFR reading from NA MAP sensor? Both are reading around 100 kPa atmospheric and both are only offset by 6-7 kPa on idle reading. This shouldn't require me alter the VE table, no?

[knightrous]

Why don't you use the onboard MegaSquirt MAP sensor?

[thechuckster]

if you've gone from an NA to a boost-capable MAP sensor, you really need to edit the kpafactortable with regards to the max and min output rather than a point (or 2) along that curve/line.

You shouldn't have to edit the VE table at all, if the kpafactor table is correct.

I vaguely recall there being a thread/discussion on here (haven't found it yet) that discussed what the min/max kpa ranges of several toyota/denso MAp sensors and they unfortunately didn't neatly fit into the 2.5/3/4 bar ranges that meqasquirt resellers sell sensors in.


edit: if using MS3, you can just put in the calibration figures here during initial setup:


edit 2: if using MS2-extra, 'You can use other 0-5 volt pressure sensors, but you will have to calibrate it using the 'Tools/Sensor Calibration' dialog in MegaTune.'

[ballpencil]

if you've gone from an NA to a boost-capable MAP sensor, you really need to edit the kpafactortable with regards to the max and min output rather than a point (or 2) along that curve/line.

i don't see why i can't edit the table with two points along the curve as long as i extrapolate them correctly? i mean, the curve is linear right?

I vaguely recall there being a thread/discussion on here (haven't found it yet) that discussed what the min/max kpa ranges of several toyota/denso MAp sensors and they unfortunately didn't neatly fit into the 2.5/3/4 bar ranges that meqasquirt resellers sell sensors in.

i would very much like to see this thread. i based my kpafactor table by following some reference i found on the net and wrote about it on my blog here. they could be wrong so if i could get another comparing reference, it would be great. i'm off to search then.

[nuk1ear]

as above and also, why not use the built in MAP sensor? who knows what could be wrong with the GZE one

[ballpencil]

Let's just say i didn't get the complete kit and preferred to buy just the part i need to save cost. Anyway, i don't think GZE one is faulty, the car drove normally just now. Most probably it's my kpafactor edit that's still off. If anyone could share a correct kPa vs volt output for a GZE MAP sensor, that would be great.

[thechuckster]

easy solution is to make up a jig that simulates vacuum/boost - a large syringe (30 - 50ml) and a boost/vacuum gauge will do the job.

- attach a tube to the MAP sensor
- connect a t-piece to the tube you just attached
- connect syringe to one side of the T
- connect guage to other side of the T
- power up the ECU (fuel and spark power supplies disabled) so you can get a 5V ref supply to the MAP sensor
- measure voltage output of MAP sensor at atmo (~100kpa)
- measure voltage out at 0-10 kpa (max vacuum)
- apply increasing amounts of pressure until output pegs at 4.5 or 5V and then note the amount of boost (you'll have to convert it to kpa)

then edit the table using the min/max values - if you extrapolate between the two, use the 100kpa measurement to check your calculations.

And yes, it should have a linear output (e.g. a 250kpa sensor should be ~0.1V at 0kpa and ~4.9v at 250kpa).

[drew22]

Just clocked over 2000Kms with the ms3 and its running well. Just need to run it up on the dyno to sort out the top end highspeed stuff.

nuk1ear what type of cops are you running?

[nuk1ear]

Hi all,
Putting my dizzy back in with G2 wired up to my megasquirt. How do i know which cam sensor is G2, and when i find out do i just put the tooth inline with that sensor and install the dizzy with the crank at 0deg? (using COP, no plug leads and gen 2 3sgte)

[knightrous]

Refer to the service manual on how to install the dizzy in the correct position
Then if G2 doesn't work for you, try G1.

[nuk1ear]

well im retarded. Just had another look at the dizzy and it can only fit in one way. Anyone know if you use G1 or G2? I know i can test myself, but would be nice to know lol