pulse width just goes to 0

t_cel_t · Post by **t_cel_t** » Tue Jul 13, 2010 8:50 pm

I've been having this problem for a while, when driving sometimes it feels like the car misses or something. when it happens it jerks pretty good.
finally caught it on the datalog.
can somebody check this out, i just don't see why it does this. may be fresh eyes will help.
i am running the launch control, but at the point that is the problem i wouldn't have had the clutch in.

it occurs at second 1414.800, it looks similar to what the launch logs(1409.7-1410.9) but it doesn't show a cut in the spark angle.

on an unrelated note (hopefully) can anyone see why the engine acts like it does at around the time 1426 seconds. its very annoying, i think it might be from having the bottom row of my ve table at 20kpa and not 15? during driving down slight hills it just doesnt like the low pressure/low tps.

nukkinfuttz · Post by **nukkinfuttz** » Wed Jul 14, 2010 6:40 pm

The only thing i see out of the ordinary is your required fuel setting... why is it 25.5ms??? Either you have the worlds smallest fuel injectors, or you messed up on the Required Fuel Wizard somehow. Could you please tell us what size injectors you have and what size engine you have?

t_cel_t · Post by **t_cel_t** » Wed Jul 14, 2010 7:17 pm

lol, i had to set it to 25.5 to initially get it to run. the basemap i was using had the ve's way too low, so to counteract that i had to set it super high.
it shouldnt matter right? its just that the ve's are just not 100% representative of the actual efficiencies?

anyway its a toyota 5efe 1.5L with high imp 185cc injectors.
the req fuel says to use 14.4 but it just would run way to lean. i read in the manual that in megatune it would rescale the ve's if you changed it, but i can not find that setting in tunerstudio.

kjones6039 · Post by **kjones6039** » Wed Jul 14, 2010 8:27 pm

i read in the manual that in megatune it would rescale the ve's if you changed it, but i can not find that setting in tunerstudio.

In TS highlight the cells you want to increase/decrease by selecting one and then dragging the cursor. (ie. select the top left cell and drag the cursor to the bottom right cell if you want to select the entire map)

Right click on the highlighted cells and you will be allowed to perform any number of operations on the selected cells.

Ken

nukkinfuttz · Post by **nukkinfuttz** » Wed Jul 14, 2010 8:53 pm

In your Wizard, you should set your engine size to 1500 CC's. your injectors to 185CC's and your Air-Fuel Ratio to 14.7 <--- which is proper for gasoline engines. the resultant "Required Fuel" is then 13.5ms. this is HALF the value you have now. what good is information if its not real information? if your car doesnt run right with these numbers, then you will need to tune your VE table to make it run right... and when your done, your VE table will actually represent your engine rather than your engine divided by 2. I guess that point is just a matter of princable. do what you want, but there is a "right" way, even if for no other reason than your information will be accurate.

im looking i see some activity on port B in association with your PW failure. I wonder which bit it is?

nukkinfuttz · Post by **nukkinfuttz** » Wed Jul 14, 2010 9:12 pm

It looks like your Port B likes to go ... 112, 48, 112, 48, during the mess up. so, lets decode the word...

00000111 = 112

00000110= 48

0 MAP
1 MAT
2 CLT
3 TPS
4 BAT
5 EGO
6 "X7" spare, EGO2, fuel pressure or 2nd MAP
7 "X6" spare, EGT

looks like everytime X7 goes high, you get your 0 PW. look in your logs and add the trend for Fuel Pressure and you'll see it. This is an input.. it should not be "floating" around. See in your schematics for pin X7 and make sure there are no solder bridges to any other components. You might even want to add a pull-down resistor to ground to keep that X7 at ground potential and keep it from floating up and cuasing you problems...

this is all assuming you did not puposefully hook up something to X7... in which case, plese let us know what that is.

t_cel_t · Post by **t_cel_t** » Wed Jul 14, 2010 9:43 pm

thanks man, i owe you a beer.
also this is a v3 board, so i assume x7 is the same as js5
this may be a dumb ques but is there a reason the fuel pressure trend follows the AFRwbo2 trend almost exactly? with the port b following somewhat closely?

does that mean there is a short between the circuit for the wbo2 input and the x7 (js5?)?

Post by **jsmcortina** » Thu Jul 15, 2010 2:54 am

Unless you have a fuel pressure sensor connected, then that analogue input "floats" and will usually harmlessly follow the pin next to it.

James

t_cel_t · Post by **t_cel_t** » Thu Jul 15, 2010 4:14 pm

adding a pull down resistor entails what?
what resistance do it use?

Post by **jsmcortina** » Fri Jul 16, 2010 3:01 am

You don't need to.

99% of Megasquirt installs have nothing connected to ADC6 and ADC7.

James

t_cel_t · Post by **t_cel_t** » Mon Jul 19, 2010 11:00 pm

ok i was doing it bad again earlier, heres a new datalog.

with the pulldown resistor, what ohm do i use?

Post by **jsmcortina** » Tue Jul 20, 2010 3:33 am

Why do you want a pulldown resistor?

James

t_cel_t · Post by **t_cel_t** » Tue Jul 20, 2010 2:34 pm

because nukkinfuttz suggested it could help.
the car is practically undriveable now.

does fuel pressure factor into the calculation for the injection duration? if it does, can i turn it off?

Post by **jsmcortina** » Tue Jul 20, 2010 3:03 pm

Not at all.
Megasquirt does not know about or make any reference to that so-called "fuel pressure" reading. It is not used in fuel calculations.

It is an optional place to DIY connect a sensor and if that is done it shows in datalogs. I don't know anyone who has installed a fuel pressure sensor (with MS1.)

James

Post by **jsmcortina** » Tue Jul 20, 2010 3:38 pm

I've looked through your datalog and MSQ and don't immediately see anything particularly obvious.

A couple of observations though:
-what is your overboost set to? I'm seeing 49kPa ?
-what is your "open loop" kPa setting? I'm seeing 20kPa which doesn't make any sense - it would mean that you are in open-loop AFR correction except when you are in overrun?

If you turn off the launch feature do you still get this behaviour? It might be worth turning off the extras to try to narrow things down.
In other logs do you see an rpm spike or drop around the time the pulsewidth goes to zero? I'm wondering if the tach input goes wrong or has noise and shows a really high rpm that trips the rev limiter?

James

t_cel_t · Post by **t_cel_t** » Wed Jul 21, 2010 12:15 pm

turned off the overrun and set the open loop to 80kpa
car runs PERFECT.

i cant thank you enough

Pampamas · Post by **Pampamas** » Sat Jun 03, 2023 10:54 am

t_cel_t wrote: ↑Wed Jul 21, 2010 12:15 pm turned off the overrun and set the open loop to 80kpa
car runs PERFECT.

i cant thank you enough

Hey Buddy, I'm installing an MS2-Extra in my 1995 5E-FE Paseo engine and it'll be parallel to its original ECU.

Could you share with me your current maps?

Many thanks for considering my request.

Megasquirt Support Forum (MSEXTRA)

pulse width just goes to 0

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