Author Topic: effective rampup problem  (Read 6826 times)

Offline ecutec

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effective rampup problem
« on: June 23, 2008, 01:49:44 pm »
Hello
Im doing a nissan coupe 16VT
i bough siemens 630cc deka injectors from vems site and the unit is equipped with 30v tr diode
car runs nicely only when is set the effective rampup to over 3ms
injector settings should be around 1ms by datasheet but then the pw starts droping up and down
pwm'ing is disabled as they are high impediance injectors...
opening time is 0 and rampup battfac is 4080
pin 23 goes to injector common +

any ideas what should i check?

Thank You!

Offline rob@vems.co.uk

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Re: effective rampup problem
« Reply #1 on: June 23, 2008, 04:39:25 pm »
Hi, first off what firmware are you using?

Secondly, what is actually happening when te PW starts dropping up and down?  Is it because the engine is running roughly?  If you are holding your injectors open for longer with the effective ramp-up time at 3ms it might be because the fuel map is too low at idle - so you are overcoming this by forcing the injectors open for longer with the ramp-up time.

What I would do is:
Check the req_fuel value.  Save my current maps.
Halve the req_fuel value, and set all of the values in the maps that are around idle and low load (so a 4x4 or 6x6 part of the table) to 100 on the VE table, and what ever the correct sort of idle advance is for your engine (something around 15-20degrees), ensure that your lambda table is also set to 1.00 in the 4x4 or 6x6 part of the table.
Set the effective rampup to 1000
Now start the car and start to map VE at idle - if you change the values in all the 4x4 or 6x6 cells at the same time you should have an easier time as the engine is less likely to run off an lean out or get too rich as the RPM & vacuum rises and falls.

Once you are happy with the idle make a note of the VE and PW values and compare this with your original fuel map (remember to half the VE number when comparing it with the original value).

Why do you half the req_fuel value?  Well thats because it gives twice the resolution of adjustment, which can really help with getting idle fuelling spot on.

Rob

Offline ecutec

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Re: effective rampup problem
« Reply #2 on: June 26, 2008, 09:42:10 pm »
thank you! this solved the problem ev tho i thought that i tried raising the ve table before also...
so what i did now was that i lowered the req fuel and effective rampup (to 1200)
and then raised ve until i got nice idle