Recent Posts

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1
Solenoids / Re: IAC setup
« Last post by DZGunner on November 18, 2020, 01:10:47 am »
So i adjusted the factory screw on the ISV to get rid of the safe mode all together, sinse VEMS doesn't seem to care what i set at the min PWM. The car runs a lot better.
2
Solenoids / IAC setup
« Last post by DZGunner on November 17, 2020, 03:38:13 am »
I'm very new to much of this stuff so this is all a learning experience for me, just bare that in mind please. So I have an ISV that has a limp home mode in its full resting position. I used the IAC lock to determine that 31% PWM would hold it in its closed position past the safe mode. I enter that value as the MIN PWM, and left max at 100%. With the key in the on position, but not cranking or running. the ISV duty cycle shows the 31% i entered as the min. (good) and when cranking or idling, it will show either the input cranking PWM or what ever PWM for that given temp according to the reference table. (good) However when I actually drive the car, i see that the ISV duty cycle goes all the way to 0% when im just cruising. Shouldn't it only be going to 31%? sinse i set that as its min duty cycle? What would cause it to do this?
 
So again, I'm very new to this, but how steady exactly should an idle be with a properly set up ISV. Are we talking like rock solid 850 RPM + or - 5 RPM? or is it pretty normal for a car with this setup to fluctuate between lets say 830 RPM and 880 RPM?

I've been messing with the ISV with the IAC lock to see what sort of impact i can have on the engine, and it seems like after a certain amount of opening, it has no influence on the idle speed.

I know i should prob ask this next question in a different thread, but whats the proper sequence of adjustments to get the idle at cold starts to actually respond to input. I ask this because basically my cold starts (-4c - 10c) are very rough, and the car idles very very low, i force the ISV open and it seems to not help. I've also used the ign lock to raise the advance to like 25 degrees to help get the car just to start. I guess i just dont understand what exactly i should be changing first, so that i dont have to keep changing other things (like the VE table)

If you guys like i could upload a vems log of the car starting (cold) all the way to driving. If you think a shorter log might be better or two separate logs let me know. Thanks in advance.
3
Wiring & Sensors / Re: VR to hall converter unusable!
« Last post by pamarakos on November 14, 2020, 05:38:55 am »
It's the second vr2hall converter that I'm receiving and cannot get it to work, I own a Toyota corolla 99 model equipped with ABS of course, so ordered this to make use of the sensors as wheels speed source to feed my link ecu digital input.

Things are like this: I've wired the +5v, GND and signal out to ecu using the /8 from the one side and vr+ and vr- from the other side. Have I done something wrong? Do I need to connect the Reset counter pin to GND?

Results are when and if the converter is working, it's working just fine, with the /8 I needed a little adjustment in the link ecu settings and voila my speed was there. After my first 2-3km driving around, it stopped. So you say I guess wiring issue..but same time once it's working and next moment it's not. Even tried a 2nd sensor, same results, even ordered a 2nd adapter again same results. On the 2nd order received there were 3 triplets of resistors, 470, 2k7 and 4.7 if I remember correctly,so where shall I test/install these?

Two hints: One is if while driving around and no sign of the converter working I touch it with my hands and pushing it, it starts showing speed just fine, this was happening with both the converters.

Second is if I let it "rest" for a while, then the first time spinning the wheel even by hand having the car on a jack, is always successful, BUT not the second one.

Again PLEASE don't start asking me about the wiring, I've tested it with a MAX9926 circuit and working just fine every time, using it two days in a row not a single problem anywhere. I need the VEMS one and ordered it for it's divby steps because my ecu can handle up to 500hz signal and MAX circuit which doesn't offer divby options has already 1000hz at 70kph. If someone can point me how to use only the 4024 part of the VEMS, it's fine for me although the MAX one is a bulk pcb, so I keep on struggling to make the vems one working ok, having it in its connectors-casings!

Ive also tried to set it to the most sensitive mode with the solderblob on the first two points with the >=150mv threshold, no luck too. I can't figure out what more to try, can you please help to get to the bottom of it as it drives me crazy? How is it possible to "squeeze" something by hand and have it working great like this until you leave it? Is ther something wrong with the ground?

One more hint (maybe) : If I add a 4024 ic after my max9926, I get no signal too no matter what /x I choose to use or at what speed I drive!

The 1:1 output on the vems one is directly from the lm1815 just to give it a try tomorrow?

What does anyine need to measure so as to help?

Thanks for your time

4
Wiring & Sensors / VR to hall converter unusable!
« Last post by pamarakos on October 31, 2020, 11:19:44 am »
Hi all
Just received the LM1815.4024 so as to use my stock toyota corolla 99 model abs sensor as wheel speed sensor for my link ecu Digital Input.
After wiring it all assuming correctly leaving everything at default and "stealing" signal from the abs sensor from one wire of the two passing by the drivers seat from the rear LHD sensor (since the other wire gave no readings) I have erratic readings with the car standing still from 120kph to 20kph. Messing around with the filters on the ecu menu for the digital input gave no better results.
So couple of questions to check my wiring at first
On the pcb: 1) Wired the pcb vr signal input (without soldering just for testing) to the abs sensor wire (tried both, only one gave readings but the unstable ones, either miving or not moving the wheel having the car on a jack) 2) Ground was wired together with the dsub9 male connector ground either to the ecu sensor ground or tried also to a chassis ground on a bolt (same readings on both)

On the dsub9 male connector: 1)pin 1 5v from the ecu 2) Reset pin is underlined on the instr.page to be grounded or for expert users to have it 0 or 5v, anyways, I just grounded it by bridging it to pin5 (but also tested it without having it grounded)
3) pin5, together with the pcb gnd, grounded to sensor ground from ecu
4) used the /4 output but I guess didnt matter at all since I wasnt able to get stable readings even by having the car still.
From readings I ve found in here mode 1 (which is the default one)is the correct one for stock abs sensors, so didnt mess it with it at all, what more can I try? Have I done something wrong?
Thanks for your time
5
i cant figure out how to add an attachment, how can i post a config?
6
Calibration & Mapping / Injector settings - divider/# of injectors, vs Reqfuel, etc.
« Last post by v2rocket on October 26, 2020, 09:42:04 pm »
Hello,

I bought a PnP VEMS kit for my SOHC Porsche 944 n/a 5 years ago.
It is made to plug into the 944 engine harness with some wiring adapters.

With this setup there is no cam sync, only primary and secondary VR crank triggers.
Engine runs a coil and traditional distributor on camshaft.
In the Porsche wiring harness the injectors are wired as 2 pairs but a single driver; the engine runs simultaneous/batch injection.

I have been having an issue for several years that I can't quite figure out - the engine idles extremely rich (target 0.97-1.00 lambda, actual WBO2 ~0.75 or so), but it does run smoothly.
I have tried asking other 944 VEMS users for advice along with the tuner who built the ECU but have not sorted it out.

Engine is 2931cc, 4 cylinder, 400cc injectors which Reqfuel equation says should be 11.88ms. I am running E85 fuel (actual ethanol content ~80%) so that should theoretically be as high as 14-15ms. But even taking Reqfuel down to 5ms with engine idling does not really affect the actual lambda reading. Seems to run better with reqfuel 10ms vs calculated 11.88. Injector dead time was set to the injectors being used. At operating temperature total enrichment is 100% but still seeing 0.72-0.78 lambda at idle.

Remember this is LAMBDA not AFR so the numbers are correct whether E85 or gasoline.

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What I want to know is, does the reqfuel value need to change when changing the injector divider or # of injectors under Injector Settings? I can run fine on 1;4 and 2;2 (very rich), but going to 4;1 runs extremely lean (1.3 lambda) and sounds like cylinder(s) are missing, even when wildly increasing the reqfuel to bring lambda closer to 1.00. I tried 2;4, 4;2, without luck. 3;2 got lambda of 1.00 but sounds like cylinders are missing.

I have searched several times on google and on this website and there are no useful definitions to be found for Divider, or how # of injectors in the tune relates to how injectors are wired.


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I will post a config file when I get home today.
7
Ignition / BMW M20 Ignition Issue
« Last post by FullGasCZ on October 25, 2020, 12:48:46 am »
Hi,

i solve problem with ignition on 6-cyl BMW.
I have 60-2 trig on front pulley, i set TDC 13 teeth after missing tooths (FTT 2 +60 deg TDC) and hall sensor. No Trig Error.
6 pack coil wasted spark.
At cranking engine fired to exhaust and intlake. Firing order is confused. In ing output table is 6 output, in order:
33(1and6)
34(2and5)
35(3and4)
33(1and6)
34(2and5)
35(3and4)

I dont understand Reference tooth table, what does mean this numbers:

0
5
4
3
2
1
Can anyone help me?
Sorry for my english :-\
8
Wiring & Sensors / Re: Fuel pressure sensor for safety
« Last post by kalns on October 14, 2020, 06:17:00 pm »
I have noticed this sensor on webshop, I dont get how this is diffrent from what i want to achieve with the sensor i have. Does vems cannot calculate differential pressure between two sensors, ie map and fuel pressure sensor ?

So if I would install this dufferential pressure sensor, I would not have to have onboard map sensor, is that right ? Or is it making some kind of compensation since there would be boost pressure to account for ?

Anyway, can you give some more info about onboard opamp, so I can educate myself a bit ? I will take a look into this approach, maybe its mutch easier to install this sensor and get what i want..
9
Wiring & Sensors / Re: Fuel pressure sensor for safety
« Last post by GintsK on October 13, 2020, 03:07:07 pm »
If you wnat switch configs from warning lamp, yes just wired solution. I do not think it is optimal way because you do not even notice warning light by eye...

Regarding fuel trim there is just workarounds until you have no differential pressure signal - actual value from what you want corrections. VEMS sell such sensor. Or it can be "calculated" by using free onboard opamp.
10
Wiring & Sensors / Re: Fuel pressure sensor for safety
« Last post by kalns on October 06, 2020, 11:38:10 am »
I will wire up warning lap also, and I was thinking about table switching to limp mode table but for that I will need a lot more help later to understand what should be done, to set it up correctly. To set up warning lap to switch tables, its output should be routed back to table switching pin and if nececery use inverted state ?

Could you explain more about fuel trim idea ? If fuel pump is dying and fuel pressure is dropping, then add X % of fuel. Is this correct ?
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