Author Topic: Electronic VNT control DIY (Read 38468 times)

Hey · « **on:** April 23, 2009, 11:51:44 am »

I've build an electronic VNT controler and I've decided to share it with everyone on this part of the forum since it seems to be the most popular part.

The build is working on a dodge dakota m-tdi AND a in my car (m-tdi). Both engines run a VNT17. If you have a tdi, the circuit uses the #3 injector to calculate the quantity of injection and then adjust pressure accordingly. I can even calculate my consumption with the boost.

The build could also work with a td. In which case, a simpler PCB can be built (not tested though) or the same pcb can be built and some parts can be left unsolder. To use with a TD you will also need to buy a varying resistor to install on the throttle shaft of the pump. The bosch numbers are, accorgind to esitronic:
1 467 217 319 potentiometre,
1 460 326 400 ( potentiometre support)

Note that I haven't tested it for the tds, so the programming code might not work right away... but if someone builds it, I will help him make it work. Also, I don't have the potentiometre from bosch so I don't know what is the resistance value at WOT and at idle... that would be needed if someone knows it.

I will explain how to make the PCB, solder everything, etc. The only thing that I want to insist on is that I don't want anybody selling it. I've worked on this on my free time and I will take the time to explain it to everyone. I would like it to stay free for everyone. So if you want to build it for someone, please don't make a profit out of it... ask the person to buy the parts and do it or better... help him do it.

For this reason, I would like to know who is going to build it. I will give at the end of the procedure the code for programming the microcontroler. The program will limit the boost to 10psi. Contact me, and I will send you the code for ... as many psi as you want. I can also send the microcontroler already programed for those that don,t want to buy a programmer. I think the PIC costs about 20$/unit... add shipping, it should not be over 40$ in North America.

How does it control boost?
The circuit uses 2 AAZ vacuum valves. The ones that are installed besides the air box. One of these valve controls the idle when the engine is cold... I don't use it anymore. And the other one was to actuate the k03 turbo and I don't need it anymore. These valves are cheap so.. it should not be a problem to buy.

For the boost not to fluctuate too much, I modify the valves. There is a small cap that allows to air to get in/out when 0V is applied to the valves. I get rid of the cap and fill the hole with a screw+glue. This way the valves are one way only.

One the valve connects the vacuum to the VNT actuator. Then I installed a T connector on the hose going from the valve to the actuator and put the other valve there, with the exit at amosphere.

When valve #1 is ON and valve #2 OFF, the actuator is vacuumed! If the pressure is ok, valve #1 AND valve #2 are OFF. IF the pressure is too high, valve #1 is OFF AND valve #2 is ON.

Hey · « **Reply #1 on:** April 23, 2009, 12:16:22 pm »

Step 1: Buy the required hardware to make the PCB. You can find pretty much everything on an electronic.

1) The developper (to get rid of the UV rays photosensitive layer)

It is the bottle on the left

Mix one part of developper with 10 parts of water in a bottle. The product becomes green when you use it but it's still good... reuse it.

2) The etching (to get rid of the cooper at the right places... where the UV didn't interacted)

You have 2 choices

#1) The products on the left of the picture are not expensive and easy to find. The leftmost product is muriatic acid or chloridric acid (HCL). You can buy that in an hardware store where the thinner, acetone, paints are. The other one is hydrogen peroxyde that you can buy in drug store.

Vous mix the acid AFTER in peroxyde. Always acid IN water, not the other way. In this case, it's not dangerous but... !! But twice as much peroxyde than HCL.

advantage:
-Cost less and doesn't stain clothes( and everything esle)
-You can but it on the sink (not stainless steal sink!!!) once finish (not poisonous)

disadvantage:
-will IMMEDIATELY eat stainless steal sink (don't do that in you sink)

#2) Ferric Chloride. Available in electronic store.

advantage: Might be a little faster and precise in perfect condition (bubbles+heat)

disadvantage:
-It stain everything
- $$
- need some heat
- Highly toxic at the end.. don,t put it on the toilet!

ALWAYS BE CAREFUL WORKING WITH THESE PRODUCTS. USE GLOVES, GLASSES AND A VERY WELL VENTED AREA.

3) UV rays to print the circuit.

You will need :
-To print on an acetate. Printer in black and white with the highest quality set if the configuration. It must be VERY blanc so that the UV won,t go through the ink.

- A glass to have the acetate match the board perfectly. VERY higly IMPORTANT.

- A black light. The one I have is big. A smaller one should do just fine. With mine I wait 2min:15 sec before turning it off at about 20cm. A smaller one will required a little more time.

- A board with a presensitized single side copper layer sur un seul côté.
It's called a Presensitized copper clad board.

Electronic store only... in a black envelope!

- A small container for your PCB bath

LAST THING: Buy 1 or 2 drill bit of a MAXIMUM of 60mil to drill the holes on the board. The electronic store will guide you.

Hey · « **Reply #2 on:** April 23, 2009, 12:17:36 pm »

I will continue tomorrow.. next lunch break!

French version
http://www.vwquebec.ca/forum/showthread.php?t=254418

Op-Ivy · « **Reply #3 on:** April 23, 2009, 01:12:26 pm »

Wow very nice writeup! I wish I had a VNT

Thanks for taking the time to share this! I'm sure there will be lots of people on here interested.

Hey · « **Reply #4 on:** April 23, 2009, 05:19:03 pm »

The mouvement is progressive because even if you put full vacuum, the actuator will move slowly.

Hey · « **Reply #5 on:** April 23, 2009, 07:19:31 pm »

Step 2 Building the PCB

Here is the PCB. In red, there is "roads" that you need to build using wires. Also, use this image to verify that you put the acetate on the right side.

1) Using your printer with the highest black white quality (so the UV won't go through)

PRINT THIS on an acetate:
http://www.4shared.com/file/100291621/7a463eea/boost_control_tdi_MPMP2202.html

2) Using scissor cut the acetate

3) Cut a piece of the circuit presensitized board

4) Put the printed acetate over the side that has the white protective layer. VERIFY that the acetate is on the right side. The side of the acetate that has the ink should face the board. You can be sure by looking at the PCB shown above.

You will put the components on the other side. So if you etch the PCB on the wrong side you will have a mirror effect. Veryfiy with a chip that you are ok by comparing with the color board above.

5) Prepare the developper bath. (a sink is perfect.. this will not stain)

6) Rapidly, remove the protective layer and put the acetate over the board (on the right side), put the glass and ONLY THEN turn the UV light on for 2min15s.

7) Put your board in the developper bath until there is noting left but the printed circuit. Make it move on the bath without splashing water everywhere, but vigorously enough.

Everywhere where there is still some resine, the will be some copper left. When done... rince with fresh water.

9) Prepare the acid bath. you will need to agitate for about 20minutes. Watch out for the fumes. At the end, you should have a perfect PCB. If you put the PCB in front of a light (or sun) you should see through.

Go here to have some more details on the combo HCL/peroxide
http://forum.allaboutcircuits.com/showthread.php?t=9451&highlight=acid+etchant

For the ferric chloride, don't heat over 45°C... the fumes will be toxic.

10) Once the PCB is done, use acetone (your wife varnis remover should do just fine with a q-tips) to get rid of the UV sensible resine. You won't need much.

11) Then you can use liquid flux to solder all the roads on the PCB. It'll be easier after that to solder the components and if there is a "cut" road you should see it right away.

If you decide to go over step 11, verify ALL the roads. Repair them if necessary.

12) Drill the holes s s s s s!!

Hey · « **Reply #6 on:** April 24, 2009, 05:23:37 pm »

Step 3 Soldering of components

It's where most mistakes are made. BE CAREFULL... it can take me a long while to debug a PCB and I design them, so...

-You should solder them one by one
-Don't bend the pins/wires.

- For the PIC 16F876A, buy a thin 28 pins support (PDIP-28 ) and solder this support instead of the microcontroler. This way you will be able to change the code if you like.

- For the pressure captor mpxm2202. It's a surface mount. YOU MUST absolutely solder the "roads" before you can solder the component. Then you heat up the roads without adding anymore tin/lead and bring the component.. not the other way around. IF YOU HEAT THE CAPTOR TOO MUCH YOU WILL RUIN IT.

Also, if you don't solder the roads before you will solder to "legs" of the captor and it,s difficult to get rid afterwards (you need a special wire to unsolder)

-For all components, DONT HEAT THEM UP TOO MUCH. Buy a nice and good iron with a sharp tip.

-Don't forget to solder the last 3 wires (in red in the PCB in color above)

Step 4Adjusting the PCB and installation

Resistance R7 and R3 need to be adjust (5k variable resistor)

-R3 resistor (adjust first), the red wire bringing the current to the pressure captor needs to carry at least 12V. The engine running (the alternator needs to be running) turn the screw to have as much as you can but not over 13V. (usually 12.5V)

-For the R7 resistor. Adjust it to 2.7k before you solder it. Then to fine tune it, you need to replace (for the fine tuning only) the injector #3 connector by a ~10k resistor (just put a 10k resistor instead of the #3 injector temporarily ) . When you put the resistor pin #1 of the IC4 components must change to 0V and stay at 0V until the resistor is pulled out. When you pull it out, the voltage should go back to 5V.

The best way to proceed is to look at the voltage on pin#2 of IC4. It should be around 2.5V. Then when you put the ~10k resistor, the voltage on pin #3 should vary of about 0.1V around this value (2.5V).

Exemple:
pin2 = 2.3V.
Resistor ON: pin3 = 2.4V.
Resistor OFF: pin3 = 2.2V

Always leave you voltmeter on pin #3.. don't get if off or you won't see the variation. (the voltmeter will act like the 10k resistor)

To know where is the pin1 or pin3 or pin2, you should know that the little "U" on one side of the chips represents the "UP" side. The pin # then starts at #1 on the left of the "U", just under you have #2, etc. The last number is always the one at the right of the "U".

-For Rtrim, adjust it BEFORE or you can use a standard 680ohm resistor. If you put LESS than 680ohm, you will have less boost at all regime/load. If you put MORE than 680ohm, you will have more boost at all regime/load.

Here is the list of materials:

Part Value Device Package Description
ALT_POW 14V instable AB9V AB9V 9-V BATTERY CLIP
C1 47nF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C2 1uF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C3 0.1uF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C4 0.1uF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C5 1uF C-EU025-024X044 C025-024X044 CAPACITOR, European symbol
C6 1uF C-EU102-043X133 C102-043X133 CAPACITOR, European symbol
C7 220uF CPOL-EUB45181A B45181A POLARIZED CAPACITOR, European symbol
C8 15pF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C9 15pF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C10 0.1uF C-EU075-032X103 C075-032X103 CAPACITOR, European symbol
C11 0.1uF C-EU025-024X044 C025-024X044 CAPACITOR, European symbol
D1 1N4148 1N4148 DO35-10 DIODE
D2 1N4148 1N4148 DO35-10 DIODE
D4 1N4007 1N4148 DO35-10 DIODE
D7 1N4007 1N4148 DO35-10 DIODE
IC2 LM317TS 317TS VOLTAGE REGULATOR
IC3 PIC16F876A PIC16F876A DIL28-3 MICROCONTROLLER
IC4 LM2903N LM2903N DIL08 COMPARATOR
IC5 78MXXS 78MXXS VOLTAGE REGULATOR
Q2 20MHz CRYSTALTC26H TC26H CRYSTAL
R3 5k R-TRIMM43P RTRIM43P Trimm resistor
R5 1k R-EU_0207/2V 0207/2V RESISTOR, European symbol
R6 1k R-EU_0207/5V 0207/5V RESISTOR, European symbol
R7 100k R-EU_0207/5V 0207/5V RESISTOR, European symbol
R8 100k R-EU_0207/10 0207/10 RESISTOR, European symbol
R9 3.8k R-EU_0207/10 0207/10 RESISTOR, European symbol
R10 3.5k R-TRIMM43P RTRIM43P Trimm resistor
R11 15k R-EU_0207/10 0207/10 RESISTOR, European symbol
R12 15k R-EU_0207/10 0207/10 RESISTOR, European symbol
R13 390 R-EU_0207/2V 0207/2V RESISTOR, European symbol
R16 10K R-EU_0207/2V 0207/2V RESISTOR, European symbol
R19 330ohm R-EU_0207/5V 0207/5V RESISTOR, European symbol
SL1 Con_ injecteur M02 02P AMP QUICK CONNECTOR
SL2 Selenoide2 M02 02P AMP QUICK CONNECTOR
SL3 Selenoide1 M02 02P AMP QUICK CONNECTOR
U$1 MPX4250A MPX4250A 867C-H
U$3 MC1413 MC1413 DIL-16

Hey · « **Reply #7 on:** April 24, 2009, 05:27:23 pm »

IDI PCB!(non tested)

The programming code is not done for this PCB, I will certainly ask for $ for the code as I don't have time to do it and I don't need it.

PCB print:
http://www.4shared.com/file/100299086/dff4179e/boost_control_AAZ.html

PCB schematic

List of material:
Part Value Device Package Description
ALT_POW 14V instable AB9V AB9V 9-V BATTERY CLIP
C4 0.1uF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C5 1uF C-EU025-024X044 C025-024X044 CAPACITOR, European symbol
C6 1uF C-EU102-043X133 C102-043X133 CAPACITOR, European symbol
C7 220uF CPOL-EUB45181A B45181A POLARIZED CAPACITOR, European symbol
C8 15pF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C9 15pF C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C10 0.1uF C-EU075-032X103 C075-032X103 CAPACITOR, European symbol
C11 0.1uF C-EU025-024X044 C025-024X044 CAPACITOR, European symbol
D2 1N4148 1N4148 DO35-10 DIODE
D3 1N4007 1N4148 DO35-10 DIODE
D4 1N4007 1N4148 DO35-10 DIODE
IC2 LM317TS 317TS VOLTAGE REGULATOR
IC3 PIC16876P PIC16876P DIL28-3 MICROCONTROLLER
IC5 78MXXS 78MXXS VOLTAGE REGULATOR
Q2 20MHz CRYSTALTC26H TC26H CRYSTAL
R3 5k R-TRIMM43P RTRIM43P Trimm resistor
R5 1k R-EU_0207/2V 0207/2V RESISTOR, European symbol
R13 390 R-EU_0207/2V 0207/2V RESISTOR, European symbol
R14 47k R-EU_0207/12 0207/12 RESISTOR, European symbol
R15 1k R-EU_0207/2V 0207/2V RESISTOR, European symbol
R16 10K R-EU_0207/2V 0207/2V RESISTOR, European symbol
R17 R-EU_0207/12 0207/12 RESISTOR, European symbol
SL2 Selenoide2 M02 02P AMP QUICK CONNECTOR
SL3 Selenoide1 M02 02P AMP QUICK CONNECTOR
SL4 Variable resistor M02 02P AMP QUICK CONNECTOR
U$1 MPXPAUL MPXPAUL 867C-H
U$3 MC1413 MC1413 DIL-16

you will need this to install on the pump (bosch part #)

1 467 217 319 potentiometer, 1 460 326 400 (potentiometer socket )

Hey · « **Reply #8 on:** April 24, 2009, 05:46:33 pm »

Step 5 The PIC programmation

I can send you an already programed pic, just add pic price+shipping, but it would be better if you could DIY.

If you need to buy a programer for the microcontroler you can look here:
http://www.winpic800.com/tienda/inde...emart&Itemid=8
or here
http://www.canakit.com/pic-programme...FSAgDQodm1OTGA
or here
http://www.electronickits.com/kit/co...rog/ck1708.htm
or on ebay

(be careful as some may need a power supply as extra cost) anything that can program a PIC 16F876A is good.

The code is a HEX file. you can rename it .hex (erase .txt) FOR TDI PCB ONLY.

:0600000000308A007C289C
:10000800F30003088301BA000A08BB008A017408D8
:10001800BE007508BD008B180B1E6F288B1083124D
:1000280003131014831601170130F4000030F50192
:100038008B180130F402031CF50375087404031DC2
:100048001828831210100F08A200A301A401A5010B
:100058002408A5002308A4002208A300A2010E0872
:10006800B600B701B801B901A2043708A3043808DB
:10007800A4043908A50410148B1083160113013049
:10008800F4000030F5018B180130F402031CF5036D
:1000980075087404031D4328831210100F08A60066
:1000A800A701A801A9012808A9002708A80026086F
:1000B800A700A6010E08B600B701B801B901A60449
:1000C8003708A7043808A8043908A9048B10A01415
:1000D8000C1820148B10031383123E08F4003D08FB
:1000E800F5003B088A003A088300F30E730E0900F6
:1000F800203084003A3086200A128A119829040692
:100108008001840A0406031D8328640000348401E6
:1001180083120313BC01FC01FD01FE01FF017808F5
:1001280079047A047B0403199C28C030BC05A728ED
:10013800F401F501F601F70113290310F80DF90D83
:10014800FA0DFB0DBC0AFB1FA128BC0A0310FC0D0D
:10015800FD0DFE0DFF0D7B087702031DBD287A08F3
:100168007602031DBD2879087502031DBD2878088D
:100178007402031CCF287C147808F4027908031C45
:10018800790FF5027A08031C7A0FF6027B08031C24
:100198007B0FF7020310FB0CFA0CF90CF80CBC03EC
:1001A8003C083F39031DAA283C1FE7280310FF30ED
:1001B800F407F409031CF507F509031CF607F6090B
:1001C800031CF707F7097408F8007508F9007608A2
:1001D800FA007708FB007C08F4007D08F5007E082B
:1001E800F6007F08F700BC1F13290310FF30F4073F
:1001F800F409031CF507F509031CF607F609031CA7
:10020800F707F70913290008F400840A0008F50025
:10021800840A0008F600840A0008F7008C2884087D
:10022800031900347708800084037608800084036B
:100238007508800084037408800000348301240852
:10024800A5002308A4002208A300A2012608F8009C
:100258002708F9002808FA002908FB002208F400FA
:100268002308F5002408F6002508F7000A128A1169
:100278008B200A128A117408AE007508AF00760840
:10028800B0007708B1000530F4000310AE0DAF0DD3
:10029800B00DB10DF40B49292F08F5002E08F40014
:1002A80008008E30831603139F00813083129F004D
:1002B8002830A10000000000A10B5E291F151F199E
:1002C80063291E08AA00AB01AC01AD012C08AD00E2
:1002D8002B08AC002A08AB00AA0183161E080313DA
:1002E8008312B200B301B401B501AA043308AB0408
:1002F8003408AC043508AD041F10080083018701D9
:100308008E3083169F00803083129F000130831641
:1003180086008701073081008C018D0180308B00B9
:100328003030831290000800822155212130AA071D
:1003380001300318AB070318AC070318AD070330E7
:10034800F4000310AA0DAB0DAC0DAD0DF40BA529EF
:100358000310AD0CAC0CAB0CAA0C0330F800F9017F
:10036800FA01FB012A30840083130A128A1107213B
:100378000A128A110530F400031083120313AD0C1E
:10038800AC0CAB0CAA0CF40BC0290530F40003101C
:10039800AA0DAB0DAC0DAD0DF40BCB298E018F0161
:1003A8008316011383122010A0100C100B168B1C3F
:1003B800A01CDB2922210530F4000310B10CB00C7D
:1003C800AF0CAE0CF40BE1290630F4000310AE0DAF
:1003D800AF0DB00DB10DF40BEA292D083102031D44
:1003E800FF292C083002031DFF292B082F02031DAB
:1003F800FF292A082E02031C132A00302D02031D90
:100408000F2A00302C02031D0F2A01302B02031D76
:100418000F2A5F302A020318132A201C162A0713F2
:100428008716071631082D02031D242A30082C02CE
:10043800031D242A2F082B02031D242A2E082A0212
:100448000318392A00302D02031D342A00302C02EB
:10045800031D342A01302B02031D342A5E302A0280
:100468000318392A87120712071731082D06031DAA
:10047800472A30082C06031D472A2F082B06031D80
:10048800472A2E082A06031D9929071387120716DB
:1004980099298301B2000430B300FA30A1000000AA
:1004A8000000A10B532A6400B30B512AB20B4F2A48
:1004B80008008301B2000430B300FA304D22640012
:1004C800B30B612AB20B5F2A080083013308B2001C
:1004D800752AB203FD30A10000000000A10B702AAC
:1004E80064000130320203186D2A3208A1000000AE
:1004F8000000A10B7B2A080004308301B200FA3007
:10050800A10000000000A10B852A6400B20B832A19
:10051800FF30B207031CB303330832040319080081
:10052800802A8301B2000430B300FA30A100000031
:100538000000A10B9B2AB30B992AB20B972A08003B
:02400E00723D01
:00000001FF

I don't want to build any PCB for anyone, my price would be 300$ if you force me to. So I think you better DIY... it a lot of fun! Remember not to breathe the fumes!

regcheeseman · « **Reply #9 on:** April 27, 2009, 11:28:39 am »

Hi,

I'm thinking of designing my own VNT controller. I was considering a rotary actuator with belden cables to the vane arm.

I can get an actuator with built in position pot for feedback.

What are you monitoring for VNT control?

I was considering a pot on the accelerator pedal for throttle position
A piezo pressure sensor for boost?

Do I need to account for revs as well - I can take a signal from the tacho if required.

gigaz2 · « **Reply #10 on:** April 27, 2009, 12:43:55 pm »

uuuuuu

I like

you measure IQ, pedal position and ActualBoost and generate a PWM signal to get to DesiredBoost right?

if you wish send me the files and I'll put them on my personal FTP where they can be linked to this forum without limitations.

Hey · « **Reply #11 on:** April 27, 2009, 07:18:27 pm »

I have change the PCBs. I built a new version of the boost controler for tdi today and it's a little bit better.

An expensive part (10$) has been removed and the pressure captor is also better ... up to 36psi instead of 29psi.

The code and part list have been updated.

gigaz2 · « **Reply #12 on:** April 28, 2009, 05:18:47 pm »

I have an electronic injector on my IDI (off a Ford Mondeo TD), this controller would work just fine on my setup controlling a VNT right?

Hey · « **Reply #13 on:** April 28, 2009, 11:02:42 pm »

Yes... it should work.. be sure to have a rising edge when fuel is injected... if it doesn't work, just invert the wires at the injector.

starrd · « **Reply #14 on:** April 29, 2009, 01:31:54 pm »

I have a few questions on the part descriptions

MPXPAUL =

? actual part number

I know it is a motorola MPX series, and dual port but I can't figure out the pressure rating from the supplied part number.

also IC3 PIC16876P =

Again, it is a pic chip, but what is the actual part number?
I know they come in PIC16F**** and PIC16C***

I can find these PIC16F876 or PIC16F876A but that is as close as I can get.

Thanks for your help and for sharing this.