MS3X A4 1.8T Quattro Running and partically mapped

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Drunken_M
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MS3X A4 1.8T Quattro Running and partically mapped

Post by Drunken_M »

Hello, im new to the megasquirt scene, but i have just assembled a MS3X for my A4 1.8T.
I have no connected power and VR signal cables to the MS3 ecu, but i dont get any crank signal.
I want to get crank signals before i hack up the stock harness and mount ms3x.
I have tried to jump d1 and d2 on the ms3 board, is this wrong?

Hope someone can give me some ideas. I want to set it up for full sequential, but i tried waste spark now because i have only tried to get the vr signal from the crank.


Edit:
Car is running, and is particaly mapped with Live analyze, totally worth the money BTW. The problem to the sync dissapearing at low RPM was VR sensor wired wrong way.
Last edited by Drunken_M on Mon Jul 29, 2013 12:51 am, edited 3 times in total.
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Re: MS3X 1.8T no crank signal

Post by prof315 »

Drunken_M wrote:Hello, im new to the megasquirt scene, but i have just assembled a MS3X for my A4 1.8T.
I have no connected power and VR signal cables to the MS3 ecu, but i dont get any crank signal.
I want to get crank signals before i hack up the stock harness and mount ms3x.
I have tried to jump d1 and d2 on the ms3 board, is this wrong?

Hope someone can give me some ideas. I want to set it up for full sequential, but i tried waste spark now because i have only tried to get the vr signal from the crank.
Did you follow the build instructions in the manuals linked at the top of this page? They they recommend simply not installing d1 and d2 unless using coil- for trigger which you are not. No jumpers needed.

Have you tested the MS3 with a stim? Sequential on this motor is easy, but you'll need to know if the cam sensor has a single tooth or 4 (2 narrow and 2 wide).
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

I followed the instructions, but i installed the d1 and d2 anyway for some reason.
I will remove them again, and i will buy jimstim today.
But am i suppose to use a 1kohm resistor 5v on proto area to the tachoselect when using bot crank and cam sensor?
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Re: MS3X 1.8T no crank signal

Post by prof315 »

Drunken_M wrote:I followed the instructions, but i installed the d1 and d2 anyway for some reason.
I will remove them again, and i will buy jimstim today.
But am i suppose to use a 1kohm resistor 5v on proto area to the tachoselect when using bot crank and cam sensor?
No, a 1.8T uses a VR sensor for the 60-2 crankshaft trigger wheel. It should be connected as follows, VR+ to mainboard pin 24, VR - to mainboard pin 1 and sensor shield to mainboard pin 2. The camshaft sensor is a hall effect type. I have found they work well powered by the 5V Vref and can be grounded to the block. Since you have an MS3/3X, hook the cam sensor signal wire to pin 32 on the 3X connector and be sure to have the jumper installed on JP7 as well as the R11 and R32 pots set correctly.
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

You mean 5vref from the ms3 board, to power the hall sensor?
Do you know how the pots should be set?
And can i hook up the vr sensor and hall sensor and 12v to the ms3, and then crank the engine to get trigger signals and rpm in tunerstudio?
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Re: MS3X 1.8T no crank signal

Post by prof315 »

Drunken_M wrote:You mean 5vref from the ms3 board, to power the hall sensor?
Do you know how the pots should be set?
And can i hook up the vr sensor and hall sensor and 12v to the ms3, and then crank the engine to get trigger signals and rpm in tunerstudio?
Yes, use the 5VREF from MS for both the TPS and to power the hall sensor.

Turn both R11 and R32 fully CCW and then turn R11 2 turns CW. Both mainboard pots (R52 and R56) should be fully CCW

You'll need both 12V and ground as well as hooking up the VR and hall sensors but then yes you should be able to see rpm in TunerStudio while cranking. Do yourself a favor and remove the spark plugs while testing it will allow the engine to crank faster.
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

Thanks a lot, i will try this tomorrow, but is it possible to share the vr and hall sensor with the stock ecu? So i can start and run it with the stock ecu and wire the ms3 in paralell on the vr and hall sensor?
And what pin is the 5vref on the ms3? Or do i have to wire this in some way?
Thanks again.
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Re: MS3X 1.8T no crank signal

Post by T3Bunny »

If you study the ecu pinout for your board, you will likely see that 5vref comes out on pin26 (it is the same on the old v2.2, v3.0, and v3.57. Not sure on the other EMS-Pro boards etc). First step might be to tell us what board you have. :P MS3 is the processor. And it will fit on the newer main boards (the v3.0 and v3.57) with no mods. It can be "MADE" to fit on a v2.2, but not recommended. :twisted:

There are several different methods to wiring up the 1.8t... I would explain the tricks I used to wire in my VR and Hall, but they would defiantly confuse!!! (Basically laziness prevailed and I left my original Hall wiring in place, and simply rerouted it inside the ecu with some trickery) You can also choose to bring 5vref out on another pin. You "probably" could also power the VW/Audi hall off of 12v. I have seen both 12v and 5v used successfully. In my installs, I have always used 5v though, and never had a failure. I have seen hall failures on 12v powered sensors (including my old Audi). Years ago, there was a lot of debate on this... Lets just say, stick to using 5vref though.

I am missing in your post where you might have mentioned the ECU mainboard version you have, but it does appear you are running a V3.0 main boars, MS3 processor, and MS3X expansion board. You should likely simplify things as much as possible and use the expansion card for the cam input... In mine, while running the MS3X board also, I just used the normal ECU pins and routed both hall and VR through the main board conditioner circuits.

Unfortunately, if you want to see VR and Hall cranking signals going into the Megasquirt, you will not be able to have the crank/cam sensors connected to the stock ecu at the same time. If you simply can't afford to have this car be down for more than a few hours... Your going to need to wire up separate plugs and swap in for testing. Pull your plugs as mentioned, and maybe squirt in a LITTLE bit of oil.

But if you follow Prof135's VERY detailed explanations, pinouts, and also potentiometer setup, you should be rewarded with a good stable cranking rpm signal.
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Drunken_M
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

Really stupid of me not to tell you guys what board I have. But as you guessed I have the MS3 on v3.0 board with the MS3X board.
I will connect the hall sensor to the MS3X board, as this is where its supposed to be used I guess.
I can afford downtime, because this is not a DD car, but I just want to see these trigger signals before I go along with the whole conversion to the MS3.
But I am thinking of just using the stock harness, and just cut the stock plug, and solder the DB37 plugs on to the stock harness, is there something wrong with doing this? Instead of making a whole new harness?
And do someone of you know what wire that is VR sensor shield on the stock harness? Becaus this was not soldered in when i tried last time, could this cause the problem not getting any signals? This is an AEB engine harness with the 2 connector ecu.

Thanks again everyone for the help :)
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Re: MS3X 1.8T no crank signal

Post by prof315 »

It's possible that the shield for the crank sensor is grounded somewhere other than the ECU in the factory harness. That's ok, it's just there to reduce EMI type noise and I have successfully gotten several VW motors using that style crank sensor up and running with the shield grounded somewhere other than MS.

As long as the factory engine harness is in good shape you can certainly cut the original ECU connector(s) off and solder the DB37s on. I have done this on several cars and it works fine.
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

Ok, i will try to find out if the shield goes to the stock ecu or not, and i will use the stock wiring harness and weld the DB37 on this harness. I think the harness is in good condition so it should work fine. I will try to start soldering the DB37 this weekend i think, so if it doesent work i will have to test the ms3 with the jimstim when i get it to see if there is something wrong with the MS3 itself.
Thanks guys :)
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Re: MS3X 1.8T no crank signal

Post by T3Bunny »

WV always grounds the sensor shield at the ECU. The 3-4 Audi's I have squirted also did, but I won't swear to "all Audi's" on that one. Still, a pretty safe bet they do.

Your OE harness will work with a bit of effort. The hardest part, is figuring out exactly where everything is grounded. Followed by getting GOOD wiring diagrams. I would not even attempt an ECU plug cut and switch without a Bently shop manual.

If it is an OBD2 car.... The problem child in the OE harness, is very likely to be the throttle body. A lot of the OBD2 VW's and Audi's use a dual feedback circuit for the TPS. As one side goes up, the other goes down. This prevents dead spots, and also helps as the throttle body itself contains the idle control motor. The easy fix is to swap in an earlier one. The hard fix, but cheap, is modding one of these to work.

Also if it is an OBD2 car, as it is an Audi, be warned.... Pulling the OE ECU, will almost defiantly break other systems. Dash, ac, tiptronic tranny, etc... I can't tell looking up the model and motor what the year range is. They were available as early as 1994 it seems.
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

The tach, and ac will not work if i remove the stock ecu, but can't i use megasquirt to drive these things?
I think i have the obd2 tps, but i do have an vr6 aaa throttlebody with tps lying around, this is the 3 pin tps. This should work right?
I think i can get a hold of an wiring diagram to find out where everything is grounded :)
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Re: MS3X 1.8T no crank signal

Post by T3Bunny »

Tach and AC are pretty easy fixes to make the MS control. The 3 pin early VR6 throttle body works a treat. Even modified, the OBD2 ones show a very limited range into the ECU. The early ones have at least double the resolution.
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

I will probebly use the vr6 throttle then, its bigger also so compatible for more hp also :)
I will start the installation of the ms3 this weekend, and will se if it works or not, if not i have to wait for the jimstim to arrive and test the ms3 module :)
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Re: MS3X 1.8T no crank signal

Post by prof315 »

Let me bust a couple of myths here.....
VW OBD2 throttle bodies (be they for a 1.8T, ABA or VR6) work just fine with Megasquirt. Yes, there are in fact 2 throttle position sensors in them but you can use just one without issue. On the 8 pin connector use pin 4 for sensor ground, pin 5 for sensor signal and pin 7 for 5Vref.

The built in idle valve can also be controlled with MS using PWM. I have found that it works best connecting 12V to pin 2 and Fidle or idle (with an MS3/3X) to pin 1 and then setting up the control INVERTED.

Using the OBD2 throttle bodies on FI motors is particularly nice as it reduces the amount of plumbing needed and thus reduces the chance of a boost leak.

Concerning the instrument cluster (tach) and A/C......

Things can get a little sticky here since most newer VW/Audi vehicles use CAN to run the clusters starting around 2000-2001. If the cluster is not CAN then you can use either the MS3X tacho pin ( don't forget the pull up jumper on the 3X board!) or one of the IAC pins to run the tachometer. For A/C I generally have MS take control of things. Good schematics of the A/C system are a must, but here is a quick and dirty on how I usually do things.
Most VW/Audis use a 12V turn-on signal from the A/C controller. I send this signal through the low pressure side of the trinary pressure switch and then to NO2 in on the 3X. This is my A/C request, I then simply use one of the outputs to activate a compressor relay and another (output and relay) for the cooling fans. Everything else is settings in the msq.
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Re: MS3X 1.8T no crank signal

Post by T3Bunny »

No myth busting here lol! On a VR6 car, the throttle both works with MS. But not with a "stock pinout" harness. To get the most resolution, you have to swap pins around or cut wires near the plug. I forget the exact reason why, but I think it has to do with the ground not being on the ideal pin. I could dig up some old wiring diagrams... But, even doing that, the OBD2 throttle body has a very narrow ADC range. On MS3, this probably wouldn't make much difference. On MsnSe, it was a problem as closed ADC was something ridiculous like 140. In fact, I think one of the older coded was modified just because of this problem!

As for the idle control, I never bothered to try. I know a few had gotten it working, but nobody had seemed to get it working "well."
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Re: MS3X 1.8T no crank signal

Post by lotus23C »

Hi Guys, sorry to hi-jack this thread.
There is some talk of throttle bodies and IAC. Is it possible to use the AEB's throttle body idle control? I had heard no one had much success and I have planned to use a 2 wire PWM valve and ABA throttle body.
Thanks
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Re: MS3X 1.8T no crank signal

Post by Drunken_M »

My car is an 96 aeb, so no can system here, and thank god for that.
I think i will use the vr6 tb anyway because this is bigger and easier to modefy the idle with the tb with. I don't care about idle valves. I like the tb adjustment screw way. Just less to mess around with. But i will try to start it with the stock tb though.
For the tacho i only need to install the pullupjumper an connect the wire from the 3x board to the tacho and set the values in tunerstudio? The ac is not an issue yet, because i dont have any gas in the ac system now. But i want to make it work of course.
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Re: MS3X 1.8T no crank signal

Post by prof315 »

T3Bunny wrote:No myth busting here lol! On a VR6 car, the throttle both works with MS. But not with a "stock pinout" harness. To get the most resolution, you have to swap pins around or cut wires near the plug. I forget the exact reason why, but I think it has to do with the ground not being on the ideal pin. I could dig up some old wiring diagrams... But, even doing that, the OBD2 throttle body has a very narrow ADC range. On MS3, this probably wouldn't make much difference. On MsnSe, it was a problem as closed ADC was something ridiculous like 140. In fact, I think one of the older coded was modified just because of this problem!

As for the idle control, I never bothered to try. I know a few had gotten it working, but nobody had seemed to get it working "well."
Every VW throttle body I have ever tried using with MS that has a TPS, has a closed throttle ADC count between 110 and 140. Wide open ADC is typically in the 800s, plenty of resolution there.

Well I have gotten idle control to work "very well" on the OBD2 throttle body in my car and that includes dealing with the addtional load of A/C and fans
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