Sequential Modded MS2 doesn't output +5v

[okubricko]

Hello all,

I have a MS2 that is set up to run fully sequential ignition (with logic level outputs to LS2 coils) and injection. I have done the mods required for both the ignition and injection. Both ignition and injection works fine when connected to my JimStim and driving the LEDs on the JimStim board.

When tested using tunerstudio and attached to the vehicle the ignition works fine. But, I can not get the injectors to fire. I have tested my injection drivers (separate board) and they are able to open the injectors.

But, if I use the MS2, with everything connected per the megamanual, the injectors don't fire. When I put a meter on the output I never see more than 0.2v. I thought that the output from the spots indicated for the outputs (INJ1 - left of R32, INJ 2 - left of R36, INJ 3 - the left of R22 or bottom of R23, and INJ 4- the top of R23)

Am I missing something in thinking that the output should be +5v?? What would make the output voltage as only +0.2v?

Thanks in advance for the help.

[racingmini_mtl]

If you're using a multimeter/voltmeter, you will only see a voltage that is proportional to the duty cycle from the injector output. You need to use an oscilloscope to see the signal and its voltage. You also need to check it without your drivers connected to the injector outputs to make sure that they are not pulling the voltage down for some reason.

Jean

[okubricko]

I won't have access to a scope until tomorrow and will check then, but...

Hypothetically, if the injector driver works when +5v is applied in a test setup, but doesn't work with the signal from the MS2, what could be the cause? I'n trying to trouble shoot and narrow possible causes down.

Thx

[racingmini_mtl]

The CPU (which is what is powering the injector outputs) can only supply a few mA of current per output. The power source you used to test your injector drivers can likely supply a lot more (possibly hundreds of times more). If your drivers need more than about 10mA each to work, you have a problem because the CPU will not be able to provide the current.

By the way, what are you using as drivers?

Jean

[DaveEFI]

If the injectors fire with your Jimstim, but not using test mode, I wonder if test mode on an MS2 can cope with other than the standard 2 on board injector drivers?

[racingmini_mtl]

If the injectors fire with your Jimstim, but not using test mode, I wonder if test mode on an MS2 can cope with other than the standard 2 on board injector drivers?

Yes it can. But on the JimStim you have to use other LEDs to see it because the injector LEDs are connected to the standard injector outputs. Even if you do keep the standard injector driver components, the injector LEDs will not light up with only one sequential injector output active.

Jean

[okubricko]

I was just able to put the scope on my MS2. Weird stuff

INJ1 @ R32 = 0.0v
INJ2 @ R36 = 3.4v
INJ3 @ R22 = 4.8v
INJ4 @ R23 = 3.4v

Any thoughts?

[racingmini_mtl]

What do those voltages mean? Do you mean the difference between the top of the pulse and the base? Did you measure that in DC or AC? It should be in DC with the base of the signal really at 0V (make sure there is no offset). Is anything connected to those measurement points? And where are you grounding your probe?

It would be a good idea to post screen shots from the oscilloscope to better show what you get. And posting pictures of your board mods would also be a good idea. Make sure to get clear pictures of both the MS2 card and the v3.0 board.

Of course if 0V means there is no signal at all, there is obviously something wrong. The 4.8V signal would be ok and while 3.4V is less than I would expect (so there is likely something wrong), it should still be enough to trigger an injection driver. And you still haven't mentioned what you're using as drivers.

Jean

[okubricko]

The voltages I measured were VMax voltages. As you stated, the 3.4v and 4.8v signals are enough to pulse the injector I am testing with but obviously injector #1 with 0v does nothing.

As for the injector driver I'm using, it is this at the moment.

inj_3.png

Found here >> http://www.corollarytheorems.com/Articl ... les_25.htm

For the drivers I will use in the final version, I have your P&H board. I had to make a component switch for the FR302DICT-ND, it was no longer available so I used MR852RLGOSCT-ND >> https://www.digikey.com/product-detail/ ... ND/1139931

I was going to IM you separately on that change to see if it was okay. The major differences are -> Voltage - DC Reverse (Vr) (Max) is 200V DC instead of 100V and Voltage - Forward (Vf) (Max) is 1.25v @ 3A instead of 1.3v @ 3A.

All the injector driver stuff aside... why the three different voltages? To muddy the waters, at one point I had a +12v wire cross the drain from the injector driver. It fried my MS2 board and I had to get a new one. I know that is good. Could some of the traces or components be bad??

[jsmcortina]

I'm afraid that design is rubbish. D2 the 1N4007 to Vbatt will give very lazy injector closing. Don't do that!

Here's a sample scope shot of a correct injector driver with a high clamp voltage >30V

100_5671.JPG

Here's a different injector driver (doing some PWM) and then with broken flyback causing poor injector control.

100_5670.JPG

James

[racingmini_mtl]

Yes, that replacement diode is fine.

And as James mentioned, this driver circuit will not give you anything close to a good injector behaviour. So you should plan to use the P&H board as soon as you can.

But before that, you need to find out what is going on with your setup. As I mentioned, good pictures would likely help. However, if there is a burned trace in one of the inner layers of the main board you won't be able to see it. And that is possible if 12V was applied accidentally where it shouldn't have. You need to check the resistance of the path from the CPU to the injector driver connecting points. I will assume that there is no continuity for injector 1. You might be able to correct that by running a jumper wire from the 40-pin header or simply connecting your driver there (you need a wire anyway).

As for injector 2 and 4, there may also be some partial break or short. You might also need to run wires to the 40-pin header but you may also have to cut traces to remove anything that pulls the voltage down. You will need to use the schematics and follow the path from the MS2 card to the injector connecting points.

What is more problematic is that these issues might also affect some other circuits on your board so you might need to go over everything to make sure that the board is fully functional. You might again have to use the schematics and do the tedious task of following the different paths of all the circuits. You'll have to decide how much effort you want to put into it before thinking of a replacement board depending on what you find when you check the injector paths.

By the way, since your MS2 is new you will want to do your checks with the MS2 removed and starting from the 40-pin socket. If everything checks out that way, you may have done something to your MS2 that created the problems there when you performed the mods needed for the 4 injector channels. This is also something I'd like to see in pictures.

Jean

[okubricko]

James and Jean, thanks much for the feedback. It's getting close to dinner time and we have company coming over tonight so I'll have to hold off on doing the investigating until tomorrow.

I have thought about getting a new board and have also thought about going straight to a MS3X. I think with having sequential ignition and injection, a cam sensor, FIDLE valve, and all the associated sensors, along with a Flex Fuel sensor it may just be better in the long run. But, I'll do my due diligence first and investigate the resistance and continuity of each path. I may consider also checking or taking the signal directly from the 40 pin header. But, it seems like kludge and I'm trying to avoid that altogether, this conversion to fuel injection is supposed to be giving me more reliability, not failure points.

Once again, thanks so much for all the help and input!

[okubricko]

Jean,

Quick question on your P&H board. Where is the best place to pull +5v from to drive the board. I am currently pulling it off of the prototype area. Grounding to the prototype area as well.

Thanks.

[racingmini_mtl]

Jean,

Quick question on your P&H board. Where is the best place to pull +5v from to drive the board. I am currently pulling it off of the prototype area. Grounding to the prototype area as well.

Thanks.

That the right place to connect them. As long as you mean the low current ground pad that is just besides the 5V pad. For the injector grounds, you need to wire those directly to the car ground either through a dedicated connector or DB37 pins as per the web site examples.

Jean

[okubricko]

So I was able to get back to my MS2 tonight. I was looking at the voltage at the pins on the MS2X daughterboard. They mirror what I am seeing at the point where I would connect the wires for the injectors. I checked continuity from the pins to the wires and that is good. I checked resistance on each pin to wire and those are good/read infinity. I decided to check the pin voltages.

Pins 1 and 2 show +4.9v, Pins 19 and 20 show +4.9v, Pins 31 and 32 show +4.9v, but when I check Pin 16 I show 0v. See the picture below, which comes from the Megamanual. It should be +12v correct?

PinVoltage.JPG

[racingmini_mtl]

You probably don't have the S12C to JS9 jumper: http://www.msextra.com/doc/pdf/html/MS2 ... 4-193.html. But that won't have any impact on the injector outputs, only the IAC outputs.

When you say 4.9V for pins 1 and 2, you mean you checked the voltage between the 2 pins? You should also check the pins independently with respect to the main ground. But from what you see, it should be ok and 4.9V is close enough to 5V to be fine.

Jean