Flooding/1 Sequential Injecter Open - MS3X Expansion Card

[tscta61]

Hi,

I have a 1960 VW type 1 engine that I installed a MegaSquirt-III EMS System with MS3X Expansion V3.57 and I have problem with what appears to be the injector driver shorting to ground.

When I initially set the car up, i had the same problem and replaced the MS3X expansion card and all was well. Since then, i have put about 500 miles on the car and took the car out for a Sunday drive. Lucky, i didn't get the car far from home before i noticed blue smoke and knew something wasn't right. When i got home, I found another injector being held open.

I tested the injectors. The have around 16 to 17 ohms of resistance. Using RC Racing Injectors SL2-240 https://www.rceng.com/Saturated-Injecto ... P21C6.aspx

I tested the injector ECU wiring for ground shorts. - None found after i unplugged the MS3X Expansion card. All the injectors share the same 12 V circuit, no blown fuses.

In TunerStudio, all the injectors work correctly, except the one held open, in test mode.

Any help would be appreciated.


TunerStudio Version MSv3.0.28
Firmware MS3 1.5.0
MSQ File Attached.
Datalog Attached. - (Pull the fuel pump fuse to prevent flooding. Ran the injector test mode)

[billr]

Is this a "hard failure" now, the injector is stuck on at all times? If so, pull off the small cable (10-pin) from the MS3 to MS3X at the 3X end, see if that injector turns off. I am suspicious of that cable since you have had this problem with two different MS3X boards.

[Marek]

If you swap the position of two injectors around, then you can see whether the fault follows the injector or follows the harness and MS3X.

kind regards
Marek

[tscta61]

It appears to be a hard fault and is independent of the injector. When you plug the injector up, you can hear it click. Also, i tried unplugging the 10 pin connector. Nothing changed.

I went ahead and Ohmed the injector #1 and #4 circuit and found the following:

Injector #1 (The one that is always "on")

Power On: 105 - 120 Ohms
Power Off: 77 Ohms

Injector #4

Power On: 680 Ohms
Power Off: 288 Ohms

When i used my multimeter to drive a mA current through the ECU in the injector test mode, i could see the injector circuits opening/closings as expected. However, the injector #1 was allowing more current that injector #4.

It sounds like i fried a transistor, but i cannot figure out what caused it. All of the injectors share the same 12 volt fused power source and made sure to examine the #1 injector connector to make sure it didn't have a intermittent short circuit.

I checked the injectors again. All had 16.2 - 16.3 Ohms.

Thanks again,

[lotus23C]

I have had same issue twice with those surface mount inj drivers, but on a different board.