INJ2 inop on MS1 to MS2 upgrade - mainboard issue SOLVED

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Paul_VR6
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INJ2 inop on MS1 to MS2 upgrade - mainboard issue SOLVED

Post by Paul_VR6 »

I have one that's stumping me a bit. Customer built V3 ecu sent in for a MS1 to MS2 upgrade, simple, usually.

With MS1 processor works perfectly on the stim, as far as I can tell. Once MS2 is installed, I get no activity from INJ2. I can remove the processor and manually trigger INJ2 by jumpering U1 pin 39 to ground. I can reinstall MS1 and INJ2 comes right back. Tried using this processor on a spare 3.57 and it works flawlessly. Already replaced U4. No signal from U1/39 even when U4 was removed.

I get activity on MS2 U2 pin 4, but nothing (0v) on Pin5 which I think is the signal pin. Also no activity (0v) on MS2 U2 pin 8.

I think it's an issue on the mainboard but nothing obvious, but I haven't dug into it that deeply. Looking for a direction at this point.. never been down this road before. More reading on how the MS2 inj driver system works is in order...

Thanks in advance!
Last edited by Paul_VR6 on Thu Sep 24, 2015 3:29 am, edited 1 time in total.
-Paul
1992 Corrado SLC 3.6 VR6 11.38@120 - MS3 Pro Ultimate - Microsquirt I/O - Can EGT - Racepak IQ3s
kptuned.com - Megasquirting the World! Megasquirt Sales, Service, Tuning and More!
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jsmcortina
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Re: INJ2 inop on MS1 to MS2 upgrade - mainboard issue

Post by jsmcortina »

Perhaps a physical connection problem on the INJ2 pins?

Have you scoped out the INJ (+ FB) signals in test mode?

James
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Paul_VR6
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Re: INJ2 inop on MS1 to MS2 upgrade - mainboard issue

Post by Paul_VR6 »

One odd thing I get on INJ2:

MS2 U2/6 is 5v
MS2 U2/4 is pulsing (from PWM2)
MS2 U2/5 is 0v

Which using the NAND truth table makes the output high, makes sense.

BUT going by the schematic (if I am reading correctly!) MS2 U2/5 is connected to fb2 on U1/39 which I am scoping at 5v!

Seems to behave the same in test mode as in "std" mode driving with the stim. No PWM current limiting enabled either way.

Anyway MSQ attached but I don't think it's the problem as it works on another mainboard.
-Paul
1992 Corrado SLC 3.6 VR6 11.38@120 - MS3 Pro Ultimate - Microsquirt I/O - Can EGT - Racepak IQ3s
kptuned.com - Megasquirting the World! Megasquirt Sales, Service, Tuning and More!
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billr
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Re: INJ2 inop on MS1 to MS2 upgrade - mainboard issue

Post by billr »

It wouldn't hurt to do a "drag test" on the individual CPU sockets on the mainboard. I have only done that on two boards, but neither had sockets that were all tight.
Paul_VR6
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Re: INJ2 inop on MS1 to MS2 upgrade - mainboard issue

Post by Paul_VR6 »

Billr can you describe what you mean by drag test? I can check continuity from board bottom to cpu top when I get a few minutes.
-Paul
1992 Corrado SLC 3.6 VR6 11.38@120 - MS3 Pro Ultimate - Microsquirt I/O - Can EGT - Racepak IQ3s
kptuned.com - Megasquirting the World! Megasquirt Sales, Service, Tuning and More!
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billr
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Re: INJ2 inop on MS1 to MS2 upgrade - mainboard issue

Post by billr »

Get a pin .017" - .018" diameter and try inserting it in each socket, see if the clip in the socket gets a grip on the test pin. You will feel a difference in the insertion/removal force required, from socket-to-socket, but worst case will be the test pin will fall out from its own weight if you turn the board over. I get pins out of an old/broken DIP "component holder". A loose socket doesn't mean it is a certain problem, as the pins on the CPU won't all be deadly straight or spaced. So, in actual use, all CPU pins may be touching the sockets and making contact, even if individual sockets don't seem tight enough. However, if you find that the socket associated with INJ2 is loose, then that is something to consider...
Paul_VR6
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Re: INJ2 inop on MS1 to MS2 upgrade - mainboard issue

Post by Paul_VR6 »

Fixed. Injector flyback fb2 u1 pin 39 internal short to ground IN the mainboard. Added a second socket with cut pin pulled up right side of r36 and soldered it directly and now works great.

Crazy one.
-Paul
1992 Corrado SLC 3.6 VR6 11.38@120 - MS3 Pro Ultimate - Microsquirt I/O - Can EGT - Racepak IQ3s
kptuned.com - Megasquirting the World! Megasquirt Sales, Service, Tuning and More!
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