All sensors show max

[Space387]

Working on my LT1 build I kinda blew this off thinking it was the conflict caused by using the wrong input for the optispark for the hires signal, but, all my sensors read max. voltage is showing 29v tps map everything is showing maxed out on tuner studios but I have checked and my 5v ref line is still only reading 5v. What would cause something like this?

[Matt Cramer]

Does the problem happen on a Stim too, or just on the car?

[Space387]

yes shows the same maxed values when out of the car. I reflashed the s19 file to make sure that it was not an issue of an incomplete update. After doing the update to 1.4.0 was the first time I noticed this becoming an issue. This ms unit is the same one I have been running on 1.3.1 in my v6 firebird for the last 2 years without an issue. The only hardware changes I have made was readjusting the resistors for the main board crank in, the resistors for the 3x cam in and jumped jp7. The 3x changes where an error thinking the optispark high res input went to pin 32 not 31. Im really not sure whats doing this. There is no burnt items on the boards and I have made it a priority to ensure no wires could have crossed during the build.

[Matt Cramer]

Please post an MSQ.

[Space387]

There we go.

[Space387]

I have gone over the unit to make sure I dont have a short anywhere and to what I can see I do not. the v3 board will check out for a 5V probe in both locations for the cpu in the proto area and on the reference area. power feeding the cpu is less than 1v less than input voltage, nothing gets hot and there are no burn, scratch or damage marks on any of the cards. Im really not sure where else to look or what could be causing this

[DaveEFI]

What voltage do you see at R4?

[Space387]

Rw is 4.94 on both sides

[Space387]

For the sake of making sure I have not botched something in my tune I have reverted back to the base ms3 tune available with the 1.4.0 update. I went through and checked over a few of the schematics and decided because the issue is seen across all voltage based readings I will focus on the actual voltage reading and see if I can get a proper voltage readout on tuner studios. It currently shows 29.7v. I found the input pin for voltage measurement on the cpu pins ( ad4 pin 27) and it reads 1.9v. After a little calculation the voltage drop for that circuit should very well put it at about 1.9-2v so at this point I know the cpu is getting proper signals and it is still communicating with my computer but it seems it is referencing a different voltage than it should for determining values

[jsmcortina]

Check the build guide in the manual and perform the voltage check on the DIP40 processor socket.

James

[Space387]

already done.
pin 1 5v
pin 2 0v
pin 16 11.5v
pin 19 0v
pin 20 5v
pin 27 1.9v

[Space387]

everything I can find leads to a software issue. This came bout after updating to 1.4.0 but even reverting back to 1.3 wont fix the issue any suggestions?

[billr]

Pin 27? I didn't see that in the manual... how about pins 31 and 32, do you have correct voltages on those? The chances of this being a software problem, with nobody else (including me) having it are slim-to-none. How about posting pictures of both sides of the mainboard, so we can do some visual inspection?

[Space387]

31 and 32 show 5v across them. pin 27 is the adc in for voltage detection and after the 50k resistor drops the voltage about 10v its putting the proper signal into the cpu.






There is the pics I have. Im not set on it has to be programing related but it seems odd the sensor inputs are not measured right but all other cpu functions are going fine

[Space387]

Being I am not seeing something does any one know what if anything the adc voltages are compared to by the cpu to determine where it finds it voltage? I can only sumize that either once the signals inter the cpu they are being boosted by 5v or that a reference voltage of 5v is coming in as 0. With all voltages and grounds being correct at the 40pin connection is there anywhere else to test and maybe correct this? If the cpu has burnt a circuit then I will have to buy a new one but I am trying so hard not to. This particular system ran for 2 years without a single problem in my V6 firebird, and on day one trying to transition to the v8 car this began.

[kaeman]

looking at the lower picture(last), the square chip with all the terminations (mc9s12xf etc...) seems to have 2 places that look like solder has bridged the terminals on the top horizontal set of connections. I don't think that those are supposed to be shorted together in both those spots.

[Space387]

I'm about 99% sure that's how I received the card 2 years ago and remember asking the same question but it has been working until now. I checked to see if those bridged pins shared a connection with any other pin, it seems all 4 pairs aremail connected. I would assume they are grounds but I did not check.

[jsmcortina]

That's normal and has been mentioned many times before

James

[Space387]

James any other ideas on what will cause this issue? I have set up a bread board to allow isolation of all circuits so I can see whats going on.