MS3 Intermittent RPM Issue
#1
MS3 Intermittent RPM Issue
I've got a strange issue with my MS3, mostly because I'm a retard. It was working perfectly on the stim, but when doing a trial fit in the car I dropped the box about half a metre (2 feet)
Now when I hook it up to the stim, the RPM's act very strangely. No matter where the RPM pot is turned to, the RPM will sit at 0 but jump to where it should be about once a second. I've scoured the board looking for a cold solder joint, but everything looks fine. Given that I'm somewhat of an electronics noob, I've probably missed it.
Does anyone have any other suggestions what could be causing the issue, or which components to take a close careful look at? For reference, I built it using Brain's writeup here. If a log of what's going on would make things easier to diagnose, I can put one up, but I've still got to get my head around MLV.
Now when I hook it up to the stim, the RPM's act very strangely. No matter where the RPM pot is turned to, the RPM will sit at 0 but jump to where it should be about once a second. I've scoured the board looking for a cold solder joint, but everything looks fine. Given that I'm somewhat of an electronics noob, I've probably missed it.
Does anyone have any other suggestions what could be causing the issue, or which components to take a close careful look at? For reference, I built it using Brain's writeup here. If a log of what's going on would make things easier to diagnose, I can put one up, but I've still got to get my head around MLV.
#3
I can't get an attempted start, I haven't built my harness yet (I was wanting to fix the MS before continuing the install). I can give you a log with the jimstim, it should still give you the sensor info you need?
I've attached an example composite log using the stim (set up for 4G63), which shows the RPM spike.
I've attached an example composite log using the stim (set up for 4G63), which shows the RPM spike.
#4
I can't get an attempted start, I haven't built my harness yet (I was wanting to fix the MS before continuing the install). I can give you a log with the jimstim, it should still give you the sensor info you need?
I've attached an example composite log using the stim (set up for 4G63), which shows the RPM spike.
I've attached an example composite log using the stim (set up for 4G63), which shows the RPM spike.
You've got problems with your cam signal, the top graph in the composite logger window.
#5
Thanks! Well, aside from the obvious wires between TSEL and OPTIN and such, which components are involved in the cam input circuit? Worst comes to worst, I'll reheat the joints for all of them and see what happens.
On another train of thought, are there any components that can be damaged if the box is dropped? Just checking that I'm not supposed to be replacing something instead of hunting for a cold solder joint.
On another train of thought, are there any components that can be damaged if the box is dropped? Just checking that I'm not supposed to be replacing something instead of hunting for a cold solder joint.
#9
So I've reheated those solder joints (and all the other wire solder joints), and it hasn't changed anything. I've carefully check out the cam input wiring, and everything seems fine. I can't see anything shorting with the pullup, and I get continuity across it (at 460 ohms).
I checked the composite logger again, and when I zoomed right out I noticed that the cam signal just seemed to be way too uniform to be a dodgy connection. Any other ideas for what's going on?
I checked the composite logger again, and when I zoomed right out I noticed that the cam signal just seemed to be way too uniform to be a dodgy connection. Any other ideas for what's going on?
Last edited by Kain; 03-05-2011 at 12:41 AM. Reason: added detail
#13
I'm pretty sure I hadn't changed anything between dropping the MS and discovering the issue (I had it working perfectly prior), but just in case, I have the Jimstim set up with DIP switches 2 and 3 on (for 4G63), the primary tach jumpered for a square wave signal (no idea if this is correct, but I think it is) and with the second trigger going to pin 25 (I1A). Here's my TS settings in case the error lies there.
#15
Yeah, I figured that'd be the outcome. It was working perfectly before I dropped it
I'll keep messing with it, and see if I can figure it out. I'm pretty sure it's a hardware issue, but looking at those TS settings again, I'm not so sure about the 'skip pulses = 3' setting (only because I have no idea what it actually does, and it sounds like it could be a likely candidate for a strange yet uniform cam signal).
I'm going to cross-post this to MSEXTRA tonight (I assume they have better knowledge for the hardware side of things), and if I end up finding a solution I'll report back. That said, if you guys happen to have any more ideas, I'll gladly hear them!
I'll keep messing with it, and see if I can figure it out. I'm pretty sure it's a hardware issue, but looking at those TS settings again, I'm not so sure about the 'skip pulses = 3' setting (only because I have no idea what it actually does, and it sounds like it could be a likely candidate for a strange yet uniform cam signal).
I'm going to cross-post this to MSEXTRA tonight (I assume they have better knowledge for the hardware side of things), and if I end up finding a solution I'll report back. That said, if you guys happen to have any more ideas, I'll gladly hear them!
#16
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IF you dunno what something does, why not look it up in the manual.
skip pulses is the number of ignition pulses the MS skips before doing anything in order to calculate the RPM correctly.
But if that's the composite log you are getting with the ignition settings posted above, then something IS messed up for sure.
skip pulses is the number of ignition pulses the MS skips before doing anything in order to calculate the RPM correctly.
But if that's the composite log you are getting with the ignition settings posted above, then something IS messed up for sure.
#17
Well, jsmcortina at MSEXTRA figured it out. DIP switch number 2 on the Jimstim wasn't working, so it was giving a 36-1 signal instead of 4G63.
I can't believe that the Jimstim decided to go crazy at the exact moment I dropped the MS3, but crazy things happen huh?
Thanks for the help guys, I appreciate it.
I can't believe that the Jimstim decided to go crazy at the exact moment I dropped the MS3, but crazy things happen huh?
Thanks for the help guys, I appreciate it.
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