The man who says something is impossible, is usually interrupted by the man doing it.
Yeah but not as much fun as this one...
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
Could be moreso, 2 channels, and PC based. AWWWWW YEEEEAAAAAHH!
The man who says something is impossible, is usually interrupted by the man doing it.
So did you get it? I was looking at a PC based osiliscope when I bumped into this MAC at a pawn shop for $400. Since it's automotive it gives sample signals of what things are supposed to look like which is sweet for troubleshooting. But only one at a time... Since it was $3500. new it was sweet deal too. Has found some weird issues for me since.
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
Yeah I bought it today, I've been looking at getting one for a few years, and today, while picking up some capacitors to fix a Mitsubishi ECM, I decided to pull the trigger on this one.
I almost bought a Blue Point Oscilloscope a few years ago, that had a slight issue, a couple diodes came off the board and the battery was pooched, but decided to pass on it.
I'm hoping that I can use this O'scope to diagnose LHM and even on the road vehicle problems. This one is powered through the USB!
The man who says something is impossible, is usually interrupted by the man doing it.
I'll say this one not only saved my butt a couple times when perplexed but also taught me some things about conversions and RF noise that I don't make those mistakes in wiring anymore!
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
It's been fun seeing some of the signals..
Mostly looking at DRP, EST, and injector.
Playing with a '7730, and some $8D, and $59. Injector pulse is definitely every 4th DRP, as information has always said, but what I have found interesting is when AE is added, I had always assumed that the AE was just PW added to the current injector pulse, but it appears that it is actually additional injector pulses between the main injector pulses.
The man who says something is impossible, is usually interrupted by the man doing it.
that's how A1 works as well. currently contemplating code that actually does just add/subtract into the sync PW and remove async almost entirely.
and obviously, every 4th DRP meaning a MPFI V8 application.
1995 Chevrolet Monte Carlo LS 3100 + 4T60E
Scopes are a really great way to see whats going on. Agree with EagleMark. Checked most of my ECM wiring to be sure I had proper signals without any noise in the circuits. Being new at trying to calibrate caused me to be very careful with the install and verify component integrity. Last thing I wanted was a wiring or sensor problem to mess with me. I used a four channel Pico scope that has a trigger so you can stop the jitter in the patterns. You can freeze and save the pattern and also zoom in to suspect areas. If you zoom in on an injector you can see the pintle bump in the pattern. Current ramp fuel pumps to check there health. Guys are establishing large databases of correct patterns for different cars and there components. Oh no another database for GH forum.
Really! The MAC oscilloscope I have has samples of everything, I do mean every possible sensor,circut etc... just found one for Turbo Boost Solinoid, also found Crank and Cam in magnetic, Hall and Optical, 2 VSS, I had no idea these samples were that handy! Don't have to guess it tells you exactly what it looks like so you can see an issue.Originally Posted by POZE
I don't know if I can get to them with PC to store samples but worst case if you didn't have one I could take a picture...
I'd like to see an injector go static? Might try that on the bench...
Where it has saved my butt on conversions that could not be diagnosed with scan tool or DVM was coil, spark plug wires and distributor near harness! One was three inches away. Now I can look at a conversion and see that issue though...
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
Good practice using scope. Use cursors to measure time between REF and EST pulse. Rising edge to rising edge. Then use rpm of engine when measurement was taken to calculate the amount of advance. See if it matches scantool reading and calbration. Also neat to watch dizzy EST pulse "dissappear" when 5V applied. Compare pulse at coil to pulse at REF and you'll see one go missing when 5V is applied. Technically, the REF generated when the first cyl in the firing order passes TDC gets used for the next cylinder in the firing order.It's been fun seeing some of the signals..
Mostly looking at DRP, EST, and injector.
Looks like solid line. Static means injector is commanded on for more time than it can be on. Voltage signal never changes.I'd like to see an injector go static? Might try that on the bench...
What's fun to watch is TBI peak and hold vs saturated PFI signals. Also fun to watch knock sensor line into knock filter and compare to signal out. It's amazing what doesn't get through. Another neat thing is look for faulty ignition using FM antenna and scope. Pass antenna over engine, wires, dizzy. Anything requiring more voltage makes higher lines on scope. Just like old days using AM radio and listening to engine "whine" through the static.
Last edited by 1project2many; 04-06-2012 at 02:37 PM.
Man your old... I remember high school auto shop, OK I'm old too as electronic ignition was coming out then. But we got a Tune up center had vacuum gauge, dwell meter, volt meter, timing light, etc... and scope. Scope was cool to learn as you could find a bad plug wire or which cylinder was mis firing.
We got the scope at school becuase the auto shop teacher had made a deal with SnapOn and got one for his gas station and we got one at school, I also worked for him after school and weekends. He showed me the old way to check ignition system by running a power wire to AM radio and tuned channel and you could here steady static that went up and down with RPM or a click... click was a problem. But the scope was cooler and could isolate the cylinder.
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
Hey! I resemble that remark.Man your old...
My son, who is two and a half, announced last weekend "Daddy, you a dinosaur!" I knew he wanted me to be the "bad guy" from the Superman cartoon he watched the night before. My wife, however, almost lost her breakfast she was laughing so hard.
Hey Six Shooter! You deal with the MAC tool man right? Think you could get me software CD for MAC ET 3480 Scope? I got the USB cable and tryed hooking it to PC but no drivers found, searched for at least an hour and can't find any software for it. If I could get in I may be able to get sample signals out? This thing is loaded with everything including DIS...
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
If this was about a year ago, that likely would have been no problem, but since the MAC guy I used to deal with changed positions (became a regional rep) and took about 6 months to find a replacement, we haven't even seen the new MAC guy. The old MAC guy was awesome. :(
The man who says something is impossible, is usually interrupted by the man doing it.
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