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#1
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W124 Tachometer Signal Injection
Say I wanted to simulate on the bench an engine speed and compare it to the tachometer reading.
Would I need to inject the 144 Pulses x RPM? And what are the Voltage and Pulse Width needed? I am not building a test bench myself but trying to gather information for someone wanting to do this. Thanks to dieseldiehard for the following quote: Quote:
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1993 W124 300D 2.5L Turbo, OM602.962 2000 Chevrolet Cavalier, 2.4L DOHC 2002 Ford Explorer, 4.0L SOHC 2005 Toyota Prius, 1.5L http://www.fuelly.com/sig-us/40601.png |
#2
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I used my Fluke to measure the frequency of the green wire today at idle. I got 1.610 kHz. The red wire (Voltage) was 13.64 VDC.
Has anyone else taken this measurement? Care to share?
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1993 W124 300D 2.5L Turbo, OM602.962 2000 Chevrolet Cavalier, 2.4L DOHC 2002 Ford Explorer, 4.0L SOHC 2005 Toyota Prius, 1.5L http://www.fuelly.com/sig-us/40601.png |
#3
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I will put a scope on the tach signal, see what I get. In the meantime, 1610 Hz divided by 144 is 11.18 RPS or 671 RPM which is reasonable for an OM603 at idle.
Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#4
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Thanks Jeremy. I have a 602 btw, but I suppose the signal should be the same.
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1993 W124 300D 2.5L Turbo, OM602.962 2000 Chevrolet Cavalier, 2.4L DOHC 2002 Ford Explorer, 4.0L SOHC 2005 Toyota Prius, 1.5L http://www.fuelly.com/sig-us/40601.png |
#5
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Oldwolf, I checked your fuel mileage link. Your mileage is falling off the chart! Using the AC more these days?
Sixto 87 300D |
#6
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It's been really hot here in Raleigh so the A/C has taken it's toll. Plus I had my instrument cluster worked on and the guy put 100 miles on my cluster when on his test bench. AND to top off all the other issues, I filled my last tank at a new station, the concrete pad with the dispensers were on a slant, so I didn't fill my tank totally last time (I thought my fuel gage was bad but it isn't I found out today). So all these errors accumulated to today's sucky mpg calc of 28 mpg. Hopefully soon the mpg will be back up to 32+.
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1993 W124 300D 2.5L Turbo, OM602.962 2000 Chevrolet Cavalier, 2.4L DOHC 2002 Ford Explorer, 4.0L SOHC 2005 Toyota Prius, 1.5L http://www.fuelly.com/sig-us/40601.png |
#7
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Quote:
The tach/clock module is removed from the instrument cluster. I tested the tach/clock module just now by connecting the module to the clock power and the tach signal/power plug. Ground was a set of alligator clips from the metal back to exposed metal behind where the cluster sits. Clock is running fine. I'll check it in about an hour or so to reconfirm. Tach is still dead. I checked signal and V on the solder joints of the back end of the connector plug. At idle: VDC=12.6 Signal=1660 Hz VAC of Signal=3.6. Would this be how I'd know if the signal is weak? Any idea what the normal VAC would be? What would casuse a "weak" signal anyway? -Thanks
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1993 W124 300D 2.5L Turbo, OM602.962 2000 Chevrolet Cavalier, 2.4L DOHC 2002 Ford Explorer, 4.0L SOHC 2005 Toyota Prius, 1.5L http://www.fuelly.com/sig-us/40601.png |
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