MPS Mapping, How and what info do you want? |
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MPS Mapping, How and what info do you want? |
FlacaProductions |
May 30 2024, 01:06 PM
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#1
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Senior Member Group: Members Posts: 1,735 Joined: 24-November 17 From: LA Member No.: 21,628 Region Association: Southern California |
Many of you may remember my 123 Distributor install that finally worked out.
(here: http://www.914world.com/bbs2/index.php?sho...370332&hl=) I now have a vacuum pump and multi meter - TELL ME WHAT YOU WANT TO SEE. Unit is an 041 and has obviously been cracked open - before my time. It's marked with a Sharpie "74-76 2.0" which I believe is incorrect and should be for a 71-72 1.7. Maybe this accounts for the opening and potential adjustment. Currently holds 15in pretty much indefinitely and I get 93ohms between pins 7 and 15, and 344ohms between pins 8 and 10. All that seems pretty much right on - but it would NOT start after putting in the 123. Prior to the 123, it ran "fine" but then started running warm due to a distributor vacuum issue (more in another thread) Distributor was an 011 with a Pertronix Igniter II. Installed a "correct" 043 MPS and it fired right up and works great with the 123. Honestly - I'm just looking to acquire some database info for the World and then move this on, so if someone wants it, just yell. I have no idea what it's worth. |
JamesM |
May 30 2024, 09:23 PM
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#2
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Senior Member Group: Members Posts: 1,958 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
Honestly - I'm just looking to acquire some database info for the World and then move this on, so if someone wants it, just yell. I have no idea what it's worth. Given that one has been cracked open any data gathered from it wouldn't be of much benefit as its unknown what material diaphragm was used and how it was calibrated/adjusted. Also any inductance readings are only of value at the place and time they are initially read as due to the nature of the device they will read differently in a different location and even a different day. Ive said this before but its worth repeating. Having someone send you the numbers from their MPS will at best get you in the ballpark. The only way to get a factory adjustment on one is to have a good reference sensor on hand to clone as you are doing it. |
rjames |
May 30 2024, 10:33 PM
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#3
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I'm made of metal Group: Members Posts: 4,110 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
Honestly - I'm just looking to acquire some database info for the World and then move this on, so if someone wants it, just yell. I have no idea what it's worth. Given that one has been cracked open any data gathered from it wouldn't be of much benefit as its unknown what material diaphragm was used and how it was calibrated/adjusted. Also any inductance readings are only of value at the place and time they are initially read as due to the nature of the device they will read differently in a different location and even a different day. Ive said this before but its worth repeating. Having someone send you the numbers from their MPS will at best get you in the ballpark. The only way to get a factory adjustment on one is to have a good reference sensor on hand to clone as you are doing it. I agree that just tuning by inductance numbers doesn’t usually work, especially since one will get different numbers from different LCR meters, but different numbers on different days? I don’t think so. Numbers will vary by location, but that’s due to altitude. I’m offering to take readings just to provide the curve because there was interest. I’m not calibrating it for his car. If Brian wants me to open it up to see what material the diaphragm is made out of I’m happy to do so, but that’s his call. I have rebuilt 2 MPS’s and calibrated 3 of them, including one that had been rebuilt by someone else and set to spec using an LCR meter which made my car run extremely rich. You really need a wideband O2 sensor to tune them correctly (which I also have installed in my car). |
JamesM |
May 31 2024, 02:13 AM
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#4
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Senior Member Group: Members Posts: 1,958 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
I agree that just tuning by inductance numbers doesn’t usually work, especially since one will get different numbers from different LCR meters, but different numbers on different days? I don’t think so. Numbers will vary by location, but that’s due to altitude. They are impacted by altitude because of the change in atmospheric pressure which can vary by location and day even at the same altitude. |
rjames |
May 31 2024, 10:10 AM
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#5
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I'm made of metal Group: Members Posts: 4,110 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
I agree that just tuning by inductance numbers doesn’t usually work, especially since one will get different numbers from different LCR meters, but different numbers on different days? I don’t think so. Numbers will vary by location, but that’s due to altitude. They are impacted by altitude because of the change in atmospheric pressure which can vary by location and day even at the same altitude. You're right- I thought about that later after I posted. Nice catch. |
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