Differences in Knock Sensor Filters 7730
12-31-2018, 11:48 AM
#1
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Car: 1989 Camaro-1LE
Engine: TPI(s)
Transmission: 5 speed (MM5, MK6)
Axle/Gears: 3.45, 3.73
Differences in Knock Sensor Filters 7730
I am trying to find some donor MEMCALs to use for V8 projects. The Knock sensor filter appears different over the years and as well different between 2.8, 3.1 and V8s.
My reference is a 1990 7730 V8 setup.
I have found a 1990 3.1 (ATTA) with same filter. Also a 89 2.8L (ARBW) has same.
I have an older 2.8L from 87 (ASMJ) which is not the same.
I have newer 3.1L from 1991's which are not the same.
I am simply doing a visual comparison on the traces. It looks like the ones made around the same year use the same circuit. Rather than difference between V6 and V8.
What was the difference with them? Can they work with a V8? Or no go.
Mark.
PS. Anyone have info on converting 165 Memcals to V8? I did the searches and only found the 7730 stuff.
My reference is a 1990 7730 V8 setup.
I have found a 1990 3.1 (ATTA) with same filter. Also a 89 2.8L (ARBW) has same.
I have an older 2.8L from 87 (ASMJ) which is not the same.
I have newer 3.1L from 1991's which are not the same.
I am simply doing a visual comparison on the traces. It looks like the ones made around the same year use the same circuit. Rather than difference between V6 and V8.
What was the difference with them? Can they work with a V8? Or no go.
Mark.
PS. Anyone have info on converting 165 Memcals to V8? I did the searches and only found the 7730 stuff.
12-31-2018, 11:57 AM
#2
Re: Differences in Knock Sensor Filters 7730
https://www.thirdgen.org/forums/diy-...d-density.html
a v8 165 memcal all will work as a 730 memcal all you just need to disable the knock sensor and change the chip from a 27c128 to a 256 or 512.
to use a v6 3.1l ect you jumper 56 to 62 and Need to disable the is.
a v8 165 memcal all will work as a 730 memcal all you just need to disable the knock sensor and change the chip from a 27c128 to a 256 or 512.
to use a v6 3.1l ect you jumper 56 to 62 and Need to disable the is.
Last edited by Tuned Performance; 12-31-2018 at 01:58 PM.
12-31-2018, 02:14 PM
#3
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Car: 1989 Camaro-1LE
Engine: TPI(s)
Transmission: 5 speed (MM5, MK6)
Axle/Gears: 3.45, 3.73
Re: Differences in Knock Sensor Filters 7730
https://www.thirdgen.org/forums/diy-...d-density.html
a v8 165 memcal all will work as a 730 memcal all you just need to disable the knock sensor and change the chip from a 27c128 to a 256 or 512.
to use a v6 3.1l ect you jumper 56 to 62 and Need to disable the is.
a v8 165 memcal all will work as a 730 memcal all you just need to disable the knock sensor and change the chip from a 27c128 to a 256 or 512.
to use a v6 3.1l ect you jumper 56 to 62 and Need to disable the is.
I have 2.5L 165 proms, but I'd guess I need to ground a pin or add a resistor to make it work with a V8. Similar to 7730. I've not measured them out - was hoping someone beat me to it.
I'm still curious why the knock circuit appears different on the different years ... and really if it matters.
Mark.
12-31-2018, 03:14 PM
#4
Re: Differences in Knock Sensor Filters 7730
http://www.gearhead-efi.com/Fuel-Inj...t=Knock+filter
you should post a ad in the classifieds section for the needed mencals. A external esc can be used with the 730 ecm. How many are you looking for ?
I have a half dozen of the v8 maf memcals and more than a dozen of the sd ones. You can also find them on eBay not much of a shortage of them.
https://m.ebay.com/sch/i.html?_from=...nkw=tpi+memcal
you should post a ad in the classifieds section for the needed mencals. A external esc can be used with the 730 ecm. How many are you looking for ?
I have a half dozen of the v8 maf memcals and more than a dozen of the sd ones. You can also find them on eBay not much of a shortage of them.
https://m.ebay.com/sch/i.html?_from=...nkw=tpi+memcal
Last edited by Tuned Performance; 12-31-2018 at 03:38 PM.
12-31-2018, 03:39 PM
#5
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Car: 1989 Camaro-1LE
Engine: TPI(s)
Transmission: 5 speed (MM5, MK6)
Axle/Gears: 3.45, 3.73
Re: Differences in Knock Sensor Filters 7730
http://www.gearhead-efi.com/Fuel-Inj...t=Knock+filter
you should post a ad in the classifieds section for the needed mencals. A external esc can be used with the 730 ecm. How many are you looking for ?
I have a half dozen of the v8 maf memcals and more than a dozen of the sd ones. You can also find them on eBay not much of a shortage of them.
you should post a ad in the classifieds section for the needed mencals. A external esc can be used with the 730 ecm. How many are you looking for ?
I have a half dozen of the v8 maf memcals and more than a dozen of the sd ones. You can also find them on eBay not much of a shortage of them.
So ... in my GM RACE memcal, it doesn't have a number on the knock filter! But when I compare the circuit, it matches the 2.8 V6. I'm thinking GM may have used it intentionally to detect knock early vs. late. Yet another mystery to check into. BUT this is what they ran in the race cars back in 1990.
For donors, then it makes sense to use the knock filter from a 5.7L TBI (which are easier to find). The chips underneath should be OK for limp home? The TBI vs multiport probably won't work.
Mark.
12-31-2018, 03:44 PM
#6
Re: Differences in Knock Sensor Filters 7730
Limp home will only happen if the prom fails a very rare occurrence unless your using a sst27sf512 eeprom I have had a few fail. I have tried a 3.1l memcal in a 5.0l as car to test limp home mode and it ran super rich. TBI as in your 2.5l ones ? Yes they should work if cylinder select is set. A 5.7l tbi truck memcal might be hard to source. It might also use a 100 ohm ks.You would have to measure it’s resistance.
Last edited by Tuned Performance; 12-31-2018 at 04:12 PM.
12-31-2018, 03:56 PM
#7
Re: Differences in Knock Sensor Filters 7730
Post 6 shows how to identify the knock filter based off resistance.
14k is from a 305 iirc 18-19k is a 350.
If you ohm pin 31 to 48 you get a value of the knock filter of 14k
http://www.gearhead-efi.com/Fuel-Inj...oss-Tuned-port
https://www.thirdgen.org/forums/dfi-...305-or350.html
14k is from a 305 iirc 18-19k is a 350.
If you ohm pin 31 to 48 you get a value of the knock filter of 14k
http://www.gearhead-efi.com/Fuel-Inj...oss-Tuned-port
https://www.thirdgen.org/forums/dfi-...305-or350.html
Last edited by Tuned Performance; 02-27-2019 at 12:34 PM.
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12-31-2018, 04:54 PM
#8
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Car: 1989 Camaro-1LE
Engine: TPI(s)
Transmission: 5 speed (MM5, MK6)
Axle/Gears: 3.45, 3.73
Re: Differences in Knock Sensor Filters 7730
Post 6 shows how to identify the knock filter based off resistance.
14k is from a 305 iirc 18-19k is a 350.
http://www.gearhead-efi.com/Fuel-Inj...oss-Tuned-port
14k is from a 305 iirc 18-19k is a 350.
http://www.gearhead-efi.com/Fuel-Inj...oss-Tuned-port
1987 2.8K is 2.0 ohms
1989 2.8K is 47 ohms
1990 3.1K is 25 ohms.
1994ish 5.7L TBI is 860ohm.
1990 5.0 TPI is 14K ohm
1994 4.3 L35 is 767 ohms
1989 2.0 Turbo is 36.8 ohms.
Curious the 1989 2.8L knock filter board looks identical in every way, where as the other ones have different traces. Obviously the parts themselves are different. So ... there really isn't a true donor memcal that is a direct swap for a V8 without a tradeoff in the knock filter. I guess it will fun fine with the Cylinder select jumpered, but the limp home won't run right.
Interesting. Maybe I'll make a mobile out of all of these PROMS. :-)
Mark.
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