MJLJ V3 vehicle installation guide - Revision history

Alhbln: /* Smiths RVI type tachometers */

2010-01-05T07:53:25Z

Smiths RVI type tachometers

← Older revision		Revision as of 07:53, 5 January 2010
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	====Smiths RVI type tachometers====		====Smiths RVI type tachometers====

	Note that there are two types of older Smiths tachometers: RVI - current sensing, and RVC - voltage sensing. These letters, and numbers indicating exactly which variant you have, are printed in small white lettering on the bottom of the face of the tachometer. RVI type tachometers work by routing the coil +ve supply wire through an inductive loop of wire inside the tachometer, and are not compatible with the MJLJ. If you have an RVI type tachomoter, you can replace it, have an add-on circuit board added inside, or replace all the inside working parts with those from a newer tachometer ie retain the original face, but change everything else. For that approach you need a donor which has the same angular swing per 1000rpm, as the Smiths gauge.		Note that there are two types of older Smiths tachometers: RVI - current sensing, and RVC - voltage sensing. These letters, and numbers indicating exactly which variant you have, are printed in small white lettering on the bottom of the face of the tachometer. RVI type tachometers work by routing the coil +ve supply wire through an inductive loop of wire inside the tachometer, and are not compatible with the MJLJ. If you have an RVI type tachomoter, you can replace it, have an add-on circuit board added inside (or build one yourself, see http://www.dinoplex.org/tachoconversion for a start), or replace all the inside working parts with those from a newer tachometer ie retain the original face, but change everything else. For that approach you need a donor which has the same angular swing per 1000rpm, as the Smiths gauge.

	===User defined outputs and Shift Light===		===User defined outputs and Shift Light===

Alexander: /* Tachometers that require a high-voltage kickback pulse */

2008-02-25T00:18:42Z

Tachometers that require a high-voltage kickback pulse

← Older revision		Revision as of 00:18, 25 February 2008
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	====Tachometers that require a high-voltage kickback pulse====		====Tachometers that require a high-voltage kickback pulse====

	Some OEM-style tachometers detect the RPM signal by sensing the high voltage fly back pulse from the ignition coil. In distributor based setups, there is only one ignition coil, from which to detect this pulse. With a wasted spark system, this 'signal' is spread across multiple coils. As a result, you will need a way to combine these pulses across multiple coil packs to drive your tachometer.		Some OEM-style tachometers detect the RPM signal by sensing the high voltage fly back pulse from the ignition coil. In distributor based setups, there is only one ignition coil from which to detect this pulse. With a wasted spark system, this 'signal' is spread across multiple coils. As a result, you will need a way to combine these pulses across multiple coil packs to drive your tachometer.

	The following circuit allows the fly back pulse to be detected across individual coil packs while still isolating the coils from each other.		The following circuit allows the fly back pulse to be detected across individual coil packs while still isolating the coils from each other.

Alexander: /* Tachometers that require a high-voltage kickback pulse */

2008-02-25T00:18:16Z

Tachometers that require a high-voltage kickback pulse

← Older revision		Revision as of 00:18, 25 February 2008
Line 121:		Line 121:
	====Tachometers that require a high-voltage kickback pulse====		====Tachometers that require a high-voltage kickback pulse====

	Some OEM-style tachometers detect the RPM signal by sensing the high voltage fly back pulse from the ignition coil. In distributor based setups, there is only one ignition coil to detect this pulse ~~from~~. With a wasted spark system, this 'signal' is spread across multiple coils. As a result, you will need a way to combine these pulses across multiple coil packs to drive your tachometer.		Some OEM-style tachometers detect the RPM signal by sensing the high voltage fly back pulse from the ignition coil. In distributor based setups, there is only one ignition coil, from which to detect this pulse. With a wasted spark system, this 'signal' is spread across multiple coils. As a result, you will need a way to combine these pulses across multiple coil packs to drive your tachometer.

	The following circuit allows the fly back pulse to be detected across individual coil packs while still isolating the coils from each other.		The following circuit allows the fly back pulse to be detected across individual coil packs while still isolating the coils from each other.

Alexander: /* Existing Vacuum Advance vacuum port */

2008-02-25T00:17:13Z

Existing Vacuum Advance vacuum port

← Older revision		Revision as of 00:17, 25 February 2008
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	Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole, which is actually covered by the edge of the throttle plate at idle. That is called Ported Vacuum. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.		Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole, which is actually covered by the edge of the throttle plate at idle. That is called Ported Vacuum. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.

	You can test whether you have ported vacuum or not: pull the vac hose off the vacuum advance unit. With your finger over the end of the hose, you should feel vacuum with the engine revved above idle. Assuming yes, let the engine speed drop back to idle. Is there still vacuum? If not (most likely), that means you have ported vacuum, and should find another source of vacuum somewhere on the manfold.		You can test whether you have ported vacuum or not: pull the vac hose off the vacuum advance unit. With your finger over the end of the hose, you should feel vacuum with the engine revved above idle. Assuming yes, let the engine speed drop back to idle. Is there still vacuum? If not (most likely), that means you have ported vacuum, and should find another source of vacuum, somewhere on the manfold.

	====TPS Sensor operation====		====TPS Sensor operation====

Alexander: /* Existing Vacuum Advance vacuum port */

2008-02-25T00:16:06Z

Existing Vacuum Advance vacuum port

← Older revision		Revision as of 00:16, 25 February 2008
Line 107:		Line 107:
	====Existing Vacuum Advance vacuum port====		====Existing Vacuum Advance vacuum port====

	Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole which is actually covered by the edge of the throttle plate, at idle. That is called Ported Vacuum. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.		Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole, which is actually covered by the edge of the throttle plate at idle. That is called Ported Vacuum. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.

	You can test whether you have ported vacuum or not: pull the vac hose off the vacuum advance unit. With your finger over the end of the hose, you should feel vacuum with the engine revved above idle. Assuming yes, let the engine speed drop back to idle. Is there still vacuum? If not (most likely), that means you have ported vacuum, and should find another source of vacuum somewhere on the manfold.		You can test whether you have ported vacuum or not: pull the vac hose off the vacuum advance unit. With your finger over the end of the hose, you should feel vacuum with the engine revved above idle. Assuming yes, let the engine speed drop back to idle. Is there still vacuum? If not (most likely), that means you have ported vacuum, and should find another source of vacuum somewhere on the manfold.

Alexander: /* Using existing Vacuum Advance port */

2008-02-25T00:15:27Z

Using existing Vacuum Advance port

← Older revision		Revision as of 00:15, 25 February 2008
Line 105:		Line 105:


	====~~Using existing~~ Vacuum Advance port====		====Existing Vacuum Advance vacuum port====

	Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole which is actually covered by the edge of the throttle plate, at idle. That is called Ported Vacuum. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.		Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole which is actually covered by the edge of the throttle plate, at idle. That is called Ported Vacuum. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.

Alexander: /* Using existing Vacuum Advance port */

2008-02-25T00:14:37Z

Using existing Vacuum Advance port

← Older revision		Revision as of 00:14, 25 February 2008
Line 107:		Line 107:
	====Using existing Vacuum Advance port====		====Using existing Vacuum Advance port====

	Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole which is actually covered by the edge of the throttle plate, at idle. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.		Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole which is actually covered by the edge of the throttle plate, at idle. That is called Ported Vacuum. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.

			You can test whether you have ported vacuum or not: pull the vac hose off the vacuum advance unit. With your finger over the end of the hose, you should feel vacuum with the engine revved above idle. Assuming yes, let the engine speed drop back to idle. Is there still vacuum? If not (most likely), that means you have ported vacuum, and should find another source of vacuum somewhere on the manfold.

	====TPS Sensor operation====		====TPS Sensor operation====

Alexander: /* Using EDIS PIP signal */

2008-02-24T22:39:21Z

Using EDIS PIP signal

← Older revision		Revision as of 22:39, 24 February 2008
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	====Using EDIS PIP signal====		====Using EDIS PIP signal====

	An ~~alternate~~ approach that appears to work with older 'Smiths' type tachometers is to share the PIP signal that is emitted from the EDIS module. The PIP output is a 12V square wave with a larger duty cycle than the TACH_OUT provided by the MJLJ. Simply wire the EDIS PIP output to both the MJLJ PIP input as well as the tachometer sense wire.		An alternative approach that appears to work with older 'Smiths' type tachometers is to share the PIP signal that is emitted from the EDIS module. The PIP output is a 12V square wave with a larger duty cycle than the TACH_OUT provided by the MJLJ. Simply wire the EDIS PIP output to both the MJLJ PIP input as well as the tachometer sense wire.

	If this approach is used, you should check to make sure the MJLJ receives the PIP signal consistently, since the PIP line has extra current demand placed upon it. The current demands of the MJLJ PIP input is low, so it should work fine- and a few field reports have shown this. However, a quick check using the configuration software for consistent RPM readings would be prudent.		If this approach is used, you should check to make sure the MJLJ receives the PIP signal consistently, since the PIP line has extra current demand placed upon it. The current demands of the MJLJ PIP input is low, so it should work fine- and a few field reports have shown this. However, a quick check using the configuration software for consistent RPM readings would be prudent.

Alexander: /* Using EDIS PIP signal */

2008-02-24T22:32:03Z

Using EDIS PIP signal

← Older revision		Revision as of 22:32, 24 February 2008
Line 134:		Line 134:

	If this approach is used, you should check to make sure the MJLJ receives the PIP signal consistently, since the PIP line has extra current demand placed upon it. The current demands of the MJLJ PIP input is low, so it should work fine- and a few field reports have shown this. However, a quick check using the configuration software for consistent RPM readings would be prudent.		If this approach is used, you should check to make sure the MJLJ receives the PIP signal consistently, since the PIP line has extra current demand placed upon it. The current demands of the MJLJ PIP input is low, so it should work fine- and a few field reports have shown this. However, a quick check using the configuration software for consistent RPM readings would be prudent.

			====Smiths RVI type tachometers====

	Note that there are two types of older Smiths tachometers: RVI - current sensing, and RVC - voltage sensing. These letters, and numbers indicating exactly which variant you have, are printed in small white lettering on the bottom of the face of the tachometer. RVI type tachometers work by routing the coil +ve supply wire through an inductive loop of wire inside the tachometer, and are not compatible with the MJLJ. If you have an RVI type tachomoter, you can replace it, have an add-on circuit board added inside, or replace all the inside working parts with those from a newer tachometer ie retain the original face, but change everything else. For that approach you need a donor which has the same angular swing per 1000rpm, as the Smiths gauge.		Note that there are two types of older Smiths tachometers: RVI - current sensing, and RVC - voltage sensing. These letters, and numbers indicating exactly which variant you have, are printed in small white lettering on the bottom of the face of the tachometer. RVI type tachometers work by routing the coil +ve supply wire through an inductive loop of wire inside the tachometer, and are not compatible with the MJLJ. If you have an RVI type tachomoter, you can replace it, have an add-on circuit board added inside, or replace all the inside working parts with those from a newer tachometer ie retain the original face, but change everything else. For that approach you need a donor which has the same angular swing per 1000rpm, as the Smiths gauge.

Alexander: /* MAP Sensor operation */

2008-02-24T21:55:59Z

MAP Sensor operation

← Older revision		Revision as of 21:55, 24 February 2008
Line 103:		Line 103:
	''Alternate technique which may offer a more balanced signal''		''Alternate technique which may offer a more balanced signal''
	</center>		</center>


			====Using existing Vacuum Advance port====

			Most vacuum advance takeoff ports are designed in such a way that vacuum is measured through a hole which is actually covered by the edge of the throttle plate, at idle. That is done to cut off all vacuum advance at idle, which in turn slows the engine and makes it easier to achieve stable idle with the tiny throttle plate opening used at idle. Vacuum measured on such a port, therefore, has no vacuum at idle, moves to maximum vacuum just off idle, and then decreasing vacuum as the throttle is opened further. The discontinuity just off idle makes such a port awkward to deal with on the load map.

	====TPS Sensor operation====		====TPS Sensor operation====