Tec-GT install issues, IT RUNS!! Thread updated
#17
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Brad,
The only logical reason that I can think of for the diode, is to prevent pulling the fuel pump to ground while in a non running or starting state.
I think the LH was wired into the alarm system.
To clarify, when the key is NOT in the ignition, it might be possible that the LH Relay socket will pull to ground. Like maybe when the door opens, and this might send a false signal to the fuel pump.
You wouldn't want the pump to ever run unless you intended to start and run the car. So you only want a true signal from the Tec GT for the Fuel Pump.
Just a thought. Might be only worth 2 cents.
The only logical reason that I can think of for the diode, is to prevent pulling the fuel pump to ground while in a non running or starting state.
I think the LH was wired into the alarm system.
To clarify, when the key is NOT in the ignition, it might be possible that the LH Relay socket will pull to ground. Like maybe when the door opens, and this might send a false signal to the fuel pump.
You wouldn't want the pump to ever run unless you intended to start and run the car. So you only want a true signal from the Tec GT for the Fuel Pump.
Just a thought. Might be only worth 2 cents.
#18
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I think it is almost certainly used here as a spike protector. Its an odd arrangement they have made. Normal spike protector configuration would be a reverse biassed diode to a permanent supply either Battery+ or ground - with or without a series resistance - depending on the size of the inductor (motor winding in this case).
This config uses the LH relay coil as a series resistance to Battery+ and protects against spikes when the pump is turned off.
I'd have configured it differently.. but depending on what they are trying to protect against
Alan
This config uses the LH relay coil as a series resistance to Battery+ and protects against spikes when the pump is turned off.
I'd have configured it differently.. but depending on what they are trying to protect against
Alan
#19
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Thanks Alan.
I am going to connect it up as per the instructions tonight.
Carl sent me an e-mail and said that with the diode in there it will work as it should so I will connect it up with some test leads and see what happens.
Right now I know that with a multimeter and checked with a test light I have 12 volt power, but it is possible that the tec ECM may switch to ground when it see's the connection with the diode. I don't know.
If it dose then it will turn the relay on as it should.
I wish this was my only problem as I still do not have any spark but that is in a different thread.
Couldn't expect it to go smooth now could I.
Brad
I am going to connect it up as per the instructions tonight.
Carl sent me an e-mail and said that with the diode in there it will work as it should so I will connect it up with some test leads and see what happens.
Right now I know that with a multimeter and checked with a test light I have 12 volt power, but it is possible that the tec ECM may switch to ground when it see's the connection with the diode. I don't know.
If it dose then it will turn the relay on as it should.
I wish this was my only problem as I still do not have any spark but that is in a different thread.
Couldn't expect it to go smooth now could I.
Brad
#20
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Yes the fuel pump relay is activated by ignition power on terminal 86 and a ground on terminal 85 - so when 'active' the TEC ECM must pull terminal 85 to ground.
The diode has no functional part in any of this operation - its purpose is likely purely for protection.
Question - what does the LH relay drive now in your configuration - nothing? anything? (I'm assuming nothing - but depending on your answer there may be another reason for this configuration...)
Alan
The diode has no functional part in any of this operation - its purpose is likely purely for protection.
Question - what does the LH relay drive now in your configuration - nothing? anything? (I'm assuming nothing - but depending on your answer there may be another reason for this configuration...)
Alan
#21
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Yes the fuel pump relay is activated by ignition power on terminal 86 and a ground on terminal 85 - so when 'active' the TEC ECM must pull terminal 85 to ground.
The diode has no functional part in any of this operation - its purpose is likely purely for protection.
Question - what does the LH relay drive now in your configuration - nothing? anything? (I'm assuming nothing - but depending on your answer there may be another reason for this configuration...)
Alan
The diode has no functional part in any of this operation - its purpose is likely purely for protection.
Question - what does the LH relay drive now in your configuration - nothing? anything? (I'm assuming nothing - but depending on your answer there may be another reason for this configuration...)
Alan
Old coils are removed, brown wire at coil is left open and both black are joined.
Edit: I think the LH relay feeds power to relay XXII, or the fuel relay ???
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No - in stock configuratioin the LH Relay feeds the LH ECU itself, the ignition final stages (drives the stock coils), power supply for: the flappy valve, Idle Speed Positioner (Idle Air Valve),Tank Vent, coding element and MAF. The LH controls activation of these.
I assume your new ECU drives new coils somehow - assume it also controls the Flappy/Idle Air valve/Tank Vent (how about stock MAF) - so are all these new items or stock but totally rewired (all leads wired) or is it just just spliced into existing wiring?
If its spliced in you'd still need the LH relay to activate all these.
Alan
I assume your new ECU drives new coils somehow - assume it also controls the Flappy/Idle Air valve/Tank Vent (how about stock MAF) - so are all these new items or stock but totally rewired (all leads wired) or is it just just spliced into existing wiring?
If its spliced in you'd still need the LH relay to activate all these.
Alan
#23
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here is a link of the basics to the install on Carl's site
ftp://928m:928m@12.234.229.133/insta...uide32v928.pdf
Ya i took a look at the online wiring digram
The green fuel relay wire from the Tec connects to W21 which goes to 85 on the LH relay XXV, but I don't know why
ftp://928m:928m@12.234.229.133/insta...uide32v928.pdf
Ya i took a look at the online wiring digram
The green fuel relay wire from the Tec connects to W21 which goes to 85 on the LH relay XXV, but I don't know why
#24
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The LH relay is removed and left out with this system, isn't it?
The ECU gets power from where the relay used to be.
The diode is going to pin 85 on the fuel pump relay, I believe.
The ECU gets power from where the relay used to be.
The diode is going to pin 85 on the fuel pump relay, I believe.
#25
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Well these instructions are fairly poor because they assume relays are the same for all years - in fact they moved around quite a lot year to year - the XXII relay is the EZK/DI relay for most years & the Backup Light Relay for other years ('87-'89) - revealingly it was never the LH relay - I think this is a terminology issue.
You need to remove the EZK/DI relay in slot XVI ('87'89) and connect power as shown in that socket...
It seem you have a replacement for the final stages & coils & MAF - but what now drives the flappy (anything?) the Idle valve and the tank vent... these are still needed I think? so you probably still need the actual LH relay - which is in position XXV for all S4+ years ('87-'95) to power them..
So this diode will actually also cause the LH relay in XXV to activate whenever the fuel pumps are on. Since the LH ECU is gone and nothing else connects to this line the diode is not needed functionally. A smaller dioide than what you show would be sufficient for spike isolation protection for 2 realy coils (in fact the built in coil resistors should be sufficient without any protection diodes). However it won't do any harm so you can leave it in if you like.
You do need to see how the connections to these other required features are accomplished...
Its important to understand whats still used & how - I don't think you can do this project without that understanding... the years assumed for Carl's instructions and the year of your car need to be matched for one... The instructions seem to be written for a '90-'95 and your car is an '89...
Alan
You need to remove the EZK/DI relay in slot XVI ('87'89) and connect power as shown in that socket...
It seem you have a replacement for the final stages & coils & MAF - but what now drives the flappy (anything?) the Idle valve and the tank vent... these are still needed I think? so you probably still need the actual LH relay - which is in position XXV for all S4+ years ('87-'95) to power them..
So this diode will actually also cause the LH relay in XXV to activate whenever the fuel pumps are on. Since the LH ECU is gone and nothing else connects to this line the diode is not needed functionally. A smaller dioide than what you show would be sufficient for spike isolation protection for 2 realy coils (in fact the built in coil resistors should be sufficient without any protection diodes). However it won't do any harm so you can leave it in if you like.
You do need to see how the connections to these other required features are accomplished...
Its important to understand whats still used & how - I don't think you can do this project without that understanding... the years assumed for Carl's instructions and the year of your car need to be matched for one... The instructions seem to be written for a '90-'95 and your car is an '89...
Alan
#26
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ECU power is to come from relay XX11 and for some reason there is no power at that relay now, but there was?
#27
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Well these instructions are fairly poor because they assume relays are the same for all years - in fact they moved around quite a lot year to year - the XXII relay is the EZK/DI relay for most years & the Backup Light Relay for other years ('87-'89) - revealingly it was never the LH relay - I think this is a terminology issue.
You need to remove the EZK/DI relay in slot XVI ('87'89) and connect power as shown in that socket...
It seem you have a replacement for the final stages & coils & MAF - but what now drives the flappy (anything?) the Idle valve and the tank vent... these are still needed I think? so you probably still need the actual LH relay - which is in position XXV for all S4+ years ('87-'95) to power them..
So this diode will actually also cause the LH relay in XXV to activate whenever the fuel pumps are on. Since the LH ECU is gone and nothing else connects to this line the diode is not needed functionally. A smaller dioide than what you show would be sufficient for spike isolation protection for 2 realy coils (in fact the built in coil resistors should be sufficient without any protection diodes). However it won't do any harm so you can leave it in if you like.
You do need to see how the connections to these other required features are accomplished...
Its important to understand whats still used & how - I don't think you can do this project without that understanding... the years assumed for Carl's instructions and the year of your car need to be matched for one... The instructions seem to be written for a '90-'95 and your car is an '89...
Alan
You need to remove the EZK/DI relay in slot XVI ('87'89) and connect power as shown in that socket...
It seem you have a replacement for the final stages & coils & MAF - but what now drives the flappy (anything?) the Idle valve and the tank vent... these are still needed I think? so you probably still need the actual LH relay - which is in position XXV for all S4+ years ('87-'95) to power them..
So this diode will actually also cause the LH relay in XXV to activate whenever the fuel pumps are on. Since the LH ECU is gone and nothing else connects to this line the diode is not needed functionally. A smaller dioide than what you show would be sufficient for spike isolation protection for 2 realy coils (in fact the built in coil resistors should be sufficient without any protection diodes). However it won't do any harm so you can leave it in if you like.
You do need to see how the connections to these other required features are accomplished...
Its important to understand whats still used & how - I don't think you can do this project without that understanding... the years assumed for Carl's instructions and the year of your car need to be matched for one... The instructions seem to be written for a '90-'95 and your car is an '89...
Alan
I removed relay XV1 EZK and checked the 86 slot and it is switched. I plugged the ecu power in and it turns on and off with the key.
-1 thing done.
The flappy and idle valve have separate outs and should work (fingers crossed)
The tank vent has no wires or instructions on what to do with it. I noticed that the electrical vent valve is normally open (i can blow through it) and i connected the vacuum diaphragm as it was stock to the throttle side not the intake side. I should vent as driving.
So now I have to find out why I have no spark and get the tach to work.
#28
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I found that I have no power to the engine feed. Glad I found something.
I draw power from W22 and it looks like it jumpers from U12 which is from the battery.
It must have a connection somewhere?
any ideas where I should check
I draw power from W22 and it looks like it jumpers from U12 which is from the battery.
It must have a connection somewhere?
any ideas where I should check
#29
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To update; I have been chasing some issues which are related to the Tec-GT engine management Install instructions and some confusion with them.
Many, Many thanks to Alan, RC and Malcolm for their help and encouragement
It seems the confusion is with the instructions matching the MY of the car.
-The Tec-GT will not ground the fuel relay vi the ECU green wire until the power is cycled.
- The green wire has 12 volts when not connected and tested. (this will throw you off track as it will ground when connected and power is cycled)
-Depending on the MY, Relays XVI, XXII, XXV may be named different in the WSM vs the instructions
-The switched power for the Tec-GT ECU is now connected to Relay XVI, EZK
Note; I had to spend lots of time checking continuity from one relay to the other one that it feeds to verify function
(the LH relay in XXV activates when the fuel relay turns on) on my 89 euro
Unrelated issue
I lost power to the W22 large red wire that is the main feed to the engine
pulled down the CP and inspected, replaced relays but the open circuit eludes me, for now.![Roll Eyes (Sarcastic)](https://rennlist.com/forums/images/smilies/rolleyes.gif)
I am borrowing power from the rear defog relay which I removed for now. Ill update when I find the problem
![](http://i103.photobucket.com/albums/m158/bwmac/Brads%20Porsche/IMG_1202.jpg)
![](http://i103.photobucket.com/albums/m158/bwmac/Brads%20Porsche/IMG_1203.jpg)
![](http://i103.photobucket.com/albums/m158/bwmac/Brads%20Porsche/IMG_1205.jpg)
Many, Many thanks to Alan, RC and Malcolm for their help and encouragement
It seems the confusion is with the instructions matching the MY of the car.
-The Tec-GT will not ground the fuel relay vi the ECU green wire until the power is cycled.
- The green wire has 12 volts when not connected and tested. (this will throw you off track as it will ground when connected and power is cycled)
-Depending on the MY, Relays XVI, XXII, XXV may be named different in the WSM vs the instructions
-The switched power for the Tec-GT ECU is now connected to Relay XVI, EZK
Note; I had to spend lots of time checking continuity from one relay to the other one that it feeds to verify function
(the LH relay in XXV activates when the fuel relay turns on) on my 89 euro
Unrelated issue
I lost power to the W22 large red wire that is the main feed to the engine
pulled down the CP and inspected, replaced relays but the open circuit eludes me, for now.
![Roll Eyes (Sarcastic)](https://rennlist.com/forums/images/smilies/rolleyes.gif)
I am borrowing power from the rear defog relay which I removed for now. Ill update when I find the problem
![](http://i103.photobucket.com/albums/m158/bwmac/Brads%20Porsche/IMG_1202.jpg)
![](http://i103.photobucket.com/albums/m158/bwmac/Brads%20Porsche/IMG_1203.jpg)
![](http://i103.photobucket.com/albums/m158/bwmac/Brads%20Porsche/IMG_1205.jpg)
![](http://i103.photobucket.com/albums/m158/bwmac/Brads%20Porsche/IMG_1204.jpg)
#30
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Brad, Sounds like you are getting close!
Question: Did the Tec GT come with a power distribution harness with two relays and a large fuse block with 4 fuses?
The reason I ask, is that the harness I'm talking about would have one relay to turn on the fuel pump (and the wideband heater, if used) and provide the + 12v to the injectors.
The other relay supplies the power to the ECU and DFUs. The harness makes the entire EMS a stand alone system if hardwired into the actual wires to the fuel pump and battery, only needing a trigger wire from the ignition switch to turn it all on.
Just out of curiosity, are the wires you're connecting to the Central Electric panel coming from the ECU or the power distribution harness I'm talking about?
Question: Did the Tec GT come with a power distribution harness with two relays and a large fuse block with 4 fuses?
The reason I ask, is that the harness I'm talking about would have one relay to turn on the fuel pump (and the wideband heater, if used) and provide the + 12v to the injectors.
The other relay supplies the power to the ECU and DFUs. The harness makes the entire EMS a stand alone system if hardwired into the actual wires to the fuel pump and battery, only needing a trigger wire from the ignition switch to turn it all on.
Just out of curiosity, are the wires you're connecting to the Central Electric panel coming from the ECU or the power distribution harness I'm talking about?