Toyota MR2 Message Board - View Single Post - 93 5sfe

mrturrari · 08-26-2007, 02:41 AM

I've actually had the SMT6 installed for almost a week but I finally got the time to run the serial cable to the cabin and make sure that it was fully working and I could modify fuel and timing.

The install is very similar to the 3sgte install in that you ignore what the instructions say about using the signal from the distributor. Instead you have to intercept the signal to the igniter after the ECU. The Toyota ECU seems to have a problem reading the signal from the SMT6 and no matter what output I used or how I configured it I could not get the misfires to go away. My Dad who is an EE and I actually figured out a way to make it work using the distributor signal but it would involve building two rather complex circuits, one for each side of the SMT6. We built one of them to use with an EMS later and it was working but since you can use the igniter instead I opted for the easy way out.

So far I have only noticed a couple of hick-ups, a misfire or two caused by low voltage from a dying alternator and one annoyance I noticed, the map signal is a few tenths of a volt lower on the ECU side of the SMT6 when everything is set to zero and the engine is just started and for a little while after. It makes things run slightly leaner but not enough to cause concern. It may even give me better gas mileage for now.

For those wanting to install an SMT6 on a 5sfe, the wiring goes like this:

Black ---> Ground (I T'ed into E01 on the ECU and it works fine)
Red ---> 12v+ (I T'ed into +B1 on the ECU)
Yellow ---> Cut the IGT wire from the ECU and connect the yellow wire, add a 1k Ohm resister to ground and Blue/Black pull-up from the SMT6
White ---> Connect the other side of the IGT wire you cut her which goes to the igniter
Purple ---> Cut the PIM wire coming from the ECU and connect the purple wire to the ECU side
Blue ---> Connect the other side of the PIM wire here which goes to the MAP sensor
Brown ---> Connect to same place as blue if you are planning any forced induction. In 93 5sfe's you can T this to the TPS instead if you plan to stay NA. I can't remember the ECU pin but if you need it I can look where I found it.
Black/Brown ---> T into OX1 for an oxygen sensor reading
Green/Yellow ---> T into ECTS for a water temp reading

It should be the same on the earlier 91-92 5sfe's except you must use the MAP sensor for your load signal (Brown wire). The gen 1 TPS is basically an on/off switch so you won't want to rely on it for load.

For setting it up you will want:

Mode: 10-Single ignition advance and retard + frequency fuel
Teeth per turn: 2
Teeth per firing: 1
Cylinders: 4
Positive input pol: off
Positive output pol: off
Low level input: off
RPM deflection low: 700 worked for me but it will be different on different motors. Set it so the red highlighted square is on the second row up at idle.
RPM deflection high: 6300
Analog deflection scale minimum: Turn off all accessories including fans, A/C and stereo and warm up the car. This will give you the lowest vacuum at idle. Read the Load Deflection % at the bottom of the tuning screen and set the minimum to 5% more then what you read.
Analog deflection scale maximum: Take the same reading as above but without the engine running. This will give you close to zero manifold pressure which is as high as an NA can go. If you plan forced induction you are going to need a way to simulate your maximum boost at the MAP sensor to take the reading and set it to 5% lower then what you read.
If you use the TPS on the brown wire then for analog deflection all you have to do is take the readings with the engine off for the minimum and then engine off and the gas peddle floored for the maximum.

08-26-2007, 02:41 AM	#1 (permalink)
mrturrari I <3 my 5sfe Join Date: Mar 2005 Location: Salt Lake City, Utah Posts: 511 Thanks: 2 Thanked 125 Times in 82 Posts iTrader Rating: (0/0% )	93 5sfe - SMT6 installed and working I've actually had the SMT6 installed for almost a week but I finally got the time to run the serial cable to the cabin and make sure that it was fully working and I could modify fuel and timing. The install is very similar to the 3sgte install in that you ignore what the instructions say about using the signal from the distributor. Instead you have to intercept the signal to the igniter after the ECU. The Toyota ECU seems to have a problem reading the signal from the SMT6 and no matter what output I used or how I configured it I could not get the misfires to go away. My Dad who is an EE and I actually figured out a way to make it work using the distributor signal but it would involve building two rather complex circuits, one for each side of the SMT6. We built one of them to use with an EMS later and it was working but since you can use the igniter instead I opted for the easy way out. So far I have only noticed a couple of hick-ups, a misfire or two caused by low voltage from a dying alternator and one annoyance I noticed, the map signal is a few tenths of a volt lower on the ECU side of the SMT6 when everything is set to zero and the engine is just started and for a little while after. It makes things run slightly leaner but not enough to cause concern. It may even give me better gas mileage for now. For those wanting to install an SMT6 on a 5sfe, the wiring goes like this: Black ---> Ground (I T'ed into E01 on the ECU and it works fine) Red ---> 12v+ (I T'ed into +B1 on the ECU) Yellow ---> Cut the IGT wire from the ECU and connect the yellow wire, add a 1k Ohm resister to ground and Blue/Black pull-up from the SMT6 White ---> Connect the other side of the IGT wire you cut her which goes to the igniter Purple ---> Cut the PIM wire coming from the ECU and connect the purple wire to the ECU side Blue ---> Connect the other side of the PIM wire here which goes to the MAP sensor Brown ---> Connect to same place as blue if you are planning any forced induction. In 93 5sfe's you can T this to the TPS instead if you plan to stay NA. I can't remember the ECU pin but if you need it I can look where I found it. Black/Brown ---> T into OX1 for an oxygen sensor reading Green/Yellow ---> T into ECTS for a water temp reading It should be the same on the earlier 91-92 5sfe's except you must use the MAP sensor for your load signal (Brown wire). The gen 1 TPS is basically an on/off switch so you won't want to rely on it for load. For setting it up you will want: Mode: 10-Single ignition advance and retard + frequency fuel Teeth per turn: 2 Teeth per firing: 1 Cylinders: 4 Positive input pol: off Positive output pol: off Low level input: off RPM deflection low: 700 worked for me but it will be different on different motors. Set it so the red highlighted square is on the second row up at idle. RPM deflection high: 6300 Analog deflection scale minimum: Turn off all accessories including fans, A/C and stereo and warm up the car. This will give you the lowest vacuum at idle. Read the Load Deflection % at the bottom of the tuning screen and set the minimum to 5% more then what you read. Analog deflection scale maximum: Take the same reading as above but without the engine running. This will give you close to zero manifold pressure which is as high as an NA can go. If you plan forced induction you are going to need a way to simulate your maximum boost at the MAP sensor to take the reading and set it to 5% lower then what you read. If you use the TPS on the brown wire then for analog deflection all you have to do is take the readings with the engine off for the minimum and then engine off and the gas peddle floored for the maximum.