MR2 Owners Club Forum banner

61 - 68 of 68 Posts

·
Registered
Joined
·
72 Posts
Discussion Starter #61
How are you doing the test?
I used a paperclip and pushed it beside where the wire goes into the connector and measured there, I'm not sure if this is the correct way but I saw a couple videos on YouTube and they didnt seem to have a problem
 

·
Registered
Joined
·
2,043 Posts
I used a paperclip and pushed it beside where the wire goes into the connector and measured there, I'm not sure if this is the correct way but I saw a couple videos on YouTube and they didnt seem to have a problem
Ok. Seems logical. Are you earthing through the sensor?
We should be expecting 5V in from the ECU on pin 3 VC and earthing through pin 1.
I assume you are looking for data based on testing shown here in the wiring diagram document?
GEN4 3SGTE PIM MAP Sensor Test.JPG
 

·
Registered
Joined
·
72 Posts
Discussion Starter #63
Ok. Seems logical. Are you earthing through the sensor?
We should be expecting 5V in from the ECU on pin 3 VC and earthing through pin 1.
I assume you are looking for data based on testing shown here in the wiring diagram document?
View attachment 70443
Ok so I've done a little more testing, with plug block b disconnected from the ecu I'm getting around 11 volts to the map sensor and other 5v sensors. With it plugged in I'm getting 5v. Im assuming the ecu steps down the voltage from 12v to 5v so that issue is solved. I believe when I first started my car I had the ecu disconnected so I could just crank the engine and get oil moving around before it actually started, so I may have blown up all of the 5v sensors, the map and throttle position sensor. What do you think the likelihood of this situation is?
 

·
Registered
Joined
·
2,043 Posts
Ok so I've done a little more testing, with plug block b disconnected from the ecu I'm getting around 11 volts to the map sensor and other 5v sensors. With it plugged in I'm getting 5v. Im assuming the ecu steps down the voltage from 12v to 5v so that issue is solved. I believe when I first started my car I had the ecu disconnected so I could just crank the engine and get oil moving around before it actually started, so I may have blown up all of the 5v sensors, the map and throttle position sensor. What do you think the likelihood of this situation is?
I have no idea on this one sorry. Very keen to find out but with no car to test it on or break I can't offer much advice on this. Maybe you have damaged the MAP and TPS with 12V. The other items connected to this 5V circuit are temperature sensors but they could be damaged too. I don't know how they react to more than 5V so can't be sure.
 

·
Premium Member
Joined
·
277 Posts
Ok so I've done a little more testing, with plug block b disconnected from the ecu I'm getting around 11 volts to the map sensor and other 5v sensors. With it plugged in I'm getting 5v. Im assuming the ecu steps down the voltage from 12v to 5v so that issue is solved. I believe when I first started my car I had the ecu disconnected so I could just crank the engine and get oil moving around before it actually started, so I may have blown up all of the 5v sensors, the map and throttle position sensor. What do you think the likelihood of this situation is?
If you have plug B disconnected there should be no power to those sensors at all.
5v system should be completely isolated and connect ONLY to the ECU and does not connect to any other wires, fuses or relays.
You definitely have the 12v system tied to the 5v system somehow and need to eliminate that connection.

Even though 12v is more than double 5v I think the odds of actually "frying" the sensors is small, a short would be more dangerous. most of the sensors are just some form of resistor so they just cut the voltage down but its based on input.
 

·
Registered
Joined
·
72 Posts
Discussion Starter #66
If you have plug B disconnected there should be no power to those sensors at all.
5v system should be completely isolated and connect ONLY to the ECU and does not connect to any other wires, fuses or relays.
You definitely have the 12v system tied to the 5v system somehow and need to eliminate that connection.

Even though 12v is more than double 5v I think the odds of actually "frying" the sensors is small, a short would be more dangerous. most of the sensors are just some form of resistor so they just cut the voltage down but its based on input.
I have no idea on this one sorry. Very keen to find out but with no car to test it on or break I can't offer much advice on this. Maybe you have damaged the MAP and TPS with 12V. The other items connected to this 5V circuit are temperature sensors but they could be damaged too. I don't know how they react to more than 5V so can't be sure.
Hey guys! Great news that map sensor fixed my problem. Really wish there was a better way of diagnosing the problem when I first got it. But thanks guys I really appreciate the help learned lots about electrical things and got a very in depth understanding of this engine. It does idle high but runs very smooth compared to how it was. Im sure there will be a couple other things that pop up but I will keep you guys up to date. Really appreciate the help!
 

·
Registered
Joined
·
2,043 Posts
I'm glad you've finally sorted the major issue! High idle could be a vacuum leak after the throttle or the throttle body is slightly open. Or the ECU is just trying to sort things out now it has a sensor that is working an the fuel map is resetting. Not sure if that's actually a thing on these ECUs though.
 

·
Premium Member
Joined
·
277 Posts
Hey guys! Great news that map sensor fixed my problem. Really wish there was a better way of diagnosing the problem when I first got it. But thanks guys I really appreciate the help learned lots about electrical things and got a very in depth understanding of this engine. It does idle high but runs very smooth compared to how it was. Im sure there will be a couple other things that pop up but I will keep you guys up to date. Really appreciate the help!
Very awesome that its running for ya =D
I too had high idle issues after resolving electrical. For the time being I just adjusted the stop screw on the throttle body. It worked for a while but idle seems to creep up again, assuming the ECU is opening the ISCV more to compensate. I just put the car in the garage to tune up, gonna check and do the regular stuff as well as try to get the TPS/Throttle set to spec.

I do think the ECU builds from a base fuel map so driving the car with good sensors set/reading correctly should make it run "better" but I am just guessing. I do plan on spending some time logging data this season and exploring how the ECU functions a little more. I don't think I am gonna gain much but I like to know how the things I use work. I've also heard tale of people using 3SGTE ECUs on 4AGTE builds and I have at least one of those in my future....

again really happy that its up and running
 
61 - 68 of 68 Posts
Top