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Re: Voltage Effected Rough Idle


Specter
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Galant VR-4 org Post #: 887522 posted 04/05/10 01:11 PM     Remind Me!  Send Private Message   Edit Post      
I have some, not so good news. I took out the power transistor but then i thought, why not check the input of the transistor first rather then checking another one. So i checked for the pulse at pin 10 and pin 23 at ecu, voila i had pulse. I checked it at the relative pins on the power transistor grip, no pulse there. I thought its a broken wire, so i got a new wire laid down to the power transistor, i check the pulse again at the transistor grip, and there is no pulse. I checked it at the ecu, and there is no pulse. Cranked the car couple of times but could not get any pulse. I think the the ecu wants to give the pulse out, but it sometimes does so, and sometimes cannot do so. All the wiring which i had re-done had proper current. I am thinking either:
1) Bad grounds to the ecu
2) Loose pins on the ecu connected of the grounds or the power input wires.
3) ECU Problem. ( GOD NO! The ecu board is perfect, no leakages, no smell )

What do you think?


Edited by Specter (04/05/10 01:12 PM)

Posts: 367 | From: Karachi, Pakistan | Member Since: 04/20/08 | IP: (221.120.225.243) | Report this post to a Moderator

Specter
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Galant VR-4 org Post #: 887891 posted 04/06/10 11:46 AM     Remind Me!  Send Private Message   Edit Post      
Need help here...I rechecked everything. My ecu grounds are fine, my power wires to the ecu is fine, my mpi relay is turning on. I noticed that i am not getting any voltage on Pin 1 of the mpi relay when the ignition is on, it goes to the fuel pump terminal. And i am getting 8.5 volts positive current at pin 5 of mpi relay which goes to the pin 8 of ecu (mpi fuel pump power supply). When i turn the ignition off pin 8 is grounded by the relay.

Is 8.5 volts good to signal the ecu? Or is it low? I do not need mpi relay pin 1 as my fuel pump is independent. I only need to know if 8.5 volts is enough to signal the ecu from the relay.

Thanks!

Posts: 367 | From: Karachi, Pakistan | Member Since: 04/20/08 | IP: (221.120.225.243) | Report this post to a Moderator

Specter
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Galant VR-4 org Post #: 888278 posted 04/07/10 10:19 AM     Remind Me!  Send Private Message   Edit Post      
It starts! There were 2-3 loose connections i made. Also i did not know that the ecu throws negative pulse to the transistor, i thought it throws positive pulse. That is why i could not detect its signal because it was throwing negative pulse all the time and i was checking for positive pulses. Any ways as soon as i found that i out, i hooked the same old power transistor and coil pack, started right up. The spark is very strong now, checked it before starting, before the spark used to be weak and bluish, now it is very bright yellow with good thick spark arch.
The car is standing very stable, no problems yet, but it is blowing a hell lot of smoke out the exhaust, i am assuming there is a lot of carbon on the pistons which was made due to extreme richness of a 1g maf coupled with a weak spark that could not burn the fuel. The now stronger spark is cleaning up i guess, either that or its the turbo.

Thanks again toy breaker for all your detailed posts, your kindness and all the time you dedicated to this problem, not to mention a couple of strings you pulled around here to get those wiring diagrams. Without you i would not have come so far this fast.
Thank You Sir, God Bless You!

Posts: 367 | From: Karachi, Pakistan | Member Since: 04/20/08 | IP: (221.120.225.243) | Report this post to a Moderator

toybreaker Galant VR4.org Moderator
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Galant VR-4 org Post #: 888329 posted 04/07/10 01:33 PM     Remind Me!  Send Private Message   Edit Post   

Posts: 3547 | From: Never Summer Ranch, Colorado | Member Since: 04/30/06 | IP: (208.54.7.161) | Report this post to a Moderator


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