no start after rebuild

discord · 12-22-2009, 05:39 AM

yes obviously, was hoping for a place toi start on this

cre · 12-22-2009, 07:22 AM

Ah, my apologies. As +B and +B1 are both sourced from the Main EFI relay and the Circuit opening relay I would check the harness in between. I am quite surprised that you have power to one and not the other.

Batt gets its power from the 15A EFI relay. If you are getting power to one of the +B lines though this fuse is unlikely to be the cause of the problem and again, you are most likely looking as a wiring problem.

All three should have power whether the harness is plugged in or not, so long as the ignition switch is in the "ON" position. Have you perhaps tested the ignition switch?

Have you inspected your wire harness since reinstalling the engine?

Here is the wiring diagram for the ECU:
http://www.cygnusx1.net/Supra/Librar...px?S=Main&P=46

discord · 12-22-2009, 06:20 PM

i did a visual check of the harness before installing. I didnt unwrap the the wire loom tho to check inside. I will check the ignition switch as well as try to get power to the ecu. I am also suprised that only b1 is getting power and not the other two. your right, sounds like a wiring problem. when I hoocked up my multi meter to those other 2 the voltage actually showed a negative of about 1.5v on both. not sure what that means...thanks much cre for your input.

discord · 12-22-2009, 07:22 PM

ok, I removed all engine grounds and made new ones. now I'm showing a voltage at b2 and batt but its only between 4v and 5v.... still no start tho

cre · 12-22-2009, 08:13 PM

Do you know how to test for voltage drop across a line? You place one test lead at each end of the wire (the wire needs to be connected so there is voltage to read), place the negative lead on the side closest to the + terminal in the circuit then place the negative on the other end. The voltage you see reported will be the total drop across the wire. More than a couple hundred mV and the wire should be replaced.

When testing across a larger circuit it is sometimes easier to test the whole thing and then slowly close in until you've found the individual point of failure. So in this case you'd place the negative probe on the battery's + terminal. Then you'd place the positive probe at the harness' +B connector resulting in a reading of a drop of about 10v. Now you move back along the circuit to the next junction and test. If the voltage drop is still present you move along to the the next junction closer to the battery. If it isn't then you test the voltage drop across the wire at the ECU harness and that first junction.

discord · 12-23-2009, 02:15 AM

now the car is back firing thru the intake and exhaust pipes are getting warm...I havent check any voltages yet, but the back firing thing has been the most activity since it was installed? good thing?

cre · 12-23-2009, 05:18 AM

The back firing means the mechanical timing is a mile off. Realign everything to 0? then look into the voltage issues.

discord · 12-29-2009, 12:01 AM

ok finally got it started. doesnt run long as i expected due to vaccuum bugs. I am tho pretty sure oil should not shoot out the exhaust side of the turbo, am I right?

cre · 12-29-2009, 12:19 AM

Ummm.... oil + exhaust.... not unless turbo technology has gotten VERY strange in recent years.

discord · 12-29-2009, 12:27 AM

haha ya I know. turbo is blown apparently so off it goes and back to the drawing board. thanks for all your help cre!!

12-22-2009, 05:39 AM	#1
discord Stock Join Date: Dec 2009 Location: puyallup, wa Posts: 16	yes obviously, was hoping for a place toi start on this __________________ 1991 supra targa turbo full rebuild, garrett turbo, chrome header, custom made adjustable wastegate and matching bov, elec fan, hks evc pro, greddy turbo timer, hks 2.0mm hg, arp head bolts, arp rod bolts, 2.5" intercooler and piping, lexus ls400 MAF. AC, power steering, and clutch fan deleted.

12-22-2009, 07:22 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Ah, my apologies. As +B and +B1 are both sourced from the Main EFI relay and the Circuit opening relay I would check the harness in between. I am quite surprised that you have power to one and not the other. Batt gets its power from the 15A EFI relay. If you are getting power to one of the +B lines though this fuse is unlikely to be the cause of the problem and again, you are most likely looking as a wiring problem. All three should have power whether the harness is plugged in or not, so long as the ignition switch is in the "ON" position. Have you perhaps tested the ignition switch? Have you inspected your wire harness since reinstalling the engine? Here is the wiring diagram for the ECU: http://www.cygnusx1.net/Supra/Librar...px?S=Main&P=46 __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-22-2009, 06:20 PM	#3
discord Stock Join Date: Dec 2009 Location: puyallup, wa Posts: 16	i did a visual check of the harness before installing. I didnt unwrap the the wire loom tho to check inside. I will check the ignition switch as well as try to get power to the ecu. I am also suprised that only b1 is getting power and not the other two. your right, sounds like a wiring problem. when I hoocked up my multi meter to those other 2 the voltage actually showed a negative of about 1.5v on both. not sure what that means...thanks much cre for your input. __________________ 1991 supra targa turbo full rebuild, garrett turbo, chrome header, custom made adjustable wastegate and matching bov, elec fan, hks evc pro, greddy turbo timer, hks 2.0mm hg, arp head bolts, arp rod bolts, 2.5" intercooler and piping, lexus ls400 MAF. AC, power steering, and clutch fan deleted.

12-22-2009, 07:22 PM	#4
discord Stock Join Date: Dec 2009 Location: puyallup, wa Posts: 16	ok, I removed all engine grounds and made new ones. now I'm showing a voltage at b2 and batt but its only between 4v and 5v.... still no start tho __________________ 1991 supra targa turbo full rebuild, garrett turbo, chrome header, custom made adjustable wastegate and matching bov, elec fan, hks evc pro, greddy turbo timer, hks 2.0mm hg, arp head bolts, arp rod bolts, 2.5" intercooler and piping, lexus ls400 MAF. AC, power steering, and clutch fan deleted. Last edited by discord; 12-22-2009 at 07:25 PM.

12-22-2009, 08:13 PM	#5
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Do you know how to test for voltage drop across a line? You place one test lead at each end of the wire (the wire needs to be connected so there is voltage to read), place the negative lead on the side closest to the + terminal in the circuit then place the negative on the other end. The voltage you see reported will be the total drop across the wire. More than a couple hundred mV and the wire should be replaced. When testing across a larger circuit it is sometimes easier to test the whole thing and then slowly close in until you've found the individual point of failure. So in this case you'd place the negative probe on the battery's + terminal. Then you'd place the positive probe at the harness' +B connector resulting in a reading of a drop of about 10v. Now you move back along the circuit to the next junction and test. If the voltage drop is still present you move along to the the next junction closer to the battery. If it isn't then you test the voltage drop across the wire at the ECU harness and that first junction. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-23-2009, 02:15 AM	#6
discord Stock Join Date: Dec 2009 Location: puyallup, wa Posts: 16	now the car is back firing thru the intake and exhaust pipes are getting warm...I havent check any voltages yet, but the back firing thing has been the most activity since it was installed? good thing? __________________ 1991 supra targa turbo full rebuild, garrett turbo, chrome header, custom made adjustable wastegate and matching bov, elec fan, hks evc pro, greddy turbo timer, hks 2.0mm hg, arp head bolts, arp rod bolts, 2.5" intercooler and piping, lexus ls400 MAF. AC, power steering, and clutch fan deleted.

12-23-2009, 05:18 AM	#7
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	The back firing means the mechanical timing is a mile off. Realign everything to 0? then look into the voltage issues. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-29-2009, 12:01 AM	#8
discord Stock Join Date: Dec 2009 Location: puyallup, wa Posts: 16	ok finally got it started. doesnt run long as i expected due to vaccuum bugs. I am tho pretty sure oil should not shoot out the exhaust side of the turbo, am I right? __________________ 1991 supra targa turbo full rebuild, garrett turbo, chrome header, custom made adjustable wastegate and matching bov, elec fan, hks evc pro, greddy turbo timer, hks 2.0mm hg, arp head bolts, arp rod bolts, 2.5" intercooler and piping, lexus ls400 MAF. AC, power steering, and clutch fan deleted.

12-29-2009, 12:19 AM	#9
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Ummm.... oil + exhaust.... not unless turbo technology has gotten VERY strange in recent years. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

12-29-2009, 12:27 AM	#10
discord Stock Join Date: Dec 2009 Location: puyallup, wa Posts: 16	haha ya I know. turbo is blown apparently so off it goes and back to the drawing board. thanks for all your help cre!! __________________ 1991 supra targa turbo full rebuild, garrett turbo, chrome header, custom made adjustable wastegate and matching bov, elec fan, hks evc pro, greddy turbo timer, hks 2.0mm hg, arp head bolts, arp rod bolts, 2.5" intercooler and piping, lexus ls400 MAF. AC, power steering, and clutch fan deleted.

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