Got Infinite Resistance between G2 and G- P/U Coil

colorado · 08-05-2010, 07:01 PM

So, I am having issues upon acceleration which seemed electrical in nature. I noticed I was not getting spark to 1,3,5!
I troubleshot down to P/U coil resistance of the following:

NE - 169
G1 - 166
G2 - Infinite

The manual says to go ahead and replace the CPS....so G2 must be responsible for firing 1,3,5 no?

CPS anyone?

colorado · 08-06-2010, 03:15 PM

I put it all back together and now the car would fly if it had wings!!!
SaWEET!!!
I still dont get spark from coil 3 or 5 except for the first crank!
It must be shorting during the test (in fact I saw then when I dimmed the ambient lighting), b/c the car is not missing as far as I can tell.
I will tbleshoot further, b/c it is what I like doing, but wierd that the car runs will with the Infinite Ohms between G2 and G- Pickup Coil!!???

MA70-3.0GT · 08-07-2010, 11:02 AM

I don't think anything is shorting, as infinite ohms is open circuit... (I'm assuming a typo here but did you mean zero ohms/short or inf. ohms/open?)

With the connector for coil 3/5 removed (they unplug seperately under the coil pack iirc) are you getting any signal through those wires with the engine running? (bear in mind CDI signal voltage although short will be probably over 100Vdc and likely easier detected on a scope)

If there is a signal there it's possible the coil itself is u/s, have you checked & compared the 3 coil pack's primary/secondary resistances? it may be easier/safer to prove out the coils by this method.

colorado · 08-07-2010, 01:04 PM

I meant OPEN...no short! All the Coil/Igniter tests pass just fine...
Now the car runs pretty good, but the diagnostic on the P/U coil is baffling me!

Technically, the car is probably NOT running perfect, but very smooth acceleration once again, and for that I am happy!!

The harness between the Igniter and the Coils was falling apart, so I had to remove the connectors and simply plug the bare connectors into the coils. I thought that this would definitely be a problem, but no problem so far. I have another cable on the way, though.

cre · 08-07-2010, 05:28 PM

I'd just find a CPS or a GE distributor to swap in to see if it changes anything.

I would plan on rebuilding the harness too.

08-05-2010, 07:01 PM	#1
colorado Stock Join Date: Jun 2010 Location: Colorado Posts: 17	Got Infinite Resistance between G2 and G- P/U Coil So, I am having issues upon acceleration which seemed electrical in nature. I noticed I was not getting spark to 1,3,5! I troubleshot down to P/U coil resistance of the following: NE - 169 G1 - 166 G2 - Infinite The manual says to go ahead and replace the CPS....so G2 must be responsible for firing 1,3,5 no? CPS anyone? Last edited by colorado; 08-06-2010 at 02:59 PM.

08-06-2010, 03:15 PM	#2
colorado Stock Join Date: Jun 2010 Location: Colorado Posts: 17	Wierd... I put it all back together and now the car would fly if it had wings!!! SaWEET!!! I still dont get spark from coil 3 or 5 except for the first crank! It must be shorting during the test (in fact I saw then when I dimmed the ambient lighting), b/c the car is not missing as far as I can tell. I will tbleshoot further, b/c it is what I like doing, but wierd that the car runs will with the Infinite Ohms between G2 and G- Pickup Coil!!???

08-07-2010, 11:02 AM	#3
MA70-3.0GT 12psi boost Join Date: Oct 2009 Location: Crewe, England Posts: 356	I don't think anything is shorting, as infinite ohms is open circuit... (I'm assuming a typo here but did you mean zero ohms/short or inf. ohms/open?) With the connector for coil 3/5 removed (they unplug seperately under the coil pack iirc) are you getting any signal through those wires with the engine running? (bear in mind CDI signal voltage although short will be probably over 100Vdc and likely easier detected on a scope) If there is a signal there it's possible the coil itself is u/s, have you checked & compared the 3 coil pack's primary/secondary resistances? it may be easier/safer to prove out the coils by this method. __________________ '89 MA70 Supra GT aero 3.0turbo JDM, Rebuilt motor, K&N intake, 3" stainless turbo-back. New turbo and braided line kit... '89 Honda NC27 400, NC23 cams, open pipe, PC36a shock & possibly Showa USD forks... '83 Yamaha 29R XJ750E-II, number 69 off the line, only runner in the country? Original except Koni shocks '95 Honda PC26 CB500R, Winter hack, hateful, trying to sell it I'm not paranoid, they really ARE after me!!! Last edited by MA70-3.0GT; 08-07-2010 at 11:08 AM.

08-07-2010, 01:04 PM	#4
colorado Stock Join Date: Jun 2010 Location: Colorado Posts: 17	Yeah...sorry I meant OPEN...no short! All the Coil/Igniter tests pass just fine... Now the car runs pretty good, but the diagnostic on the P/U coil is baffling me! Technically, the car is probably NOT running perfect, but very smooth acceleration once again, and for that I am happy!! The harness between the Igniter and the Coils was falling apart, so I had to remove the connectors and simply plug the bare connectors into the coils. I thought that this would definitely be a problem, but no problem so far. I have another cable on the way, though.

08-07-2010, 05:28 PM	#5
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I'd just find a CPS or a GE distributor to swap in to see if it changes anything. I would plan on rebuilding the harness too. __________________ 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 --->

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