2005 Altima 2.4L cooked ignition coils #1 and #3 (drivers?)

bought this car cranks/wont run. they also stole all ign coils. I put all new denso coils in and new NGk's immediately upon cranking Ign coils 1 & 3 got real hot(still not running btw) no codes except P0300. so I compared the signal wires to coil from ecm and 2 & 4 have about .7-.8v bias koeo. but # 1 & 3 have about 2.8v and 3.2v respectively, so it seems coils are staying on (according to diagram this is a power feed signal driver to coils (not ground side driver). so I pulled ecm and checked cont. for all signal pins to coils (pins-61, 62, 80 and 81, all ok and none are shorted to each other or powers/grounds. Im ready to call the ECM drivers for #1 and #3 as shorted, those coils wont shut off, please tell me I'm wrong.. thanks a ton.

Tom
Fedex Freight til death or retirement whichever comes first

Do the good coils fire normally when cranking? Do you have a scope to watch the signal wires on a known good and then on the suspected bad? Also it would be handy to check the current ramps while cranking, as well. I found a service manual on nicoclub and thought I'd post a screen shot of it so others could help you better. Just looking at the diagram, and by what you describe, it does sound like the ECM is keeping them powered.

Do the connectors for the #1 and #3 coils appear new? I've seen replacement pigtails that got wired in with reverse polarity, and it results in the coils cooking themselves. :lol:

but # 1 & 3 have about 2.8v and 3.2v respectively

Is that a steady voltage measured with a DMM? Was that reading taken with the coil connected or disconnected?

I think you need to prove that the stray voltage is coming from the ECM, and nowhere else. KOEO, coil disconnected, does the voltage remain? If yes, turn the key off, disconnect the ECM, then turn the key on again. Does the voltage remain?

John I have the exact diagram, I do not have a scope, but the other coils are not firing either, plus there are no codes in vehicles at all. I could pick up a scrap yard ecm but I dont have a programmer. so we will see what happens, thanks.

Ill try, thanks Tyler

so thanks for your help you auto pros. replaced the ecm with a used one, replaced ground cable to body, added another ground to body and engine, but... I have one more question, how do I get rid of P0605? or can I?

If you replaced the ecu with a used one and that code poped up with the replacement ecu then the only way to get rid of that code is a checking powers and grounds to ecu by back probing connector. If theyre good and no green crusties and no resistance in wires from power or to ground then you will need a new (brand new) ecu

Here is a tsb I found regarding this code as well. I would check this first before buying ecu.

Hi there.
I had this before on 2 Nissan’s. Both times the coils were on constantly and red hot.
ECM coil drivers were at fault. The customer had somehow jumpstarted the vehicle and blown a main fuse on one of them and the other vehicle was just sitting around for 8 months and couldn’t get it started. One was a micra and the other was a maxima.
Sent ECM away for repair as a new one was sooooo expensive!