obd 1320

[chepolino22]

1997 q45 with 153k.

I have 1320 code, i have been having misfire issue for the last 8-10 months, a couple of months ago i took it to a good shop and they changed one of the coils, misfiring went away but then came back, i took to the shop again and they changed another coil. Engine has been mifiring even t hough 2 new coils were put. So i changed the other 6, engine stopped misfiring but the code 1320 is still there. I did erased the code and after starting the vehicle the codes comes back and the check engine is still on.Any possible resolutions? Note that i dont have oem plugs and have Autolite double platinum that i put about a year ago, when i put them car worked fine so i am thinking it is not really spark plugs eventhough the are not oem. My guess is that maybe the two coils that were put by t he shop are no good anymore but if that's the case then the engine would report misfire and it doesnt. I also recently changed fuel filter, cleaned throttle body and seafomed through pcv hose.???thanks

[maxnix]

Autolite plugs have known to be fatal to VH series engines!

Start by reading the FSM!

http://www.nicoclub.com/FSM/Q45/

You may have to reference the 1998 FSM if the 1997 is still incomplete.

[chepolino22]

thanks for the reply, i will put ngk plugs this weekend.

[chepolino22]

fsm stating to check ecm relay, i cannot find it, i checked under the hood and found relay box but there were no ecm relays. Do i need to look somewhere else.thanks

[Q451990]

I think I would very carefully examine the connections and subharness feeding the coil packs when you change the spark plugs this weekend. I would be looking for a bad connection to one of the coil packs...

Heath

[loystock]

There is no ECM relay in the 97Q. It applies to some model years of the I30/Maxima. Even if one exists in your Q45, the fact that the engine is running (though with misfire) indicates it's good.

Before you replace the spark plugs, make a visual check of the harness, connectors, and ignition coil. Clean and secure the main engine harness ground points (near oil dipstick). Then run a 'Power Balance' test to isolate a faulty cylinder (Disconnect one ignition coil at a time and check engine response. A good cylinder will cause a drop in RPM while a bad one will have no effect).

Check Ignition Coil pins 2 and 3 resistance - 0 ohm indicates a shorted Base-Emitter junction in the transistor inside the coil; other than 0 ohm is Ok.

Ignition Coil Connector Signal:-Pin 1 (W/R wire): Battery voltage if Ignition switch is ON-Pin 2 (B wire): Ground connection (of emitter)-Pin 3: (striped wire): Signal from ECM (base bias to coil transistor), - 0.38VDC with Ignition ON or engine at Idle; 0.56VDC at 2000 RPM.

Verify Ignition Coil Pins 1 and 3 are not shorted to ground. Ensure Pin 2 is connected to ground. Check continuity of coil connector Pin 3 (striped wire) to ECM connector. Check condition of condenser (capacitor if leaky, open or shorted).

If all of the above are OK, then you need a Known Good Coil (preferably new OEM) to move around each cylinder (may have to drive for several days to identify a defective coil).

[chepolino22]

thanks i will try that. i was reading fms and as far as checking the resistance on the coil i believe that i need to check it between 3 and 2 pins not 1 and 3. unless i am missing somethingthanks again

[chepolino22]

Check condition of condenser (capacitor if leaky, open or shorted).

i am sorry but where is condenser?, if it would be leaky then my ac would not work and it works fine therefore i dont think that there is an issue with condeser. How does condenser affect engine misfire?thanks

[loystock]

You are right, it should be Pins 3 and 2 (base and emitter, Pin 1 is for the primary winding of the coil). The condenser is the capacitor which is connected in parallel with the ignition coil and acts more like a a 'shock absorber' for voltage spike. It's usually mounted at or very close to the main engine harness. It's not the same as the A/C condenser (heat exchanger). It seldom fails.

[chepolino22]

i installed new oem ngk platinum sparks and checked connections to each coil. Car does not misfire but the 1320 code is still there.

I couldnt find the condenser someone suggested. I also reset my battery and checked ground connectors. checked all my coils and they are fine. also did the balast check and everthing seems fine.

if i got to the dealer they will probably charge $200-300 just to find the problem or suggest to change main harenesses which is like $800 just for the part! I might take it to my local mechanic to have them look at it.

[chepolino22]

someone also suggested to check the main harness connections which are near by oil dipstick and also to clean each ignition harnesses connector (how do i clean it, do i use air to clean it?).

thanks for all of your help

[loystock]

i installed new oem ngk platinum sparks and checked connections to each coil. Car does not misfire but the 1320 code is still there.

So how did you check the connections to each coil. Did you use the info from my earlier posting?

DTC P1320 means "Ignition signal primary circuit not sent during cranking/starting. The problem may be due to - harness/connector, ignition coil internal power transistor, or camshaft position sensor/circuit.

Please refer to page EC-270 (description of of P1320 fault) and EC-273 onwards (Wiring Diagram) of the FSM which Brian (maxmix) provided a link to you. These pages will give you a better understanding on how to diagnose the problem.

Replacing the harness is an expensive and time consuming process. I personally won't recommend that unless the harness was damaged or burnt. As for the main engine harness ground points, I recommended that you clean them. There are 2 ground lugs bolted to the engine close to the oil dipstick. Disconnect the ground lugs and clean both the lugs and ground points with sand paper and then reconnect.

As for cleaning the connector and receptacles of the ignition coil, use contact cleaner available from electronics parts store. Even the CRC MAF Cleaner (@ $8) from Autozone should do the job. Then apply dielectric grease (Permatex Dielectric grease @ $5 from Autozone) to the connector and receptacles to prevent corrosion.

I'm assuming that you have already tested the coils and they are brand new anyway. So we can focus on the wiring.

Ignition Coil Connector Signal:-Pin 1 (W/R wire): Battery voltage if Ignition switch is ON-Pin 2 (B wire): Ground connection (of emitter)-Pin 3: (striped wire): Signal from ECM (base bias to coil transistor), - 0.38VDC with Ignition ON or engine at Idle; 0.56VDC at 2000 RPM.

You have to check each connector to the ignition coil. With Ignition ON (engine OFF), check that:-Pin 1 has Battery voltage (@ 12.6VDC on a good battery). If not, you have a break somewhere between the Fuse Block and the connector.-Pin 2 at 0VDC. If other than zero, that means the ground connection is poor, dirty or broken.-Pin 3 is @ 0.38VDC. If there is no signal, you have a break somewhere between the Ignition Coil connector and the ECM connector.-Also make sure that Pins 1 & 3 are not shorted to ground.

[chepolino22]

thanks for the reply. Yes coils are good and yes they are new. I am a little confused with:Ignition Coil Connector Signal:-Pin 1 (W/R wire): Battery voltage if Ignition switch is ON-Pin 2 (B wire): Ground connection (of emitter)-Pin 3: (striped wire): Signal from ECM (base bias to coil transistor), - 0.38VDC with Ignition ON or engine at Idle; 0.56VDC at 2000 RPM.

You have to check each connector to the ignition coil. With Ignition ON (engine OFF), check that:-Pin 1 has Battery voltage (@ 12.6VDC on a good battery). If not, you have a break somewhere between the Fuse Block and the connector.-Pin 2 at 0VDC. If other than zero, that means the ground connection is poor, dirty or broken.-Pin 3 is @ 0.38VDC. If there is no signal, you have a break somewhere between the Ignition Coil connector and the ECM connector.-Also make sure that Pins 1 & 3 are not shorted to ground.

I have voltmeter but i am not an electrician or mechanic could you specificaly tell me how to test each connector (to what pin i put negative end of the voltmeter and to what pin positive?).thanks

i also did balast power check and it worked out fine. each time i discconected a cylinder and dropp in the rpm was observed and engine ran rougher.