Replacing Ignition Coils

[sontakke]

I guess it is too late now but I should have told you this before. On my Nissan, I have driven for months with the intermittent P1320 code until it spit out specific cylinder code. So far two coils went bad. When the 2nd one went bad, I replaced them all. The 2nd one gave me intermittent P1320 code for almost a year. I even managed to sneak an inspection (pure luck) in between.

Unless the code comes back immediately and unless you have engine running problems, you could wait until better weather to fix this.

- Vikas

 

[Capt Caveman]

I guess it is too late now but I should have told you this before. On my Nissan, I have driven for months with the intermittent P1320 code until it spit out specific cylinder code. So far two coils went bad. When the 2nd one went bad, I replaced them all. The 2nd one gave me intermittent P1320 code for almost a year. I even managed to sneak an inspection (pure luck) in between.

Unless the code comes back immediately and unless you have engine running problems, you could wait until better weather to fix this.

- Vikas

My big problem right now is that it's due for inspection. The repair shop called me back and they also recommended replacing out all six ignition coils and sparkplugs. They want $110 for each ignition coil and $185 for labor.

They're fine with me ordering the parts and just doing the labor. They deal with Standard Motor Parts quite a bit and fine with me ordering them.

 

[Capt Caveman]

Spark Plugs. If I plan to only keep the vehicle for another year at most, does it matter? The Denso Platinums for $2.60 look like a good deal but getting better plugs isn't going to cost much more.

 

[Vette73]

Spark Plugs. If I plan to only keep the vehicle for another year at most, does it matter? The Denso Platinums for $2.60 look like a good deal but getting better plugs isn't going to cost much more.

The Denso Plats will do what you want just fine. Probable good for 60k depending on how its driven and condition. So yea go for those.

 

[Capt Caveman]

The Denso Plats will do what you want just fine. Probable good for 60k depending on how its driven and condition. So yea go for those.

Thanks! Coils and spark plugs ordered for $328. Labor for $185, it'll end-up $513 to get them replaced.

 

[Zivic]

Boston. Dropped it off at another place today. Gave them a print-out from Infiniti on the computer code and the installation print-out that Marlin provided(Thanks!). If the ignition coils need to be replaced, they think it will take 1.5-2 hrs to replace.

2 hrs seems very reasonable for a shop.

 

[Capt Caveman]

Crap! Finally, got the parts and had the ignition coils and spark-plugs replaced. But after they ran the engine for a hour, the Service Engine Light went off with the same error code. I had them reset the computer but it turned back on after starting the vehicle twice. I plan to bring it back to the local place tomorrow.

Based on the possible causes, eliminating the ignition coils, any ideas?

Possible causes
- Ignition primary circuit is open or shorted
- Ignition primary circuit poor electrical connection
- Faulty power transistor unit built into ignition coil
- Faulty ignition system condenser
- Crankshaft position sensor circuit

P1320 INFINITI Description
The ignition signal from the Engine Control Module (ECM) is sent to and amplified by the power transistor. The power transistor turns on and off the ignition coil primary circuit. This on-off operation induces the proper high voltage in the coil secondary circuit.
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
Possible causes
- Ignition primary circuit is open or shorted
- Ignition primary circuit poor electrical connection
- Faulty power transistor unit built into ignition coil
- Faulty ignition system condenser
- Crankshaft position sensor circuit
Possible solution
The most common cause of the problem is the ignition coils
When is the code detected?
- When the ignition signal in the primary circuit is not sent to Engine Control Module (ECM) during engine cranking or running.

 

[bruceb]

Since you already replaced all the ignition coils look at the list in this order

Possible causes

Ignition primary circuit poor electrical connection

Faulty ignition system condenser

Crankshaft position sensor circuit

First one can be nothing more than corroded or loose wiring terminals.

Second one is an easy change and should not be costly.

Third one is a bit costly (around $50 for part) and labor to swap it, depending on what must come off to get to it.

 

[Capt Caveman]

I would suspect the Power Transistor as referenced above, as it is common to all the ignition coils.

From what I can google, the power transistor is built into the ignition coil.

 

[bruceb]

I noticed that and edited my post to reflect that. Correct list is above.

You can download the factory service manual here if you do not already have it. You can get 2 files a day free. Or for a small donation, unlimited downloads for 1 year.

http://x.infinitihelp.com/forum/showthread.php/2001-infiniti-qx4-service-manual-1666.html?t=1666

 

[Capt Caveman]

Thanks. Does the third one require opening up the engine?

 

[Capt Caveman]

Found this, looks like there are two sensors - http://forums.nicoclub.com/camshaft-position-sensor-t275957.html

 

[bruceb]

You should not need to open the engine, but it is likely buried behind the crank pulley, which may need to come off. Get the service manual from the link I posted.

 

[AMCRambler]

Found this, looks like there are two sensors - http://forums.nicoclub.com/camshaft-position-sensor-t275957.html

Makes sense I guess. Dual overhead cams probably so one sensor for each. They sound pretty easy to replace, I'd probably try that.

That intake looks ungainly. Why the hell is it so large and sticking up so high? Seems like they could have just mounted something directly to the cylinder heads instead of having a giant mushroom shaped thing on top of the motor. Reminds me of the 5.0 intakes from the 80's which I never really understood either:

 

[Zivic]

Since you already replaced all the ignition coils look at the list in this order

Possible causes

Ignition primary circuit poor electrical connection

Faulty ignition system condenser

Crankshaft position sensor circuit

First one can be nothing more than corroded or loose wiring terminals.

Second one is an easy change and should not be costly.

Third one is a bit costly (around $50 for part) and labor to swap it, depending on what must come off to get to it.

OP, does the car have a harder time starting than usual? maybe a couple extra cranks?

If so, it is likely the CAS (crank angle sensor). that is my first guess.... but being the net, it is hard to diagnose.

 

[5150MyU]

Camshaft position sensor.
Crankshaft position sensor will usually cause a no start while the cam sensor will let it run some what OK or fine.

 

[5150MyU]

Also note that when diagnosing P1320 the crank sensor is not even looked at-just the coils and cam sensor(s).

 

[Capt Caveman]

OP, does the car have a harder time starting than usual? maybe a couple extra cranks?

If so, it is likely the CAS (crank angle sensor). that is my first guess.... but being the net, it is hard to diagnose.

No. I have had no issues starting the vehicle and it runs smoothly. The only noticeable thing is my mileage has gone down drastically.

Dropped the car off again this morning. They believed that if it had been the crankshaft, MAF or another sensor, I should have received an additional code with the P1320. Will call them now for an update.

 

[Capt Caveman]

Autoshop called to tell me that they're still not able to determine the issue. All sensors, circuits and fuses are working. After clearing the codes again, the service engine light doesn't come on til the vehicle is restarted for the second time.

They plan on keeping the vehicle overnight to go thru the process of checking all the wiring. If they're not able to find anything wrong there, they think it may be an issue with the computer and I'll have to bring it back to the dealership.

edit - I did give the guys the service manual section on the P1320 code with all of the diagnostics.

 

[5150MyU]

Intermittent failures suck-very hard to duplicate even if you can get it to do it in the shop once or twice.
I think you have narrowed it down to the cam sensor(s) or the computer.
Cam sensor for the win -good luck!

 

[Sukhoi]

For the stuff that is reset (but needed for inspection) when clearing the codes, how much of it requires a certain number of engine on/off cycles to gain a stored value? Is most of it just by miles driven?

What I'm getting at is could you clear the codes, drive around for a while to get whatever necessary values to an acceptable sample quantity, and then get it inspected without turning the engine off?

 

[Capt Caveman]

For the stuff that is reset (but needed for inspection) when clearing the codes, how much of it requires a certain number of engine on/off cycles to gain a stored value? Is most of it just by miles driven?

What I'm getting at is could you clear the codes, drive around for a while to get whatever necessary values to an acceptable sample quantity, and then get it inspected without turning the engine off?

I've heard everything from 1/2 mile at 15mph to needing 100 miles to 3 cold starts. I'm past the inspection expiration date already and need to get it fixed to get anything on a trade for it. Just stinks that both the dealership and these guys all thought it was the ignition coils.

 

[5150MyU]

You have coil over -wouldn't it kick a 300 code,301,302,303,etc.if were an individual cylinder mis fire.
P1320 points to the CAM sensor or computer

 

[iGas]

It won't take long to replace the coils/coil packs, nor spark plugs, however it could be pricey.

It look like the coils are going to be $60~$75 * 6 = $360~$450 + spark plugs from what I have seen on the internet.

You are lucky that they are cheap in the US. A coil pack for my Camry cost me $109CAD (cheapest that I found), and dealler wanted $145 each.

 

[exdeath]

Just reading above, the power transistor being mentioned is what is known as the igniter or ignition module. Never heard of one built into a coil, it's usually a metal box with heatsink fins on the firewall or fender.

edit: nvm coil on plug = digital ignition controller in ECU with individual low power logic signals to each coil requiring a "driver" or amplifier transistor in the coil packs themselves.