Engine drama with coil packs in V6 ST-X

[murf6]

G'day guys,

I am hoping to find some info from the many knowledgeable people on this forum. I have a 2008 ST-X V6 with 90 thou K's

Over the last couple of weeks every know and then my engine seems to start running in 5 cylinders. It come and goes for a few minutes and then the engine light flashes. Once I turn it off and on again a few times it goes back to normal.

I have been to the local nissan dealer and they believe it is a problem with one of the coil packs (they do seems to be scratching their heads a bit and then just guessing at the cause though). The diagnosis machine is just reading a misfire with no further details.

The problem is they have told me there is no way to isolate which pack is causing the problem and tell me there is no possible way to test a coil pack, so they want to just replace all 6 at a cost of..... what for it..... $2,000!!!!!!!!!!

I have tried pulling the plug of each pack in an attempt to isolate which one may be causing the problem. Of course it is not either of the three that you can actually get to easy, and my hands do not bend enough to reach the other three without pulling covers of etc.....

It is a real pain, as it only happens every now and then so I can really start pulling things apart to get to the other three packs until the problem actually happens where I can try and isolate it....

Any advice anyone could possibly give would be greatly appreciated. I really don't want to spend the 2 grand to replace all 6 packs......

cheers murf

 

[raywise]

Well they are talking out their bums, as normal. You can get Nissan 4.0 ltr V6 coil packs like these 05-09 NISSAN Frontier 4.0L V6 IGNITION COIL | eBay

and you can see the price. I replaced the coil packs on my V6 Commodore before I sold it and they only cost $190.00 for a set of 3, (1 bank). I'm not sure about the Nissan, but the Holden was a 15 min job to do, very easy.

 

[murf6]

Thanks for that ray, I knew that Nissan would well and truly trump up the cost of replacement. Has anyone else had this problem or am I the only unlucky one........??????

 

[Dave]

How'd you go ?

 

[murf6]

No luck for repair yet. Everyone seems to be guessing at what the problem is. I dont want to go spending a fortune replacing coil packs if that isnt even the problem. Very frustrating chasing these kind of issues........

 

[Dave]

Look to the US, VQ40's are the only engine they get in the D40's and R51 Pathfinders.

VQ35DE coils should work to.

VQ35DD not so sure.

 

[Old.Tony]

The misfire could be caused by the leads too, not just the coils. It could also be a connection on the coils. Coils generally are fairly hardy things - there's not a lot that can go wrong with them.

It could also be the crank sensor, it could be loose or it could have some debris on it.

Nissan techs just follow their recipe book. Step 1 is to hook up the Consult device and read the error codes. Step 2 is to look that up in the manual and go through the steps one by one.

It's a good way to deal with problems - 99% of problems are resolved quickly this way. The problem is that the remaining 1% don't follow the recipe.

 

[od_40]

^^ Check the crank angle sensor. It's a common thing on the vq35de, not too sure about the vq40de though.

It happened on my missus 350z and they ended up having to replace both of them. It sounds like the same problem you have. The check engine light would come on and the car would stall while driving (auto).

 

[Krankin]

The coils can be tested.

use a decent multimeter and check the winding resistances on all the coilpacks, they should all be very similar and with no open circuits,
also,
1 by 1, pull a coil off the plug but with the primary winding cables connected (wiring loom), plug another spark plug into that coilpack, sit it down on the engine so the plug is grounded and turn the engine over and you can see if it is sparking...should be a nice fat blue spark....
see how ya go.

 

[ONLOCK]

Multimeters.dont put out enough voltage to break down the insulation if there is a problem, so that wont work, you might have to wait untill it starts breaking down again and when it does unplug the loom from the coil packs one at a time, take covers off and leave them off if you need to, also have you tried replacing your plugs, you.could test the loom for the coil packs for any extra resistance as iv seen that as a problem before too, good luck and let us know how you go

 

[Krankin]

Whats insulation breakdown got to do with windings that may be open circuited????

 

[od_40]

Because insulation breakdown puts 500 or 1000v into the circuit to see if there is a short in the circuit.

 

[Krankin]

Because insulation breakdown puts 500 or 1000v into the circuit to see if there is a short in the circuit.

you two are still talking about another test totally diferent to my original post?????

using a MM to test if the primary or secondary windings are open or closed (BASIC ELECTRICAL CIRCUIT TEST)
is not the same test as injecting 1000Vdc to see if the insulation is broken down/leaking..

Two different tests..


and, if there was a 'short' in the circuit the MM would show it,
what it wont show is if High Voltage is leaking through the insulation if it is compromised.

and 'short circuit' is not an 'open circuit'

 

[ONLOCK]

If it was an open circuit it wouldnt be coming and going, hence why a normal mm wouldnt pick up the fault

 

[Aussie Frontier]

True onlock but what Krankin is talking about it measuring the resistance of the coils low and high side and comparing that to other packs. If the resistance is close then it wont be a problem with windings.
If its coming and going its more like something else as windings usually wont work/not work as such and if its insulation breaking down it just does it doesnt come and go.It could however be the connector onto the coil heating up from a bad connection and opening and closing the circuit as it heats and cools.
I would try to get some dyno time and see if you can replicate the error and do some measuring

 

[Krankin]

If it was an open circuit it wouldnt be coming and going, hence why a normal mm wouldnt pick up the fault

If the MM found an open circuit on the high tension side, which it can, as when checking high tension leads to check if their resistance is within spec...usually 'tween 10Kohm and 30k ohms, this is performed with a MM as we are not checking for "insulation leakage",
moreover I have had a late model vehicle with intermitant misfiring and after many a fustrating checks, this and that I found it to have had an open circuit on the high tension lead, where the carbon core conductor had a gap of around 5mm at the time of finding it, now what was happening was the plug was still firing some of the time due to the high output voltage on the secondary side of the high energy ignition coil "jumping the gap" and onto the plug but not at every ignition pulse hence the intermitant misfiring.

 

[Aussie Frontier]

Only problem with our coils is we have no high tension leads as such. The coil bolts direct over the top of the plug so no way to test anything really when its mounted

 

[Krankin]

Only problem with our coils is we have no high tension leads as such. The coil bolts direct over the top of the plug so no way to test anything really when its mounted

yes i realise that, but it still has a high tension component, if only a couple of inches long
you can test it when it is removed.

 

[Aussie Frontier]

Yuppers still a pain in the butt although nothing says you cant leave the plug in the head and put another plug in the pack and run up the engine for a second to see how fat the spark is

 

[Krankin]

t although nothing says you cant leave the plug in the head and put another plug in the pack and run up the engine for a second to see how fat the spark is

just what i suggested in my first post...and try with a hot engine tho