Iridium plugs in Q45

[OwnerCS]

I agree with qship that there could be some wiring breakdown that may be contributing to the issue.

Many years ago when I first bought my 91 Q I changed the plugs and installed Iridium. I noticed a slight improvement over the well worn OEM plugs that had been installed by a dealer some 55,000 miles earlier.

Soon afterward I had two injectors fail and my V8 became a V6. Now that was a miss that I could feel.
So I did a major refurbish on the Q and eventually replaced the Iridiums with OEM NGK double platinum. The car has been running great ever since. Now I have about 40,000 miles on the NGK double platinum plugs. I'm sure I will replace those plugs with another set of NGK double platinum plugs in about 15 to 20 thousand miles.

For my other 99 model Infiniti and Nissan cars with a VQ30DE, I use NGK copper V-Power plugs. I get them for less than $2 each. I have already changed one set at approximately 22,000 miles. I don't mind the more frequent change on that engine because I like to check on on how the plugs are burning on at that mileage point. Spark plug tube oil leaks are common and you need to keep an eye on the plugs for those older engines. The VQ30DEs seem to really like the NGK V-Powers. I think it has to do more with the fact the coils are older and becoming a bit weak. The copper plugs seems to work well in that situation. Also, the VQ30DE is known to pitch a fit if you aren't using OEM coils. I try to keep spare OEM coils that I've picked up at junk yards on hand for those engines.

[Jttoka]

Edit update.

*DID NOT FIX PROBLEM!!! ONLY DECREASED JERKING.

Well,
I can relate. I have just finish with this issue.

First let me start with I have 8 New coils OEM. 8 old coils.
The Ohm test.
New ones 1.4 ohm
Old varied 1.30-1.38

Now I also had a slight miss at idle, and hasitation.

I ran BG, Lucas, Seafoam.
I put it in the gas tank, and into to vacuum line of the brake booster.
While the products were in the car, she ran great. once they were gone, she was back to missing.

So i decided to do a test.

I removed the iridium spark plugs and installed OEM spark plugs
She ran better, Still a slight miss, when sitting at a light, or idling in or out of gear.

So I changed the OEM with Autolite copper. she ran even better. The miss was gone.

I then, wanted to know if the old coils would respond the same way as the new ones.
So i swapped out the new coils with the old coils. But kept the copper plugs.

And lo and behold,
The miss was still gone.

So in ending, anyone that has a miss/ jerking idle.
Try the copper plugs. Yes, i know ill have to change them more often, but im alright with that.

Cheers[/quote]

[Jttoka]

Sadly, qship was correct.
New full tank, zero additive.
And 75 miles into the trip, first off ramp.
Slight miss while waiting at Red light.
Then stumbles when accelerating from green light.

Scan tool, has now been ordered.
Will keep you posted.

Cheers

[OwnerCS]

Does your Y33 have a Nissan consult port like the one in the picture behind the fuse panel door?

[Jttoka]

No.
Mine is white and under the steering wheel, obd2 connecter.

[Jttoka]

Yes, I forgot the basic. To do list. Yes, I am slapping myself around.
I found a vacuum hose that was burnt in half going to the EGR.
Replaced hose, still missing at idle.
So now I will do the smoke test while the car is at operating temperature.
I don't have a fog machine so I made one.
Home depot shop vac, with ping pong balls for smoke. It works, not great. But it works. http://i1381.photobucket.com/albums/ah2 ... l45ryl.jpg

http://i1381.photobucket.com/albums/ah2 ... vpruvu.jpg

[Jttoka]

Yes, I forgot the basic. To do list. Yes, I am slapping myself around.
I found a vacuum hose that was burnt in half going to the EGR.
Replaced hose, still missing at idle.
So now I will do the smoke test while the car is at operating temperature.
I don't have a fog machine so I made one.
Home depot shop vac, with ping pong balls for smoke. It works, not great. But it works.

[3Q Jay]

Sadly, qship was correct.
New full tank, zero additive.
And 75 miles into the trip, first off ramp.
Slight miss while waiting at Red light.
Then stumbles when accelerating from green light.

Scan tool, has now been ordered.
Will keep you posted.

Cheers

Did you ever put back the new coils? I ask because the after highway cruisin waiting at light initial take off stumble was EXACTLY the symptom on my outrageously maintained 97. the fix was indeed to replace all the coils with OEM new (22448-3H000). Check the p/n of the old and the new.
i have not yet heard of a consult like interface for OBD-II, but they might exist. on the '97 i was fortunate enough to have BOTH an OBD-i port as was pictured as well as an OBD-ii. of course obd-2 is far superior, but if you can't access the detailed ecu parameters......just a scan tool won't let you see the MAF, TPS, fuel trim, etc.

[3Q Jay]

oh and your busted hose is for the BPT. i had the same issue--one of the few instances where i simply replaced with hardware store grade generic. it would not cause idle issues though.

[Jttoka]

I returned the new ones. Now waiting for 8 new replacements. (22448-3H000)
without being able to get a code.

I just cant seem to wrap my head around the fact it runs so well whenever it has a fuel additive. whether in the tank or the intake. also runs great when its just started.
If indeed it is the coil paks, then it should have ran well with the new ones. Coils have to work harder in lean conditions,
the only thing i can think of is that the additive raises the octane level enough to compensate for the lack of spark energy.

in the morning i drive 1 mile, park, 5 minutes it sits. i jump back in it runs like crap(stumbling /surging) lack of acceleration till about 2k-3k rpm. drive back home. It sits a couple hours. starts drives great for miles on the freeway, then as soon as i get off the freeway. Back to crappy.
so...is it running rich (fuel injector leaking) thus runs bad till the excess fuel is burned off. or is it running lean.

If i get a chance today i will be installing a fuel pressure gauge.
i will also be making a coil pak/ misfire tester. Using spark plug wires and a timing light.

The OBD2 scanner ive ordered is BAFX Products 34t5 Bluetooth OBDII Scan Tool

On aside note.
If the coolant temp. sensor is disconnected will it run in limp mode or ?
I want to disconnect it and see if the drivablity improves with the ECU not being able to detect the coolant temp.

Thanks for all the assistance and help, Cheers

[3Q Jay]

i never got a true code either.
i beat on it pretty hard when misfiring, and eventually got a pending P304, but replacing coil pak #4 by itself didn't cure it. I had to replace them all.

[3Q Jay]

some have wired a fixed resistor into the ECU harness bypassing the sensor that is in the Y-pipe. They seemed to choose a value that would always tell the ECU it was running at ~175F so no timing would be pulled when the true water temp got above 194.

[OwnerCS]

On the OBD-ii vs. OBD-i topic, I have a 99 I30 and a 99 Maxima (yea double trouble) that came with both type of plugs. However, the OBD-ii only provides basic information and allows for CEL codes to be reset. I can only use NDS1 when I work with the SRS or want to do any serious diagnostics on that.

I have used NDS2 with the OBD-ii port on a 2000 Maxima. It works. It can also reset NATS which can save an expensive dealer charge in the event keys need to be re-synced with the ECU.

To get NDS2 to work on a 2000 Maxima, I had to use a Volkswagen Audi Group (VAG) USB cable from the OBD-ii plug to a Windows 7 or earlier computer where I was running NDS2.

[OwnerCS]

Ohhhh --- WAIT A MINUTE. I'm about to FORGET about what happens when Phase II injector get old.

The o-rings and pintle caps deteriorate. Then the injectors start passing too much fuel -- thus causing a random misfire on the cylinder with the leaking injector.

A couple of years ago, I had two injectors with broken pintle caps and leaking o-rings on my 99 model Maxima cost me a bunch of money on failed dealer diagnostics. The dealer couldn't figure out the misfire and hard to start issue. We first thought it was failing ignition coils. Eventually, the catalytic converters were destroyed from receiving too much fuel over a period of time from the leaking injectors. It was an expensive mess that I ended up having to fix in my own garage. The dealer said I needed a new engine for $4,800. The engine had approximately 73,000 miles on it so I called it BS and had the car towed to my home where I found and fixed the problem.

Here's a picture of the Phase II injectors that were causing the misfires below. I know other 99 model owners who have had to get their injectors serviced to replace screens, o-rings, and pintle caps. I actually reburbished my own injectors using a kit I purchased on eBay. The kit worked and the car is still running great two years later.

For whatever reason, the injector leak problem has appeared the most on 99 models. I don't know if the financial woes Nissan was experiencing in that time period caused the supplier to use a lower cost material on the injectors or what happened. But 99 models seem to see this issue more than earlier Phase II injector years.

Many of here with 1st gen Q45's replaced the original Phase I injectors years ago, so the replacements haven't been around long enough to deteriorate from age.

This is just a thought and I can see how we may start to see leaking injectors occur more frequently as our cars age. Once the weather gets better, I'm planning to refurbish the injectors on my 99 model I30 as preventative maintenance. It's just a matter of time before those will start to leak.



Here's a picture of the kit I purchased from eBay to refurbish the 99 model VQ30DE injectors. I think I paid $34 for the kit. There is a kit for 8 cylinders as well.

[maxnix]

As I recall, Autolite and Champions were specific brands known to to break electrodes in VH45DE and crater the engines.

It is in the old posts, so check it out or don't redline it for now.

[Jttoka]

I yanked the autolite plugs out. running NGK again. Thank you for the heads up on the plugs.