Iridium plugs in Q45

[ismael-robert]

Hey guys I put iridium plugs in my q45 a while back and I honestly don't remember how long after it was, but my idle is bad now. I've read that our cars require a certain plug, but on the ngk website it says there is an iridium substitute. So is it okay to use iridium substitutes in our cars or not? I have tried cleaning the throttle body and maf sensor, replaced air filter and fuel filter and one other cheap little part (I can't think of the name right now) and several types of fuel injector cleaner.

[TXCumtrensh]

I dont see why iridiums would be bad

As long as you stay away from Bosch, and stay with NGK's.. you will be fine.. Id just go to the dealer for plugs

[maxnix]

I dont see why iridiums would be bad

As long as you stay away from Bosch, and stay with NGK's.. you will be fine.. Id just go to the dealer for plugs

Because only the NGK PFRG Laser Cut Platinums were designed for the engine. They are optimal, everything else is a degradation, many are dangerous.

[nimbyfaygo]

Because only the NGK PFRG Laser Cut Platinums were designed for the engine. They are optimal, everything else is a degradation, many are dangerous.

Could you please elaborate as to why different brand plugs would be dangerous?The engines 10.xx compression ratio isn't very high. The timing isn't exotic, and the heads are a pretty normal hemispherical design with 4 valves.

[szh]

Could you please elaborate as to why different brand plugs would be dangerous?The engines 10.xx compression ratio isn't very high. The timing isn't exotic, and the heads are a pretty normal hemispherical design with 4 valves.

There are some horror stories here about less-than-optimal plugs breaking, falling in, and scoring the walls!

Safer to stick with the original design plugs for sure!!!

Z

[ScottJackson]

Bosch platinums are a no-no (and you like it, says Gunther). Ohm test your injectors. EDIT: I see you have a '94... ohm test them anyway as it's easy to do.

[lino]

I replaced my spark plugs with oem and that's what I've been doing with my other cars. I have read and heard from others reporting problems when they use other kinds of plugs. I have no evidence suggesting or supporting any claim, but I have no interest in trying something else, especially when I feel that the oem plugs work great. I don't think I'm going to gain significant power with an alternative. However, I aways was curious about the beru silverstone plugs. I've heard Japanese car owners say Bosch causes them problems and German car owners saying that NGK causes them problems. In my Mercedes, I change the plugs once a year with the oem copper plugs that cost approximately $2 each. It's easy and routine, no stories, no headaches.

[Rex]

Here's a link that shows actual failure of "other" plugshttp://forums.nicoclub.com/zerothread?id=35940

[maxnix]

the heads are a pretty normal hemispherical design with 4 valves.

Actually, they are a pent roof design.

You must think the "new" Chrysler "Hemi" is really a hemispherical design.

Anyone posting who thinks otherwise merely show their ignorance of previous posts. It really pays to read the archived posts here. If you don't, you miss a lot fo the detail.

[PopPop]

Hey guys I put iridium plugs in my q45 a while back and I honestly don't remember how long after it was, but my idle is bad now. I've read that our cars require a certain plug, but on the ngk website it says there is an iridium substitute. So is it okay to use iridium substitutes in our cars or not? I have tried cleaning the throttle body and maf sensor, replaced air filter and fuel filter and one other cheap little part (I can't think of the name right now) and several types of fuel injector cleaner.

Plugs are not your problem most likely injector issue. We go threw this same conversation about plugs and U will always get the same answers. Most will say stick to OEM NGK Platinum's and to stay away from BOSCH which is true. The plugs that U have in your car would most likely be the best replacement to the OEM plugs but were not avail. at the time the VH45DE was produced. I have ran the NGK Iridium Plugs with no problems for the last few years in 2 of my Q's and 4 others that I have worked on. Both are the same plug just that one has the Iridium tip and the other Platinum. Iridium is a harder material than Platnium and are suppose to be good for 100,000 miles under normal driving conditions with normal maintenance. Look somewhere else for your engine problem because it's not your plugs.Some people damage their coil packs or their coil harness during R&R of the plugs and this will cause a mis-fire and then they are quick to blame the plugs! Also always check your gap because they can be dropped and gap will be wrong even though they are said to be pre-gaped.

[elwesso]

Honestly i have no issues with the iridium plugs, but theyre not really cheaper so why change whats known to work... Its not like youll get more power out of a differnet spark plug, but you can certainly make things worse by using the wrong one!

[Falkdesigns]

I run the NGK Iridium IX plugs and am very happy with them. Felt slightly peppier off the line than the standard NGK's that came out (and looked new), gas mileage is about the same. Like Wes said, there's not much price difference, but according to NGK it's the most advanced, and best plug they've ever made, so that's good enough for me.

[elwesso]

Were the ones you put in the same heat range as the OEM?

[Falkdesigns]

It's been a few years now, but I'm pretty sure they were the same range. It doesn't say on NGK.com but it's this part, BKR5EIX-11.

[Rex]

It's been a few years now, but I'm pretty sure they were the same range. It doesn't say on NGK.com but it's this part, BKR5EIX-11.

Pretty sure those are heat range "5", which IIRC is what stock should have been ... though not sure on CA emissions cars

[PopPop]

Were the ones you put in the same heat range as the OEM?

If I remember correctly they have the exact same as OEM and lower and higher also avail. depending on your application need!The only difference is the tip is made of Iridium. Variety is a good thing because everyone can't benefit from the same identical plug when living in different environments. Plus all VH45DE were created equal from the factory but, if U put 3 different engines on the DYNO U will get 3 different Dyno readings 15 years later. With this in mind an engine that has 40,000 miles will be able to get away with a factory plug where a engine with over 200,000 miles and leaking valve cover seals require a different heat range to prevent fouling. NGK makes R5, R6,R7,R8,R9,R10,and R11's. Variety is the spice of life!

[silkysmoothyjud]

A misfire that is intermittent can be caused by an open injector, but if you foul a plug due to an open injector, better change that plug too. My last injector failure gas fouled the plug so badly, it felt like my brand new injector was bad; I pulled the plug literally dripping wet and replaced it. I went ahead and did iridium replacements. I can hear the belts whisper, but I cant feel a thing!

[maxnix]

Like the NGK Platinum plugs, there are two grades of NGK Iridium plugs.

If you think you will benefit over the OEM recommended Laser Platinum PFR series, use the Laser Iridium IFR series, not the cheapy BKR series.

[bullittandy]

I think it is important to note that the only plug that is reported to cause problems is the Bosch design and specifically the +4 design.

It would not be accurate to say "nothing but the OEM platinum" but it would be accurate to say "No Bosch".

This distinction is important for new people who need accurate info to make an informed decision not hysteria.

[jimbyjimb]

Let's also throw out Champion since they go from new to fouled in ten minutes. I'd personally be just fine with an Autolite, never seen anything from NGK outlast Autolite. I still run the factory plug since it's the same price as the Autolite platinum.

[silkysmoothyjud]

I am tearing up anything that wants to race on the highway with iridium XI. Totally smooth when cold, then slight misfire when warm: No cel was the sign of plug fouling in my case. Even after the bad injector was changed, it still did that till I switched out the plug. I thought I changed out all of the cream colored injectors with purple, but I had one cream one left!

[Infinitiguy19]

So the plugs caused the slight miss?

[qsiguy]

I've been running the NGK Iridiums since I installed the turbo. I got one stage cooler than OEM to battle detonation under boost. I have no issues with them. Car runs smooth, no missing I can detect when cold or warm. I can't compare to anything except the plugs that were it in when I purchased the car years ago. This is the first set I've ever put in it. The old ones were fine, I just changed them when I did the turbo.

[silkysmoothyjud]

The failing open injector caused the plug to foul, but after the injector was replaced, the plug was too foul to recover. My dad told me to just let it dry out, but I just changed it. The slight misfire caused huge performance issues, jerky transmission shifts throughout all gears, knock sensor timing retardation (just like an injector failure).

[chipahoy]

I bought my 1999 Infiniti Q45t new from Orlando Infiniti in November 1999. The car now has 237k on it. The first plug change was about 60k. I have never used anything but NGK BKR5EIX-11 IRIDIUM IX in the car. This is my fourth set of plugs in the car and still running strong. With the most recent plug change at 230k, I replaced the coils (thanks eBay - got all 8 delivered for <$100 - beats the hell out the the dealer price!). The springs in the tip had long ago lost their pressure and after 16 years of service it was time for a replace. I could tell when i installed the new coils I had to exert downward pressure to tighten the screws. I also replaced the MAF sensor (thanks again eBay, $26 delivered). The car runs like a scaled dog.

[94Q45Beast]

Has anyone tried the NGK G-Power Platinum Spark Plugs BKR-5E-GP?.....based on what i've read about them they look like a budget OEM plug.

[qship96]

Budget for a reason.....investigate what both contact surfaces are made of vs the laser platinum plug.

[Jttoka]

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

[qship96]

nonsense, pure coincidence or the act of fiddling with the various parts/wires temporarily "fixed" the issue.

[Jttoka]

I'll let you know, qship. But my fingers are crossed, and my little toe. So I'm hopeful.
Almost 200 miles so far, granted mostly freeway.
Still good.
Although I did forget to knock on wood. Lol