BOSCH Spark Plugs do not go with Q45's

[Jeff Williams]

In case any one cares, Dennis is right.

I have been fretting about my injectors, and plenum for over a week, now. It's a good thing I bought a new set of NGK's last month, for my next scheduled plug change.

I bought Bosch Platinum +4's for my car, when I first got it and installed them. I bought BOSCH, because I have been using their products for over 20 years, and have had no problems, until now.

Dennis warned me about the Bosch plugs, but I honestly thought that he was just giving me the "pat Nissan mechanic answer" about factory products. It turns out I was wrong, and he was (and is) right.

I took the car out for a spin, after I replaced the plugs, and I do mean "spin" when I talk about the rear wheels, off the line, now. WOW, the car runs like a dream. I had to smoke an IS300, that was getting on my nerves, while I was out.:ylsuper

I was real careful, to blow out the plug hole, and clean the coil pack, before inserting the new plugs (NGK).

Take a look at this - Bosch Platinum +4, after 59,000 miles:

[AZhitman]

Lesson learned.

Boy, those look like the Champion plug from my weedwacker after seven Phoenix summers.

[crubio]

Is that right...

quite cool

crubio

[maxnix]

Is the third plug down missing some electrodes?

[sijoko]

I am on my second set of Bosch Platinum +4. I took the first set out at around 40k. There were no problems. Looked brand new.

One thing that I have done is install an adjustable fuel pressure regulator. I advanced the timing as well as run the car with a richer mixture.

When I see broken electrodes, I wonder if the car was running hot or lean.

-sijoko

[Jeff Williams]

I am not a spark plug expert, by no means. The 7 good plugs are all nice and white, with a little carbon on the tips. No real cause for alarm. I did idle the car for a few minutes, to get it in the garage (my main repair, was the front rotors), so the color may be a bit skewed.

I scheduled a Consult hook-up for Wednesday, at Brewbaker Infiniti, so I decided to pull the plugs, to see if it was the #5 injector, and to see if that cylinder was running lean. I wanted the servcie tech to be able to see the plugs, without the extra 2 hours of labor on my bill (I'm a cheapskate).

When I pulled the coil pack, and saw all the carbon, I was sure #5 was the culprit. Not sure if the injector ruined the plug, I checked the injector, and it ohmed out fine. The recent rail flush, makes me think that it would not be clogged. The top of the plug is completely gone. I think the culprit is those stupid screw-on tips. The BOSCH plugs have hollpw points. The Infiniti coil pacs, use a spring for contact. The contact was not good, causing the arching at the tip of the plug, and created heat, which deteriorated the plug, and possibly lead to the erosion of the electrodes.

I was still concerned about the injector, until I test-ran the car.

I could have not tightened the plug tip, or theremight have been some trash in the wire, who kows.

I will be sending the plugs to BOSCH, to have them evaluated.

[Q45tech]

""pat Nissan mechanic answer" " How insulting!

As most members know I am about as far from a mechanic as you could get! I am an electronic engineer who dabbles in automotive technology. Don't even own a tool box other than a few small suitcase like transportables. But if it is electronic and expensive or the more exotic and esoteric I probably have it.

Believe me no business in their right mind would eat $500 worth of spark plugs and relegate them to the junk pile if there was not a problem/reason............come on by and I'll GIVE you 8 New Bosch +4 free of charge [no shipments].......I don't want records in case your engine fails.

[Jeff Williams]

Boy, is my face red. I know I hate it when some one calls me a technician, or worse yet, a salesman.

Although, if you had "Engineer" listed in your occupation, I might have called your advice a "pat Nissan engineer answer".

I doubt it would have made you feel any better, though.

Always glad to hear from you, on my questions and problems.

Keep up the good advice, and I promise I will start taking it, sooner or later.

I just hope I don't screw up my car, in the mean time.

:icesangel

[Q45tech]

"I wonder if the car was running hot or lean. "

ALWAYS, the Q engine runs lean at idle , slow acceleration, and cruise to minimize emissions......hot is normal for any used engine/radiator............why would we be replacing so many Knock Senors from cracking.

Thank goodness it's almost Fall everywhere, most will make another 9 months.

There is a lot more to ignition system maintenance than just slapping in a new set of generic plugs, unfortuntely a rushed technican doesn't have time for more.........unless you subsidize his time.

Every plug change [120k, 180k, 240k] should include compression/leakdown testing and accurate timing checks to monitor the chain stretch and VISUAL INSPECTION of plugs, coils and extensions, contacts and harnesses.

[Q451990]

So did this solve your miss Jeff? It would be great if you don't have to replace that injector (and those four electrodes didn't damaged your cylinder walls)! If the bad plug damaged your coil pack boot, remember the boots are replaceable separately for just a few dollars.

Heath

[Jeff Williams]

So far. so good. The boot had a lot of carbon on it, and the spring was intact. I cleaned it up, and it looked good. the coil ohmed out the same as the others, so I stuck it back on.

I have 90 miles on the car, so far, and no miss.

I think the electrodes were burned off, not borken off. The entire top of the plug was burned up, as well.

I did not do a compression test, which I should have done. The car seems to run fine. I will do a more thorough job, when Im working in the daylight.

Yes, it is great, that I don't have to replace the injector, or remove the plenum. I would much rather it be a scheduled event, rather than a hasty repair.

I had the timing checked last week, when I had it in for service. I instructed them to just find the problem, not to fix it. $$ are a little tight right now, and I didn't want to spend a lot of money on repair labor, if I could just loose a few extra hours of sleep. Pinching pennys is starting to be very common, around the house, lately.

[DAEDALUS]

Does that qualify as a "bad coil"? Do I get my sandwich now? The intermittent miss was a big clue.

[DAEDALUS]

Sorry, I was thinking of Kdkrone's problem. Same symptoms. I hesitate to blame the plugs for this...they might only be a by-product. Jeff I sent you an email.

[sijoko]

I read that if you have higher than normal cylinder temps, the Bosch +4 will cause pre-ignition. The extra electrodes can become heat sinks which will lead to detonation.

What could have caused one cylinder to run hot like that?

-sijoko

[AZhitman]

Siju - If you had been privy to the conversation I had with a Bosch plug ENGINEER here in Mesa, you'd be pulling those pieces of junk out before your next tank of fuel.

His precise words were: "Our +4 plugs are NOT to be used in the VH45DE. The combustion chamber of that engine is a VERY inhospitable place for a plug designed without internal *******(something over my head) and without the additional layer of ****** (also over my head)." He added that the means by which the electrodes are forged (or cast or whatever) makes them more susceptible to damage in an engine like the VH.

I can't imagine why someone with such advanced knowledge of automotive engineering, such as yourself, would take a chance on losing an electrode in a cylinder in such a wonderfully-built car, to save a few bucks on a plug that offers NO verifiable and replicatable additional benefit over the factory-spec NGK's.

[elwesso]

Its been said, but Ill say it again......

YOU DONT BUY CHEAP PARTS FOR SUCH A GREAT CAR.... NO MATTER HOW MUCH YOU BOUGHT IT FOR, ITS STILL A 50K LUXURY CAR AT HEART.........

[Jeff Williams]

Siju - a Bosch plug ENGINEER here in Mesa, ... His precise words were: "Our +4 plugs are NOT to be used in the VH45DE. The combustion chamber of that engine is a VERY inhospitable place for a plug designed without internal *******(something over my head) and without the additional layer of ****** (also over my head)." He added that the means by which the electrodes are forged (or cast or whatever) makes them more susceptible to damage in an engine like the VH.

I plant to return the plugs, to BOSCH, for testing and analysis. This little bit of information will be nice to quote, if I might?

[AZhitman]

Go right ahead.

If I could afford it, I'd put it on a billboard.

Wait - Dennis probably already thought of that.

[Q45tech]

Please please take me up on the free +4 plugs, things were slow today [Mondays usually are] and we need to do some engine swaps. We have 88 so 11 Q could be SELF serviced.

FREE PLUGS GET THEM WHILE THEIR HOT.....be brave do your own plug changes WITH FREE PLUGS.

Changed the 4 passenger NGK plugs today after 55,000 miles [37 months] and did another rail flush [only had 2 hours]. #2 spark plug well had oil [resealed only 55k ago]. With my mileage nothing lasts as long.

The 295k 1994 Q was in today for a belt change.......this is the current high mileage champ that is running WELL. We were joking about - could he sell it at 300k, who would buy. He is stuck with it.

[elwesso]

Was the 295k 94q owner as festidious about maintenance as you are???

[sijoko]

Hitman,

" I can't imagine why someone with such advanced knowledge of automotive engineering, such as yourself, "

I would never describe myself as an expert. I am only relating my experience. I am not in love with Robert Bosch nor do I own any shares in that company.

I am planning to take these plugs out soon anyway, since I am going down the forced induction road.

Based on the advice given by Q45tech and others, I would not recommend these plugs for a Q45.

-sijoko

[Q45tech]

He gets his oil/filter changed every 90 days [uses 10w/30 valvoline + MOA], all fluids except ac oil changed annually. that's all I can remember. He's a salesman and travels all over South, he has Michelin Pilots V4 on 225/60/15. Ac was totally replaced a few years ago, 2nd transmission, shocks, the usual stuff, master cylinder, valve cover reseals, engine mounts, transmission mounts, knock sensor, tension rods, upper links, new rad, new hood struts,..................how many times, I'm not sure.

Same diff, same rear subframe, same drive shaft, etc.

[elwesso]

So he didnt really do much other than what is required...... So theres still a change that mine might make it that far......

[AZhitman]

Hitman,

" I would never describe myself as an expert. I am only relating my experience.

No offense intended brotha - You know a hell of a lot more than I do, so in my eyes you're an expert...

[Jesda]

I think I'll hit 250k without a hitch. I might need a new transmission by then, but no biggie. Already overhauled my AC and the radiator upon examination by my mechanic, was in great shape. New water pump.. chain guides coming soon!