2000 Q45 intermittant misfiring...Help!!!

A Q45 forum / Cima forum for the President of Infiniti's lineup. Brought to you by Infiniti Parts USA, your OEM source for Q45 parts!
kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

Really, I have searched and I haven't found these exact circumstances, so any guidancewill be appreciated.

I bought this Q in April after a long and happy relationship with a '95.

When I first went to look at it, the owner had it at a mechanic getting new belts, hoses and spark plugs.

From April to about three weeks ago, it drove and ran flawlessly.

Then it began to misfire intermittantly.Some days smooth as glass, other days the misfire would show up immediately upon startingMost easily replicated at idle in drive or reverse (with foot on brake).

I took to a local indie mechanic who diagnosed and replace the coil on the #3 cylinder.

Ran fine for one day.

Then the misfire was back (#3 cylinder again).Mechanic decides the coil was fine, puts my old one back on and looks closer at the plug being the cuprit (even though only four months old).

Upon removing the plug, mechanic advised that the plug was bad and the previous mechanichad installed AC delcos.

All 8 plugs were removed and replaced with NGK PFR5G-11's.

Car runs perfectly for 8 days.

Then, it's baa-aaack.

After many errands and stops between two hours and some as short as 10 minutes,I'm sitting at a red light and misfire.......misfire.

Doesn't misfire the next 3 miles driving home.

I park it for three hours and then start it up and consistantly it misfires at idlein drive and reverse.

I take it back to the mechanic and now he can't replicate.

FYI the previous mechanic (the one that put in the AC delco plugs) replacedthe "left rear O2" and the "right rear knock sensor" on 1/26/08.

I would like to believe that I did not make the mistake of the decade by buying this Q and selling my '95.

Any guidance I can give to this new mechanic is hugely appreciated.

FYI I'm in San Diego and used to have Jerry Tucker do my Q work.

He sold the business and my experience with the new owners have notbeen compelling.



Qproject
Posts: 401
Joined: Tue Oct 10, 2006 10:11 am

Post

there are three or four sensors on top of the engine, take of the engine plastic cover and you'll see those sensor connections. Disconnect those sensors and clean it out with dry Q tips. Clean all of them

Hopefully this helps.

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

Would like to hear your expand your comment on Jerry Tucker's new ownership.

By misfire, do you mean miss or stumble? Not a backfire or predetonation, I presume?

Switching coil pack locations is the best way to determine if it is truly the coilpack or the plug and/or the injector. It is a real good thing you changed the plugs to the correct ones. Other plugs have been known to destry VH series engines when their electrodes separate from the plugs.

You don't mention much about fuel system maintenance nor the intake path.

Rear KS? Both and the harness should be replaced, and there is only Left and Right.

Please complete your profile when you have time.

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

I will look for or show your post to the mechanic and he can look for the sensorsto clean them (although that sounds like something even I could do.

Thanks.

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

RE: Jerry Tucker.

He worked on my 95 Q for the five years I owned it.

The person that bought the business was an employee of Jerry's.

It's probably more me than the new owner.It has always been a pain to take it there as they are 20 miles from my house.Mainly I needed something closer to home since they have no loaners or shuttles.I don't really want to bad mouth anyone, so I'll just leave it at that.

If this indie mecahnic doesn't work out, I'll probably go to the dealer; but I seriously don't have money to burn and would like to avoid that if possible.

It's a misfire as far as me, my neighbor and the mechanic that has it right now can tell.

He called it a misfire. Beyond telling you that he hooked up a scanner(?) the thing that told him both times that it was the #3 cylinder, that's all I know.

When I think of a backfire, I think loud bang; (is that wrong?).No loud bangs, just a quiet "chug" and a gentle sensation in the cabin (in drive stopped at idle)

BTW the "check engine" light has not ever come on and according to John (the mechanic)it's not giving him any codes.

The fuel. Well, sadly I don't know the maint history on the fuel system.The previous owner told me that she used only premium as do I.

Exxon, Chevron and sometimes 7/11.

Actually, this first started after a tank of Exxon. When it did I put prestone fuel injectorcleaner (only 1/2 bottle) and a tank or so of Chevron in it since.

I'm thinkin' I might oughta stick with Chevron from now on.

If the fuel injector is having issues, would that show up on the mechanic's scanner?(go ahead and laugh at my stupid question I don't mind....)


maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

Only cylinder misfires will throw a code. If no other issues with JT, 20 miles is not far for expertise, but you're correct in assuming diagnosing your problem may take more time than you want to wait.

Download an FSM so you can understand teh OBD II codes the analyzer sends records. I presume he reset the ECU?

http://www.nicoclub.com/FSM/Q45/

If you haven't changed them in the last 9 months, order fuel, cabin and airfilters from Joe and his crew at IoS.

http://www.infinitipartsusa.com

I also prefer the M1 oil filter he has at a great price (don't forget the crush washers).

Tier 1 Premium only. No 7-11. Try some Iso Heet (not Heet) in a couple of tanks to see if you might have water. If your gasoline has ethanol, I would run it every other tank or so.

I think you have to address the IAC, PCV (2x) and EGR valves and the TB. YOu will need gaskets for all of these to remove, clean and replace.

My own experience is that after I diagnosed a faulty coilpack and replaced it, I very infrequently had a little faint hiccup at idle in drive with AC that would not throw a code. When I replaced my valve cover gaskets I removed the plenum and cleaned it and the lower runners to as new as well as the IAC and EGR valves, TB and the EGR tube inside the plenum. Although I had done all but the lower runners just 20K previouslly, the plenum was filthy again. So far, in intense heat this summer, not one slightest hint of any misfire so far.

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

Brian; thanks for the info (a little overwhelming for a non gear head like myself, but still really helpful).

Thanks also for the link to the FSM.For some reason, AT, BR and BT won't open.

Fortunately, EC opened quite nicely (what an awesome resource).

I Printed out EC-4 which shows the codes for cylinder misfires and pages EC-260 thru 264 which walk a tech thru diagnosing a misfire.

I'm gonna bring those pages to the mechanic and also give him the link to the whole FSM.

You'd probably mess your pants if you knew how much I paid for the NGK's.This is not the kind of mechanic where you can bring your own parts; they want theirmarkup; don't know what their wholesale price was but I found those plugs onlinefor $11.37 each; I paid them $28.00 each (ouch) but that's what happens when you don't do this sort of thing yourself (see how fortunate you are???).

In any case, if he can't replicate the problem by late afternoon today, I'm just gonna pick the car up and wait for it to happen again; maybe make a deal with him that when it does, I'll bring it to him right then and there and he'll drop what he's doing and connect the consult or scanner or whatever he's using. Hopefully after not fixing the problem three times he won't feel like that's an unreasonable request.

Thanks again,

Kevin


maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

Go luck!

I think $28 per plug is too high for even San Diego.

If not Jerry, then you must find some place else. Try Z specialty shops and see if their technicians ahve any experience with the VH series.

Qproject
Posts: 401
Joined: Tue Oct 10, 2006 10:11 am

Post

yo foo, try disconnecting those sensors, cleaning them out with q tips and reconnect them.

this problem has occurred over and over, the dealers don't have a clue.
kevinis wrote:Brian; thanks for the info (a little overwhelming for a non gear head like myself, but still really helpful).

Thanks also for the link to the FSM.For some reason, AT, BR and BT won't open.

Fortunately, EC opened quite nicely (what an awesome resource).

I Printed out EC-4 which shows the codes for cylinder misfires and pages EC-260 thru 264 which walk a tech thru diagnosing a misfire.

I'm gonna bring those pages to the mechanic and also give him the link to the whole FSM.

You'd probably mess your pants if you knew how much I paid for the NGK's.This is not the kind of mechanic where you can bring your own parts; they want theirmarkup; don't know what their wholesale price was but I found those plugs onlinefor $11.37 each; I paid them $28.00 each (ouch) but that's what happens when you don't do this sort of thing yourself (see how fortunate you are???).

In any case, if he can't replicate the problem by late afternoon today, I'm just gonna pick the car up and wait for it to happen again; maybe make a deal with him that when it does, I'll bring it to him right then and there and he'll drop what he's doing and connect the consult or scanner or whatever he's using. Hopefully after not fixing the problem three times he won't feel like that's an unreasonable request.

Thanks again,

Kevin

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

Okay, Okay.... I'm picking up the car in a few minutes as they were unable to replicate the problem and in the cool of the morning tomorrow I shall go a huntin' for dirty sensors.

Is there a specific picture or page in the FSM that would show me exactly what I'm looking for?

Thanks,

Kevin

Q45tech
Moderator
Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

Post

New members must be very careful and become educated before blindly following every posters vague theories.Unfortunately the same thing happens with some dealer technicans and independent shops.

On 97 and newer Cima [Q] 9 out of 10 times the coils are the problem due to a design change and integrating the ignitors [transistors] inside the coil housing.

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

Q45tech wrote:On 97 and newer Cima [Q] 9 out of 10 times the coils are the problem due to a design change and integrating the ignitors [transistors] inside the coil housing.
On my failed coil, the translucent window looked a little darker. Difficult to explain, but compare your suspect one to a couple of good ones and see if you notice any difference.

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

Well the coil...

That's the weird thing.

It was the first thing they changed.

The new one (at a cost of $158.00) only gave me no misfires for one day.

Before replacing the coil, the #3 cylinder was giving a code.

The next day with the new coil I had the same symptom feeling and hearing the "chug"what I would call a misfire.

Even though it was "misfiring" all over the place with the new coil, this time it was notgiving a code. That's when they put the old coil back on and installed the new plugs.

After that, ran perfect for 8 days, then the day I did all these crazy errands with varyingtimes with the engine off (from 10 minutes to 2 hours) it was after the last errandthat lasted about 30 minutes (meaning the car was parked and turned off for 30 minutes)that I turned on the A/C (not having it on previously) and after about a mile at a red light it started. Then again after being parked for 3 hours.

After two days with the mechanic it hasn't done it since in varying engine temps and driving conditions.

So I guess I wait til next time it happens, and the mechanic will have his Scope and Scanner that combined cost more than the car itself ready

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

If ignition and fuel system checks out as good, I think you will find the answer in the conditon of the intake path. And it probabably not just one thing.

Qproject
Posts: 401
Joined: Tue Oct 10, 2006 10:11 am

Post

kevinis it's easy, just remove the plastic engine cover and you'll see like 3 sensor connections. disconnect, clean out the dirt and reconnect.

maxnix and the other guy till this day, STILL DON'T HAVE THE DIAGNOSIS TO THIS.
kevinis wrote:Well the coil...

That's the weird thing.

It was the first thing they changed.

The new one (at a cost of $158.00) only gave me no misfires for one day.

Before replacing the coil, the #3 cylinder was giving a code.

The next day with the new coil I had the same symptom feeling and hearing the "chug"what I would call a misfire.

Even though it was "misfiring" all over the place with the new coil, this time it was notgiving a code. That's when they put the old coil back on and installed the new plugs.

After that, ran perfect for 8 days, then the day I did all these crazy errands with varyingtimes with the engine off (from 10 minutes to 2 hours) it was after the last errandthat lasted about 30 minutes (meaning the car was parked and turned off for 30 minutes)that I turned on the A/C (not having it on previously) and after about a mile at a red light it started. Then again after being parked for 3 hours.

After two days with the mechanic it hasn't done it since in varying engine temps and driving conditions.

So I guess I wait til next time it happens, and the mechanic will have his Scope and Scanner that combined cost more than the car itself ready

User avatar
bullittandy
Posts: 1415
Joined: Thu Jul 21, 2005 4:57 pm
Car: 2003 Q45, 70K miles, 1999 Q45 touring 180K miles, 1997 Q45 270K miles, (sold), 1997 Q45 186K miles (junk-sold)
Location: Atlanta
Contact:

Post

I'm a bit stumped on this one b/c its become clear that the coils are the problem on these cars but your bad #3 should have fixed it.

I still think "a" coil is the problem but if you can stand it-wait it out.

Another thing don't buy any more parts from your mechanic-$28 for a $11 plug and $158 for a $70 coil is nuts. Worst case scenario is to replace all 8 coils, $560 and be done with it.

Q45tech
Moderator
Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

Post

We are constantly finding POOR QUALITY aftermarket coil copies that are worse than oem and may fail the day of installation.

Unless you purchase from a dealer don't assume oem...............the copies look perfect and are designed for discount stores and ebay sellers.

Believe me we have tried to find a cheaper alternative but with no success so far.

After all 60-100k is good life considering the new design. Transistors operates at much higher temperature than old design...........same with dielectric [potting] compound.

Look at page 7 for life testing in hours:http://delphi.com/shared/pdf/p...s.pdf

The engineers KNOW these products have a limited life!!!!!!!!!!!!!!!!Even Delco is PROUD of a 50% failure at 5.5 years

User avatar
OnTheRoadAgain
Posts: 66
Joined: Fri Sep 28, 2007 1:30 pm
Car: 1991 Q45

Post

Quote »After many errands and stops between two hours and some as short as 10 minutes,I'm sitting at a red light and misfire.......misfire.

Doesn't misfire the next 3 miles driving home.

I park it for three hours and then start it up and consistantly it misfires at idlein drive and reverse.

I take it back to the mechanic and now he can't replicate.

[/quote]you probably need to take it to the tech, park it for whatever time you need, then ask him to come out and start it; it should be easy to replicate if you observe carefuly exactly the circumstances;

on the other hand: my 1991 owners manual says to "DEPRESS THE GAS PEDAL 1/2 way on hot restarts", so maybe you are having some sort of vapor lock, and maybe it is better or worse depending on the outside temp?;

Check your owner's manual, as I've never seen THAT recommendation on other (fuel injected) cars I've had.

I will tell you that Infinity of Scottsdale gives VERY GOOD PRICES online, even with shipping added. I think they are giving wholesale (dealer trade prices) to the public; Of course, ask your tech if they mind, as they probably want to make a profit on the parts, which they should; it is just that the dealers (ALL dealers) suggested retail prices are VERY high on many items.

Order some maintenance items in quantity to save shipping; I don't think an independent shop owner would mind you using OEM parts instead of aftermarket, as long as you don't expect him to GUARANTEE the parts or his labor for using YOUR parts.

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

Qproject wrote:kevinis it's easy, just remove the plastic engine cover and you'll see like 3 sensor connections. disconnect, clean out the dirt and reconnect.

maxnix and the other guy till this day, STILL DON'T HAVE THE DIAGNOSIS TO THIS.
Well, if there is dirt in the sensors (MAF & ???), that will be a problem.

Actually, I was able to diagnose mine and repair it with a new coilpack. However, gradually a very slight hiccup that wouldn't throw a code crept back in randomly, only on a hot day with AC on in gear at idle with brake applied. When I did the VC gaskets, completely cleaned plenum, lower runners, IAC adn EGR valves and inner EGR tube in the plenum. Not even a hint since then in 105° F heat. Runs like new.

qship96
Posts: 6624
Joined: Sun Nov 24, 2002 11:31 am
Car: 1996 Q45

Post

maxnix wrote:Well, if there is dirt in the sensors (MAF & ???), that will be a problem.

Actually, I was able to diagnose mine and repair it with a new coilpack. However, gradually a very slight hiccup that wouldn't throw a code crept back in randomly, only on a hot day with AC on in gear at idle with brake applied. When I did the VC gaskets, completely cleaned plenum, lower runners, IAC adn EGR valves and inner EGR tube in the plenum. Not even a hint since then in 105° F heat. Runs like new.
Brian, I have a feeling that idle hiccup you describe in your above quote is exactly what I have felt and finally determined it to be the idle momentarily dropping due to the aux. condenser fan starting up...its like a very short 150-200rpm drop in idle speed,then back to normal as the ecu/aac readjusts idle speed.....I cleaned MAF for the first time in 216,000 miles yesterday...it looked clean even before I gave it a shot of CRC MAF cleaner. Cleaned throttlebody for the first time in 101,000 miles, little dark residue drained out, not as much as I expected...maybe Byron cleaned it last fall when he did underplenum work?

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

My plenum was filthy even though I had cleaned it just 20K before. Just too close to the edge, I guess. Never any hesitation on acceleration, even with bad coilpack.
Modified by maxnix at 11:04 AM 8/10/2008

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

Wow; you guys are awesome (wish you were here to attack this).

Here's the latest as of 30 seconds ago....

Well lets start with this, as for in depth mechanical stuff I'm really a dolt; a buffoon if you will.So while changing the car battery is something I can do; the other stuff is probably more risk to the car than potential problem resolution.

I will say that when I first got the car, it was running hotter than my '95 ever did and I heardthe electric assist fans running driving around at low speeds. Odd, I thought.When I looked in the engine compartment, I noticed coolant sprayed around and so removed the shield (just above the radiator) and lo and behold, when the previous owners mechanic put in those AC delco plugs and replaced belts and hoses, they left the hose that connects to the neck of the radiator cap that goes to the coolant recovery bottle unconnected. So I found and fixed that (and added a gallon of coolant YIKES!!! yes it was that low).

Anyway, that's about as good as I get.BTY I haven't heard the aux (electric) cooling fans go on since).The car (engine temp) always runs slightly below 1/2 hot (not dead on half like my 95 did)

I did remove the plastic cover last night, q tips in hand, but without a picture of a "Sensor"didn't know what to clean (like I said, I'm a dolt). There are what I would call small wiring harness plug-ins. I was only able to unconnect one (the brown one), but again, I don't know if that was even a sensor (yes I did clean the inside of it).

Okay, so, on to 30 seconds ago; I started her up let it idle in park for about a minute or two. No chug.

Put in reverse, brake pedal applied...chugPut in drive, brake pedal applied...chug

Put in park (now idling higher) turned on A/C (my electric aux fans do not come on at this point) NO CHUG.

Get back in car, A/C still on, put in reverse, brake pedal applied...chug...chug.chug.....Same thing in drive.

So, low idle in gear and we get the chug, or hickup or possible misfire.

Same exact scenario last night after the car was not driven since Friday Afternoon.

So, it sorta sounds like what Brian experienced; perhaps not a true misfire any more(but it did initially throw a code before the new NGK's were installed). While I'm notsome computer, the end result still feels the same and sounds the same behind the wheel.

Throttle body... was supposedly cleaned in April by the previous owners mechanic (when they put in the AC delco plugs, new belts, hoses and left the coolant overflow hose unconnected).

I suspect the soonest I can get this back to the mechanic is Tuesday afternoon as he will likelywant to keep the car, and I will not be able to leave it with him before then.

I don't like the sounds of new valve cover gaskets etc; they've already quoted meat least $350.00 to do that (noticed the beginnings of a slight leak).

If those little "wire harness" things are "sensors" how do I unplug them without breaking anything. Is the little "wire harness" thing that goes into the shield right before theair cleaner the mass air flow sensor? should I try to q tip that????

Oh another thing, I mentioned I printed out the EC pages and brought them to the mechanic;he was like "I don't really need that, we have Mitchell, NAPA " and I think All Data was the third one. I had to convince him to take the pages (he did to humor me I think).

He did at least go thru the 11 "check" items on page EC-260 with me; I believe there were only two items on that list he had not felt satisfied were okay (magnetized signal plate) and I can't remember the other one.

So there you have it.Let me know your thoughts.

Thank you all...

Kevin


maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

Well, the sensor post was imprecise to say the least, so ignore it.

$350 for VC is good, but should have been performed wehn the plugs were replaced. Sounds like your IAC is covering for a low idle. If you were at an Infiniti specialist, I would have them inspect, clean and adjust your IAC valve.

Presume all filters are fresh? You might just consider deriving it until codes appear in a periodic scan, unless it hseitates on acceleration also.

Qproject
Posts: 401
Joined: Tue Oct 10, 2006 10:11 am

Post

u have to clean out-disconnect reconnect all sensor clips. not JUST ONE.

anyhow it's your car! do as u please.
kevinis wrote:Wow; you guys are awesome (wish you were here to attack this).

Here's the latest as of 30 seconds ago....

Well lets start with this, as for in depth mechanical stuff I'm really a dolt; a buffoon if you will.So while changing the car battery is something I can do; the other stuff is probably more risk to the car than potential problem resolution.

I will say that when I first got the car, it was running hotter than my '95 ever did and I heardthe electric assist fans running driving around at low speeds. Odd, I thought.When I looked in the engine compartment, I noticed coolant sprayed around and so removed the shield (just above the radiator) and lo and behold, when the previous owners mechanic put in those AC delco plugs and replaced belts and hoses, they left the hose that connects to the neck of the radiator cap that goes to the coolant recovery bottle unconnected. So I found and fixed that (and added a gallon of coolant YIKES!!! yes it was that low).

Anyway, that's about as good as I get.BTY I haven't heard the aux (electric) cooling fans go on since).The car (engine temp) always runs slightly below 1/2 hot (not dead on half like my 95 did)

I did remove the plastic cover last night, q tips in hand, but without a picture of a "Sensor"didn't know what to clean (like I said, I'm a dolt). There are what I would call small wiring harness plug-ins. I was only able to unconnect one (the brown one), but again, I don't know if that was even a sensor (yes I did clean the inside of it).

Okay, so, on to 30 seconds ago; I started her up let it idle in park for about a minute or two. No chug.

Put in reverse, brake pedal applied...chugPut in drive, brake pedal applied...chug

Put in park (now idling higher) turned on A/C (my electric aux fans do not come on at this point) NO CHUG.

Get back in car, A/C still on, put in reverse, brake pedal applied...chug...chug.chug.....Same thing in drive.

So, low idle in gear and we get the chug, or hickup or possible misfire.

Same exact scenario last night after the car was not driven since Friday Afternoon.

So, it sorta sounds like what Brian experienced; perhaps not a true misfire any more(but it did initially throw a code before the new NGK's were installed). While I'm notsome computer, the end result still feels the same and sounds the same behind the wheel.

Throttle body... was supposedly cleaned in April by the previous owners mechanic (when they put in the AC delco plugs, new belts, hoses and left the coolant overflow hose unconnected).

I suspect the soonest I can get this back to the mechanic is Tuesday afternoon as he will likelywant to keep the car, and I will not be able to leave it with him before then.

I don't like the sounds of new valve cover gaskets etc; they've already quoted meat least $350.00 to do that (noticed the beginnings of a slight leak).

If those little "wire harness" things are "sensors" how do I unplug them without breaking anything. Is the little "wire harness" thing that goes into the shield right before theair cleaner the mass air flow sensor? should I try to q tip that????

Oh another thing, I mentioned I printed out the EC pages and brought them to the mechanic;he was like "I don't really need that, we have Mitchell, NAPA " and I think All Data was the third one. I had to convince him to take the pages (he did to humor me I think).

He did at least go thru the 11 "check" items on page EC-260 with me; I believe there were only two items on that list he had not felt satisfied were okay (magnetized signal plate) and I can't remember the other one.

So there you have it.Let me know your thoughts.

Thank you all...

Kevin

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

Qproject wrote:u have to clean out-disconnect reconnect all sensor clips. not JUST ONE.
Might help if you define "sensor clip" and "u."

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

Okay, so here's the latest.

I've been driving the car with it's hickup, stumble, whatever terminology you want to use(except "misfire").

Today was the first time I had the time and was mentally in a place to deal with it again.

So I took it to the facility that first said it was a coil on the #3 cylinder (when there was a true misfire throwing a code). After putting on the coil, it did the same thing the next day (they removed the coil and put the old one back on).

Then they said spark plugs. At that time they installed the NGK's that are supposed to be in the car and no "stumble" for about a week.

TODAY...

Per the tech's instructions, after it "stumbled" several times this morning, I stopped inand left the car running.

He hooked up his expensive scanner and no codes.

He scrolled thru several screens and after revving the car in park noticed the right rear02 sensor was not doing it's job; stated that (and showed me on his screen) it was showingrunning "lean" at points when it should have been running rich.

Okay; third diagnosis and after an obscene markup on the sparkplugs (remember, $28.00 each) I did a little battle with the service writer stating that basically $450.00 later I havenice new proper sparkplugs but the problem I brought the car in for is still not fixed.

I quoted him $11.37 for those plugs (I think it was sparkplugs.com or net - can't remember) and stated that I'm not paying any more outrageous markups. I am not so stupid as to not understand that there needs to be markup at a business, but I am also not so stupid as to pay over 100% markup when the solution didn't fix the problem it was supposed to fix.

So, they have agreed to let me bring in an 02 sensor and will install it at no additional labor charges.

I'm going to order from "Joe" Infinitipartsusa and get some light bulbs and an oil filter toowhile I'm at it. I have not ordered from him/them before and I seem to remember a threadwhere he's not overly kind to newbies.

Do I need to have my ducks so in a row when I call him, having exact part numbers,or can I just say I need a right rear 02 sensor, a package of brake lamps and an oil filterfor a 2000 Q45t.

FYI, the right rear knock sensor and the left rear 02 sensor was replaced by the previousowners mechanic (that put in the AC delco plugs) in January of this year.

Any thoughts???

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

qship96 wrote:
Brian, I have a feeling that idle hiccup you describe in your above quote is exactly what I have felt and finally determined it to be the idle momentarily dropping due to the aux. condenser fan starting up...its like a very short 150-200rpm drop in idle speed,then back to normal as the ecu/aac readjusts idle speed.....
Not that much variance for me, maybe at most a 50 rpm drop, more like 25 rpm. But plenum was coated although EGR and IAC were fine from 20K mile previous cleaning. TB was coated. Of course, all the VH41DE have the integrated TCS throttly body immediately before the actual TB, so somewhat different from the 1996 VH45DE.
Modified by maxnix at 7:58 PM 8/27/2008

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

Post

I prefer the M1 filter from Joe for the VH41DE. He has a great price. Buy 6 and 6 crush washers.

O2 sensors best replaced in pairs to match the duty cycle side to side, but not as critical on secondary trim sensors.

I also recommend 3 or 4 airfilters, 2 cabin filters, at least 2 fuel filters.

Also the transmission kit (gasket, one time-use bolts, interior filter screen and O ring).

Various intake and EGR, TB, IAC and plenum gaskets to be truly prepared. Brake pads, tension rod bushings, and brake shim kits are good to have on hand.

Belts?

User avatar
SteveTheTech
Posts: 4505
Joined: Sat Aug 16, 2008 3:20 pm
Car: 15 Sentra SR
12 G37x Coupe
-Formerly-
05 Mazda 6 L3 Sport, 95 J30, 94 D22
Location: Chantilly, Va

Post

So after several shops it sounds like the plugs are not the issue. There are several sensors that when heated or cooled may break contact with each other. I know alot of the guys here recommend cleaning contacts, there are commercial products out there that are designed to remove corrosion and apply contact lubricant where applied and they work great. You need to careful not to damage any connectors as this will only make things worse.An Infiniti dealer should be able to help you with this, the price may be offset by the warranty they offer, and after having so many hands on it it may be reassuring to know what has been replaced with aftermarket parts. Qs do not take well to aftermarket parts and they have some electrical not found in cars of that year. They can be a challenging with some of these intermittent issues, but if you get a guy whose been there for a while he should know what to do.

You could very well have a coil issue, and a power balance test would show you if it is indeed number three. Since the coil has been replaced it may be the connector terminals. It may be an injector, it may be a widening gap in the drive gear on the cam position sensor. This is a very difficult issue to diagnose over the computer. If you can provide some engine data numbers I might be able to give you an idea but there are just too many possibilities at this point

kevinis
Posts: 29
Joined: Mon Nov 10, 2003 3:53 pm

Post

Steve, Brian...all...thanks.

I had a little shopping spree at infinitipartsusa.

I ordered many of the things you had suggested (Brian) but my main issue wasto get the 02 sensor (so I have a three pack of oil filters, a fuel filter, air filter, cabin filter andhopefully the correct bulbs for the brake lamps).

As I may have said, I just bought this car in April, paid cash and sold my 95Q at an insanelylow price (wish I coulda kept it but wiffey thinks 4 vehicles for two people is too much) all that to say that I don't have alot of cash laying around right now to carry a large parts inventory.

I was tempted to also get one coil too since that was his initial diagnosis, but decided to waitand hope the ten thousand dollar scanner as well as it's operator are correct on this nowthird diagnosis.

Can't really see how I could get any numbers (Steve) so will hope this does the trick.

If not, this "satisfaction guaranteed" "AAA approved" "BBB" blah, blah blah facility willnot be working on this car in the future.

Since I raised such a fuss about the markup on the plugs, and their previous two diagnosis have not resolved the problem, they are allowing me to bring in the 02 sensor and they will install it at no additional labor cost "we want you to be happy".

I am considering having them do an oil change (using one of my new filters).They have a fancy schmancy oil change for about 50 bucks which includes, I guess it's a treatment of some kind; MOC. It also includes some kind of warranty.

Heard of it? Worth it?

In the five years of Jerry Tucker servicing my 95Q, he never offered or mentionedMOC (though I did see it on invoices from the dealer that the previous owner gave me with the car when I bought it).

If they really wanted to make me happy, they'd do the oil change install the fuel filtertoo, but I suspect that's expecting too much. It might not seem like it, but if you knew how much time I've given them and how many days I've left the car with them (shuttle or not) I suspect you might agree this would be reasonable for you to "be happy".

If I gave the impression that this mechanic is a little hole in the wall, let me correct that.It's a pretty big place (high overhead) with several mechanics which do foreign / domesticwork; shuttle, free (with those $28.00 spark plugs) car wash with every service etc, but by nomeans an infiniti specialist.

The size of this place easily rivals a dealer (and is about six times bigger than Jerry Tuckers - which is now owned by a guy named Brian - funny coincidence Brian???).

Anyway, the same mechanic has worked on it since this problem began; so at least for this specific problem, the car has not been thru several sets of hands.

So there you have it; when I get the parts, I'll make an appointment to have the 02 sensorput in and give an update from there.

Your thoughts and ideas are much coveted.

Thanks

Kevin


Return to “Q45 Forum / Cima Forum”