Let us bow our heads and give a word of thanks for T-3.
You may have a case against the dealer, so have T-3 save the parts. At the very least, corporate Infiniti will be very unhappy with the dealer for not using OEM parts. If the dealer says the prior owner made them install the Autolites, then it should be noted on the work order. If you don't have this, get to your dealer immediately and get copies of all work orders! Don't say anything else to them about the car.
Serious engine trouble on my 94 Q45.
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Q45tech
- Moderator
- Posts: 14296
- 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
I didn't hear any front noise when we finally were able to get it cranked at 5pm yesterday, then the glowing cats and the refusal to idle without extra rpms showed up.......today they are going to open the exhaust and look to see how much melting plugging has occurred.
Thank goodness for junkyards because a single exhaust manifold cost over $750 new and there is a national backlog.......come to think of it we have seen 2 other 94/95 Q with melted precats.......never on a 90-93..........were there changes to the cats we don't know about?.........the 90-93 exhaust won't bolt up to the 94-95-96 and the converse ..........the passenger side location of the cat output flange is about 2" different.
This just in, the passenger precat is melted almost solid and we will punch it out to attempt to proceed with diagnosis...............more Monday.
Thank goodness for junkyards because a single exhaust manifold cost over $750 new and there is a national backlog.......come to think of it we have seen 2 other 94/95 Q with melted precats.......never on a 90-93..........were there changes to the cats we don't know about?.........the 90-93 exhaust won't bolt up to the 94-95-96 and the converse ..........the passenger side location of the cat output flange is about 2" different.
This just in, the passenger precat is melted almost solid and we will punch it out to attempt to proceed with diagnosis...............more Monday.
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Q45tech
- Moderator
- Posts: 14296
- 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
Quick light off cats welded to the exhaust manifolds [headers] inches behind the O2 sensors. To take care of some HC emissions after the first 30 seconds - 2 minutes of startup [cold start emissions].
The core expands when hot to offer little back pressure then. The main cats are a few feet to the rear.
http://www.aecc.be/en/current_technology.htm
http://www.engin.umd.umich.edu....html
A large engine like 4.5 produces twice-3x the amount of exhaust gases at idle as a more conventional 4 banger.
Proper long lived emissions system would have at least 4 cats some newer models have 6 cats.
Prior to 2000, The JDM engines only have 2 cats [no precats] but the main cats are larger and more expensive.
Removal [punching out] the precats offers only a tiny increase in performance but it screws up the O2 sensor/ecu calibration at 2,000 rpm cruise making the ecu enrich the mixture more than is necessary.............highway mileage drops by 10% or more and it is tricky to get a emission test on a dyno to pass in cold climates when it is below 70F ambient..............don't ask how I know but the hint is my Birthday is in Jan. so that when I get tested.
THE JDM takeout engines all come without precats so you must swap the old engine's exhaust manifolds to become US legal.
Side by side testing of an illegal JDM with my engine/car 2 years ago [both with JWT ecu] indicates at most a 1 car length advantage by 120 mph...................most of that or more probably had to do with the differences in mileage.......better compression.
32 valve engine are very very bad polluters at low rpms because of the large valve area.........US 16 valve engines tend to be more optimized for low rpm so they can save some money on cats.
After 1996 OBD2 most have two cats per bank of cylinders.
The core expands when hot to offer little back pressure then. The main cats are a few feet to the rear.
http://www.aecc.be/en/current_technology.htm
http://www.engin.umd.umich.edu....html
A large engine like 4.5 produces twice-3x the amount of exhaust gases at idle as a more conventional 4 banger.
Proper long lived emissions system would have at least 4 cats some newer models have 6 cats.
Prior to 2000, The JDM engines only have 2 cats [no precats] but the main cats are larger and more expensive.
Removal [punching out] the precats offers only a tiny increase in performance but it screws up the O2 sensor/ecu calibration at 2,000 rpm cruise making the ecu enrich the mixture more than is necessary.............highway mileage drops by 10% or more and it is tricky to get a emission test on a dyno to pass in cold climates when it is below 70F ambient..............don't ask how I know but the hint is my Birthday is in Jan. so that when I get tested.
THE JDM takeout engines all come without precats so you must swap the old engine's exhaust manifolds to become US legal.
Side by side testing of an illegal JDM with my engine/car 2 years ago [both with JWT ecu] indicates at most a 1 car length advantage by 120 mph...................most of that or more probably had to do with the differences in mileage.......better compression.
32 valve engine are very very bad polluters at low rpms because of the large valve area.........US 16 valve engines tend to be more optimized for low rpm so they can save some money on cats.
After 1996 OBD2 most have two cats per bank of cylinders.
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Q45tech
- Moderator
- Posts: 14296
- 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
At least with OBD2 these kind of things can't happen [a single misfire sets a MIL immediately] whereas the 90-95 are realtively unmonitored and depend on the owner to sound some alarms.
That is the problem with buying a used car you don't know how it should behave or did behave new.
The torque of the Q engine covers up a lot and drivability has to be really bad before it alarms a new used owner. Only a 100% full time cylinder misfire will get their attention.
I have always thought the Q was missing a few accurate gauges: transmission temp, head coolant temp and oil pressure.
By the way, OBD2 senses misfire by looking at the O2 sensor voltage for each cylinder then comparing that to the average and expected for each condition........so the O2 must be replaced more frequently as their sensitivity wanes.
That is the problem with buying a used car you don't know how it should behave or did behave new.
The torque of the Q engine covers up a lot and drivability has to be really bad before it alarms a new used owner. Only a 100% full time cylinder misfire will get their attention.
I have always thought the Q was missing a few accurate gauges: transmission temp, head coolant temp and oil pressure.
By the way, OBD2 senses misfire by looking at the O2 sensor voltage for each cylinder then comparing that to the average and expected for each condition........so the O2 must be replaced more frequently as their sensitivity wanes.
Re: (Q45tech)
We have come full circle!!
Hate to dig up a post from 1.5 years ago but we find ourselves in the same predicament. The Q (94Qt, 101k) quit this morning on the way to work. I made a trip to Jacksonville last night (about 5 hour round trip) and the Q drove like a champ until we were at the end of the voyage. About 30 miles from home she began to skip and miss. This morning I decided to drive it to work and it died in the middle of the road.
I got it restarted and drove it about a tenth of a mile to a hole in the wall shop. I wasn't to picky about the shop because my experience has taught me that in my home town it doesn't really matter where I take the Q, if I don't specify exactly what the problem is and which part needs replacing they usually don't have a clue.
Long story short, they found a code for misfiring and one for the knock sensor (can't remember the code #s). Ironically enough #7 plug is missing its electrode again!! What are the chances of my Q having the same plug lose an electrode? These are the NGK plugs so it definitely isn't a matter of inferior plugs. Any ideas as to why this would happen again? There has to be something more serious going on here. These plugs have about 15k miles on them.
I am waiting on them to put in a fresh plug and see what happens, I'd gamble that the coil is shot also (that was also replaced about 1.5 years ago). Let me know if anyone has any insight as to what would cause this problem.Thanks
Q45tech wrote:The preliminary diagnosis is the Autolight plugs started the whole scenario destroying #7 coil and plug. The #7 electrode has not been found. All the even bank plugs were fouled but the electrodes were there.It appears that all the misfiring [both banks] has done damage to the precats and maybe the cats themselves. The passenger side is blocked [melted] and no oxygen sensor readings on either side they maybe melted also.
The engine can be made to run at 1500 rpm but the cats start to heat up quickly. We will be spending tomorrow trying to narrow down the details.
It appear as this point that the internals are fine other than some cam wear [previous owners oil change habits].......the only question is the exhaust valves. But we'll have to wait for the passenger side leak down till the back pressure is down to normal...........passenger exhaust manifold precats, 2 new O2 sensors and possibly cats.
Members please use nothing but NGK plugs and oem sensors.
Hate to dig up a post from 1.5 years ago but we find ourselves in the same predicament. The Q (94Qt, 101k) quit this morning on the way to work. I made a trip to Jacksonville last night (about 5 hour round trip) and the Q drove like a champ until we were at the end of the voyage. About 30 miles from home she began to skip and miss. This morning I decided to drive it to work and it died in the middle of the road.
I got it restarted and drove it about a tenth of a mile to a hole in the wall shop. I wasn't to picky about the shop because my experience has taught me that in my home town it doesn't really matter where I take the Q, if I don't specify exactly what the problem is and which part needs replacing they usually don't have a clue.
Long story short, they found a code for misfiring and one for the knock sensor (can't remember the code #s). Ironically enough #7 plug is missing its electrode again!! What are the chances of my Q having the same plug lose an electrode? These are the NGK plugs so it definitely isn't a matter of inferior plugs. Any ideas as to why this would happen again? There has to be something more serious going on here. These plugs have about 15k miles on them.
I am waiting on them to put in a fresh plug and see what happens, I'd gamble that the coil is shot also (that was also replaced about 1.5 years ago). Let me know if anyone has any insight as to what would cause this problem.Thanks
Re: (PalmerWMD)
Anyone have any insight? Do you think that the piston can be hitting the plug and causing this damage?
Help please!!
Help please!!
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SOCAL91Q45a
- Posts: 403
- Joined: Sat Aug 16, 2003 2:28 pm
- Contact:
Re: (BIONICQ45)
Has Dennis / Q45Tech gotten in touch with you on this?
That is just so bizarre .... Wish I knew more to be of help to you brother, buts its beyond me. Sure hope your Q is salvageable.
All the best
SOCAl
That is just so bizarre .... Wish I knew more to be of help to you brother, buts its beyond me. Sure hope your Q is salvageable.
All the best
SOCAl
Re: (SOCAL91Q45a)
Nothing from Dennis yet. Thanks for the words.