Domino Effect: Lugging at mid throttle...

[eagent]

Hi Heath,

Thanks for the Guiding Light... I'll check that out. I'm in this regressing Q mode right now: I fix something, and the domino effect appears to take over.

OK, so I clean all the contacts, and get them to low ohmage. Now the transmission is shifting funky, and the engine bogs unless I feather the throttle... and it feels about half power. I did handle the Throttle Body cleaning, and that smoothed the idle to butter. It's really amazing how smooth that * can be.

OK, so we have greatidle, good cold-start characteristics, but if you apply any mid-throttle effort, the thing sounds like an old Mustang 6 with those awful 2bbl carbs... you remember the ones. What could I be doing to make it bog?

Also, if I go WOT, it ramps the tach to 3100-4500, and zooms from there, but the power feels like half of what I'm accustomed to.

Finally (and this may be the culprit): I tapped with my fingers pretty hard on the lid of the AFM (that's the Bosch device right off the air filter, right?) and cracked the top of the thing. I see that there's a rubber or RTV seal on that lid, but I don't know if it's a vacuum-packed device or what. I've applied some packing tape to the top to "seal"the thing up... I'm hoping it's not a permenant problem... but if that's the throttle issue, at least it's easy access (but I'll bet that sucker is expensive).

I just checked Drivewire.com (my fave parts place), and it says $359.00. Yikes...

Alright, any help is very much appreciated. You guys have always done the magic.

Much thanks.ME

[maxnix]

Finally (and this may be the culprit): I tapped with my fingers pretty hard on the lid of the AFM (that's the Bosch device right off the air filter, right?) and cracked the top of the thing. I see that there's a rubber or RTV seal on that lid, but I don't know if it's a vacuum-packed device or what. I've applied some packing tape to the top to "seal"the thing up... ME

You mean the MAF? Do a search on MAF and you will find corrosion of the contacts can cause a multitude of problems. Start there.

[eagent]

Hi Max,

Thanks for the retun comment. I've actually been through many of the electrical connectors now, cleaning contacts and applying dialectric. I think I got this one pretty well...

Tell me: do you know if the actual probe needs cleaning ever? If so, what would you use (it looks like a filament and a resistive pad when you look through the MAF air chamber).

My greatest concern is the cracked top. THough maybe there are some other things...

Thanks much... Best,ME

[Q451990]

Clean it with brake parts cleaner... it won't leave a residue. Just make sure you have it unplugged and the car off. Don't want the heater in the MAF to ignite the cleaner! Does the idle speed change when you touch the MAF? If so you may have bad internal components. The cracked top is weird - usually that part is fairly flexible. You might check salvage yards for a new MAF. They're not particularly failure prone, except for the corrosion on the connectors.

Heath

[Q45tech]

9 out of 10 times when the protective plastic is crushed the metal shield [under it] comes into contact with the circuit board causing a MAF failure.........or at least some weird happenings!

[eagent]

Hi Q451990: OK, so I did the cleaning job, and no difference in operation there... thanks for the tip (I used electrical contact cleaner, very quickly. It looks pristine in there...)

Q45Tech: Are you snowed under at the moment? Just curious. We're "sufferning"with 69 degree days and sunny. As for the plastic top to the MAF, I was tapping it with my fingertips when it cracked, so it wasn't a ton of force. I can see inside, but the plastic has not dislocated much... just enough to cause a small gap, which I've covered airtight.

Any other troubleshooting possibilities on the throttle issue? If I feather it from idle, I can it drives better, but as I give it a little more juice to say, climb a hill, it bogs again. I have to eather go WOT, or play throttle games to try to get it to shift into a higher RPM gear. Feels like a 4-cylinder, but the perfect idle (thanks for the insight on the TB cleaning... there was a nice carbon ring around the butterfly, and you're right about the two holes on the bottom: small, and easy to clog). Following, the idle is perfect.

The contacts I've cleaned and seem to have the most impact are the MAS, the two upward-facing connectors at the front of the cams (whatever device that is), and the larger round device on the engine front, driver's side, immediately below the MAS at the front of the engine (below the cam electronics). That one, when wiggled, will shut the car off immediately.

Thanks again. I have to tell you, the insights you guys provide are making me Nissan-prone on all future rides. Sign me up for a Murano (OK, so I have to so some pretty big deal to make that deal happen, but what a gorgeous machine... and the CV transmission sounds trick...)

Thanks again!

Best,ME

[Q451990]

That one, when wiggled, will shut the car off immediately.

Still? Or was that before cleaning. Any electrical connection that causes the car to shut off when moved is a problem! I think I'd get a used MAF from a salvage yard. With that cracked top, it sounds like this one was exposed to something weird in the past...

Check out http://car-part.com/ or better yet find a buddy that'll let you swap sensors for a few minutes to see if that fixes your problem. You can unplug it, unscrew from the hose, and then just swap the whole lid assembly.

Heath

[eagent]

Hi Agents Q,

What great feedback and leads! I found a number of the parts used for under $150 (less than a 3rd of the retail... signme up!).

I'll do the swap test... any other feedback is greatly appreciated (eg. the feathering throttle issue, why so underpowered... tell me it's not the computer, etc...;-)

have a rockin' weekend, gents. Go to http://www.trikke.com and you can see what I'm doing when the driving is rough (we designed a custom Trikke with larger tires, and it zooms along at about 25mph, all from swerving...)

Thanks again... looking forward to any impactful input you may have.

Best,ME

[Q45tech]

"front of the cams (whatever device that is), and the larger round device on the engine front, driver's side, immediately below the MAS at the front of the engine (below the cam electronics). That one, when wiggled, will shut the car off immediately"

The crank angle sensor [CAS] is the most critical device on the engine.......it tell ecu rpm and #1 cylinder position....provides a signal every 1 degrees of rotation [360] and a separate signal at 90 degrees as an emergency back up!

[Q45tech]

I guess it bothers me [worries me] that almost all cars have had fuel injection, CAS, MAF [or something like it], EGR, IAC for over 10 years now...............not like a Q is anything special in engine control [other than VVT and 32 valves].

It is scarey that there is so much lack of info and understanding on the second largest monthly expense but again many don't work on washing machines either.

All these items will be on a Hydrogen V8 engine also.

Why are members so reluctant to get a Consult test every 6 months tip the tech $20 and he'll do it without a work order with other services......but then again some dealers use trainee oil changers to save money.

Why it's so important to pay the $10 extra to have a dealer change your oil every 90 days even if you supply some special oil they do look around and find problems.

[eagent]

I truly appreciate your input. Q45tech,

I know, especially since you're truly a special kind of mechanic (one who truly appreciates the car, the owner, and the technology between) who "gets" the mentality behind the auto manufacturer (do maintenance, and built in obsolesence is no longer an issue. Knowing the Japanese as wel as I do, they definitely strive to build cutting edge technology that lasts as long as the human counterpart the technology was built to serve.

OK, that being said, when I purchased the car, I was diligent in maintenance. After the crash of the dot-com boom, my resources stretched me to the breaking point. Having a 6 year history of aircraft maintenance, and having been a seasoned car builder and racer in a past life, I thought this would be cake.

It's not. These machines are a work of art and genius, and the multitude of interdependencies that are integral to the smooth and proper operation of these machines is amazing. In your list above, who would have thought all of that would be necessary to get fuel to burn in the combustion chamber, and that resulting power to the pavement. It's amazing.

So.... 'nuff said. I'll tip the Infiniti tech or whatever necessary to get this resolved. I'm just so used to meeting with these guys, and having them give me the run around... and a temporary solution... I know you understand what I mean, even though you are clearly an order of magnitude above that...

Thanks again. I'll continue diagnostics until it gets isolated enough that I can point to the problem and say "Mr Dealer, can you help here?"

Thanks again. Your insights are priceless.

best,Mark E

[911/Q45]

I think you would be well served to take the trip down to Jerry Tucker in NE San Diego. He feels just like we do about Qs and has seen all the gremlins. Check out his web site and give him a call.

[eagent]

911-Q,

Thanks for the referral. Do you happen to have a link to his shop? Again, much thanks.

Best,ME

[DAEDALUS]

http://www.jerrytucker.net

[Q45tech]

"since you're truly a special kind of mechanic " Call me that again and I will ignore you.I am am a Electrical Engineer with a MBA and a MS in Physics.

Mechanic is a terrible word to use concerning automobiles at the very minimum use technican!

[PalmerWMD]

Dennis:So do you think we should rename the "Online mechanic" the Online technician?

Fred...

[eagent]

Q45tech,

Too funny! I'm a MENSA kid (I probably shouldn't brag about that... I've met some other's and it's not pretty), and anelectronics engineer (HeNe, YAG and diode laser technologies and switching power systems, as well as scanner systems for moving beams around). So please allow me to apologize for my ignorance and crude use of terms.