trommel

Hi, I've spent many hours searching these threads for the right answer but no luck, so here goes:
When I purchased this 97 Maxima (mfg date 07/96) in the winter it needed a new harmonic balancer (crankshaft pulley) which had come apart and also damaged the crank position sensor below it. When I first replaced the balancer, the car would take a while to turn over before it fired up and then it would run just fine. When I finally realized the CPS was damaged and bought a new one, the car periodically takes a while to start and sometimes seems to misfire (like it's a timing problem) but then fires up and runs perfect. Note: The "misfire" symptom never happened prior to replacing the crank sensor. It only took a lot of cranking to fire up, which I heard is typical for a bad CPS.
The only code I'm getting is P0110 which indicates a bad IAT (intake air temperature) sensor but according to Autozone this part doesn't exist on the 97 maxima. When I looked for a possible sensor there is no such creature anywhere along the air intake passages. One woman at Autozone told me the P0110 code could be thrown by a faulty MAP sensor but I checked resistance/voltage values and vacuum function to that and it seems fine. I also inspected the MAF sensor and checked the resistance/voltage values on that, which were fine and I cleaned it with MAF cleaner.
Additionally we bought a new battery and spark plugs, cleaned the second CPS (which was loaded with metal filings), checked values on the cam position sensor and cleaned the engine grounds between the engine and transmission (We even added an extra ground strap there).
The car now generally starts better but still slightly falters on start up which immediately throws the P0110 code. In order to get through inspection in NJ the check engine light can not be on.
Can anyone think of something I've missed?...I could really use the help, especially because I picked this car out for my 17 year old son, due to its' reported reliability, and now we are both so frustrated. Please help a well meaning dad get back in the good graces with his trusting son.
Thanks, Tom Rommelmann

2brosgixxer

Follow the snorkel from the front of the car. At the elbow, before the intake box, you will see a gray connector. I believe that's what you are looking for. It's kind of hard to see but just look closely. This pic, my middle finger is touching it.



Hope this helps and welcome to the org. Also, for future reference, you can check the codes yourself by following the directions in this link http://vbxmaxima.8m.com/ecu.html

trommel

Thanks for the info and photo. The car is at his Mom's house so I'll have him take a look at where you are pointing. I have been to Autozone several times though and they tell me this model doesn't have a IAT sensor....I wonder if it's combined with something else.
Also thanks for the tip about reading codes directly from the ECU (fascinating). I just bought a OBD 2 scanner so I don't need to go directly to the ECU.
I'll repost when I hear back from my son.

rob2407

Had similar problem with starting, and kinda missing when started. Replaced MAF after cleaning didn't work. Started great, but ran worse, second problem for me (after second code) replaced a cop

trommel

Hi 2brosgixxer, I looked under the air intake housing exactly to where you indicated in the picture and there was nothing to plug into, or any holes for that matter. I've also had all these air intake parts off the car already and could find no place where a sensor would penetrate into the airstream. I did however find a grey 2 pin connector that is just dangling right in that area with no place to attach to. Thank you again for making the time to take/send me the photo but I'm still baffled. Tom
PS When I looked inside and cleaned the MAF sensor I saw two projections. One is a tiny filament, like a light bulb filament (supposed to be made of platinum) and the other projection is a tiny white plate that is also supported by two posts right next to the filament. I wonder if this could be the air intake temperature sensor built right into the MAF sensor housing. Anyone have any ideas about this?

trommel

Never having found any opening where the IAT sensor would plug into the air intake line, I called Nissan and gave them my VIN # and they said it does indeed have an IAT sensor which would cost a little over $60. I then called Pep Boys and although they could not find anything listed as an IAT sensor, they did have an "air charge sensor" which sounds like the same thing for around $27. If I do buy the part (which has a two prong connector) it looks like I'll have to drill a hole in the air intake housing to install it because as I said no holes exist...so puzzling but I guess I'm making progress.

2brosgixxer

That is very Strange that there is no sensor but the wire for it is there. I wonder if some parts were changed out good luck.

aackshun

iTrader: (3)

Tom, your IAT will not cause starting issues, the vehicle does not need a MAF, IAT, MAP to start properly.

If at all, can you make a video of it trying to start? or when the issues are present? We would also need to know the whole scenario... Car cold, warm, first start of the day, etc...

Now you will need a IAT to get rid of that CEL though, it's a simple resisitor, you can install one in the wires that are present to get rid of the code, and when you're feelin frisky you can properly tackle the issue.

Side Note: Take note on how I used breaks in my paragraphs, you can see how much easier it is to read my post then your original one. I may suck @ english, but I know how to format a post on a forum

trommel

I took another look at the top of the air box (above the air filter) and I saw what could only be described as 3 knock out points on the side opposite the battery....a small circle about 1/2 inch in diameter and 2 small circular etched points one above and one below the main etched circle. So this looks exactly like where the IAT sensor would normally go. Maybe this car had an aftermarket air filter housing and they never bothered putting the sensor back in.

I had my son take a picture of this and may be able to post it on Friday (if I can figure that out). In the meantime I ordered an "air charge" sensor from Pep Boys and will see if that will do the trick.

Considering all that I've already done, the starting issue is not as much of a problem as before. Just a slight delay in cranking and sometimes a little falter (or misfire), however in most (but not all) cases the IAT code P0110 comes right back on after start up. I was able to start and drive it for 3 miles without the engine light coming on but the next time we started it, we got the P0110 code back again.

If the new sensor doesn't work I will be interested in learning the details of putting in a resistor between two sockets in the IAT sensor plug.

Also thanks for the tip regarding paragraph spacing...That should look much better. I wish fixing the problem were as easy as reformatting my post.

2brosgixxer

Take a look at my Sig for a how insert pics link as well as other helpful Links.

aackshun

iTrader: (3)

The red highlighted section is what worries me, bad starter or bad ignition switch. I will re-iterate my previous statement for clarity sake.

The 1995-2001 Maxima does NOT need the following to start up properly:
-IACV
-MAF
-IAT
-Map/Baro Sensor
-TPS
-All 6 coil packs (when you're down to 4 things start gettin hairy, but one bad one won't prevent a nice quick, crisp start up).

The 95-01 Maxima need the following conditions to start quickly and properly
-Crankshaft Position Sensor (REF) - Not needed to start and run the car, but sure as hell helps a whole lot, w/o this properly functioning starts become long and almost impossible.
-Crankshaft Position Sensor (POS)
-Camshaft Position Sensor
-No large sources of air entering (large vacuum leaks... like... really big)
-Some Fuel Pressure
-Good clean spark plugs
-At least 4 coil packs working
-Motor in proper time
-6 properly working injectors
-Working PNP/Clutch Inhibitor Switch
-Working Battery
-Working Starter

If I'm missing something someone tell me so I can edit this post later, but I've played with a lot of this stuff personally and this is the information I've gathered by just fooling around.

trommel

Excellent tips regarding starting requirements.

My followup: I purchased an "air charge sensor" (which IS the same thing as a IAT sensor) at Pep Boys tonight and plugged it into the grey connector (outside of the airbox, since I haven't drilled a hole yet). I reset the CEL and started the car with an initial rough start but the CEL did not come on. I shut off the engine and she started right up again no problem (and no CEL)!

Now my son needs to drive it a bit to see how it starts in the future and of course I need to drill a hole in the airbox to place the new sensor back where it should have been in the first place.

Thank you all for all your great input!....What a helpful forum!!

cashoit

First off, I have a 1997 too and Whoever told u our cars do not have an IAT sensor is a fawking moron.

The IAT is more of a dianostic tool for the ECU and fuel economy. Doenst have anything to do with starting the car. It SHOULD be located on the stock air intake snorkel. If u have an aftermarket intake, someone may have unwisely deleted it.

Regarding the hard starts...

Clean TB and MAF per how tos. Throw some chevron techron in the fuel tank.

The crank and cam sensors handle starting. The test for the cam sensor is a simpple resistance test.

The test for the crank sensors is a voltage test and will require two ppl.

You stated that u replaced the belt side crank sensor. Did u replace wit a used or new sensor? Used sensors are hit/miss. Replace with new sensor, if necessary.

The tranny side crank sensor is well known to cause hard starts. You stated it had metal shavings on it. How did u clean it? The crank sensors are magnetic and you may have wiped off all its magnetic properties based on the solvents u used to clean it. Test, and or replace if necessary wit a new sensor. Add a ground cable (8 or 4 awg) from the negative battery terminal to a bolt on the tranny housing.

aackshun

iTrader: (3)

Chuuch

bobflood

+1 on the tranny side CPS causing hard starts. While cleaning it off and checking resistance are good, the sensor may still be causing the starting problems. My shop had to use a scope and some real diagnostic skills to find that problem on mine; changed that sensor out about 2 years ago and no starting problems since. New aftermarket sensor has done just fine. Good luck.

trommel

So I replaced my bad crank sensor ("REF" under the crank pulley) with a new one from Autozone and I cleaned the one by the tranny ("POS") with just a paper towel and pulled off all the acumulated metal filings (no solvent). Figuring that was the problem at the time, I didn't bother to check voltage/resistence values on the second sensor and I will now do that because I'm still having a rough start on initial start up....but almost no problem on secondary starts with engine warm.

Regarding the IAT sensor, I'm guessing that this car had it's "snorkel" removed and by snorkel I'm asking....Is that a short black plastic elbow attached to the neck of the lower half of the airbox (below the air filter)? Since it wasn't there (and hence there was no hole for the IAT to mount into) I drilled a small hole on the edge of the neck right where the air enters the box. Note: The wire harness would not allow for placement of the IAT into the top of the airbox where I originally suspected it needed to be mounted.

I'm thinking my new placement of the IAT sensor would have been very close to where the original would have mounted in the snorkel (elbow?). If I'm wrong no doubt someone will let me know.

In any case by simply plugging in the IAT sensor and not yet even mounting it in the air box, it made the P0110 code go away so I had no codes and no CEL on. My son and I were so happy and Dad (me) felt like he really accomplished something for his son Andy.

(Reminder: Autozone had no listing for an IAT sensor and neither did Pep Boys but at least with Pep Boys we were able to figure out that their "air charge sensor" was exactly the same thing. The Nissan dealer also had an IAT sensor but theirs was around $35 more than Pep Boys.)

With great anticipation we drove the car to the inspection station (total miles driven around 20). Of course this wasn't quite enough because the computer never had a chance to reset and we failed again. We left the station deciding to take a little road trip and within about five more miles the check engine light went back on (code P0136, downstream O2 sensor, post cat).

I researched to find that this rear O2 sensor measures the performance of the catalytic converter and the P0136 code was usually due to a bad sensor or faulty connections. I also checked the 15 amp fuse (# 34) in the passenger compartment and that was ok. I now need to backprobe the sensor to check its values and see if I just need to replace it.