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Credit: Tristan Friedman

Doing my upper oil pan gasket. For anyone that needs to do theirs, there’s only one pain in the ass that’s in your way. After taking the ac compressor off, the ac compressor bracket, center support, y pipe and lower oil pan, the only thing left holding the upper one on after removing all the bolts is the fkin dust cover for the axle. In the last picture you can see i had to knock it back away from the axle seal because the corner of the upper oil pan was sitting above it and ha.

Credit: Ryan Repairs

Replacing a dead Actuator for the Blend Door (a.k.a. Air mix door) in a 1997 Nissan Maxima with manual temperature control. Replacement procedure should be similar or the same for 1995-1999 Nissan Maximas.

Part Number: 27732-40U00
Part Description: Air Mix Actuator Assembly
Price: $150 – $190.00

Credit: Chrono

Hey guys, I just reset all my monitors yesterday on the interstate and passed the emissions test immediately after. Here’s some helpful info and background for anyone who has to go through this as I noticed there was a lot of confusion about this. First important thing: DO NOT go for an inspection/emission test if you have a check engine light and your monitors are not ready (check with scan tool), as they will not pass you and you’d have wasted your time. The first step is to fix the issue causing a check engine light if it’s on and then clear the code. In my case I replaced my O2 sensor and was good. When you clear the code the monitors will show as ‘not ready’ and you need them to show as ready. So remember for future: every time you clear your ECU with the scan tool, your monitors will become ‘not ready’ and will need to be reset – this is important to keep in mind if you have an inspection/emissions test coming up soon as you’d want adequate time to make your car ready for testing before your deadline.

The easiest/fastest way to do this is to complete the Nissan Driving Pattern for your car which can be found here:

NTB98-018c (Found this for 96 and 97 Nissan cars, for other years check your owners manual)

SB 1996-1997 Nissan; System Readiness Test (SRT) Drive Patterns

“As part of an enhanced emissions test for Inspection & Maintenance (I/M), some States may
require the System Readiness Test (SRT) status be checked. – The SRT is used to indicate
whether the engine control module (ECM) has completed self diagnosis of major emissions
systems and components. – In these instances the State may require completion of the SRT
before permitting the emissions inspection to proceed.”

Find your Maxima by year and transmission style in that document, and follow the directions carefully. I got my monitors ready in 50 mile trip on the interstate when their were few cars on the road. BEFORE you start the drive you should use an OBD scanner to check which monitors are not ready, it may be that only 4 need to be reset so you now know to only complete portions of the drive pattern that pertain to those specific monitors, saving you time. If you don’t own a scanner I highly suggest buying one as not only will it help big time here but will let you diagnose and learn a lot about your car, plus they really don’t cost much. Ideally you want to monitor the status of all monitors in real time as you’re driving, other wise you’re driving blind not knowing which ones are ready/not ready.

Your best bet is to do the drive at a non-peak driving time on a less busy interstate. Doing this in city/suburbs will be difficult if not impossible due to constant stop lights etc that interfere with the drive pattern. Stay in the slow lane, maintain plenty of distance between cars behind and in front of you. Driving hundreds of miles to get monitors ready is not necessary, it won’t make a difference unless you follow the specific steps in the drive pattern. For example in one of the steps you have to have AC on, be on cruise control etc to make the monitor ready.

I used a bluetooth OBD Scan tool hooked up to my Droid that continuously displayed the status of all my monitors while driving (this was cool ). Once they all showed up as ready I turned around and drove to the emissions facility and passed.

Below is the drive pattern I did for my 97 SE, I annotated some important points in red that will apply to any year 4th gen (95-99). Click on it for a larger view.

Other Reference:

 

Credit: vbxmaxima

So there you are, happily driving your Max like I was, when the dreaded Check Engine Light came on. There is a simple procedure you can do to find out what’s wrong without having to take it to a dealer.

So there you are, happily driving your Max like I was, when the dreaded Check Engine Light came on. There is a simple procedure you can do to find out what’s wrong without having to take it to a dealer.

1. With the car parked and the engine off, pick up a flat head and phillips screwdriver.

2. The ECU is located by your gas pedal and is protected by a plastic cover.
Remove the cover by a quick twist of two screws:

You’ll find that the screw heads will pop up. Gently, but firmly pull the screws out – they’re the plastic snap-on type.

3. Remove the panel to expose the ECU. The Diagnostic Test Mode Selector is the screw indicated by the arrow.

4. Here is a close up of the screw. It is protected by a warning sticker.
You’ll have to poke through the sticker to get to the Selector screw.

If you have a hard time reading what the sticker says (like I did) here’s what it says:

DO NOT FORCE PAST STOP

AFTER PERFORMING SELF DIAGNOSIS
TURN SELECTOR FULLY COUNTER-CLOCKWISE
TO STOP

5. Put your key in the ignition. Turn your key to “ON” but don’t start the car.
Your dash lights and the check engine light will come on.

6. With a flat head screwdriver, turn the ECU selector screw clockwise until you feel it go against the stop.

7. After waiting for at least 2 seconds, turn the selector counter-clockwise until it’s stop.

8. Now watch your check engine light. It should be blinking at you. You will see a series of slow blinks or pulses, followed by a series of quick pulses. You need to count each type. If you missed it, don’t worry, it will continuously repeat. The trouble codes are 4 digit numbers. The long pulses represent the first two digits and the short pulses the last two digits.

Note: If there is more than one error code, they will be displayed in sequence.

FOR EXAMPLE:

(LONG PULSE) (LONG PULSE) (LONG PULSE) (SHORT PULSE)(SHORT PULSE)
….means trouble code 03 02

ANOTHER EXAMPLE:

(LONG PULSE)(SHORT PULSE)(SHORT PULSE)(LONG PULSE) (LONG PULSE)(SHORT PULSE)
…means you have TWO trouble codes: 01 02 and 02 01

9. Got the codes? Good! Time to find out what’s wrong. Time to use the ECU Decoder!

10. Now that you found the codes and what they mean, it’s up to you whether you want to take it to a mechanic or fix it yourself.

11. If you do fix it yourself, don’t forget to reset the check engine light! The check engine light will not go away if you don’t, even after the repairs have been made.

RESETTING THE CHECK ENGINE LIGHT

To reset the engine light is a simple procedure.

  1. Turn the selector screw clockwise to its stop.
  2. Wait 2 seconds.
  3. Return back by turning the screw counterclockwise to its stop.
  4. IMMEDIATELY REPEAT steps 1 to 3.

The next time you start your engine, the check engine light should go away!

Credit: davey6693

Just successfully overhauled my a/c – report (long)

I think I’m one of the few people that have done this, so I’ll post my findings here. In short, a/c repair IS possible if you do some research, take a little care with O-ring connections and buy a set of pressure gauges. I saved myself 600 dollars and I now have a set of gauges and a vacuum pump for any work on future cars. If you can rent a vacuum pump or get a garage to do the vacuum/recharge you can save more in the short term.

Here’s how I got my ice-cold air back

1. Bought a set of gauges and did some research at aircondition.com and ackits.com. These are excellent boards with a/c service professionals making daily contributions. The gauges I bought from the tool warehouse.

2. Found that my low side pressure was too high and my high side pressure was too low. Diagnosis: shot compressor. This was fairly easy because it was starting to make noise and get worse with time.

3. Unfortunately a dead compressor can spew metal parts around other components (black death). In my case I couldn’t just replace the compressor because that crud can cycle around to the new compressor and kill it very quickly. Our condensers are parallel flow condensers, so flushing often fails. I decided to replace it.

4. At this point I had a choice to make – get an a/c shop to vacuum and recharge my system or buy a vacuum pump. They can apparently be rented too but I couldn’t find any in my area. I figured why not pick one up, it’ll serve me well for years. Got some vacuum pump oil and a pump from the tool warehouse.

5. As an expansion valve is only 45 bucks, I picked up one of those too. O-rings are important to prevent leaks, and should be replaced whenever a system is opened up. My shopping list was now:
compressor, dryer, expansion valve (all from Carlisle Auto Air).
condenser, o-rings, compressor oil, nylog (an excellent o-ring conditioner that minimises leaks) and flush solvent (all from ackits.com).

6. The whole job took about 10 hours, but it’s pretty straightforward.

a) Add six ounces of oil to the compressor and 2.5 to the dryer (do the dryer bit right at the end).
b) Undo the drivebelt and bolt on the new compressor.
c) Drain coolant, remove radiator and install condenser.
d) Expansion valve was the trickiest – remove glove box (six screws), unbolt refrigerant lines near the firewall (two bolts), remove evaporator housing (four screws), open up evaporator case (six screws), remove old expansion valve (three bolts and a bit of tape). At this point I added flush solvent to the evaporator and blew some compressed air through it. Then I replaced the expansion valve.
d) Replace dryer last it’s good to keep it sealed until it’s needed so that the dessicant bag doesn’t get saturated with moisture).

7. When each pipe between components was unhooked at both ends, I poured in some flush solvent and blew compressed air through to clean them out. One of the tubes is long and most of the others are pretty short so it wasn’t much of a big deal. O-rings were replaced and covered in a thin layer of nylog as I went along.

8. Vacuumed system down for an hour, added a bit of refrigerant and watched the pressure gauges for 20 minutes. No leaks, so continued to fill until almost two cans of 12 oz refrigerant (1.4 lbs) had been added. Air was cold, job done!

This probably looks long, and in some ways it is. But some of you guys do much more complicated stuff than this. One thing I don’t like is being told by mechanics to never touch my a/c because it’s “complicated” or “beyond the DIYer”. The truth is it’s a pump, valve, two heat exchangers and a dryer, and no-one should be scared about doing work on it. I would say if you’re serious about it, buy a set of gauges for 60 bucks. If you don’t want to buy the gauges, then it’s probably not for you.

The old saying of “Do it right, do it once” definitely applies, but providing you do some research and don’t cut corners you’ll be fine and can save a lot of money.

Credit: h0ldem_8o8

Helpful Tips:

  • Remove ac blower/fan first (it’s the white one to the right of the black box (a/c expansion chamber) then remove expansion chamber.
  • Be sure to remove all screws holding the “black box” (a/c expansion chamber/valve housing) first! don’t muscle your way and pry it open with brute force!
  • When putting everything back in, remember to completely reassemble the “black box” (a/c chamber housing) first then put everything back in.
  • This is time consuming, and removing/replacing the a/c chamber housing is a b*tch, practically no room to take that thing out.

Helpful Videos:

The mixture ratio feedback control system monitors the mixture ratio signal transmitted from air fuel ratio (A/F) sensor 1. This feedback signal is then sent to the Engine Control Module (ECM). The ECM controls the basic mixture ratio as close to the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as originally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes during operation (i.e., fuel injector clogging) directly affect mixture ratio.

Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is then computed in terms of “injection pulse duration” to automatically compensate for the difference between the two ratios.

“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim includes short term fuel trim and long term fuel trim.

“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical value. The signal from air fuel ratio (A/F) sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in fuel volume if it is lean.

“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences, wear over time and changes in the usage environment.

Instructions

  1. Start engine and warm it up to normal operating temperature.
  2. Turn ignition switch OFF.
  3. Disconnect mass air flow sensor harness connector, and restart and run engine for at least 3 seconds at idle speed.
  4. Stop engine and reconnect mass air flow sensor harness connector.
  5. Make sure Detected Trouble Code (DTC) P0102 is displayed.
  6. Erase the DTC memory. (This could be done by disconnecting the car battery for 30-45 min or with a scanner)
  7. Make sure no codes are stored in the ECM.
  8. Run engine for at least 10 minutes at idle speed.