1996 I-30 - Stalling / Loss of Power

[rosettiski]

My 96 I-30 (165K miles) has begun to have issues stalling and losing power on an intermittant basis. On occasions, it will stall 3-4 times in a row when placed into gear; sometimes while driving it will epxerience a momentary loss of power / hesitation, and the tachometer reflects a loss of RPMs. Most of the time time, though, the car drives great. The cnheck engine light is not coming on....

The engine is stock. I put a K&N air filter in a year ago, and the NGK plugs are also fairly new. After the problem surfaced, I first cleaned out the IAC valve, and then replaced the fuel filter. Still no resolution yet.... I should note that the car for several years was run on 87 octane gas; it is now running on 93 octane gas.

Read-ups on the forum suggest an MAF sensor issue is most likely. So:
- While it doesn't appear dirty, should I use some CLC cleaner to clean the MAF sensor first? Can that solve it?
- If I replace the MAF sensor, is the Nissan-branded part the way to go? Maybe a slavage yard part?
- What is the other most likely culprit if not the MAF sensor?

It is my daily driver, so any help is greatly appreciated. Thanks much.

[NutriaforBreakfast]

While the engine is running, pull the MAF sensor connector from the air cleaner
apparatus. If it runs better with out the MAF plugged in, your MAF is bad.

I would try to clean it first the MAF sensor cleaner

I would go OEM. I have used Oreilley's MAF but the quality of it may not be as
high as the OEM

I it's not the MAF it might be the EGR valve or the associated "carbon buildup"
you can read about on NICO

Seems like the check engine light should come on though. Usually the irregular missing
/not running correctly will trigger the knock sensor code as well as the MAF code.

[rosettiski]

Well, i pulled the MAF sensor connector from the air cleaner apparatus, and it definitely does not run better without the MAF plugged in. In fact, the "check engine" light came on as a result.

I'll clean ou the MAF sensor connector with some cleaner, and check out the EGR valve possibility. In the meantime, I suppose you know the correct fuse to pull to reset the check engine light now tht it has been tripped?

[rosettiski]

I reset the check engine light, using the "self-diagnosis" tool under the dashboard and near the accelerator. I also removed the MAF sensor and sprayed some CLC brand MAF sensor cleaner onto the filament area; it looked clean already. I put everything back together, and now the car won't even turn over /try starting.... Note: At first, I did not have the diagnostic test mode selector (the check engine light screw) in the full "counter-clockwise" position; I corrected that the following morning....

What is going on? Have I done something wrong in resetting the check engine light? Is this just a MAF total failure? Does it just need some time to rest? Help, anybody?

[rosettiski]

Ok, so the starter went kaput! Great timing on that.... It takes a tow truck driver (and proud owner of a 99 Maxima with 300K miles on it) to point out the obvious to this shade-tree mechanic. I hate it when something new goes wrong while you're trying to fix something else; it fries the cognitive areas of the brain or something.

Will update the forum once I get the new part put in later, and see if my MAF sensor cleaning job did the trick....

By the way, is there a reliability issue with Nissan starters? I've heard that Maxima starters don't last very long with the 3.0L engine for some reason.... Just trying to keep this string from being a monologue, you know....

[NutriaforBreakfast]

Have had good luck with starters
Try to get it rebuilt

[NutriaforBreakfast]

Put on a glove when motor is hot and push on the EGR valve stem to see if it is stuck open or closed

You might want to make sure the PCV valve is not plugged

[rosettiski]

Here"s where we are at.... The starter is in and working, and the MAF sensor has been cleaned with CLC sensor cleaner. I havent' done anything else yet (EGR or PCV valve related).

The car is still stumbling, but only in the first minute of being started up. When starting it sounds like the motor is wheezing, and it doesn't want to idle; not sure if it is getting too much air or not enough. It takes time for the gas pedal and the engine speed to get in sync, so to speak (tachometer fluctuates). After those first few moments, though, everything evens out, idle is fine, and engine performance becomes as smooth as butter. It drives fine. Whether the engine is warmed up or not does not matter; if I cut the engine off, the same issue recurs when I go to restart it.

Hopefully, these symptoms point towards one solution more than another? I understand that messing with the EGR valve involves removing both the throttle body and the plenum, two tasks I have never done before. As always, thoughts are appreciated.

Also, I do not find any articles on how to clean the EGR valve (and maybe even with pictures); they don't appear to be on the "common issues" thread for Gen 4 vehicles....

Thanks again.

[NutriaforBreakfast]

You can check to see if there is a stuck EGR valve without removing anything

same way with PCV

[rosettiski]

Will check the EGR and PCV ASAP (posibly not til tomorrow night, though).

FYI, though, I did have the CEL come on this weekend; I got both a P0100 (MAR sensor) and a P0110 code (air intake temp sensor). I replaced the air intake temperature sensor, but no help.... It appears that I should be able to partially test the MAF sensor with a voltmeter, but I'll need a bud to help me out with that....

Thanks for the continuing help.

[rosettiski]

Looks like my EGR valve is stuck! There's no movement of the valve stem when accelerating. The symptoms (problems starting hot or cold, and stalling only occasionally at low RPM driving) appears consistent with an EGR issue.

I tested the MAF sensor with a voltmeter, and it is reading fine through all the tests....

Gonna see if there is a good write-up in here for cleaning the EGR valve out. My Haynes manual is straightforward, but typically there is more to the story than just what is written there.... Space looks a little tight in there...

Will keep the thread posted.

[notbrant]

Does this only happen when the engine is cold?

[rosettiski]

No; cold and hot have both been problematic from a "starting" standpoint. The stalling has occurred generally within the first 5-10 minutes of operation, however....

It looks like I need to remove the IAC valve to access the EGR.... To remove the big EGR pipe nut, should I be using just a big crescent wrench, or is there a better choice? The space in there seems awfully small from an access perspective....

[rosettiski]

Still can't get sufficient access to the EGR pipe nut to remove it! There has to be a technique I'm missing here....

Should I try from underneath the car? Should I remove any other components first, besides the air box/MAF stuff? The hose that appears most in the way appears to be a coolant hose, but nowhere does the Haynes manual / FSM suggest removal of anything else.... I'm not sure what to do next.

Help, anybody?

[rosettiski]

OK, here is where the car is at....

It is running at 100%! After reading up a little more on the MAF sensor, and how it can be working improperly even when it passes the various check/multimeter tests, I replaced it. I also replaced the IAC valve, the PCV valve, and the intake air temp sensor. Performance is optimal, it now appears.

However, the car still starts like crap. I have to use the gas pedal to get the engine to fire up (what is that a clue of?), and have to continue revving the engine for 15-20 seconds to keep it from dying out; once it settles in at normal RPMs (700 or so), everything is golden. I've had the fule pump pressure verified as satisfactory, so I doubt it is a fuel issue....

The starter and battery are relatively new. I have to assume there is some combination of emissions/sensor issues at play here. Any thoughts?

[NutriaforBreakfast]

Use a vacuum gauge on the EGR valve
You can do this with a cold engine not running
If it won't hold vacuum then you have a bad EGR valve
The vacuum should pull the valve open and you should be able to tell with your hand
The valve could be stuck open OR stuck shut
Generally it should only be open when the engine is hot (ie normal operating temperature)
My guess is it's stuck open
If you are looking by the IACV, you are thinking of the EGR temperature sensor not the EGR valve
The valve is down low on the engine but the pipe you are thinking about does connect to the egr valve
Try spraying electronic cleaner in the valve to see if it will loosen some of the carbon as you use
the vacuum gauge to check it
If you remove the EGR valve also remove the pipe to clean carbon off of inside it and the back of the
plenum where it connects. You will probably need a new gasket there as well i think.

Diagnose this carefully -If it is a different problem you need to move on through your diagnosis

[rosettiski]

So the EGR valve was bad, and the EGR pipe clogged up; R&R'd the whole thing. But the starting problem remained.

Went back to another friend and had a diagnostic completed. Turns out the fuel pump had gone bad! Replaced the fuel pump, screen assembly, etc., and now the car is running great. Problem solved.

Just curious. I was told that fuel pumps can go bad on these cars when you run the gas tank really low for extended periods, and that it is recommended that the gas tank never get below about 1/4 full to reduce strain on the pump! Has anyone else heard of this, or is this some sort of old wive's tale?

Thanks for the help!

[NutriaforBreakfast]

I believe it-i never run my car down to the last drop
I also use Chevron Techron when we have wide temperature swings
during the winter. Remember you can have condensation in your tank

oil to the top -water and sediment to the bottom

[timvector]

I have a 96 Maxima that stalled out during idle (in gear or not), starting a couple of months ago. This was infrequent but enough to make me nervous. Engine would have to be warm for this to occur.

I found the IACV easy to disassemble and clean (at 110K miles, 18 yrs old, it was a little dirty). Car ran fine for about a week, then stalled again. Cleaned the MAF sensor with MAF sensor spray; car ran for a week then stalled again. Checked for vacuum leaks, EGR valve movement; all OK. No codes were ever thrown, BTW, and car would re-start up right away, though exhaust smelled rich after stalling.

Unusual problem; difficult to find. Finally got a lead on it though; may be helpful to others: my car has a slow front oil seal leak, or perhaps a PS pump leak. This occasionally throws oil on the passenger side o2 sensor: a look at the sensor showed it had oil on it. Replaced both o2 sensors on the engine; car has run fine since then.

Reading up, the o2 sensors generate the signal based on comparing o2 level in outside air with that of the exhaust stream. In "closed loop" mode the engine tweaks injector open time to achieve an o2 level in the left and right manifolds that is right on the edge of where the sensor transitions. The o2 sensor on the passenger compartment side of the engine looked original; it had a few vent holes in the back unlike the newer Bosch replacements. I suspect now and then some oil may have been slung into the sensor: based on temp of the sensor (engine warmed up), the oil would vaporize, and block the sensor from the atmosphere side, making it look like the exhaust stream was lean. Engine control unit would then try and compensate by making the mixture more rich, so much so that idle speed would "cough" now and then. (Higher speeds were always fine).

Also, my guess is that the car would run well for a week or so after the earlier repairs because disconnecting the battery for several minutes causes the engine control unit to un-learn its tweaks for injector timing; after a week or so of driving (for me) it re-learned some questionable values based on the contaminated o2 sensor.

Still have the oil leak; car has been stellar for > 1 month; the new o2 sensor design looks less susceptible to trapping oil. So, if you are having an occasional stall at idle speed and there is an occasional oil drip in the driveway, add check the o2 sensor on the passenger side to see if it is oily to the quick-check list.

I am grateful to this forum for the info that helped me in pursuing this; hope this info helps someone in the future.