reallywildstuff

I'd appreciate any help diagnosing an intermittent stalling issue. All possible culprits I can think of (like dirty IACV, dirty TB, failing fuel pump, dirty gas tank, loose serpentine belt) should also be causing other drive-ability problems that do not present.

My wife's daily driver is stalling while she is driving on city streets - only very occasionally (perhaps once out of every seven days), and always under otherwise unremarkable circumstances: sub-40 mph speeds and non-spirited driving.

She reports: "I was driving around the corner on my way to work like I do everyday and the RPMs all of a sudden dropped to zero, all the dash lights came on, and the power steering didn't work as I struggled to get to the side of the road" There was no indication it was going to stall beforehand"

After it stalls, it always starts right back up again - on the first try, every time. I have asked for confirmation that the key has remained in "Run" the next time the car suffers this stall condition. It has to date not stalled during higher speed driving. The stalling cannot be duplicated on demand.

Other than this random, intermittent stalling, the car runs really well - it always starts right away under all temperature conditions, idle is always consistent and steady, RPMs don't drop even a tick at stoplights, no CELs, passes emissions, gets decent milage, sounds good etc. It consistently pulled hard all the way to 6k RPM on a recent spirited test drive ("Hell I'll drive this car, this car is _nice_").

1998 i30, 112k miles, owned since 2011, all service records since new (one-family ownership).

Presently has a pretty hefty oil leak (RMS, upper and lower pans, timing cover, valve covers) - spending either the time or $$ to reseal this motor is going to depend on whether I can get the stalling issue corrected. Crankcase oil level is checked once a week / every fill up and more is added every time (2 quarts/month).

It does not burn oil - it just leaks engine oil like a sieve. Leaking Transmission and PS hoses replaced 2014.

The following corrective steps were undertaken JUST BEFORE (the weekend before) the car stalled yesterday:

Seafoam treatment (through brake booster vacuum line, also in fuel tank)
After Seafoam smoke was gone:
replaced spark plugs & fuel filter (last changed in 2007 @ 61k miles)
PCV valve (old one had a little bit of rattle but not much)
remove all keys but ignition, house, and remote fob from key ring

Cylinder 3 spark plug hole had oil in it - needs valve covers/spark plug seals

Once removed, the old fuel filter displayed very dirty gas coming out of the tank side - but the engine side seemed clear.

Four months ago:

air filter had not been regularly serviced - black with carbon, and torn
replaced MAF (failed - ranging for idle, also CEL said "failed MAF")
replaced alternator

six months ago:
radiator went pop on the hottest day of the year - replaced

Appreciate any tips and thanks -

Brian in Houston

Turbobink

iTrader: (2)

Check and adjust your TPS, clean your throttle body and clean your MAF.

Then report back.

PH98I30

Clean your crankshaft position sensors off with MAF or electrical parts cleaner spray.

LJay

I cleaned my MAF &TB. I wanted To IACV also but didn't have the time to. I had the same issue but it doesn't stall as much now. Cleaning the TB, MAF, IACV & EGR tube would help a lot.

Turbobink

iTrader: (2)

+1 on this as well.

While the crank sensors are removed be sure to check them for damage.

Also have a look at the cam sensor.

njmaxseltd

iTrader: (19)

I'd focus on the MAF sensor, the connections inside tend to loosen up and cause a stalling issue. This can be corrected with a soldering iron.

reallywildstuff

thanks to all who replied.

I see lots of other recent posts re: cleaning IACV and TB as solutions to stalling at stoplights/bad idle...my issue seems different (too isolated) BUT I will clean the IACV/TB/TPS to baseline regardless. Is it worth cleaning the EGR tube out at the same time? Do you recommend the hacksaw trick?

What's your recommended MAF cleaning product?

Are the connections referenced ("...on the MAF sensor, the connections inside tend to loosen up....") inside the wiring connector (a part of the electrical harness) or are they inside the MAF component itself?

Do you have a picture of which connections to check? Would a short in these connections cause an "engine off" condition? I now can't decide whether it's "stalling" or instead "shutting down" - maybe that's a distinction without a difference. I also see other posts re: MAF connectors but didn't find pictures.

The MAF currently in use was installed six months ago (by myself - maybe I messed up the connections above).

At that time I had to replace the MAF re: MAF-related CELs and driving issues - in colder weather, and almost certainly brought on by "the world's dirtiest air filter" - embarrassing, epic dirty. We thought the shop that did the oil changes was checking air filters but turns out not so much - this air filter was black and engine intake vaccuum had sucked/torn a hole through it.

The old MAF had an awesome Japanese pink sticker on it that made me think it was original OEM (I saved the sticker somewhere...). After replacing the air filter the ECM continued to throw MAF-related CELs until I replaced the original OEM MAF...I knew that perhaps the MAF could have been cleaned instead of replaced but I had to get it fixed that evening...

njmaxseltd

iTrader: (19)

Was the new MAF an OEM, name brand or cheap aftermarket?
Did the stalling issue start shortly after said MAF was installed?

DBear

Here's what they mean by soldering the MAF connections: https://maxima.org/forums/4th-genera...ml#post7963527

MAF would be my first guess. I had similar symptoms when mine went out, but I don't think the engine died completely. But it's been a while and I could be wrong on that.

It almost sounds like the power to the engine is cutting out (dying instead of stalling). I'd be suspicious of the ignition switch. They're pretty cheap to replace.

FWIW, I had the exact same problem on an old Saab. I finally traced it to a break in the board that held the fuses. Evidently that was killing the power at random times. But that also kept me from being able to start it occasionally too. You might think about possible circuit breaks. There's a bend in the main electrical harness in front of the passenger side firewall that supposedly can cause all kinds of problems, although it seems like it only happens rarely.

reallywildstuff

The receipt and the car are not with me at this moment. I paid $252.40 @ O'Reilly in September 2015 - probably A1 Cardone reman.

I had a feeling I was going to regret buying reman - however, at least a couple of months elapsed between MAF replacement and the onset of this stalling issue. I kept the MAF core for a good while before I returned it, too... no reports of stalling in that time.

CS_AR

Brian - I see you still have your receipt which is good.

I took a look at the O Website and see the unit in the $250 price range is A1 Cardone reman. Personally I wouldn't have bought that particular MAF -- but that's just me.

My first personal preference is to pick up a used OEM MAF from a junk yard, take it home and test it, then keep it if it works. I usually can find one good MAF out of two from a junk yard. It takes me a couple of trips to get a good MAF from junkyards in my area. There maybe one of our members selling a working used OEM MAF in the site's classified section. That would be a good place to check.

If you suspect the A1 Cardone reman MAF is the problem, and O will only give you an exchange or credit toward another unit. I noticed on the O web site they are selling Bosch branded MAFs that carry the pink OEM - JECS made in Japan label. That looks as close to OEM as I've seen. That MAF is selling in the $294 range.

Personally, if I knew the A1 Cardone MAF was bad, and I needed to quickly try a different unit from an O store, I would give the JECS unit that I see listed on their site for $294 a try.

Here's a link to O's JECS unit.

http://www.oreillyauto.com/site/c/de...d=mas+air+flow

The best price that I can find for a new OEM is $391.41 at an Infiniti dealer online site.

I think you're in luck that you have an I30. Actually I can buy Infiniti OEM parts for less than what I can find Nissan OEM parts. I have both I30 and Maxima 1999 models.

Guess where I go when I need an OEM part?

http://www.orderinfinitiparts.com/pa...&siteid=215003

For comparison purposes..

http://www.courtesyparts.com/nissan/...ir-flow-sensor



.

Cardone Industries

Hello Reallywildstuff,
Sorry about the issues you are having with our product. We would love to talk to you about this matter. If you could call our Tech Service Line [888-280-TECH (8324)] and ask for Walter that would be greatly appreciated. We look forward to hearing from you.

Thanks,
Phil Curry - Cardone Industries

reallywildstuff

I called. Walter is out for the holiday.

Cardone Industries

My apologies. Call the Tech Service line again and ask for Susan, she is expecting your call.

Thanks,
Phil Curry
Cardone Industries

reallywildstuff

I have now observed the stalling/dying issue first-hand: @ 30 mph with foot on the gas nice and easy, let off the throttle (as to coast) and RPMs drop precipitously to ~600, then (if the engine doesn't die) rise back up to normal ~1100 RPM after about 10 seconds. Without keeping your eye on the tachometer it is not otherwise appearant that the engine is turning so slowly under these conditions.

I plan to clean the TB, IACV, EGR pilot tube, and replace the MAF this weekend, along with cleaning the cam and crank sensors. I ordered 4 gaskets from orderinfinitiparts.com based on this thread:

https://maxima.org/forums/4th-genera...g-dummies.html

thread was written for a 99 i30t (MT) owner - I presume my 98 i30 (AT) will use the same gaskets (?)

reallywildstuff

I am having trouble getting this car to idle properly, especially when cold (dying) - although it seems to idle too low when warm, too. I have yet to touch the cam or crank position sensors as I didn't want to make too many changes at once.

I cleaned the TB, IACV, and EGR pilot tube this weekend - everything was pristine upon re-assembly, including new OEM gaskets. Brand new Bosch MAF.

The hacksaw step is truly regrettable - I hope there is a special place in hell for the Nissan engine designer that couldn't make the EGR tube 3 mm bigger to clear the MF rear lower pilot tube nut and stud. Pilot tube wasn't as blocked as some pictures I've seen - but there was a lot of buildup inside the intake where it meets the pilot tube. I cleaned all that up.

I disassembled and cleaned the three plungers on the IACV too - they weren't that dirty either.

TB blades were coated in carbon but seemed otherwise normal. Again, everything was thoroughly cleaned with TB cleaner.

Re: setting idle - I am "mostly" following the procedure in the FSM (not using a diagnostic computer):

1. at operating temperature
2. engine off
3. disconnect BOTH TPS plugs (FSM shows disconnecting just the rear one - ?)
4. start engine, it revs itself to 2k, then drops to ~800 and burbles/ranges for idle across approximately 300 rpm
5. use throttle to race engine to 3k several times - idle drops back to ~800, sometimes it idles strong, sometimes it drops down and starts to range for idle
6. adjust idle speed screw on top of IACV (turning CCW = higher idle) - I had been doing 1/4 turns at a time, but that was getting old, as the low idle was still a problem after 4 rounds of 1/4 turns at a time. Backed it out 1.5 turns this AM - still idling rough, and not having the high idle I kind of expected to see given how much I've turned that screw.
7. engine off
8. plug in both TPS sensors
9. start engine, test drive

The engine starts and runs OK and, performs fine at speed. But if I leave it idling (either in Park, neutral, or Drive) the RPMs eventually drop below 700 and it starts to range for idle (needle moves up and down over ~300 RPM).

Sometimes it dies. When the engine is cold, it dies in Reverse, or shifting from Reverse to Drive (due to the low idle).

I did the cleaning work and replaced the MAF re: my original post (dying from 30 mph) - I can't make it die like that anymore, but even when it was occasionally dying back then the idle was strong and solid, without the burble or the ranging I'm seeing now, and without the dying getting out of the parking spot.

I had expected, after cleaning all the carbon off the intake, that I would be having a high-idle problem - not a low-idle concern.

I'd appreciate any pointers. I am willing to accept criticism re: not touching the crank and cam position sensors before now - but I wouldn't mind understanding WHY the car will run at all if those position sensors are to blame.

PH98I30

When your upper, lower oil pan leaks, the oil runs down around the crankshaft position sensor and the accumulating dirt and sludge gum it up and mess with and block the sensors. Clean the sensors and electrical connections. You have 2 CPSensors. One by the oil filter and the other by the transmission, I believe.

reallywildstuff

The CEL came on for the ride home today, four codes (edited. I wrote them backwards earlier)

P0325 (Knock sensor) & P0325 infinite
P0171 (bank1 too lean) & P0171 infinite

I was thinking that the idle was finally set too high just before the CEL came on - I suspect that I leaned it out too much by opening the idle screw up too much, and also that the knock sensor can tell that the engine is running like poo poo.

Even though it idles high in Drive now, it was still stumbling around at low RPMs, and dying when cold.

I will clean the Crank and Cam sensors tonight for sure. I don't like the cause-effect relationship at work, but, whatever.

PH98I30

I have the same car as yours. I believe PO325 are 02 sensor readings. Looks like you might be due for new ones. The knock sensor code is usually a ghost code, but in my case my knock sensor was cracked. It can be replaced without removing the UIM. Whoops... 0325 is the KS code... my bad. A bad KS will make the car run crappy.

reallywildstuff

I appreciate the help - I will prob need more soon. I cleaned the two crank sensors and the single cam sensor - not that dirty, some metal shavings on flywheel crank sensor.

No change - Still ranging for idle and dying when cold, also throwing KS and lean codes - I took better notes re behavior and will share them if I cant fix this.

Saw a crack in the KS and removed it - it then came apart is my hand as I removed the harness connector. Ive ordered another Nissan OEM piece (expensive) and harness.

ALSO - i think this is what I get for letting other people work on this car...I belatedly realized the absolute pressure sensor has been hanging down, connected but not secured, laying against the bell housing area, THE WHOLE MF TIME ive been trying to level this idle thing out. I zip tied it back and retried setting idle (this was before the KS came apart), but still no love. Ive ordered another absolute pressure sensor (also OEM, also expensive) as well.

So this is basically just a Bump but again I appreciate the help and Ill write more after the parts show up.

BrianA in Houston

reallywildstuff

Please help me understand what the "high" and "low" states of idle (below) represent, i.e. what is actually happening/what information if going into the ECM that causes the RPMs to drop, and then rise again, in regular intervals of maybe 15 seconds each. Is this part of the regular programming? Is one state a "Test" and the other "Run" or...? Or is it indicative of something else?

I have a bound copy of the FSM and refer to it frequently - but I don't see any mention in the FSM of this "two states of idle" than I'm seeing. I don't know for sure how the system was supposed to behave when it was all brand new and perfect - so I also can't tell how much slop in the idle is acceptable after 15 years but with a newly cleaned TB, EGR guide tube, and IACV.

I replaced the Knock Sensor (you have to really will it in there huh?) and the Absolute Pressure Sensor last night and test fired/tuned. It was late last night when I got done so I haven't decided whether its really fixed or not. It definitely started and idled halfway decent from cold, without the RPMs bouncing around as much as I remembered.

Regardless of whether the TPS sensors are unplugged or not, and regardless of whether the engine is at temp or not, the idle has two distinct states:

High
and
Low

With the TPS connected and engine at temp, RPMs are 1100 "High" and 750 "Low". I can also make it switch states by revving it real quickly and sharp - when it comes back down it's usually in the "Low" state. There are two other, similar states of idle when the TPSs are disconnected and while turning the idle set screw: "High", and "Low", usually a little higher RPM figures for each state than with the TPS connected.

I have been setting the "base idle" (shooting for 750 in neutral and at temp) when the system is in the "Low" state - if I were to try to tune it to 750 in the "High" state it would die when it went down to "Low". Is that the correct approach to be taking?

Thanks in advance -

BrianA in Houston

DBear

A couple of thoughts:

1. You said you had oil in one of the spark plug tubes. Did you replace the seal? You might be leaking oil into the cylinder and fouling the plug.

2. Years ago, my RPMs would drop occasionally at idle. It didn't die, but would go down to about 300 or 400 and then bounce back up. I finally replace the plugs with NGKs, and the problem went away. You say you replaced your plugs. What brand did you use?

reallywildstuff

No I did not replace any spark plug seals.

You better believe I used NGKs - I will never use anything except Nissan OEM, and originally-specified third-party, ever again.

Steinillac

You seem to be on top of this, so I assume you would've already identified a leak if there was one. However, my personal experience with low idle and lean codes was as simple as re-securing a few hoses clamps and most importantly identifying that my iacv gasket was installed incorrectly. I had just finished replacing the valve cover gaskets and rushed through the end to beat dusk.

reallywildstuff

The above from Steinillac pushed me to the solution: putting the car back together CORRECTLY helps, i.e. the gasket between the intake and the EGR pilot tube should definitely be secured with BOTH bolts, and NOT just the bolt closest to the driver's side. The vacuum leak was the result of an incomplete seal between the pilot tube and the intake manifold, caused by an incorrectly installed EGR pilot tube upper-port gasket.

Thank you, Steinillac, and Thank You to DBear, PH98I30, CS_AR, njmaxseltd, Turbobink, and LJay (and I hope I didn't leave anyone off) for your assistance.

Thank you to Cardone Industries for RMAing their MAF thru O'Reilly's. The Cardone MAF was replaced as a matter of course re: attempting to resolve the original complaint of "dying at speed". Cardone was very pleasant to deal with.

I write for the benefit of other frustrated "mechanics" trying to solve idle problems like the one I spent so much time diagnosing and documenting (instead of identifying and fixing) - don't hesitate to SWALLOW YOUR PRIDE and liberally apply throttle body cleaner to the vacuum galley (immediately below the TB) of your running engine as a way to look for vacuum leaks that YOU ALMOST CERTAINLY CAUSED, and ALSO (this is key, especially if you just cleaned your EGR tube) to the large vacuum hose on the back of the intake that appears (as you are looking at it from from the driver's side) immediately to the left of the upper port of the EGR pilot tube.

Everyone who suggested "vacuum leak" was 100% correct. It was Steinillac's post that made me SWALLOW MY PRIDE and accept that the most likely explanation was "you're doing it wrong". Listening to everyone else's sound advice to begin with would have saved a lot of time.

I sprayed TB Cleaner at the IACV and the idle ticked up. I took the IACV off to examine the gasket - my recollection was of taking special care to make sure it was installed correctly (funny in retrospect, because that was one gasket too-late to be paying that close of attention to) - and in fact the IACV gasket is an irregular shape, and thus the gasket only fits on one way.

I had ordered two of every gasket, so I used a new IACV gasket (although there was of course nothing wrong with a brand new IACV gasket with only 2 hours of test-run time on it) but after putting it back together I still had the vacuum leak. By spraying more TB cleaner at the vacuum galley, my thoughts were that it seemed to be leaking from "everywhere", but more so from the single large vacuum hose on the back of the intake (next to the EGR pilot tube upper port).

I removed the IACV again (I got quite good at this) and removed the large vacuum hose so as to replace it - in fact I had previously removed this large vacuum hose from the intake when I used the hacksaw (see there it is again) on the EGR pilot tube lower rear bolt (I didn't want to accidentally nick or puncture the rubber vacuum tube with the hacksaw blade) and so it stood to reason that I had re-installed the hose incorrectly, or somehow damaged it.

It was only after removing this large vacuum hose from the back of the intake that I was able to discern the incorrectly installed EGR guide tube upper gasket, hanging down at a 45 downward angle and from just the one bolt on the near side. What I had mistaken for vacuum leaks "everywhere" turned out to be _just_ the _overspray_ _only_from the TB Cleaner (pointed somewhere else, at other vacuum hoses) being sucked up by the large leak at the intake/EGR pilot tube connection. I confirmed this upon re-assembly - no more uptick in idle by spraying TB cleaner at any vacuum hoses, or the IACV, or anywhere else.

I was able to replace the upper EGR guide tube gasket without touching the guide tube's lower bolts at all.

In attempting to diagnose this issue I was initially intimidated at the prospect of removing the IACV and the attendant risk of re-disassembling (and possibly breaking) parts off the air box and TB plumbing - but none of that has to be removed to take the IACV off, or to work with the EGR pilot tube after removing the IACV.

I took notes re: turns on the idle set screw - I was at 4 turns out with the leak, now I think it's something like 1.75 (substantially lower), although I admit to losing precise track late last night. After test driving to my real job this AM I think the idle is still set a little high (like 800, instead of 700). I will document how many turns out from seated ends up yielding the best idle.

I'd like to share some other thoughts I've been kicking around, as someone who tries to do a good job, and who likes to think they know what they're doing...but doesn't necessarily have the EXPERIENCE NECESSARY (this was my first time taking a Nissan system like this apart) and thus could only be armed with JUST ENOUGH KNOWLEDGE TO BE TRULY DANGEROUS:

It doesn't matter whether the car runs well on the freeway, or when it's warm - if it doesn't idle when cold, you're not doing it right. RPMs should be consistent when adjusting the base idle - RPMs that are ranging up and down AT ALL are indicative of another problem, and No, it _still_ doesn't matter how well it runs on the freeway. Ye shall reap bountiful rewards by accepting this truism at the onset - just because this car seemed to go really well above 2k with only half a gasket in-place doesn't mean that missing half of the gasket wasn't important.

BEFORE you do the TB/IACV/EGR pilot tube three-step clean-o-rama, may I respectfully suggest that you REVIEW what the final steps are to the procedure (namely, adjusting base idle via disconnected TPS sensors) and PRACTICE DOING THAT on your running car. By making friends with your project at this time you will not only be observing a baseline before you take it apart/potentially F it up, but perhaps more importantly will have put your head in there so many times times that you'll get used to what a "normally" breathing 3.0 VQ sounds like.

I did not do either of these suggested things, and I wasted a considerable amount of time not identifying what, in retrospect, was a HUGE *** SUCKING SOUND in the back of the intake manifold that resulted in CRAZY, NON-SPEC RPM FLUCTUATIONS when attempting to set idle RPMs. I did not identify the sucking noise as an issue with my own re-assembly, and mistook the RPM fluctuations for a cause (rather than a symptom of the real problem), due to Pure Noobery.

Thanks again for the help -

BrianA in Houston