"Low Battery Charge"

[dekota]

HiI have a 1991 Q45. I started getting a "low battery charge" on my dash. I replaced the battery, cleaned all the terminals. It is much better now - when I drive at high RPM no problem, at lower RPM (surface streets) the RPMS suddenly drop to zero - somtimes it jumps back up and runs again, sometimes it just dies and says "low battery charge". I had the alternator tested at two places - both came up "ok" - the readings on the tests were 3.9 and the other 4.0. I checked my manual, and it indicates the regulator should put out 4.1-4.7V. Is that small difference enought to cause these symptoms? Thanks for any help

[Jesda]

Howdy

The Q's computer display will say "low battery" or "transmission malfunction" for almost anything. Nissan tried to emulate the fancy computer displays found in German and American cars, and failed miserably.

Just put a piece of tape over it.

In your case, it could be a dirty throttle body, failing MAF, or failing FPCU (fuel pump control module in the trunk) causing it to stall. Or maybe something else.

Start by telling us the maintenance history. Don't worry, the problem has nothing to do with your battery or alternator.

Is your fuel pump getting loud?

[dekota]

After reading how hard it is to replace the alternator...it is good news that it can be something else!

The car has 138K on it. Normal maintenance such as oil changes, etc on regular interval. One fuel injector had to be replaced. When I started having this problem I replaced the fuel filter and ran some fuel injector cleaner trough it. It does seem more fuel related, the way it just cuts out. The battery is strong, lights stay bright, no difference if lights/radio on. What other information would help?

oh, I have not noticed the fuel pump getting loud.

I do get the "transmission manfunction" message sometimes too.

[Jesda]

At cruising speeds on the highway does it ever start bucking? If so, 99% likely a bad MAF.

Try cleaning your MAF, just for the hell of it, and put in a new OEM air filter if its dirty. A how-to:http://www.q45.org/maf.html

Also, a transmission-related theory:zerothread?id=102297Seems that if it happens during hard braking/sudden stopping, then its transmission related. Mine did this when it was overfilled. Evan's Q did this when the fluid was low.

[dekota]

Bucking! Yes, this is a great description of what it does. It kinda just jerks.

I will give your suggestion a try and report back - thanks so much!

[Jesda]

If cleaning doesn't help then a new MAF is about $400, or you can snag a used one from an online junkyard (90-94 only) for $30-$100.

http://www.car-part.com/ -- Its labeled on the site as "AIR FLOW METER"

[dekota]

I am looking through my manual to find the part number for the OEM air filter, cannot find it anywhere - do you happen to know? Why is it so important to use an OEM filter? Are the others inferior?

Thanks again!

[CrimsonQ]

just call up the dealer. might have VIN # handy as sometimes they ask for that.

My low charge light came on, because my alt belt had snapped. so it does mean something, sometimes

[maxnix]

1.) Normal maintenance such as oil changes, etc on regular interval.

2.) I replaced the fuel filter and ran some fuel injector cleaner trough it.oh, I have not noticed the fuel pump getting loud.

3.) I do get the "transmission manfunction" message sometimes too.

1.) Define "normal maintenance." Most of us are a little more agressive about preventative maintenance. Does it include a mechanical ATF exchange, pan drop, filter replacement? Auxiliary ATF cooler installed? 3,750 OIC? Annual filter replacements? How often are the PS and brake fluid replaced? BG44K? ISO-HEET?

Experience and Q45tech have taught us to be particular.

2.) "Some fuel injector cleaner?" You need to measure your fuel pressure with a T fitting right after the filter. Expecially if you don't know when the pump was last replaced.

3.) Run the AT diagnostic procedure in the FSM.

Despite what Jesda says, all OBD I cars are relatively stupid. Why one will at some point need to rely on a experienced G50 technician and a Consult.

OEM filters only except for oil, where an M1 from Joe will do nicely. It's all in the previous posts.

By the way, go around to the back of your car and read the trunk. I believe it will say Infiniti.
Modified by maxnix at 3:37 PM 1/30/2007

[elwesso]

Saying that "transmission malfunction" and "low battery charge" mean nothing is TERRIBLY ignorant... it may not be what is immediately obvious. Just because it says "transmission malfunction" does not necessarily mean the transmission is bad, however it CANNOT be ignored because these things do not come on for NO reason!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Anyway, do your trans diagnosis.. i posted an article in the articles forum how to do it. Many times if the car stalls then it will show low battery charge even though your alternator is fine... because technically its not charging enough if its not charging at all

Call up Joe at infiniti of scottsdale for all your parts!!!

[Q45tech]

Just because we are moderators doesn't mean we are always correct and explain things accurately for the novice.

Few of us [anyone?] have agreed to what should be a daily Opus Dei type self-flagellation [called SI in the emergency room] to purify our words.

A WARNING LIGHT ILLUMINATION is just that be warned! Plus most of them increase GLOBAL WARMING in some manner or another.

One must add humor to these boards otherwise the repetition will get you committed. Drooling and tics are a common side effect of moderation.......from holding the Tourettes at bay in public.

http://www.tourettesguy.com/in...id=27

[Jesda]

Saying that "transmission malfunction" and "low battery charge" mean nothing is TERRIBLY ignorant... it may not be what is immediately obvious. Just because it says "transmission malfunction" does not necessarily mean the transmission is bad, however it CANNOT be ignored because these things do not come on for NO reason!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thats like telling a doctor you think your ankle is broken when you're actually having a heart attack. Completely farking useless and does nothing but waste time and money while the real problem gets worse.

Fortunately, error messages have become more useful on fully computerized modern cars, instead of decorative. Of course, that computerization leads to its own set of problems.

[Jesda]

I am looking through my manual to find the part number for the OEM air filter, cannot find it anywhere - do you happen to know? Why is it so important to use an OEM filter? Are the others inferior?

Thanks again!

You can just grab an air filter at your local dealer. It shouldnt be more than $10-$15. The seal on an OEM air filter is tighter and more uniform, allowing fewer dust particles to get past. Those large dust particles will damage your expensive (and sensitive) MAF sensor.

I had a Purolator air filter installed in my last Q for a while. When I removed it, I could see areas on the plastic housing of my intake where the dust got past the poorly manufactured rubber seal.

The sick humor was that the Purolator filter, I found out, cost $1 more than OEM.

[elwesso]

some dealers will try and rip you off. I once paid $20 on an air filter when list is like $9.... You can haggle with them.. If its anywhere over $10 id argue it down to the $10 price, because they are $7 from Joe.

Thats like telling a doctor you think your ankle is broken when you're actually having a heart attack. Completely farking useless and does nothing but waste time and money while the real problem gets worse.

Fortunately, error messages have become more useful on fully computerized modern cars, instead of decorative. Of course, that computerization leads to its own set of problems.

Actually its more like telling your doctor that your arm hurts while having a heart attack. Its not your arm, but the arm hurting is a symptom of a heart attack.... Of course, all codes must be taken with some degree of haste, because as we know some codes cannot be interprited absolutely...

Until one understands WHY the message is being conveyed, ignoring it simply is not smart.

[dekota]

I removed the air filter and it was very dirty - I had had a loose oil fiter a while back, and it looks like some of the oil got sucked up into the filter. I replaced it with a filter from the dealer ($17 plus tax), cleaned the MAF sensor with CRC MAF sensor cleaner - and problem fixed!

Thanks to everyone who took the time to help - I read a lot of the posts on this fourm, and it is just a fantastic resource.

[Jesda]

I love happy endings.

[maxnix]

By a supply from Joe.

M1 for engine, OEM for air and fuel and ATF.

Air and fuel should be changed annually for optimal performance. Don't wait until they are clogged.
Modified by maxnix at 8:22 AM 2/5/2007

[bmwkiller]

After reading how hard it is to replace the alternator...it is good news that it can be something else!

Where did you read that? I just did mine, and it was a little involved, but not really too bad. The only really difficult part was getting the nut on the back of the lower alternator bolt. Otherwise, it's fairly straightforward. You gotta unbolt a few things, but nothing really hard. Just a little time consuming.

[dekota]

maybe time consuming would have been a better word for me to use. I read about it on this forum - how it took one guy 4.5 hours because of the difficulty in dealing with the location.

[dekota]

I lied - problem not fixed. It is better, but still having the hesitation problem. Just died several times at a stop light this am. Wondering if the MAF is just bad. Thought I would try cleaning the throttle body today to see if that help.

[dekota]

I just stuck my head in the truck, and can hear the fuel pump hummin - how do I know if it is "getting loud". What is the normal sound of the fuel pump? Thanks

[Haitian_King]

Idk.

My Q bucks going into the 40mph zone. Like between 37 and 40mph. What does that mean? My Q is a 92 with 84,000 miles. What exactly is cruising speed on a Q? Like 60mph and above?

[cabal1024]

A very loud humming from the trunk will happen when the fuel pump is on it's way out. As soon as you hear it, get a new one. Installation is easy. Purchasing one is easy too, but they are expensive pieces of equipment.

When your Q's RPM fluctuate at stop, do you blow black smoke out the exhaust? I saw a while ago that the transmission could be at fault for killing the engine at stop. Search the forum for it. Check yuor fluids.

[dekota]

Just wanted to provide an update on my care troubles. I cleaned my throttle body - I can only say "shame on me" - it was absolutely filthy. One can of spray and it was still coming out dirty. After cleaning with one can, I ran the car, and the problem was MUCH better - in fact it ran without a hitch for about 100 miles, then it started doing its thing again. I put in a can of 44K and will clean the throttle body again. I am convinced it is a dirty throttle body.

BTW, when I open the butterfly I see something that protrudes up inside the body of the cavity, behind butterfly valve. Not sure if this is a sensor or bolt - but it is caked with gunk. I cleaned it best as I could with the spray, but did not want to actually touch it until I find out what it is - anyone know?

[goody90q45]

BTW, when I open the butterfly I see something that protrudes up inside the body of the cavity, behind butterfly valve. Not sure if this is a sensor or bolt - but it is caked with gunk.

Is it the small diameter tube just behind the butterfly or one of the 2 larger openings, or something else? Regardless, all passages need to be clear. If your hoses aren't brittle I would recommend removing the throttle body for better access to the dirty ports. There's 4 allen head bolts and 4 hoses attached to the TB and it will pull out. Good luck.

[dekota]

I belived the one I was looking at is the larger one in your photo, deeper into the throat - it looked like something was polking INTO the throat there, that it was not just a hole... I will remove the throttlebody and check it out further - thanks

[maxnix]

Now you see why cleaning the plenum, TB EGR and IAC valves is a must every 60K or so.

[dekota]

ok, so I pulled off the TB - the passage from the plenum to the EGR valve is packed solid with carbon. I was able to dig away the carbon in the plenum, but then it makes a hard turn to go to the EGR valve- I will have to remove the EGR to clear the passage.

Could this be causing the problems I am having? Usually when the car is cold and at slower speeds the RPMs just drop, and sometimes the car stalls. When the car is warm, and at high RMP, usually no problem.

If this passage is this bad, what else is likey plugged? Will the IAC valve be as packed?

[dekota]

I have finally fixed my Q. I took off the throttle body, and cleaned it all up. I removed the EGR valve, cleaned it and unblocked the passage between the plenum and the EGR valve- which was packed with carbon. New TB gasket ($14.00 at the dealer, what a rip) - and the car ran pretty darn good - but then, boom, symptoms again. I had noticed when putting the TB back on that the electrical connector that attaches to it had become very brittle and some of the out part has broken away so that it no longer "snapped in place". I took the connector apart, cleaned it with contact cleaner, squeezed in some electrical junction gel, and the put it back together and taped the connection tight - Viola! I have over 100 miles on it, several cold starts, and not a sign of the problem.

Thanks to everyone who helped solve this, and all the wonderful archived posts that spend hours reading through to solve this problem. This is one heck of a resource.

[ceningolmo]

Glad to see you were able to resolve each issue.

Sleep well knowing that you might have fixed some things that weren't directly causing your problem...it might not have been necessary, but your Q is in better shaper for doing all that work.

BTW... I'm moving this thread to IOM because I've been trying to organize the Q forum a bit more since this thread was originally posted.