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Discussion Starter · #1 · (Edited)
Hi everyone, I’m new to this forum. My daughter has an 2009 Murano. She’s had it for a few years and has had her share of issues. For background, the engine quit while driving on a summer day. It wouldn’t even turn over. I was out of town so she took it to a place we thought was reputable. They replaced the alternator, battery and belt. It was fine for until we had a very cold winter morning, wouldn’t start. I was at work so she had a towing service try to jump start it. (he only had a gel pack that he used many times that day) He couldn’t get it started so I left work with the intention on jumping it with my truck. I neglected to try to start it and just jumped it. It struggled to start with a fuel smell so I put the pedal to the floor to clear. I got it started but she continued to have the problem. As it was the dead of winter in Minnesota and I don’t have a heated garage, I had to take it back to the shop. I did tell them the problem was similar and we had a new battery and alternator. After $1500 for a tune up (plugs), intake gasket, valve cover gasket, plenum gasket, valve cover gasket, valve cover and talk of a coil with oil on it, she got the car back. So here we are 8 months later. The car wasn’t started for about 24 hours (it never sits this long) it wouldn’t start yesterday(30 degrees out). It did crank though. I had her put the pedal to the floor and it stumbled to a start. It had a lot of fuel smell and white smoke from the tail pipe. The smell and smoke cleared out in a few minutes. I let it run a bit and shut it off. I waited 30 minutes and started it again, all normal. I waited a few hours and it started normally. She went home and it started normally this morning after
sitting for about 10 hours. I know nothing is fixed. As far as car repair, I can change most parts and have an advanced scan tool. My experience is really airliner maintenance. I’m thinking fuel is leaking down into the engine over time. I’ve changed pressure regulators over the years but it was always on the fuel rail. It seems like the fuel pressure regulator is on the fuel pump from what I can find online. I don’t know if leakage could happen with this setup. I’d appreciate any help I can get, I’d like to same he some money by doing the work myself.
I’m sorry this is long winded but I wanted to give the whole picture. One thing to add is she told me sometimes she sees her lights pulsating bright and dim. I’ve not seen this myself but thought I should mention it.
Again, thanks in advance for any help.
 

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Sounds to me the problem is electrical... I would have the battery and alternator load tested, this will definitively show whether they are good or bad...

I'm sure you have already done this, but make sure the battery terminals are totally free of corrosion and snug. If there has been severe battery terminal corrosion in the past, one or both of the battery cables may have internal corrosion and high resistance. Also check and clean ground connections, especially the one under the battery tray, and the connection to the CVT.
 
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The fuel pressure regulator is integrated into the fuel pump assembly. You say you have a high-end scan tool so you should be able to look at some live data. I would suggest looking at engine coolant (ECT) and air temperature (IAT) readings with the engine cold in the morning with key-on, engine off and see if the measurements the ECM is reading look consistent given the ambient air temperature. A high/higher than normal ECT temperature on a cold day can cause a no-start because the A/F mixture will be way too lean for a cold engine. If those look fine, I would turn the engine on (if it starts), let it warm up to operating temperature, and check fuel trims and the MAF sensor reading. In fact, the next time this no-start problem happens disconnect the MAF sensor and try to start the engine--if it does then inspect the sensor for contamination/corrosion since this can definitely cause a no-start.

If you suspect the problem is with the fuel pressure regulator (e.g. stuck open) or a weak fuel pump, I would expect fuel trims to be on the lean side (high positive) at idle for both banks with trims possibly getting worse as engine speed and load increase. Unfortunately, a special adapter needs to be installed inline to the fuel rail to do fuel pressure testing. You may want to keep a can of starter fluid (or brake parts cleaner) in the car for when it happens again and if it won't start up right away, spray some into one of the hoses attached to the intake manifold (e.g. brake booster). If it starts right up with starter fluid then that usually indicates a fuel delivery issue. If the problem is something like a leaking fuel injector that's flooding the engine then I would expect to see one bank running much richer than the other (i.e. higher negative fuel trims) and I would think a big puff of black smoke from the tail pipe would be evident upon start-up every time the car has been sitting for hours.

Hopefully, this gives you something to start with. Intermittent problems can be tough to chase. Let us know what you find. The factory service manual for the car is available here (...see the "Engine Control System" file): https://www.nicoclub.com/nissan-service-manuals
 
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Discussion Starter · #4 ·
Sounds to me the problem is electrical... I would have the battery and alternator load tested, this will definitively show whether they are good or bad...

I'm sure you have already done this, but make sure the battery terminals are totally free of corrosion and snug. If there has been severe battery terminal corrosion in the past, one or both of the battery cables may have internal corrosion and high resistance. Also check and clean ground connections, especially the one under the battery tray, and the connection to the CVT.
Thanks,
Are you talking about the failure to start or the lights flickering? The alternator and battery are a year old but I can have it checked. I’ll also check the cables and grounds. I’ll need to find where the CVT ground is.
 

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Discussion Starter · #5 ·
The fuel pressure regulator is integrated into the fuel pump assembly. You say you have a high-end scan tool so you should be able to look at some live data. I would suggest looking at engine coolant (ECT) and air temperature (IAT) readings with the engine cold in the morning with key-on, engine off and see if the measurements the ECM is reading look consistent given the ambient air temperature. A high/higher than normal ECT temperature on a cold day can cause a no-start because the A/F mixture will be way too lean for a cold engine. If those look fine, I would turn the engine on (if it starts), let it warm up to operating temperature, and check fuel trims and the MAF sensor reading. In fact, the next time this no-start problem happens disconnect the MAF sensor and try to start the engine--if it does then inspect the sensor for contamination/corrosion since this can definitely cause a no-start.

If you suspect the problem is with the fuel pressure regulator (e.g. stuck open) or a weak fuel pump, I would expect fuel trims to be on the lean side (high positive) at idle for both banks with trims possibly getting worse as engine speed and load increase. Unfortunately, a special adapter needs to be installed inline to the fuel rail to do fuel pressure testing. You may want to keep a can of starter fluid (or brake parts cleaner) in the car for when it happens again and if it won't start up right away, spray some into one of the hoses attached to the intake ma was nifold (e.g. brake booster). If it starts right up with starter fluid then that usually indicates a fuel delivery issue. If the problem is something like a leaking fuel injector that's flooding the engine then I would expect to see one bank running much richer than the other (i.e. higher negative fuel trims) and I would think a big puff of black smoke from the tail pipe would be evident upon start-up every time the car has been sitting for hours.

Hopefully, this gives you something to start with. Intermittent problems can be tough to chase. Let us know what you find. The factory service manual for the car is available here (...see the "Engine Control System" file): https://www.nicoclub.com/nissan-service-manuals
I was able to look up the readings I captured the other day. The engine wasn't fully cold tho. IAT was 73 degrees which seemed high to me and coolant about 160. I drove the car around the block monitoring the temps, I had IAT at 73 and coolant about 160 when I started. IAT got down to 58 with coolant at 170 on my drive. My last readings were IAT at 79 and coolant at 190 as it sat in the driveway.
I will arrange to get the temps without starting the car. Since it is push button start, I might have some trouble getting the cold readings but I'll try.
I think there are quite a few fuel trim parameters I can read, I'll get as many as I can.
I was thinking about an injector, I'll get the fuel trims and see what they are.
Would a bad regulator way back on the pump act the same way as one on the rail? It looks like the pump is somewhat easy to access if needed.
Thanks for the information, I'll post back with results.
The manual link is invaluable.
Thanks.
 

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Thanks,
Are you talking about the failure to start or the lights flickering? The alternator and battery are a year old but I can have it checked. I’ll also check the cables and grounds. I’ll need to find where the CVT ground is.
It all started with it quitting and not turning over, and the battery and alternator being replaced, then similar problems later...

Before troubleshooting other possible cause further, I think it would be best to have the battery and alternator load tested to be sure they are performing correctly. Bad rebuilt alternators are very common unfortunately... Marginal voltage can upset the engine computer controls and could be producing the symptoms you're working on...
 

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Discussion Starter · #7 ·
It all started with it quitting and not turning over, and the battery and alternator being replaced, then similar problems later...

Before troubleshooting other possible cause further, I think it would be best to have the battery and alternator load tested to be sure they are performing correctly. Bad rebuilt alternators are very common unfortunately... Marginal voltage can upset the engine computer controls and could be producing the symptoms you're working on...
I'll have her car tomorrow night and can take it Saturday morning to be tested. I'll check IAT temp after sitting overnight also.
 

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I'm not sure the dimming lights while the engine is running are directly related to the starting problem, but it's possible. It could just be a buggy aftermarket alternator that was used for the replacement. Unfortunately, we've heard time and again of people going through two or three aftermarket alternators before finding a good one...

If you live in a rustbelt region then you should definitely check the battery negative cable connections. The cable attaches to the frame via a bracket underneath the battery tray and terminates at the CVT. If the cable is crusty and/or any of those connections are corroded then I would suggest replacing the cable.

I would also check the drive belt tensioner and idler pulleys. Usually a shop won't replace those along with the drive belt unless you ask and if the car has anywhere near 100k miles or more those are probably shot.
 
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Discussion Starter · #9 ·
I'm not sure the dimming lights while the engine is running are directly related to the starting problem, but it's possible. It could just be a buggy aftermarket alternator that was used for the replacement. Unfortunately, we've heard time and again of people going through two or three aftermarket alternators before finding a good one...

If you live in a rustbelt region then you should definitely check the battery negative cable connections. The cable attaches to the frame via a bracket underneath the battery tray and terminates at the CVT. If the cable is crusty and/or any of those connections are corroded then I would suggest replacing the cable.

I would also check the drive belt tensioner and idler pulleys. Usually a shop won't replace those along with the drive belt unless you ask and if the car has anywhere near 100k miles or more those are probably shot.
I was able to get data when the car sat overnight in about 35 degree temps. It started normally for me, my daughter did have some trouble in the past few days with the first start of the day. My scan tool dashboard read IAT of 45 and coolant of 46 in 35 degree temp at startup. I did stream the data and the very first coolant temp recorded was 91, not sure why that is. I did watch the dashboard and the temp continuously increased and the IAT slowly climbed as the car warmed up. I also recorded the fuel trim values and MAP values. Should the long term trim values be similar for both banks? The short term values generally moved together. I made a pdf of the data and attached it, I couldn't attach the excel file for some reason.
Below is a summary of the data.

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I will look for a place to load test the charging system today and check the battery cables.
thanks for all of the guidance.
 

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I was able to get data when the car sat overnight in about 35 degree temps. It started normally for me, my daughter did have some trouble in the past few days with the first start of the day. My scan tool dashboard read IAT of 45 and coolant of 46 in 35 degree temp at startup. I did stream the data and the very first coolant temp recorded was 91, not sure why that is. I did watch the dashboard and the temp continuously increased and the IAT slowly climbed as the car warmed up.
The IAT readings are fine, but if I'm understanding you correctly you were getting 91 degrees for the ECT at start-up after the car was sitting overnight in near freezing temperatures? That is definitely not normal. ECT should normally be within 10 degrees or so of the IAT (usually warmer) and both should be somewhat close to ambient temperature if the car is sitting overnight. Not sure if I understand the jumping temperature issue--the ECT value shouldn't change from KOEO to engine start-up.

I would try to replicate that after the car is sitting overnight in the cold again. That is, see if you get an unusually high ECT temperature again, and if so, rather than start the engine try jiggling the harness connector while watching live data and see if it changes (...if it does then maybe a loose pin?). Then, unplug the ECT sensor and watch live data to see the response--creating an open circuit should cause the reading to drop to an extremely cold level like -40 degrees. If it does then probe each of the two pins of the harness connector with a DVOM to find the power feed and make sure you get about 5 volts. If that all checks out then I'd go ahead and replace the ECT sensor. Another common practice is to also bridge the pins with a fused jumper wire and see if the live reading shoots to an extremely high value like 286 degrees or so, but I'd say at this point it's pretty much certain the ECT sensor is bad.

I also recorded the fuel trim values and MAP values.
The MAF reading is technically within spec, but it looks a little low to me. 0.4 lbs/min is about 3.03 g/sec and the rule of thumb is that an engine idling at operating temperature should get a MAF value equal to about engine displacement in liters (i.e. about 3.5 g/sec in this case). However, that's just a general rule of thumb and not a law so I wouldn't say there's anything wrong with the MAF at this point, but you may want to take it out of the airbox and inspect the resistor wires.

Should the long term trim values be similar for both banks? The short term values generally moved together.
Short-term fuel trims should constantly be moving, but ideally long-term fuel trims should be 0.0 for both banks with both banks being equal or near each other. In reality, anything within +/-10 for long-term fuel trims is considered "normal", but values approaching the limit may be cause for alarm as would a relatively large difference between banks. In your case, both banks are running a bit on the rich side with bank 1 being quite a bit richer than bank 2. Not sure this is meaningful in relation to this new P0420 code, which is a bank 1 catalyst efficiency fault. A clogged catalytic converter can cause an engine or cylinder bank to run rich, but that code can also be caused by a bunch of other things besides a bad cat. You may have pulled a pending code if the MIL isn't lit since if the ECM detects the same fault criteria for two consecutive drive cycles then it will turn the MIL on.

BTW, how many miles are on this car?
 

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Forgot to upload a pic with the ECT sensor location... It's on driver's side of the engine plugged into a coolant gallery. Take off the air intake tubing and you should be able to get to it no problem.

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Discussion Starter · #13 ·
Forgot to upload a pic with the ECT sensor location... It's on driver's side of the engine plugged into a coolant gallery. Take off the air intake tubing and you should be able to get to it no problem.

View attachment 54278
Happy Thanksgiving everyone.
I was able to check my daughters car this morning,
Attached is a summary of the data and the whole report is attached. I did add rpm and opened the throttle after it was warmed up. The temp sensor data looks good to me this time. The car has about 130K miles. Does the short/long trim data suggest anything?
I can take DVOM readings at the battery terminals. Will a bad cable feel warn due to high resistance?
Due to the cars age, is it worth replacing both cables? I looked at local parts stores and the negative cables they say fit are between 25 and 72". Not sure where to find the parts, its surprisingly difficult . My go to Rock Auto doesn't have them listed. Any other suggestions on what I can check?
 

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You'll have to go OEM for the negative cable since it has a current sensor integrated into it. The part number is 24080-1AA0A.

Those fuel trims look fine as do the other readings. Has that problem occurred in the last few start-up attempts? Intermittent issues can be a pain to track down.
 
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Discussion Starter · #17 ·
You'll have to go OEM for the negative cable since it has a current sensor integrated into it. The part number is 24080-1AA0A.

Those fuel trims look fine as do the other readings. Has that problem occurred in the last few start-up attempts? Intermittent issues can be a pain to track down.
I'll look into a cable. The issue started on our first cold morning this winter. It typically starts well during the day, she had one instance where it didn't start normally.

It's been very intermittent starting issues with it starting normally most mornings, both times I read the data it started normally.

I'm concerned with our Minnesota winters that she may get stranded with a no start. I have a charging system tester arriving tomorrow. and I'll report the results.
 

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Discussion Starter · #19 ·
I got an analyzer and checked the battery and charging system. The first time I checked the battery, it reported low CCA left I the battery, around 375 CCA. I thought I captured that screen but didn’t. On the retest, it said the battery was ok. I did get a screenshot of the remaining screens. I’m still looking for a place to load test the system.
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The above, if I'm understanding it correctly, shows your alternator is most likely fine, and your battery was either undercharged or needing to be replaced...

If you have a battery charger, put it on at around 2 amps until it's fully charged. Lower charging amps is more friendly to the battery chemistry. Of course you can use higher amps if you need it charged faster... Test it with you battery analyzer after being fully charged. I would let it rest for a few hours before testing to allow surface charge dissipate.

Any local auto parts store should be able to load test the alternator and battery for free.
 
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