The other day, my 2000 QX4 quit while driving at around 45mph. Since then its been turning over or cranking but it will not start. I am at a loss as to what the problem could be. Not that I am an expert, which why I am here. Would appreciate any help with this problem. Its been many days and I need it running quick for work for dw.

Some info:
2000 QX4 with 129k miles. Had the dealers put on a timing belt before I bought it in nov last year. It had been running great till this happened.

I changed the fuel filter yesterday is all I did. And the old one was actually quite clean. I can also hear the fuel pump in the tank ....not sure if there is enough pressure in the lines however. I am not particularly savvy with electrical stuff so not sure how to troubleshoot ignition/ spark issues or any other issues. Would appreciate any help from you experts here.

I also, plugged in my cheap scanner but it returned 0 codes. A crude test also reveals compression in the #1 cylinder. The rotor turns as well during cranking. So I am guessing that its not the timing belt. Dont know how to proceed from here now.

1) Could it be the crank position sensor?
2) Ignition module?? Where is it?
3) Distributor cap, rotor, coil, other?
4) Timing is off?
5) Fuel pump, relay, other?

How do I check/test the above or any other possible issues.

Thanks for your help in advance.

Time to take it to a professional............

Or take even more time to download FSM *pdf then read and study thousand of pages. Then buy test equipment and tools to carry out detailed diagnostic proceedure in FSM.

Usually more economical to let a professional on your exact year and model do the 1 hour diagnostic proceedures.

We are here to help professionals with difficult extreme problems and laymen with economic theory.........cost benefit analysis.

Local trade-technical schools are decent places to spend 2 years learning theory, but still 6 months to 4 years of on the job appentice training to specific models is often required to become a professional.

Well...I didnt know...thanks....

If it cranks but doesn't catch, start with the basics. Since you most recently did something with the fuel system I would start there. Crap happens retrace your steps.

Maybe pull the pressure line at the engine and seeing if your getting fuel.

Could it be possible you put the filter on backwards?

Is there anything else you did that day?

Thanks for the reply. I actually didnt think to check back here. I had the car towed to the dealership the other day. The same place where I got the car from.

The car basically quit while driving at 45mph. I replaced the fuel filter AFTER that just to see if it dragged in the sediments and got clogged or something. The filter was clean actually and I installed the new one correctly too nevertheless. I didnt do anything else to the truck. The engine cranks/turns over but will not start.

The service dept lady called me today and told me its just the battery and that with a good battery it started right back up (lied). She said they would replace it and it would be 200 bucks. (testing, replacing the battery and labour).

I was little miffed. I told them that the truck was sitting in my yard for 2 weeks and that the battery was certainly low and I was aware of that and that wasnt why I left the truck there. I wanted them to troubleshoot the real problem. I didnt need to pay them 200 bucks to tell me that the battery is bad. I asked them if they checked the alternator. Or the distributor (cap, rotor, coil, spark...), fuel pump, plugs, injectors, timing belt, timing etc etc...they said they did not. I asked a guy over there to try to start the engine and sure enough, it would crank but would not start. He then tells me that they need to put a battery in before they could check anything else. I asked why they didnt do that and were trying to hand the car back to me with a "dead battery" diagnosis. I thanked them for wasting my time and told them that I would be back on monday morning and would like to speak to a dude over there who I kinda know and believe is competent. Darn! Im afraid that they are gonna throw parts at it until its fixed. Big reason why I was asking for help here.

Also, I am sorry if its in the wrong forum. I did check before posting but didnt see anywhere that this forum is for professionals only. Thanks again for the help.

Ok. Got the news from the dealers' service guys.

Nothing wrong with anything is what they say. They said the following;
1) timing belt is fine (rotors spinning so its fine)
2) Timing is fine - kept cranking the engine until the no#1 hit TDC and say that the rotor was pointing correctly at no#1
3) Spark plugs are fine - produced spark when grounded to the block and cranked...
4) Fuel pump is fine - didnt start when he put some fuel in through the throttle.

So pretty much exactly the things I did before I took it to them.

Now they are saying it could be a bad MAF sensor or alternator... Also that hes unable to think of anything else. I told him to just hang on till tomorrow. I am thinking I will just bite the bullet and get it towed to the nissan stealership...

What do you guys think..Any info? help? ideas?

Personally I won't work on a car with a dead/dying battery. I usually suggest buying one it really makes things much easier.

Fuel Pressure?
Securtiy system?

Unplugging the MAF and cranking the car should yield different results (fail safe operation).

So does the car start or is it still dead?

Thanks for the reply. I had the truck towed back the other day. Just went about checking everything again.

1) Distributor was fine
2) Plug wires were fine.
3) Unplugged the MAF sensor and tried to crank it and it was no different.
3) Started with the plugs. Previously no1 plug produced spark. It did not this time. I got all the plugs out and didnt even need to check them. They were really bad. Went straight to a shop and bought new plugs and put them and the truck started right back up!!

Damn plugs! Elementary I suppose...

So, now I took it for drive and it drove good. But on the way back, the engine was almost quitting or dying everytime at a red light or a stop sign. Even while driving it was skipping or hesitating a bit. All this is with the air conditioning ON.
If the I turn the AC OFF, its fine though.

The check engine light has come on on the way back. I hooked it up and got the code P0160. No clue as to what it could be. Any help with this would be appreciated. Anything to do with unplugging the MAF sensor? Any re-learning procedures required? Whats the correlation to the Air Conditioning?

Define "really bad" in terms of the condition of your spark plugs... were they completely black and sooty?

Heath

Thats correct. Completely black and sooty. Also, the tips were not even visible. I was shocked when I looked at the plugs. I only looked at no#1 in my earlier checks and it was relatively(and only that!) better. It was black but produced a spark in an attempt.

Anyway, I did unplug and plug back the MAF sensor before checking the plugs to see if the engine would run fine in a fail safe mode. No go.

So, now that the plugs are changed, the engine starts up fine but I am getting the check engine light and the scanner is returning the code P0160. The idle RPM is also low. Around 700 but it used to be 1200 or 1300 before. The engine is stalling and occasionally dying at red lights. It somehow seems to be worse for whatever reason with the AC on.

Any thoughts on this?

A fully warmedidle speed of 1200-1300 is way too high. I'm suspecting spec. is near 700. Black plugs means something - but I don't know exactly what. Maybe SteveTheTech will stop by and give us some insignt on what sensor that could be... The only time I've seen blackened plugs was when my old Q jumped time, or when I had injector failures on it.

Code P0160 is a high voltage code from the the left rear oxygen sensor. Start at page EC-278 in the factory service manual (available at www.nicoclub.com/FSM/) and work your way forward.

That said I wonder if this isn't more of a symptom than a cause of your problems.

Heath

I bet its the maf. But it could be any number things. The MAF would cause it to run rich.

The 02 sensor will trash plugs, but as the OP said all of the plugs looked the same, meaning the problem is most likely a problem common to both banks.

However if there is no Air Conditioner signal the idle speed will not adjust and the computer alters timing and fuel mixture to compensate for the increased engine drag. There are many things that could be associated with an missing signal from the ac.

You need to start by testing the O2 sensor (as illustrated in the fsm) and if it really is leaning towards the high side replace it. Then work from there.

Thanks for the help guys.

I cleaned the MAF thoroughly today but there wasnt really any difference. The wires and the housing itself were actually pretty clean. I cleaned it nevertheless.

I am gonna test the MAF and O2 sensors tomorrow.

Looking at the FSM, I gather that the P0160 and P0140 are the codes for the rear O2 sensors on B2 (left) and B1 (right) respectively. But the manual states;

" The a/f ratio is controlled to stoichiometric by these rear sensors" and " under normal conditions, the rear sensors are not required for engine operation".

Can I ignore this Bank 2 Sensor 2 then? I have erased the code and it hasnt come back on.

Ok.

So I went ahead and got a remanufactured cardone MAF sensor from AutoAone. It has a 1 yr warranty so I figured Id go get it instead of waiting after buying something online.

Now, the hesitation/stalling problem still persists and now I have two codes.

1) P0100
2) P0100 pd

They are the codes for the MAF sensor but I dont understand why there are two codes and what the second one is for. Notably, I didnt have a code for the MAF sensor before.

I went back to the Autozone to swap out with a different, but cardone brand, MAF sensor and had the same problem still. It threw up P0100 and there was the hesitation and stalling. I put the original nissan MAF back and decided to order a genuine one online. I start the engine and it hesitates as usual and the rpm keeps dropping to less than 500. Its particularly worse with the AC on.

I go back in to talk to the guy and when I come back out, the truck wont start. Back to square one. It cranks over but wont start. I had erased the p0100 and now it shows no codes.

I unplug the MAF sensor and no difference. It wont start. Incidentally, before I went to Autozone, I unplugged the MAF sensor and it was idling fine and there was no hesitation. Hence I was convinced it was the MAF and decided to go swap it out. It drove fine except when idling.

So now, it cranks over but wont start. I take the no#1 plug out and check for spark and it has none. Its also already got some black coating on the body around the tip.

Any advice and help would be really appreciated. I am gonna have it towed to Nissan monday morning but would be great if I could fix it before then.

Id really sounds like you either have one common problem or several small broken things. Either way just having codes and throwing parts at the car does not appear to be working. Pretty much if the MAF didn't do it your best and easiest bet would be to take it to the dealer.

I agree, many think they are "saving" money by avoiding the dealers 1 hour diagnostic test.....yet they throw part after part at the problem hoping to fix it themselves......spending more and wasting time, when a trained tech could have gotten to the root of the problem quickly and efficiently. Classic case of false economy!

Thanks for the help Steve. I will do that monday morning.

Qship, As I have stated earlier, I will be taking it to the dealership monday morning.
I havent wasted parts or money. Only changed the battery and the plugs. Considering that this Q with 130 miles has all original parts except the air, fuel filters, timing belt and water pump, ive got a lot more parts to change. I am interested in learning and working on my truck myself. I am skeptical of dealerships. Especially the Nissan over here.

I tried to fix a problem and asked for help here. I couldnt and so am going to the dealership. Atleast I have learnt something and have some ideas. I think thats a lot better than if I had walked into the dealership cluelessly...

ugharin wrote:Especially the Nissan over here.

Where is here for you?

The best advocate for you is always you. This hold true whether it has to do with the medical needs, house needs, or car needs. If you read the beginning of the service manuals (EC ) section you will get a better understanding of how this truck works. It's not too complex but it is easy to get lost and many technicians have never actually read that so the more you know the less likely you are to get taken advantage of.

Here is Oxford, AL.

Just dont trust them based on past discussions and interactions with them. For instance, they stated that I was wrong about the power valve screws issue and that they had no idea what I was talking about. Later they claimed it was only for a couple of model year altimas and never happened on any other model. And then quoted around 500 bucks to loctite the power valve screws on my 02 (precaution).

The mistrust is all the more reinforced now. I explained to them everything when I dropped the truck off. They said they were gonna hook it up to consult-2 and then check everything out.

When I went back, the guy told me everything was fine and that it was only a case of a bad distributor. He told me it would be 398 for the part (dist assy) plus 2.5 hours labour to around 675 bucks. I asked him if everything checked out okay and was ruled out and he stated that he had it hooked up to the consult-2 and nothing came out and everything was a-okay. I told him to go ahead and have the new dist put in. I then went to speak to the mechanic and he stated that he hadnt checked anything at all! Zilch! nothing! . He stated that since the truck wouldnt crank, the first thing he did was try it out with a new dist and it cranked right back up. He did not hook up the consult-2, let alone manually check anything else. Not even the spark plugs. And it took him less than 10 minutes to put in the new distributor. And I paid for 2.5 hours labour.

The only reason I didnt do it myself was cause I didnt want to mess the ignition timing up and I havent done this before. Besides, I was tired and just wanted to get it over with.

But yet again and another reason why I am always suspicious of dealerships. I am glad though that this problem is fixed and thanks again to everybody who has helped.

Just remember that there's a difference between the "book time" you pay and the time the tech. actually takes to do it. Typically the spread isn't that great though. Technicians find it hard to make good money if they're not getting paid for 50-60 book hours in a 40 hour work week.

The biggest thing you should do is confirm that they timed it correctly.

Heath