For starters, my car has been down for about 2 months right now. Check engine light has been on for years but all codes were resolved and it passes emissions perfectly (I live in Georgia). I generally drive my car hard but always have hood popped and fluids filled and do other things to keep engine kool. One morning I had an emergency run to make and was gassing it down hwy 85, came to a gas station and parked. From that point on my worst dream came true. I got out and noticed the car was exceptionally hot. When I was leaving the gas station, I noticed the car didn't exactly start right and wouldn't rev properly. I pulled out and got back on hwy 85 and that's when I noticed it wouldn't rev past 2000 rpm. My temp gauge was still riding the middle as usual. Cars are flying by me and behind me goin 70 while I cant muster up 30 so I said forget it I have to just get home. Well about 10 minutes down the road, temp gauge started rising QUICKLY and easily went past the hot mark and pointed straight up past hot. next thing I know when I hit the gas my car sounded like there was a loose bike chain somewhere and it scared me ****less so I pulled over for a min. Started back up and still did the same. Almost home and car decided it couldn't take it anymore and died on me so I parked it on the bridge and called me a ride to work (I was late, which was the emergency run). Came back to the bridge after my shift was up and the chain sound was gone but still wouldn't rev past 2000 and idled fairly rough. Got to the house and popped hood, routine check and found out my radiator had a leak. Also my spark plugs got melted inside the engine so I had to buy new plugs and boots. Replaced the temp control sensor already and the MAF is working perfectly fine. Except when I unplugged it, car running, car shut off. Also have a fairly new, few months actually, fuel filter and pump. Did a ton of looking around and found the car was in limp mode. Tried disconnecting battery and still wont go past 2k. I'm a college student and have a job, I need my car up. Please guys any help. I'm sure some have had this problem before, please share how you fixed it. I am being as detailed as possible.

 

How well did you maintain the cooling system before this happened? Any problem?

From the sound of things, you overheated and probably blew head gaskets. Time to find a new engine.

 

Kept it maintained, just didn't notice the leak. I don't even run my AC. And its not the head gaskets, already checked those. No cracks and not warped. Seriously hate aluminum blocks though.

 

If your car is still low on coolant, it will behave like you described. Seen it before on a friends Maxima. You never mentioned in your story if you filled up the coolant. And did you fix the radiator leak.

 

Low coolant will cause rough idle and rpm limiting? But yes I filled it when I picked it up after work. And not yet, wanted to get this fixed first its priority.

 

Most definitely. I know it doesn't make sense, but it's true. Seen it happen and I believe I've read it somewhere in the FSM too.

 

Wow, well ill definitely fix that leak and do a refill asap and see if that works, but you think it could be anything else?

 

How did you check the head gaskets? Block test?

You seem to have had some previous cooling issues.

What I am getting at: is your engine still healthy or not. A cooked, overheated engine should be replaced and the underlying reason such as a radiator or hose as well.

In a car engine with confirmed good head gaskets cooling system repair or sensor or two,
You could be back on the road soon.

I understand how it is possible to overheat while still doing good maintenance. I was very lucky when my water pump. started leaking. There were no symptoms yet. I was under the hood for another reason when I noticed low coolant. I had also replaced all the hoses.

 

Now don't run out and fix your leak on account of me, unless of course your leak is so bad that it can't hold coolant. If it's a slow drip kind of leak, you should be able to fill up the coolant and be able to start your car and see if it idles fine and goes above 2k. If it still doesn't start, idle fine and get past 2k, you may have other issues going on...and I'd hold off too on fixing the leak until the car behaves normally.

If you leave the battery disconnected for 12+ hours, it should reset the ECU.

 

Took the engine head off. Some other kinda test too. My dad is a former mechanic and transmission builder and I'm studying for ase certification so we kinda know these things but this is just something we cant figure out.

 

OKayy will do. And 12+ hours? What happened to disconnecting the battery for 15 minutes lol

 

Do a block test first.
Also, do an OBDII scan as well for codes.
If you can fix this, I would replace the water pump and thermostat, as the overheating may have damage either or both.

 

15 minutes? No way. It really does take like 10 to 12 hours...

 

Water pump fairly new but checked that, its ok

 

So disconnecting battery for 15 minutes doesn't reset the computer? That's what I normally do tbh. Maybe I'm thinking of something else

 

2krpm limit is not due to fail safe mode?


I would thinking checking what's causing the problem, fix that, then the car should rev fine.


You can clear codes after reading them (and writing down what codes are present).

 

Had knock sensor code (replaced), coolant temp sensor code (replaced), o2 sensor code but went away when I retested

 

When was the head work done? Why did you not tell us about that in your original story?

The more information about your car, the more accurate we can be with possible diagnosis.

So if I understand your situation, the car would Rev to 2000 rpm before the heads were removed, and still only revs to 2000 now?

Does your throttle open all the way?

Wizard, I did not realize our cars have failsafe measures to protect against overheating.

 

No head work done just removed to check for broken seals or cracks and warping. And yes it did before and after removing. I kan fully depress the accelerator and pull the lines but still gets to 2000 and stutters. It'll go into the next gear of I accelerate slowly but 2k is it.

 

The ECU has implemented fail safe mode. The maf is notorious for failing and not causing a DTC. While you don't tell us what year your car is, here is a link to the 1998 service manual for diagnosing fail safe mode. It probably applies to all 4th gens, but you should look up the guide for your car if you don't have a 98.

See page 86.

http://boredmder.com/FSMs/Nissan/Maxima/1998/EC.pdf

BTW, I doubt if the knock sensor was bad. The knock sensor code shows up with practically every other code and goes away when you fix the other problems.

 

Sorry thought it was in my signature. I have a 95 GLE with poormans CAI. But tha KS for this guide. I'm just looking for any solution before that $100 diagnosis fee I'll have to pay tomorrow lol

 

I agree with the bad maf as a possible cause. You might consider getting one from a junkyard and giving it a try. Might cost less than the diagnosis and also fix your problem.

 

I'll see if I can go to pull a part and pick one up.

 

What about opening up the MAF and resoldering the contact points? That's the cheapest by far, rather than buying a used one (with an unknown history).