Okay, guys.


Drove my fiancée's G35 coupe to work the other day (an hour both ways) and had no problems until I made a stop at a store close by the house. When I got back into the car to leave, it had trouble starting, but did start. So I turned it off and back on to see if the car struggled to start again; it did. I then noticed it was over heating, not completely to the top of the gauge, but right at the lowest HOT threshold. I drove it home and the temp gauge went A BIT lower as I drove it home (kind of fluctuated). Left it alone.


Next day, I drive it around town for a few errands to see if it's still over heating; no problems at all; not even struggling to start. Drove it for like 45 mins. I decide to change the thermostat anyway. I get an oil change than head to O'reillys to pick up a thermostat. I get home, change the thermostat and now the thing won't start at all. No clicking or anything to make me think it's the battery.
Can also hear the fuel pump whine underneath the car.


Any ideas? Could a bad MAF sensor cause these problems? Please help.


PS: Car has cat deletes and catback exhaust. Has been running rich a while I believe as it shoots black soot out of the tail pipes (did this even before we bought it two weeks ago).


Any ideas before I get it towed to a shop?

 

This is the kind of thing where there are so many "things" going on, there's no way any of us could attempt a guess without at least being there.

Tow it to the shop, but be prepared to pay. Probably a lot more broken crap than you want there to be. Hope you got a good deal on the car; I wouldn't have bought it.

 

Dang, thanks. I didn't really want to purchase it (we knew hub and bearing would have to be replaced and cats replaced/removed when we bought it) but my fiancée was all for it, and we saved a bit with a lot of the mods we wanted already being done on the car.


I'm not too concerned with the car running rich as I am with it over heating the one time and now not starting. So I'm working with trouble starting/not-starting and over heating. Trying to determine the root cause of those two problems. Just bought a code scanner and going to see if I can get a code from it when I get home.


EDIT: Than again these two problems could be separate issues, lol.

 

A lot of these cars have camshaft position sensor problems. Cause a no start or rough idle condition. As to overheating it could be anything in the cooling system so just check everything and then make sure to "burp" it to get rid of all air.

 

Yeah, could be a few sensors, but until he has codes, I wouldn't go replacing them all ***** nilly.

OP, if you wanna cure the overheating issue, get a KOYO aluminum rad and do a thorough flush. The KOYO is a bit more expensive than a replacement plastic job, but, you'll never have cooling problems again. You could have a hairline crack in the plastic rad somewhere. 13 yrs of heat cycles makes that plastic very brittle. Gotta pressure test it. You can rent a pressure tester at any auto parts store for free.

 

I wouldn't go condemning the radiator or thermostat just yet. Check out your fans first make sure they spin super fast with the AC on and idling. The motors get weak or go bad, so you can overheat while idling, but not driving.

Does the RPM gauge move when it cranks? I think on Nissan/Infinti that means the crank sensor is getting a signal. It then needs the cam sensors to start and fire the coils (I think), so they could be causing your no start. You can perform resistance checks on them if you read the FSM.

You can unplug the MAF and see if the car starts, but it will set a code and run real rich in limp mode.

I know on some cars a bad engine coolant sensor can cause a no start, but I'm not sure about Nissan/Infiniti.

 

According to the previous owner, the radiator was fairly new. Didn't notice any leaks, cracks, or anything like that.


Already tried starting with MAF disconnected. Car wouldn't throw any codes either.


Bit the dust and got it towed to a mechanic (friend of mine). I get home at 6 so never really have time to fool with it before it gets dark out. Figured this would save time and money. Will let you guys know what the problem is.


EDIT: This may be a silly question, but could me not burping the coolant system after replacing the thermostat cause a no-start? I feel like I already know the answer is "no", lol.

 

You're correct, the answer is no.

 

Well guys, after wasting money on special tools to check things (extensions, special sockets, etc.), turns out the culprit for the no-start was a bad fuel gauge. We knew the gauge was a little off before we bought it, guy told us it would really be on empty when it shows a quarter tank (which we found to be true- we always refilled when it got down to a quarter). But - the car showed a half-tank when all of this went down; according to my mechanic friend, it's just gotten worse at reading the gas (was completely empty when he got it). He put gas in it and it fired right up.


You have to replace the entire fuel pump to replace the gas meter, correct?


Will have to wait to get the car back and drive it around a bit to see if me replacing the thermostat fixed the over heating issue. Question - can trying to run the car on extremely low gas (to the point where it struggles to start or doesn't start) cause over heating?


Thanks for the help guys! I'm extremely happy it wasn't something worse.

 

There are troubleshooting steps in the FSM, the quick and dirty version is from the top of the fuel pump assy with the cover plate removed (pump still entirely installed in the tank) unplug the primary connector, two of the pins are for fuel level and the resistance varies from 4ohms on a full tank to 80 on empty) if the sender tests out ok then verify the circuit is intact to the back of the combination meter (instrument cluster) white wire/black stripe. If the circuit is ok and the proper resistance is still read at the combination meter then the meter itself needs to be replaced.

Fairly common point of failure for the G35. Check the factory service manual for the details.

 

Ahh, I see the fuel gauge got you as well. Mine is all messed up and I go off the trip odometer now rather than rely on it. I ran out of gas in rush hour once and it was pretty scary.

Some people use a q-tip to clean it and have had good results. You can buy the sender separately do a search in the forums for the part number(s). There are two of them total.

There is also a diagnostic test you can do to make sure it's not the cluster that is messed up.

 

No.

There are 3 major parts of a working (modern day) car motor that won't necessarily cause major problems to each other (except if your electrical system is involved, but that's a different subject).

1. You have the top end (spark, air, fuel)

2. Bottom end (oil; lubrication is VERY important)

3. And you have the cooling system. (Hoses, water jacket, thermostat, radiator, overflow).

None of those things (save for an electrical interference) will necessarily have any effect on the other. Understand, however, that the oil is part of the cooling system as well. You're now going to have a cooling issue you've got to deal with. But that's very simple too, so just keep checking in with what's going on.

 

Well the car has been driven quite a bit now since we've gotten it back from the shop, and hasn't over heated once. So I'm guessing me replacing the thermostat did the trick.


As for the fuel gauge, I have a used fuel pump coming from my work (I'm a sales coordinator for LKQ - $40). It'll come with the pump and the sender that is attached to it. So I think I'll be replacing that one sender and cleaning the other and hope if fixes the issue.

 

Hope? There is no hope. Test! ...or test not.

 

Well, seems as though the thermostat replacement did not fix the over heating issue. It over heated for a short period of time yesterday. It's really off and on- it over heats like once a week (but never to the top of the HOT gauge).


I've noticed that the driver side fan is never on - even when the car is over heating. I'm guessing this is my culprit? Passenger side fan spins fine. Just wanted to get someone else's input before I replace these suckers this evening. Looks like it'll be an easy remove/install.


EDIT: Is there anyway I could check to make sure the over heating isn't because of air trapped in the coolant system? I read somewhere that if you remove the radiator cap, let the car get to normal operating temp, and notice bubbles, than you've got trapped air. I've also read that it would over heat more frequently than once a week if the cause is trapped air. Please advise.