I am really stumped on a problem my 97 Nissan Maxima has been having and after spending several weekends trying to solve the mystery it has become personal too!
Whenever the temperature is below about 60 degrees (F) the car starts to take longer cranking to start. I will crank for several seconds with the engine turning over nicely but no start. The second or third time I try I will get a little revving but it quickly dies and by the 4th-6th try I can get it to start.
If the temperature is somewhere below 40 degrees (F) it will crank and crank but won’t ever start.
I can get the engine to start even at the cold temperatures by squirting some starter fluid onto the air filter and cranking for about 5 seconds. Once the car is running it runs great and if I have driven it for a long time and park for a short time it will start up much easier or with no problem at all.
My check engine light was on so I started there and replaced a knock sensor and a solenoid valve on one of the vacuum hoses. This took care of all my Check engine light codes and the check engine light has remained off for several hundred miles now.
Next I replaced the coolant temperature sensor as a desperate attempt to solve the problem but with no effect.
Finally I replaced the fuel filter and cleaned the throttle body and ran fuel injector cleaner through it. No change, the next frosty morning I got no start.
I was just starting to recover my reputation as a handyman after that exploding bathroom faucet incident. My wife wants me to just take it in but now it is personal. I am stumped. Can anyone give me some ideas on what the problem could be?
One other thing I forgot to mention. I have also tried turning the key on and off several times as I hear the fuel pump cycle to build up fuel pressure. This has not helped either.
I am thinking ignition system. Buy a spare spark-plug. In the morning (ideally in a garage or before it gets totally light) pull the cable (hold onto the socket not the wire) and put the spare plug on it. Hold the plug so the threads are tight against the engine. Have someone crank the engine and see if there is a nice blue spark. Oh BTW that shocking experience you just had was because you should use a well insulated tool to hold that plug or you may be shocked.
Good Luck.
Nissan released a TSB that relates somewhat to your issue. It might give you an idea.
~Michael
Thanks, I will go through this and hopefully it is something easy.
If it is possible, accessing live data could be helpful. I would be interested in seeing what temperature the ECM is seeing. If the ECM thinks the temp is a constant 70 degrees then a cold start problem would happen as the temp goes down. The ECM will not change the air/fuel mixture as the temp goes down leading to the hard start.
I know that the temp sensor was replaced but was it the correct sensor? Sometimes there are 2 sensors, one for the cooling fan and one for the ECM temp reading. It is still possible that you replaced the correct sensor but the ECM is defective.
So are there any front curb mechanic’s tools that a regular guy like me can use to access the live data or am I stuck taking it into a shop? Here is a picture of the single pronged engine coolant sensor I replaced. I think it is the right one but could be wrong.
There will be an AIR temperature sensor somewhere in the system. THAT’S the one that controls the fuel mixture. Look in the air intake path.
Yes, there is the air intake sensor but there is also a temp sensor for the ECM. The interesting thing I found in the wiring diagram was there is a fuel temp sensor and it looks like it’s in the tank. There is also a picture of a thermal sensor next to the coolant temp sensor but no description of what it does. You have to wonder if one of these sensors is affecting how it starts when it’s cold.
Well I needed too many tools to properly diagnose it so I worked with a local shop to help me diagnose it. It looks like the computer in the Maxima has gone bad. The signal it is sending to the fuel injectors is weak. That means it is running lean all the time but is only really noticeable when starting from cold. All other sensors are sending good info but the weak injector signal prevents the cold start. Hopefully I can find a cheap used one.
A cheap used one? I sure hope you DON’T get one with issues too.
This is the reason I never buy used electrical components.
remove.
If you want to see what the sensors are showing the computer, you’ll need a scan tool; though, it’s possible to, individually, check the sensors with a digital multimeter. The Haynes, or Chilton’s, will show you how and what. You could, also, go to www.alldata.com for procedures through your local public library, or pay $25 year for a subscription to alldata.
I finally took it into a local mechanic (not the dealer). Fuel pressure was great, and basically all of the data coming back from the computer was what you would expect it to be. He hooked up a light to one of the injectors that flashed when it got signal and said that the signal looked “weak”. Even after driving it 15 miles over to his shop it was still having a hard time starting so we were diagnosing it while it had the problem. He concluded that the Engine computer was bad and sending weak signals to the injectors because everything else he could see was fine. He had never seen this type of problem before and said it was rare to need to change the whole computer.
I found a used computer from a wrecked 97 maxima and ordered it here. Put it in last night and there is no change in the problem. I think that the chances that the other maxima which crashed had the exact same problem are very small. I called back the technician who gave me the diagnosis and he didn’t know what to think…he had no ideas. So what do I do now!