QuestionQUESTION: I have a '95 Nissan Maxima GLE with about 109K on it (has been a really great car) that recently started stalling while driving.
Here's the situation:
I start the car up in the morning to go to work - starts without issue and idles fine, also no problems with acceleration. A few minutes down the road (typical city driving), after the engine comes up to operating temp, it still runs normally... until I come to a stop light or have to stop for traffic. About 75 % of the time at this first stop after warming up, rpm niddle will go down and the engine will just quit and all the lights on dashboard will come up. Starting it at this point is hard - I will have to give it a LOT of gas and crank for about 20 seconds before it will start back up. When it comes back to life, I have to immediately take it up to 3000rpms (or it will die again) and VERY gently ease off on the gas to slowly lower my rpms back down to 1000 (takes about a minute) where I can shift back into gear. If I drop too fast, it will stall and I have to start all over again. Sometimes the rpms will jump around some at 1500-2500 before settling down. This is all very frustrating when you are sitting in morning traffic.
When I drive home in the evening, I have the same problem all over again.
Other bits of information:
- If I keep the RPMs up above 1200 the whole time I'm driving (shifting into neutral at stoplights) it won't stall.
- If I drive without stopping (getting on the highway), It won't stall.
- If I drive somewhere (lunch, store, etc) and leave the car for an hour or two, I can still drive off fine when I return without issue.
Getting different tips from different people online I have done the following jobs on the car thus far:
1) I have replaced the knock sensor which made the car driving much smoother eversince. But the problem still exists.
2) I have replaced 2[before the cat] out of three total [2 before cat, one after cat] oxygen sensors.
3) I have sprayed and cleaned up the MAF sensor with CRC MAF cleaner.
4) sprayed and cleaned up the throttle body[ butterfly section] inside and out, cleaned up the deposits in that.
5) checked the fuel pressure which is 34-35, seems to be normal.
and finally recently,
6) I took apart the Idle Air Contorl Valve[IACV] and cleaned up inside with intake CRC throttle/manifold cleaner and put it back. There was significant improvement for 2 days. Car was running almost normal. Then started the old problem again with a new additional problem. New problem is, while driving sometimes it seems like car first start knocking and ultimately looses power along with sputtering SOMETIMES.
Some recommendations I have gotten so far are:
-Replace the fuel PUMP and fuel FILTER
- Replace the engine coolant temperature sensor anyway
- Replace the throttle position sensor (switch) anyway (contacts are probably worn off with this many miles)
Any further guidance from the experts here would be much appreciated! I really need my Maxima to last. Thanks!
ANSWER: Viv,
I would say the mass airflow sensor is defective. I know that sucks but that is what I really think it is. You can get a Haynes Manual and a volt ohm meter and back probe it and check to see if it reads correctly. I don't know why but the mass airflow sensor screws up and never sets a code...
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QUESTION: Thank you for your response. Your point on Mass air flow is well taken and I will do the test with volt/ohm meter following the Haynes manual.In the mean time, I thought I should give the follow up.
Today [Sat,Apr 19'08] I replaced the fuel filter. After taking apart the old filter I discovered silt was coming out from the old filter. Old filter was original nissan filter[not sure if ever been replaced or not, me being the 2nd owner of the car]. Eversince I replaced the filter, very significant imrovement with car's idle. Today I drove to couple of places[8-10 miles]. At night time when I was coming back home from soccer practice, the car knocked for couple of times and one time RPM niddle went down to almost 200-300rpm, but engine didn't shut off. Now I'm thinking, probably new silt is coming out from the fuel tank. In other words, fuel tank is PROBABLY full of silt. What should I do at this point?
Thank you once again for your help
ANSWER: Viv,
If the tank is indeed contaminated with silt I would remov ethe tank and clean it. It is a pain to do and if you remove the new filter and check it and it has even more silt in it you pretty much have verified that this is a problem. Now, since you say the car has this problem verify it be changing the filter again and add a fuel treatment like Lucas. Nissan cars do not like caustic cleaners and if you use them they tend to eat the fuel pump and injectors. So, it is not worth it to put something in that is harsh. I have had luck with Lucas so that is why I mention it. Now, other things you might do are to check the injector pressure at the fuel rail and then turn the car off to see if any are leaking down. If the pressure drops right away you have a leaky injector or two since the pressure is supposed to stay for several minutes. Remove the plugs, noting what hole they come from and if any are really black and wet those would be where I would be looking at leaking injectors. Also, in the Haynes manual there are values for the ohms rating on the injectors and check this too. If any are out of range replace them.
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QUESTION: Thanks for the response.
As you mentioned about "using fuel treatment", Now I remember I used STP brand 'gas treatment' couple of times and STP brand 'fuel injector and carburator cleaner' once within a period of last month or so. I had no idea about about such compatibilty issues with Nissan fuel pump and injector. I think that particular STP brand products did the damage..right? As you have mentioned about checking the pressure of fuel injector, I'm kinda confused on where exactly should I set the fuel pressure gauge to check the fuel injector pressure. I will also try to check the ohms rating of the injectors following the Haynes manual. I haven't checked the new fuel fulter yet[to check any new siltings inside] as it was little raining today. Thanks a million once again.
AnswerViv,
Nissan does not recommend any fuel treatment and I have learned my lesson messing up a set of injectors and a fuel pump. Now, I just use Lucas as it is mild compared to most. To check the fuel pressure there is a valve on the fuel rail and you can rent or borrow a fuel pressure gauge from Autozone or Checker. Now, just screw it in and start the engine. Then, you start the car and check the pressure against the book value and then unplug the fuel pressure regulator vacuum hose and check for a pressure increase. Now, reconnect the vacuum hose to the fuel pressure regulator and turn the engine off and see if the fuel pressure leaks off right away. If it does then you have a leaky injector or two. If not the injector pressure is holding. Also, be sure to check the ohm value on the injectors to make sure the electronics have not worn out. Again, the values are in the Haynes Manual. To do this use a volt ohm meter and set it to ohms and then probe the connector where the harness unplugs. You are checking the injector and not the harness.
