QuestionI 'm back after a week or so. In the mean time I have replaced Throttle Position Sensor(Nissan calls that switch). Anyway, I had to backorder the part and replaced that yesterday. The reason I replaced the TPS is, I did the test following the Hayne's manual, and the last test where it says "replace the TPS" came out negative(no response in ohm meter).However the result? Car still has the problem. Now I'm wondering why did I replaced that for.
Von, I wanted to ask follow up question from wherever we left off. But the system won't let me saying "too many follow ups, ask a new question". I'm not sure if you would be abel to look into your old link and recall my vehicle case. For your convenience, I'm cutting and pasting only the last leg of our previous correspondence.
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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.
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Answer Viv,
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.
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I couldn't find the valve on the fuel rail you mentioned. Therefore I did the test connecting the gauge to rail directly which comes out [not the fuel regulator end, other end rather] of the fuel rail. Anyway. here are the readings: car running(regulator hose on)-34-35psi. Took the regulator vac hose off while running-44-45psi. Put the reg hose back on-34-35psi as before. As the engine running with vac hose on, Now I turned the engine off - pressure went down IMMEDIATELY to 27-28psi. So according to your last message I think, I got one or more injector might be bad. I will have to do more tests such as testing the spark plugs, and ohm meter test of the injectors which involves taking off the intake manifold for the injectors underneath the manifold. Do you have any suggestion at this stage?
I'm kinda frustrated with this maxima, although I like this car. What do you think? Should I sell it and get a different car or it's worth of fixing
One more question, I wanted to test MAS with ohm meter follwing the Hayne's manual, but it didn't give me any reading. Hayne's manual said if it doesn't give any reading, check ECCS relay and related circuit on chap 12. I looked into the diagram,(I understand circuit), but which relay is it talking about?
Thanks a million for your continuing support.
ANSWER: Viv,
The relay should be located in the black box under the hood, on the passenger side of the engine compartment.
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QUESTION: Finally I took the car to Mechanic [which I didn't want to do, cuz it's really hard to find a reliable one] and got it fixed. I had to change the MAF sensor ($254) and IACV($154) from Advanced auto parts. Now no more stalling and any problem of that sort for few days. But it never ends, I just saw "check engine" lite came on today. I checked the short and long pulses and decoded the code with the help of online vbmaxima.com site. There are 2 trouble code and they are: 7 6 and 3 2. When I was tried to decode 7 6, it showed "undefined". So why is it showing this code or what kinda trouble is that? Next code is 3 2 which is EGR high/low pressure. Your help is always appreciated.
ANSWER: Viv,
Change the EGR valve and make sure the passages are clear that feed it. They tend to gunk up over the years. The other code leads me to think the oxygen sensor is coated and needs to be replaced. Email me back if you need more.
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QUESTION: >>My 1995 max has total of 3 oxygen sensors. Two of them before the catalyst converter and the other one after the catalyst converter. I just replaced both(before the cat) oxygen sensor not even a month ago. But I haven't changed the after the cat one yet.
>>some of the online tutorial talked about just cleaning the pipes and hoses and all passages of EGR. So should I just replace the EGR or should I just clean and put all back on?
>>There is another devise called "EGR control BPT valve" attached to EGR. Do I need to change or clean that one too when I replace the EGR?
Thanks a million.
AnswerViv,
Unless you are getting a code for the rear oxygen sensor do not bother to replace it. It only rats you out if you remove the converter. But, if there is code it needs to be replaced. If the EGR passages are clean there is no need to snake them and risk breaking crud loose. The EGR is electrically monitored and if the code sets that is all that should be replaced. If the BPT valve is working then it would not need to be replaced. Just reinstall the BPT and you should be fine.
