i checked my codes and the throttle position sensor and engine temp coolant sensor is bad.

was wondering can i keep driving without major engine harm?

thanks

 

The Engine Coolant Temperature Sensor sends a signal to the Engine Control
Module (the computer). When the ECM gets a "cold engine" signal it directs
the fuel system to provide a rich mixture to help with starting. This is
similar to the function of the choke on a carbureted engine.

If your ECTS is bad, let's assume it always sends
(a) the cold engine signal, or
(b) the warm engine signal.

If (a) you will have an over-rich mixture all the time, leading to poor performance, excessive fuel consumption, and (in the long run) a damaged Catalytic Converter.

If (b) you will have difficult cold-engine starting.

This sensor is relatively inexpensive and can be installed by the home mechanic. If you like to do your own "wrenching" and have a manual to guide you, you can replace it.

 

excellent info dan!

i think the tps is also toast as the rpms go from 2k to 3k for no reason under cruise control and codes confirmed.

bad cold weather starting (even with cold weather package) and spontenious revving , i love nissan. *sarcasm*

will be fixed, by me soon

 

I suggest you tackle one thing at a time. Do the Engine Coolant Temperature Sensor and then the Throttle Position Sensor. If you do one at a time you are able to judge which improvement resulted from each repair. Haynes and Chilton give good coverage on both items.

The RPM fluctuation may be yet a third problem. Any air which "sneaks" into the engine from a source downstream of the Mass Air Flow Sensor is called False Air. False Air will cause RPMs to increase. There are several possible sources of False Air. Because your RPM increase is seemingly random the first place to look is the flexible duct which conveys air from the MAFS to the Throttle Body. The engine moves around a bit on its flexible mounts during normal operation. If there is a crack or split in that air duct, engine movement may cause the crack to open and close. Every time it opens, RPMs go up. Every time it closes, RPMs drop.

Other sources of False Air include a leaky intake manifold gasket, bad Exhaust Gas Recirculation valve, and stuck-open Positive Crankcase Ventilation valve.

False Air is one of those problems which does not set a Diagnostic Trouble Code and turn on the Malfunction Indicator Lamp.

 

Hey Dan let me ask you a question. what if you engine light sensor stays on for a period of time then one day your driving and the light goes off?

 

This may be a normal occurrence. Here's an example. One of the conditions which can cause the Malfunction Indicator Lamp to go on is detection of a small leak in the fuel system. A loose fuel filler cap "looks" like a leak to the test routine performed by the Engine Control Module. If the ECM detects a leak on two successive trips it sets a Diagnostic Trouble Code and turns on the MIL. The ECM continues to monitor the situation and if it finds no problem on "n" successive trips, it turns the MIL off. This is as if the ECU is telling the driver "Nevermind!". I don't know the value of "n" but it is something like 20.

[Edited by Daniel B. Martin on 12-06-2000 at 02:37 PM]

 

Take it from me your Engine Coolant Temperature Sensor is more important then you could imagine. My 95 gle would cut off/shut off for no reason what so ever(so I thought). I also had a code saying this sensor was bad. Turns out that this sensor will send a signal to the computer saying something is wrong, when in fact my engine is not even near overheating. When this happens, the computer thinks my engine is overheating and therefor shuts off my fuel pump, leaving me looking like a dumb a** trying to start it again. Thirty dollars later and an hours worth of my time, my check engine light has not come on and it has not shut down for any reason. Just thought you'd like to know.

 

....can this be since I smell gas when my car is running if I stand near the exhaust.......
but I still get the good mileage (36MPG) when I run hwy..but very awful in town....
umm..
ECTS...30 bucks? Nissan OEM stuff? and TPS? how much are those?
I have not seen my car check engine light comes on but during startup, then it will light out...after I start the car....
Oh well...
BTW...Mr Daniel B Martin...my apology for mentioning your name wrongly on the other thread...I fixed it already ^_^
Thank you

 

thanks i will follow your instructions on replacement, have to get off this board sometimes.

also the aftermarket jim wolf intake needs to be removed for the stock airbox, no use whatsoever.

 

experiences help tons and exactly my car too, thanks!

symptons are not so bad nevertheless it's $30 and an hours of my time like you say.

 

The odor of raw fuel at the tailpipe is an unusual symptom. Do you also have black smoke at the tailpipe? Black smoke is a sign of an over-rich mixture.

An over-rich mixture could be caused by
- a faulty Engine Coolant Temperature Sensor
- sticking fuel injectors (don't close properly)
- bad fuel pressure regulator
- obstructed fuel return line
- clogged air filter

If you smell gasoline but don't have black smoke, look for a fuel leak in or near the fuel tank.

[Edited by Daniel B. Martin on 12-08-2000 at 06:22 AM]