Nissan Repair/1998 nissan avenir sr20det surging/losing boost while driving
QUESTION: Hi Calvin. My wifes car has an annoying problem.Once it reaches operating temperature,it will surge and have eratic boost.It runs fine for the first 10km or so then plays up.I know nothing of turbo engines so im stumped.And twice over 3yrs it wouldnt start,like it was out of fuel,but I checked the filter for fuel,and plugs for spark and it had both.We had to keep cranking it over till it started with a stumble.The filter is new.The car has only done 100.000kms and is not driven hard.Could you pleeease help us,we are poor and cant afford to take the car to the auto electricians.
Thanks for your time Calvin.
ANSWER: Hi Jason -
Can you tell me if your check engine light is on?
If so, I will need the downloaded code it displays from the OBD reader. Do you have Autozone there? I think they do it for free.
If the check engine light is not on, then i suspect the ignition module in the distributor. Normally that is the culprit when the car warms up.
Hope this helps -
---------- FOLLOW-UP ----------
QUESTION: Hi Calvin,thanks for your reply.
The checck engine lite comes on when the ignition is on,but when started the lite is not on,so i assume thats good.Is there any way I can check the ignition module at all?Could it be the o2 sensor,giving the wrong reading to the ecu making it run like this when warm?
Ive been told it could be the AFM a little dirty or the diaphram in the BOV fluttering?
So the easiest way to start a diagnosis is to have it put on a OBD programe to see if their are any faults?
Thanks again for your time Calvin
Hi Jason -
The OBD will not work in this case because the check engine light is not on while driving. That means that the ECM is not storing any codes, so the OBD will not pick anything up.
The only 2 things that do not pass through the computer sensors are the fuel pump and fuel filter, and the ignition module in the distributor. If there is anything else that is making the car run abnormally, it will trigger the check engine light. That said between the fuel system and the ignition module, the only device that fails under heat is the ignition module. Unfortunately there is no way you can check it, so I would just replace it, and you should be good to go.
Hope this helps -