pimpman81

They checked out my car today in great detail. Hooked it up to different computers and scanners and found nothing wrong. I posted earlier about how my car would just die for no reason. It wouldnt bog down, or sputter it would just die, then I would put it in nuetral and start it up and it would run fine. So anyway they found no problems with anything, ignition module, ECU, ECM, spark plug wires, spark plugs. It has only happened like 3 times over a 2 week period so im not sure what to do now. They did replace my fuel filter because it was due for a change anyway, but I dont think that has anything to do with it. He said (as a guess) that my intake may be causing the Throttle Position Sensor to throw some code or something and shut down the engine because of the greater amount of air being sucked in. But ive had my intake for over 6 months with no problems at all. does anyone have any idea on what this could be. could it be the intake causing the TPS to cut the engine or something? Please help. Thanks and sorry for the long post

Daniel B. Martin

Your engine problem is intermittent and that is the most difficult kind to identify and repair.

It was appropriate for the dealer to check the Engine Control Module for stored Diagnostic Trouble Codes. Apparently they found none. However, it is important to remember that the ECM does not check every aspect of engine operation. Therefore it is a mistake to say "No Code = No Problem". It means only that the ECM's services as a watchdog were not helpful in this instance.

He said (as a guess) that my intake may be causing the Throttle Position Sensor to throw some code or something and shut down the engine because of the greater amount of air being sucked in. This sounds like baloney. "Throwing a code" is technician slang for storing a Diagnostic Trouble Code, and they told you there were none. This fellow is giving you double-talk.

Some Maxima owners have reported problems with the Mass Air Flow Sensor which arose after installing an aftermarket engine air intake. You have an intake on your car. Considering your present predicament it makes sense to return your engine to its stock configuration and see if the problem persists.

I wish I had a dollar for every post on this forum reporting a problem which arose after installing a mod. In some cases it is a bad mod; in others it is a botched installation.

In your previous thread Need Help Fast, My car dies for no reason I suggested two no-cost relay-swapping experiments. Did you do these? If you have not used advice already obtained you have no business coming back and asking for more.

pimpman81

Yes I did try the relay swapping experiments, and the relays seemed to be fine. That and what the dealership told me is why I came back and asked for more help. I appreciate the help you have given me. thanks

Daniel B. Martin

Did you leave the relays in the swapped location? The idea is to do that and drive the car normally, and see if the symptom recurs. With an intermittent problem you are unlikely to instantly know when you've hit the root cause. It takes time and patience.

In the meantime, install your stock intake. With the engine idling, gently flex the harness leading to the Mass Air Flow Sensor and the Throttle Position Sensor to see if you can provoke a "hiccup" or a stall.

A procedure for testing the Mass Air Flow Sensor may be found in the Chilton repair manual (page 4-16) and the Haynes repair manual (page 6-9).

A procedure for testing the Throttle Position Sensor may be found in the Chilton repair manual (page 4-18) and the Haynes repair manual (page 6-8).