Problems starting the maxima when its hot.
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hachiroku781
- Posts: 1400
- Joined: Tue Oct 31, 2006 5:05 am
- Car: 1997 Nissan Maxima GXE
Problems starting the maxima when its hot.
On my 97 maxima (auto), for the past few days, the car has been having problems starting. It starts but once it starts the rpms drop and feel like its going to stall. then they jump right up. I have no clue why it started doing this. Any help would be greatly appreciated.
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hachiroku781
- Posts: 1400
- Joined: Tue Oct 31, 2006 5:05 am
- Car: 1997 Nissan Maxima GXE
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loystock
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97 Infiniti Q45
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Re: Problems starting the maxima when its hot. (hachiroku781)
You need to check the fuel pressure by connecting a fuel pressure gauge (T-fitting) downstream of the fuel filter. With Ignition ON (engine not running) fuel pressure should be @ 43 PSI. Please note that the pump will shut down automatically after @ 5 seconds. With engine running, fuel pressure should be @ 34 PSI (43 PSI if vacuum is disconnected). Once the engine has been shut off, the fuel pressure normally drops to about 30 PSI and remains at that level for several minutes.
The problem could be a clogged fuel filter (engine firewall besides brake booster), a failing fuel pump (accessible behind the rear seat, pax side) or defective fuel regulator (top of the engine, driver side).
Before connecting a fuel pressure gauge, make sure the fuel line is empty - FIRE HAZARD. To ensure line is empty, with the engine running, pull the fuel pump fuse until the engine dies. Crank the engine at least once more to ensure line is empty.
To check the fuel filter, blow air into it - there should be no or very little resistance. Otherwise, the filter is dirty and needs replacement.
With the fuel pump running, pressure should be as noted above. If the pressure is too low, fuel pump (or controller?) may be defective.
When the engine is shutdown, if the pressure drops immediately, you have a defective fuel pressure regulator.
Assuming the starter, battery, plugs and injectors are good, the starting problem could be caused by loose connections in the main engine harness (wiggle it) and/or poor ground connections (intake plenum, near cylinder #2). It would also be a good idea to clean the MAF sensor (besides air filter box) using zero-residue contact cleaner.
The problem could be a clogged fuel filter (engine firewall besides brake booster), a failing fuel pump (accessible behind the rear seat, pax side) or defective fuel regulator (top of the engine, driver side).
Before connecting a fuel pressure gauge, make sure the fuel line is empty - FIRE HAZARD. To ensure line is empty, with the engine running, pull the fuel pump fuse until the engine dies. Crank the engine at least once more to ensure line is empty.
To check the fuel filter, blow air into it - there should be no or very little resistance. Otherwise, the filter is dirty and needs replacement.
With the fuel pump running, pressure should be as noted above. If the pressure is too low, fuel pump (or controller?) may be defective.
When the engine is shutdown, if the pressure drops immediately, you have a defective fuel pressure regulator.
Assuming the starter, battery, plugs and injectors are good, the starting problem could be caused by loose connections in the main engine harness (wiggle it) and/or poor ground connections (intake plenum, near cylinder #2). It would also be a good idea to clean the MAF sensor (besides air filter box) using zero-residue contact cleaner.
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hachiroku781
- Posts: 1400
- Joined: Tue Oct 31, 2006 5:05 am
- Car: 1997 Nissan Maxima GXE
Re: Problems starting the maxima when its hot. (loystock)
thank you for the information, it is greatly appreciated. I narrowed it down to the injectors and my air filter. I replaced the air filter and cleaned the throttle body. Then i ran fuel injector cleaner, and after driving for a while with the car hot, i shut it off and turn it on again. With out any problems starting, nor did my engine idle rough.