car issues, any mechanics out there?

[Shockman54]

quick question for any mechanics out there.
1996 maxima (automatic) has trouble starting. car seems to drive fine, and i just replaced the starter and that works fine. but in order to start it now, i have to pump the gas pedal and it will just barely start. i checked the exhaust and gas sprays out when the accelerator is pressed. so obviously its not burning all the gas. anyone have an idea? or anyone know a mechanic that will check it out for me? i'm at the end of my car mechanical knowledge (btw, i cant check cylinder compression because the spark plug wells are too deep) im in plymouth, mn btw.

[Shockman54]

got error code p0440, which is the emissions system. talked to a friend and he said its probably not related.

[Rasputin]

1996 must have fuel injection, so I would check or clean the sensors in the MAF.
I have a similar issue with my 2005 GM Monte Carlo POS. It only seems to do it when it is very cold. Cleaning the MAF helped a lot but did not eliminate my problem.
Another thing that helped mine was to change the fuel filter. A plugged filter will not show up in the codes but will change the starting when you push on the accelerator pedal because it changes the pulses of the fuel delivery system in the puter.
My problem has been a mystery to many a good mechanic as it seems to be intermittent. Lets hope you have better luck than I have had.

[rpgoerlich]

Could be as simple as a loose gas cap.
Re-Tighten it, clear the code and see if it comes back.

[bikerphil]

Could be that fuel regulator in the fuel rail that returns unused fuel back to the tank. JAT

[ESJr1642]

More than likely it's the coolant temp switch. This tells the computer to either get richer or leaner based on the temp of the engine coolant. Very common problem with fuel injected cars.

[Shockman54]

would those explain the rough start and sometimes no start? and would the car driving fine, accelerating fine (all kinds of acceleration, i had to explain that to the nice officer that pulled me over for excessive acceleration today) and idling fine eliminate any of those? doesn't seem to matter if the car is warmed up or cold, the starting problem is there. fuel pressure seems to be good. i'm just trying to figure out why it is so hard to start. i replaced the air and fuel filters, checked the mass airflow sensor (seems to be working fine) and the fuel pump is working at least partially if not totally fine. i doubt its the fuel injectors (car accelerates fine and has a normal idle, plus i'm fairly certain the injectors would show up on the code reader) or the fuel regulator, because when those malfunction it usually will not idle correctly

[Shockman54]

gas tank is full too btw

[ESJr1642]

Other then the code you listed, we're there any other codes? Have you noticed a decrease in the mileage?

[crazy steve]

Keep in mind that mechanical issues may or may not show up as fault codes. The emission code you're getting is telling you it's not running right, but the cause could be any number of things.

My exs' Focus ran like crap, but threw no codes and it turned out to be a bad vacuum hose.

[Shockman54]

well this started just yesterday, so not really. beforehand the mileage was almost always exactly the same, haven't driven enough since to see a change in mileage. no other codes listed, but i checked before i replaced the fuel filter.

[BA80]

P0440 is a fuel evaporative system code. It means you have a loose gas cap or an evap hose leak somewhere. All that does is arrest fumes evaporating into the atmosphere.

Since it's hard to start I would guess that there is a vacuum hose that goes to the evap system. You should be able to hear a vacuum leak under the hood somewhere if that's it.

Not sure how much of this will transfer but maybe it'll help.......










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1996 Nissan-Datsun Maxima V6-2968cc 3.0L DOHC MFI (VQ30DE)

Vehicle » A L L Diagnostic Trouble Codes ( DTC ) » Testing and Inspection » P Code Charts » P0440

•P0440















ON-BOARD DIAGNOSIS LOGIC
This diagnosis uses two methods to detect leaks in the EVAP purge line.
The first method, the pressure test, makes use of vapor pressure in the fuel tank. The second method, the vacuum test, makes use of engine intake manifold vacuum.

Pressure test
The EVAP canister vent control valve is closed to shut the EVAP purge line. The vacuum cut valve bypass valve will then be opened to clear the line between the fuel tank and the EVAP canister purge control valve. The EVAP control system pressure sensor can now monitor the pressure inside the fuel tank.
If pressure increases, the ECM will check for leaks in the line between the vacuum cut valve and EVAP canister purge control valve. If no pressure does not increase, the ECM will perform the "Vacuum test".

Vacuum test
It pressure does not increase in the "Pressure test", the ECM will check for leaks in the line between the fuel tank and EVAP canister purge control valve, under the following "Vacuum test" conditions.
The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP canister purge control valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line oft. The EVAP canister purge volume control valve and EVAP canister purge control valve are opened to depressurize the EVAP purge line using intake manifold vacuum. After this occurs, the EVAP canister purge control valve and EVAP canister purge volume control valve will be closed.

CAUTION:

•Use only a genuine fuel filler cap as a replacement. If an incorrect fuel filler cap is used, the MIL may come on.
•If the fuel filler cap is not tightened properly, the MIL may come on.
•Use only a genuine rubber tube as a replacement.















DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

CAUTION: Always select "SINGLE TEST" with CONSULT when performing the "FUNCTION TEST".

With Consult















1.Select "EVAP (SMALL LEAK)" in "FUNCTION TEST" mode with CONSULT
2.Make sure that "OK" is displayed with "EVAP (SMALL LEAK)". (If "NG" is displayed, refer to "DIAGNOSTIC PROCEDURE".)
3.Check fuel filler cap and fuel tank when the fuel tank is more than 3/4 full. Refer to "DIAGNOSTIC PROCEDURE".

OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the EVAP control system (Small leak). During this check, a DTC might not be confirmed.







NOTE: Prepare one-way valve (Part No. 14958 V6700) for this test.


Without Scan Tools

1.Turn ignition switch "OFF".
2.Completely fill fuel tank.
















3.Set up one-way valve (Part No. 14958 V6700), pressure gauge and suitable pump as shown. Pressurize the system to 13.3 kPa (100 mmHg, 3.94 inHg, 1.93 psi). Measure the amount of depressurization in kPa (mmHg, inHg) after one minute with the system left unattended.
















4.Apply 12 volts DC to EVAP canister vent control valve. The valve will close. (Continue to apply 12V until the end of test.)
















5.Apply 12 volts DC to vacuum cut valve bypass valve. The valve will open. (Continue to apply 12V until the end of test.)
















6.Disconnect rubber tube between vacuum cut valve and EVAP shut valve. Set up one-way valve (Part No. 14958 V6700), pressure gauge and suitable pump as shown.
7.Increase system pressure until gauge registers 13.3 kPa (100 mmHg, 3.94 inHg, 1.93 psi). [If pump is rated at a discharge volume of 0.13 (1/8 US qt, 1/8 Imp qt) for one operating stroke, it is capable of increasing pressure to 13.3 kPa (100 mmHg, 3.94 inHg, 1.93 psi) with approximately 60 operating strokes. If pressure does not increase at all during the test, diagnosis will be ineffective ("NG")].

CAUTION: Do not allow pump pressure to exceed 13.3 kPa (100 mmHg, 3.94 inHg, 1.93 psi). A higher pressure may damage fuel tank and EVAP canister.


8.Make sure that after one minute the amount of pressure recovery is within the following.
9.Check fuel filler cap and fuel tank. Refer to "DIAGNOSTIC PROCEDURE".





The measured amount in step 3 + 4.0 kPa (30mmHg, 1.18 inHg, 0.6 psi).










































DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION
EVAP Canister Purge Volume Control Valve

With Consult

1.Disconnect EVAP canister purge volume control valve harness connector.
















2.Check resistance between the following terminals. terminal (2) and terminals (1), (3)

terminal (5) and terminals (4), (6)







Resistance: Approximately 3O Ohms [At 25°C (77°F)]

3.Reconnect EVAP canister purge volume control valve harness connector.
4.Remove EVAP canister purge volume control valve from intake manifold collector and disconnect hoses from the valve. (Plug the purge hoses. The EVAP canister purge volume control valve harness connector should remain connected.)
5.Turn ignition switch "ON".
















6.Perform "PURG VOL CONT/V" in "ACTIVE TEST" mode with CONSULT. Check that EVAP canister purge volume control valve shaft moves smoothly forward and backward according to the valve opening. If NG, replace the EVAP canister purge volume control valve.

OR

Without Scan Tools

1.Disconnect EVAP canister purge volume control valve harness connector.
















2.Check resistance between the following terminals. terminal (2) and terminals (1), (3)

terminal (5) and terminals (4), (6)







Resistance: Approximately 3O Ohms [At 25°C (77°F)]

3.Reconnect EVAP canister purge volume control valve harness connector.
















4.Remove EVAP canister purge volume control valve from intake manifold collector and disconnect hoses from the valve. (Plug the purge hoses. The EVAP canister purge volume control valve harness connector should remain connected.)
















5.Turn ignition switch "ON" and "OFF". Check that EVAP canister purge volume control valve shaft moves smoothly forward and backward according to the ignition switch position. If NG, replace the EVAP canister purge volume control valve.

EVAP Canister Purge Control Solenoid Valve















Check air passage continuity.














If NG, replace solenoid valve.

EVAP Canister Purge Control Valve














Check EVAP canister purge control valve as follows:

1.Blow air in port (A), (B) and (C), and check that there is no leakage.
2.Apply vacuum to port (A). [Approximately -13.3 to -20.0 kPa (-100 to -150 mmHg, -3.94 to -5.91 inHg)] Blow air in port (C) and check that it flows freely out of port (B).

EVAP Canister Vent Control Valve















Check air passage continuity.














If NG, clean valve using air blower or replace as necessary.

Absolute Pressure Sensor

1.Remove absolute pressure sensor from bracket with its harness connector connected.
2.Remove hose from absolute pressure sensor.
3.Turn ignition switch "ON" and check output voltage between terminal (2) and engine ground.

The voltage should be 3.2 to 4.8 V.
















4.Use pump to apply vacuum of -26.7 kPa (-200 mm Hg, -7.87 inHg, -3.87 psi) to absolute pressure sensor as shown in figure and check the output voltage.

The voltage should be 1.0 to 1.4 V lower than the value measured in step 3.

CAUTION: Always calibrate the vacuum pump gauge when using it.


5.If NG, replace absolute pressure sensor.

MAP/BARO Switch Solenoid Valve
With Consult

1.Start engine and warm it up sufficiently.
2.Perform "MAP/BARO SW/V" in "ACTIVE TEST" mode with CONSULT
3.Check the following.
















•When "MAP" is selected, "ABSOL PRES/SE" indicates approximately 1.3V.
















•When "BARO" is selected, "ABSOL PRES/SE" indicates approximately 4.3V.
4.If NG, replace solenoid valve.

OR

Without Scan Tools

1.Remove MAP/BARO switch solenoid valve.
















2.Check air passage continuity.
















3.If NG, replace solenoid valve.

Tank Fuel Temperature Sensor















Check resistance as shown in the figure.














If NG, replace tank fuel temperature sensor.



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[DCII]

Fuel Pressure

Some of the problems you are describing could be attributed to a bad fuel pump or some restriction in the fuel line. Low fuel pressure at the injectors will make the car almost impossible to start however once started it may run normally. I would suggest checking your fuel pressure at the injector rails and also find out what the trouble code is telling you. Hopefully it will be something minor causing your problem.

[BA80]

It wouldn't set that code though DC.

[ViperRon]

I do not know about the car you have but have seen the same conditions in some other older vehicles when the EGR valve sticks open. EGR is tied to the emissions and mixes exaust into the intake to control emissions. I have seen these rust up and stick open. It usually will cause power loss while running but to some not noticable. After the car starts and warms just a little it will run fine but starting in the cold is really bad.

Just another thing to check.