car stalls

1993 NISSAN 240SX
70,000 MILES • 2.4L • 4 CYL • 2WD • AUTOMATIC
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GERALD WISE
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Car will start and and run very fast for about five seconds and then stall. Pressure on fuel pump is good and fuel pressure regulator checks okay. I also checked injectors with noid light they checked okay. Engine will run very rough if you pump accelerator. But also a lot of black smoke car will start right back up after stalling. Okay, I found that the cruise was stuck causing the fast start. That is fixed. The problem still exist with the car stalling. The fuel pressure at turn of key is 42 psi. Start car and pressure runs at 34 psi. Runs nice for about five to ten seconds and then just shuts off like something turned off the fuel. But car will start right back up.
Mar 3, 2017 at 3:21 PM
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STRAILER
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Hey GERALD,

Please unplug the mass air flow sensor to see if the engine changes. If this sensor is shorted it will cause the mixture to be way off. Also check the air intake tube for leaks/cracks.

Check for vacuum leaks,

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run some tests and get back to us so we can continue helping you.

Best, Ken
Mar 6, 2017 at 11:45 AM
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GERALD WISE
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Hi Ken Well I unplug the Mass sensor as you suggested and the engine starts right up and runs and as soon as I plug it back in it is dead in the water. It being so old I think I will buy a new one.I really want to thank you for your help. How do I go about sending in a donation. Thanks again Jerry
Mar 6, 2017 at 2:28 PM
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GERALD WISE
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Hey Guys I replaced the Mass Air Flow sensor and the car is now running. My only problem now is that I can start it up and I have to give it a little gas untill it warms up and then it will run at about 1400 rpms for a few seconds and then drop down to about 800 rpms for a few seconds and it just keeps this up. It runs great going down the road at about 50 mph. Thanks for your help. Jerry
Apr 3, 2017 at 1:14 PM
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STRAILER
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It sounds like you have a vacuum leak or a IAC that is dirty, here are two guides that will help you get the problem fixed.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

and

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Please let us know what happens.

Best, Ken
Apr 3, 2017 at 2:00 PM
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GERALD WISE
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I have already replaced the IAC valve motor which is under the intake manifold. So I guess I will be looking for a vac leak. Thanks again
Apr 3, 2017 at 7:50 PM
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HMAC300
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have you tried cleaning throttle plate on both sides? around shaft area so tps willwork good they get sticky/gummy
Apr 4, 2017 at 6:49 AM
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GERALD WISE
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I will give it a try . Thanks
Apr 4, 2017 at 3:28 PM
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GERALD WISE
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OK I found my problem. It was the hose off the bottom of the throttle body to the Air maf tube. It was not on all the way causing a air leak. Thanks for your help Guys . It's running like a Scaulded Dog now. As we used to say!
Apr 6, 2017 at 10:36 AM
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STRAILER
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Glad you could get it fixed please use 2CarPros.com anytime we are here to help

Best, Ken
Apr 6, 2017 at 4:35 PM
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GERALD WISE
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Well I'm back. I had the car running great until it got warmed up. The Tach started jumping up and down and then stalled. Waited till it cooled down and started right back up.Someone told me it sounded like the crank sensor but I don't know if it's on the top of the trans or on the bottom or if this could be my problem. Thanks for your time
Apr 13, 2017 at 3:41 PM
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GERALD WISE
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OK The car seemed to run fine until it warms up. Then the tach will jump up and down and then stops.What do you feel could be causing this problem.
Apr 15, 2017 at 9:10 PM
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GERALD WISE
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I meant to say the engine stops
Apr 15, 2017 at 9:11 PM
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HMAC300
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disconnect the tach wire and see if I t makes a difference then run test described in pic. also when asking another question please repost not as a reply
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Apr 16, 2017 at 8:11 AM
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