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93 Sentra 1.6 Engine Surging
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Guest
Anonymous Poster
kubiakw@bellsouth.net
Mar 11, 2009, 8:09 AM
Post #1 of 17
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93 Sentra 1.6 Engine Surging
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Hi it's me again with the 1993 sentra 1.6 automatic
It now running as smooth as a goose, starts with just a touch of the key, has new found pep and smoothness until I rev it up and then it surges like the engine is being cut off and on. It has to be something I did while fooling around changing those pesky fuel injectors.
Once again I need help, read and re read the Haynes manual, hate that book, checked what I could and here I am again....
(changed subject line only)
(This post was edited by Tom Greenleaf on Mar 11, 2009, 1:56 PM)
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Loren Champlain Sr
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Mar 11, 2009, 5:49 PM
Post #2 of 17
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Re: 93 Sentra 1.6 Engine Surging
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Bill; Check the coolant level. Many times, if the CTS isn't immersed in coolant, it will cause a surge. Also, check for vacuum hoses that may have been knocked off or broken.
Loren
SW Washington
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Guest
Anonymous Poster
Mar 11, 2009, 6:00 PM
Post #3 of 17
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Re: 93 Sentra 1.6 Engine Surging
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What happens if the MAS is not working???
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Loren Champlain Sr
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Mar 11, 2009, 6:16 PM
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Re: 93 Sentra 1.6 Engine Surging
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Do you mean MAF? (Mass Air Flow Sensor). Yes, that could cause an idle problem. Make sure the connections at the plenum, MAF, and air box are tight. Any air induced after the MAF would pull Tom's hair.
Loren
SW Washington
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Tom Greenleaf
Ultimate Carjunky
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Mar 11, 2009, 6:43 PM
Post #5 of 17
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Re: 93 Sentra 1.6 Engine Surging
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Ok - Leave my hair out of it or I'll sic Kitty on you and she's having a bad hair day herself!
T
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Guest
Anonymous Poster
Mar 12, 2009, 8:24 AM
Post #6 of 17
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Re: 93 Sentra 1.6 Engine Surging
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Yes you are right, I meant the Mass Air Flow Sensor.
It does not have an idle problem now, it STARTS RIGHT UP AND idles as smooth and quiet as can be. What happens is when I go to rev it up or drive at any speed over 25mph it surges like mad.
It starts to speed up and then something pulls it down and it does it over and over until I let off the gas.
I was thinking I might have damaged something when I had the intake held up out of the way while I fooling around with the injectors.
As a side note once I got that injector fuel pressure gauge and got those injecter O rings sorted out, the darn thing held over 20 psi in the systen for several hours, I finally had to bleed off the pressure to take the gauge out.
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Guest
Anonymous Poster
Mar 12, 2009, 5:08 PM
Post #7 of 17
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Re: 93 Sentra 1.6 Engine Surging
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Is there a way to jump around the MAF???
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Guest
Anonymous Poster
Mar 12, 2009, 5:17 PM
Post #8 of 17
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Re: 93 Sentra 1.6 Engine Surging
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I was wondering it the TPS could have something to do with this and I unplugged it while the motor was running and the motor quit. Should it do that?????
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Loren Champlain Sr
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Mar 12, 2009, 5:19 PM
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Re: 93 Sentra 1.6 Engine Surging
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No, and No.  You should never unplug a sensor with the engine running. I have forgotten, but I know you checked fuel pressure, how about the filter? A restricted filter can cause a surge, as well as an air leak or a vacuum leak. Low coolant, ect....ect....ect....
Loren
SW Washington
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Guest
Anonymous Poster
Mar 12, 2009, 6:11 PM
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Re: 93 Sentra 1.6 Engine Surging
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oops my bad,,i recall someone said to disconnect the fuel regulator or something else and see if the motor sped up or down so I thought why not the TPS
Brand New Fuel Filter
I thought all the sensors or the computer had a default it would fall back on if something stopped working. Still no engine light either
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Loren Champlain Sr
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Mar 12, 2009, 6:56 PM
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Re: 93 Sentra 1.6 Engine Surging
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The fuel pressure regulator isn't an electrically operated switch. When you disconnect the vacuum, the injection will go full rich. If you were running too lean, that, of course would help.
Loren
SW Washington
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Anonymous Poster
Mar 13, 2009, 4:51 AM
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Re: 93 Sentra 1.6 Engine Surging
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Above you said No and No, did you mean that the motor should NOT have stopped when I unplugged the tps and No never again unplug anything electric when the motor is running?
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Loren Champlain Sr
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Mar 13, 2009, 3:06 PM
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Re: 93 Sentra 1.6 Engine Surging
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No, you should never disconnect a sensor with the engine running. I originally said no, the TPS wouldn't cause a surge, but after thinking about it, I suppose it is possible. The TPS is just a potentiometer. If there is a bad spot, I suppose it could. But, it would be in the same place, every time the throttle hit that particular spot. I prefer to check them with a DVOM. Lab scopes don't seem to react quick enough to 'see' a glitch. With the engine off, disconnect the connecter at the TPS. Connect the DVOM to the terminals and very slowly open and close the throttle. You'll get different resistance readings as you go...just watch for a 'quick' open. Usually, there will be three wires (connections) in the TPS; Do this to all of them.
Loren
SW Washington
(This post was edited by Loren Champlain Sr on Mar 13, 2009, 3:08 PM)
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Guest
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Mar 14, 2009, 9:44 AM
Post #14 of 17
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Re: 93 Sentra 1.6 Engine Surging
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I will do as you have suggested. But should the motor quit when you unplug the tps????
Is there a way to run the car with out the maf plugged in and fool it into going to it's default setting
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Loren Champlain Sr
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Mar 14, 2009, 10:15 AM
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Re: 93 Sentra 1.6 Engine Surging
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>>But should the motor quit when you unplug the tps?<<
Uh, don't know, as I was taught not to do it. After being married 38 yrs, I've learned to do what I'm told.
Used to be a 'trick' back in the old days to remove the battery cable with the engine running to see if the GENERATOR working. People still do that with alternators. That's a no, no, too. You can damage the alternator by doing that.
Loren
SW Washington
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bill k
User
Mar 16, 2009, 11:49 AM
Post #16 of 17
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Re: 93 Sentra 1.6 Engine Surging
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Got it fixed, the problem seemed almost insurmountable with my limited experience, but with all the help here. I got it fixed. Turned out to be a defective or non working MAF. Bought one used on E bay for 30.00 and poof, problem solved. Not one junk yard in the South Miami area had a used one and rebuilt ones went from 150 to 200 bucks and I would still have to order one because none of the part stores carry them.
It all started with a defective fuel injector and then I guess the maf was just getting ready to quit too
Thanks for all your help and advice.
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Loren Champlain Sr
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Mar 16, 2009, 3:18 PM
Post #17 of 17
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Re: 93 Sentra 1.6 Engine Surging
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Bill, you did this on your own! I wouldn't have thought that the MAF was creating such a headache. Props to ya! Great job.
Loren
SW Washington
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