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1996 Quest - Extended Crank
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Guest
Anonymous Poster
tgregg75@yahoo.com
Nov 6, 2008, 6:47 PM
Post #1 of 5
(3078 views)
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1996 Quest - Extended Crank
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Year of vehicle: 1996
Make of vehicle: Nissan
Model of vehicle: Quest
Engine size: v6
Mileage: 117k
Vehicle has an extended crank on startup after sitting for a few hours wheather it be in the morning or afternoon after work. When the engine does engage it's a little hessitant with a squeaky noise (like a serpentine belt with moisture in the morning). I can smell exhaust more than I should, and visible white exhaust. Then after a few seconds the engine runs normal. I have had the fuel pump replaced (confirmed bad), and injectors checked - one replaced (suspected leaking injector). Still the same problem persists. Thank you for any suggestions. Tony
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DanD
Veteran
/ Moderator
Nov 7, 2008, 4:58 AM
Post #2 of 5
(3064 views)
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Re: 1996 Quest - Extended Crank
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There are many different scenarios that can cause an extended crank.
My first thought reading your post was fuel related; even though you’ve replaced fuel pump; I would still confirm fuel pressure, volume and leak back.
The pressure without vacuum applied to the regulator should be approximately 43psi, with vacuum applied 34psi. Also fuel pressure should hold, after pump is turned off; loosing no more then 3-5psi during a10-15 minute time frame. If the fuel pressure drops substantially went pump is turned off; then there is some form of internal leak, allowing fuel to return to tank. If this is happening fuel will siphon back to the tank, empting the fuel rail and lines. Now when you go to restart the engine the fuel pump has too fill the system and then pressurize it before the engine will fire. The engine will act the same as if when you ran out of gas; the first start takes extra cranking.
This white smoke; is there a mysterious loss of coolant; even if it’s only in small amounts?
If so, there might be an internal coolant leak; (intake manifold gasket, cylinder head gasket?) causing one or more cylinder to misfire? Once this coolant is burnt away and internal temperature expands the metal(s); the leak is pinch closed, not showing any other issues?
This could also explain the heavy exhaust smell; while the engine is misfiring partially burnt fuel is being expelled?
Then there could be a sensor issue; a sensor that has not failed 100% but signaling the computer the wrong information; it’s is still within its parameters not triggering a code.
For example an engine temperature sensor is (for the lack of a better word) stuck at 150 degrees; when in fact the ambient temperature and engine is at 30 degrees The computer doesn’t think anything is wrong and is trying to start a partially warm engine. This could cause what is called a lean misfire; not enough fuel to keep the engine running. Again causing raw fuel to be expelled into the exhaust and possibly even creating the white smoke?
A scanner (not code reader) would be used to read sensor outputs when the engine is cold. Using the coolant sensor again as an example; it should read very close to ambient temperature after the engine has sat for a number of hours.
Sorry for the long reply but like I said there are so many different scenarios that I could keep going and still not hit on the actual cause? You need someone familiar with this vehicle and its “normals”.
Dan.
Canadian "EH"
(This post was edited by DanD on Nov 7, 2008, 5:03 AM)
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Guest
Anonymous Poster
tgregg75@yahoo.com
Dec 11, 2008, 7:01 AM
Post #3 of 5
(3016 views)
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Re: 1996 Quest - Extended Crank
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Thanks for the thoughts. So I got in the van yesterday and for some reason I decided before turning the key to push the gas peddal all the way down and let it back up one time. I turned the key and the van cranked right up with no squeal. When my work day was over at 5 and the van had been sitting all day, before turning the key I did the same thing with the gas peddal and the van fired right up, no problem. This morning I went thru the same procedure, cranked right up. Does knowing this help narrow down what could be the problem, or just complicate things more? Thanks for your help.
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DanD
Veteran
/ Moderator
Dec 11, 2008, 11:03 AM
Post #4 of 5
(3005 views)
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Re: 1996 Quest - Extended Crank
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Sorry but that doesn’t really tell me anything; by depressing the pedal before turning the ignition on, by rights doesn’t do anything?
It would be like trying to turn on a coffee table lamp, when the lamp isn’t plugged in; there no power. Same thing in a vehicle; there’s no power to a portion of the computer, to recognize that you’re doing that.
So if this is working for you; I don’t know what to say?
Dan.
Canadian "EH"
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 11, 2008, 11:41 AM
Post #5 of 5
(3001 views)
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Re: 1996 Quest - Extended Crank
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As Dan says this really shouldn't be doing anything as it's all off at the time. The only wild idea I can think of is perhaps the TPS (throttle position sensor) if mechanically moved is causing it to subsequently send accurate info for cold start ups and somehow if not moved is so wrong it can't figure it out sending totally wrong info.
That's a wild maybe! Would only be a chance if throttle was cable operated and physically moved the TPS sensor. Surprised that wouldn't throw a code??
T
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