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Crankshaft Sensor (REF) Question

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Old 01-18-2010, 06:48 AM
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Crankshaft Sensor (REF) Question

So I was having startup issues and i figured the problem was either the CKPS or the starter. The CKPS was cheaper and the problem felt like more of a sensor electronic issue than a mechanical one so i replaced the CKPS (REF).

After replacing, the car started up really smooth. That was like 3 days ago. Now, every other start or so the car will start up a lil rough.

THe old sensor had all this crud and metal shavings on it. Im thinking the new sensor has been covered wit the same crap too. Havent had a chance to look at the sensor again since the install.

I wanna clean out the flywheel housing. Can i jus use a vacuum cleaner hose and remove as much of the crap as i can thru the CKPS hole?? Is that safe?? I would be gentle lol

I dont have the resources to actually get to the flywheel myself and i dont wanna pay for it.

My other option is to remove the sensor every wk and clean it. but that will take forever to clean out the housing.

Comments??
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Old 01-18-2010, 06:59 AM
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Did you ever change the clutch? I did, then had the same problem , DTC for ref crank position sensor. Turns out l didn't clean between the two surfaces (tranny/engine) well enough, for their to be a good ground on the tranny. To fix the problem l ran a ground wire from to battery to the tranny mounting bolt next to the sensor and another one to the trans mount. No more problem, starts better than it ever did before.

Last edited by Tmars; 01-18-2010 at 07:05 AM.
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Old 01-18-2010, 11:47 AM
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Originally Posted by Tmars
Did you ever change the clutch? I did, then had the same problem , DTC for ref crank position sensor. Turns out l didn't clean between the two surfaces (tranny/engine) well enough, for their to be a good ground on the tranny. To fix the problem l ran a ground wire from to battery to the tranny mounting bolt next to the sensor and another one to the trans mount. No more problem, starts better than it ever did before.

Yes, it feels almost as the Sensor is "looking" for top dead center (TDC, I think thats what u meant). And sometimes cant find it quickly enough so the crankshaft rotates until the sensor senses TDC and everything fires up.

When i replaced the CKPS it fired better. It was quick fire up like normal. After a few startups, the CKPS began "looking" for TDC again causing slower startups. I think thats because the CKPS got fouled again or maybe even cuz the crankshaft surfaces arent clean.

Im not sure if the clutch has even been changed for this car. Might have, but i jus bought the car so i cant really say. I Think cleaning the housing would be beneficial but i dont have the resources to do so. Thats why i jus suggested using a vacuum cleaner to remove loose particles and doing whatever i cd.

I see what u mean about the extra ground so that the crankshaft would have a better conductivity and magnetic properties so that the CKPS would sense it no matter what. (thats pretty funny to rig it like that lol).

What gauge wire did u run to each location? How long have u ran this setup? Do u mean to run wire to the bolt for the CKPS?

What Do u mean by a "good ground"? Do u mean to say that there was electrical interference with the signal that the CKPS was sensing and this was corrected by making better ground points on the housing and sensor itself??



If u can send pics to my email man...cashoit@yahoo.com.

Thanks man.

Anyone else chime in too. this is a pretty good discussion.

Last edited by cashoit; 01-18-2010 at 11:49 AM.
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Old 01-18-2010, 03:19 PM
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I used two 14ga wires from the battery negative terminal with circle connectors on both ends, and put one to the engine/tranny mounting bolt as close to the sensor as possible. and the other one in between the transmission and drivers side transmission mount then put the bolt back in. From what l can tell is my stock ground was not good enough for the sensor, this made it better. And it started and idled better as a result.
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Old 01-18-2010, 06:20 PM
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Old 01-18-2010, 07:50 PM
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Originally Posted by slow_yota
I can't afford a digital camera, just bought a supercharger. So you must use your imagination.

I owe, I owe, off to work I go.

Last edited by Tmars; 01-18-2010 at 07:55 PM.
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Old 01-18-2010, 08:40 PM
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Im having a starting issue as well. I will be testing out this grounding theory tomorrow after I go buy some wire. My fingers are crossed.

I say you should try the extra grounding wires too. Never hurts to try right? And if it fixes the problem, it was a damn quick and easy fix.
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Old 01-18-2010, 09:10 PM
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Originally Posted by cashoit
Yes, it feels almost as the Sensor is "looking" for top dead center (TDC, I think thats what u meant). And sometimes cant find it quickly enough so the crankshaft rotates until the sensor senses TDC and everything fires up.

When i replaced the CKPS it fired better. It was quick fire up like normal. After a few startups, the CKPS began "looking" for TDC again causing slower startups. I think thats because the CKPS got fouled again or maybe even cuz the crankshaft surfaces arent clean.

Im not sure if the clutch has even been changed for this car. Might have, but i jus bought the car so i cant really say. I Think cleaning the housing would be beneficial but i dont have the resources to do so. Thats why i jus suggested using a vacuum cleaner to remove loose particles and doing whatever i cd.

I see what u mean about the extra ground so that the crankshaft would have a better conductivity and magnetic properties so that the CKPS would sense it no matter what. (thats pretty funny to rig it like that lol).

What gauge wire did u run to each location? How long have u ran this setup? Do u mean to run wire to the bolt for the CKPS?

What Do u mean by a "good ground"? Do u mean to say that there was electrical interference with the signal that the CKPS was sensing and this was corrected by making better ground points on the housing and sensor itself??



If u can send pics to my email man...cashoit@yahoo.com.

Thanks man.

Anyone else chime in too. this is a pretty good discussion.

DTC= Diagnostic Trouble Code, for REF Crankshaft Position Sensor. Mine logged this on occasion when starting, with a check engine light. Had the extra ground wires for, 4 months or so. The intention is to provide a better ground for the hole transmission, not just the sensor.

Last edited by Tmars; 01-18-2010 at 09:18 PM.
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Old 01-19-2010, 05:58 AM
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Originally Posted by Tmars
DTC= Diagnostic Trouble Code, for REF Crankshaft Position Sensor. Mine logged this on occasion when starting, with a check engine light. Had the extra ground wires for, 4 months or so. The intention is to provide a better ground for the hole transmission, not just the sensor.

AHhh DTC...good call. Forgot about that one. Naw no CEL issues for me man. I dont think i need to ground. The tranny shiftin fine and no other issues. But extra ground wires wont hurt. Jus find a place to mount near the sensor and on the tranny is what u saying.

But back to my OP, what do u guys think.

I stioll have to old CKPS so i may jus clean it and switch ever so often lol
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Old 02-01-2010, 01:44 PM
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I need to replace the one on the missus car, all I need to know is where its located. From the thread, it sounds like its on the drivers side, under the crank, where it meets the flywheel... I've been wrong in the past.
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Old 02-02-2010, 12:42 PM
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yea samething happens to my car... I think ima clean up my grounds sometime soon. I do have my tranny regrounded.. When i pulled the crank shaft sensor out there was madd gunk and metal shaving on it. What causes this?
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Old 02-02-2010, 12:54 PM
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Originally Posted by Maximus BCD
I need to replace the one on the missus car, all I need to know is where its located. From the thread, it sounds like its on the drivers side, under the crank, where it meets the flywheel... I've been wrong in the past.
Yeah thats it. THere are two CKPS, POS and REF. Usually the REF is all nasty and grimmy. HERE is the FSM. There is a nice pic. Honestly u cant miss it cuz its the only sensor on the bottom of the engine driver side connected to the housing.

http://www.nicoclub.com/FSM/maxima/


Originally Posted by wirelessdude04
yea samething happens to my car... I think ima clean up my grounds sometime soon. I do have my tranny regrounded.. When i pulled the crank shaft sensor out there was madd gunk and metal shaving on it. What causes this?
yo man, i have hrd of ppl who jus cleaned it off clean and the car got worst. Jus replace it. The gunk and shavings is oil and crankshaft or flywheel deposits.
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Old 02-02-2010, 08:45 PM
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No no no, HERE is the FSM..

See Sig...
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Old 03-23-2011, 06:37 PM
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Well can someone help me. I have had both crank sensors replaced and today I was driving and hit a bump in the road and my car begin to stall! Got it home and it never stared again. I have tried everything car won't start!
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Old 03-24-2011, 06:43 AM
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Originally Posted by iflexsteel
Well can someone help me. I have had both crank sensors replaced and today I was driving and hit a bump in the road and my car begin to stall! Got it home and it never stared again. I have tried everything car won't start!
Check the harness for both crank sensors and check the camshaft position sensor. Clean TB and MAF per how tos. See if that helps

How was the car acting before replacing the sensors? How was the car acting after replacing the sensors? Any codes?
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