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General Forums => The Mess Hall => Topic started by: chrisfranklin on May 09, 2011, 11:38:43 PM

Title: DIY Crank Position Sensor Modification
Post by: chrisfranklin on May 09, 2011, 11:38:43 PM
Turbo city used to sell "modified" CPS for Jeeps to apparently yield a slight timing advance. 

Was looking at this write-up http://www.docstoc.com/docs/2538922/How-to-Crankshaft-Position-Sensor-Mod-(aka-Timing-Advance-Mod) (http://www.docstoc.com/docs/2538922/How-to-Crankshaft-Position-Sensor-Mod-(aka-Timing-Advance-Mod)).  Looks like the guy just slotted the CPS to enable it to mount slightly to the right of its original position.  Anybody tried this?
Title: Re: DIY Crank Position Sensor Modification
Post by: Jeffy on May 09, 2011, 11:44:51 PM
Turbo city used to sell "modified" CPS for Jeeps to apparently yield a slight timing advance. 

Was looking at this write-up http://www.docstoc.com/docs/2538922/How-to-Crankshaft-Position-Sensor-Mod-(aka-Timing-Advance-Mod) (http://www.docstoc.com/docs/2538922/How-to-Crankshaft-Position-Sensor-Mod-(aka-Timing-Advance-Mod)).  Looks like the guy just slotted the CPS to enable it to mount slightly to the right of its original position.  Anybody tried this?
That's what the Turbo City CPS was.  You can advance or retard the timing a few degrees.
Title: Re: DIY Crank Position Sensor Modification
Post by: neale_rs on May 10, 2011, 09:52:03 AM
Does it really work or would the computer "adapt" to it and negate the effect? 

Title: Re: DIY Crank Position Sensor Modification
Post by: sharpxmen on May 10, 2011, 10:05:07 AM
Does it really work or would the computer "adapt" to it and negate the effect? 



it would only adapt if there's a knock sensor, moving it will trick the computer as to the position of TDC, so without any other input will just advance or retard the timing by the amount of offset you set when in the new location (the PCM "thinks" it's the correct position to generate the spark).
Title: Re: DIY Crank Position Sensor Modification
Post by: neale_rs on May 10, 2011, 11:18:03 AM
Thanks
Title: Re: DIY Crank Position Sensor Modification
Post by: Torch_Ind on May 10, 2011, 07:32:31 PM
cool
Title: Re: DIY Crank Position Sensor Modification
Post by: chrisfranklin on May 10, 2011, 10:21:37 PM
If anybody does this mod, would be cool to hear how it goes, effects on drivability.  Will probably give it a go myself before too long.
Title: Re: DIY Crank Position Sensor Modification
Post by: chrisfranklin on May 21, 2011, 02:19:01 AM
I'm buying a new CPS and will "notch" it and see how it goes
Title: Re: DIY Crank Position Sensor Modification
Post by: quicksand on June 22, 2011, 12:09:28 PM
Does a 97 2.5L have a CPS ?
Title: Re: DIY Crank Position Sensor Modification
Post by: aw12345 on June 22, 2011, 04:00:30 PM
Yes
Title: Re: DIY Crank Position Sensor Modification
Post by: quicksand on June 22, 2011, 04:26:40 PM
So then that can be modified right? What type of modifications can it be modified for? I have heard of map adjusters, IAT relocations, but silly me I thought CPS where only on 4.0Ls, I did not realize a 2.5L manaul had one. I know quadratec carrys them for 4.0Ls. What are benefits of this being modified? And I thought I knew it all, HUH.
Title: Re: DIY Crank Position Sensor Modification
Post by: Jeffy on June 22, 2011, 05:25:17 PM
Read the post?
Title: Re: DIY Crank Position Sensor Modification
Post by: quicksand on June 22, 2011, 08:33:33 PM
I read it, got it.
Title: Re: DIY Crank Position Sensor Modification
Post by: 95yjman on June 23, 2011, 12:27:17 AM
You'll have that heh
Title: Re: DIY Crank Position Sensor Modification
Post by: quicksand on June 23, 2011, 11:04:47 AM
I will look more into it. Hey whats you guys opinion or experience on IAT relocation, does it work or is it hype ?
Title: Re: DIY Crank Position Sensor Modification
Post by: chrisfranklin on June 23, 2011, 12:18:20 PM
Am personally probably not going to mess with the IAT since my intake setup is already piped to the outside and things are probably as cold as they are going to get.   

Had a MAP adjuster from Turbo City -- that was the last time I messed with a sensor.  I pulled the thing though.  Mine was not enabling me to set a steady voltage -- you'd turn the plastic screw a minuscule amount and the readout would take off + or -.  Headache. 

Just replacing the MAP sensor -- though I wasn't getting a code -- and replacing the tubing and cleaning out its fitting to the intake manifold, that actually helped drive-ability a great deal.   Of course, the one I replaced had been on there probably 16 years or so. 

Still haven't done the CPS mod here though i do have a new one to work with.  Have a new alternator and belt I want to get in there and then an intake manifold to work on first before getting in to that. 
Title: Re: DIY Crank Position Sensor Modification
Post by: quicksand on June 23, 2011, 03:32:48 PM
Well that map adjustment sounds spooky and like a pain in the neck, I guess i will stay away from that. Let me/us know if you ever get around to messing with the CPS. Is your IAT sensor still in the intake manifold or in your air intake tube?
Title: Re: DIY Crank Position Sensor Modification
Post by: chrisfranklin on June 23, 2011, 06:06:34 PM
Well that map adjustment sounds spooky and like a pain in the neck, I guess i will stay away from that. Let me/us know if you ever get around to messing with the CPS. Is your IAT sensor still in the intake manifold or in your air intake tube?

The IAT is still in the stock location on the manifold. 
Title: Re: DIY Crank Position Sensor Modification
Post by: quicksand on June 24, 2011, 12:54:49 AM
O I thought maybe you had relocated to the air intake tube. I always wondered how that modification had worked for someone.