Re: Need help in troubleshooting ignition problem
 

They are computer signal pins. The socket has a point that scribes the
pin every time it is plugged in. The power level is so low, the
slightest amount of corrosion kills the signal, so just unplugging them
gives a brand new contact via that scribe pin that will last for a bit.
Same for replacing them, one half just got new.

The best is to clean them with a spray contact cleaner. WD40 will work
in a pinch, but. Then sealing the plug skirt with dielectric grease
also helps keep them clean.

We were told our TPS was dead 4 or 5 years ago now and all it needed was
the spray clean with a fresh clean every couple years or so.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Lee Ayrton wrote:
>
> Which leads me to wonder if the problem is not the CPS, as is so often
> assumed, but really a fault in the computer -- some endless loop
> triggered when inputs line up _just_so_ or something (in my mind I'm
> picturing the old MS-DOS loop of "Printer not found - Abort, Retry or
> Fail? Abort, Retry or Fail?"). After all, the CPS is just a dumb
> sensor, unplugging it shouldn't fix or reset anything in it.
>
> Which then makes me wonder how many CPS have been needlessly replaced
> and paid for either in cash or busted knuckles.
>
> L.W.(Bill) ------ III wrote:
> > Merely unplugging it may bring it back to life, just like many times
> > we are forced to do that via instructions for hand held computers, my
> > phone machine, and my DirecTV satellite decoder.
> > God Bless America, Bill O|||||||O
> > mailto:-------------------- http://www.----------.com/
> >
> > Mike Romain wrote:
> >
> >>They get bad connections easy, some spray contact cleaner in them and
> >>dielectric grease on the seal helps. Just unplugging is still good, the
> >>pin gets scratched enough to make a new contact usually.
> >>
> >>Mike
> >>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >>88 Cherokee 235 BFG AT's

Re: Need help in troubleshooting ignition problem
 

They are computer signal pins. The socket has a point that scribes the
pin every time it is plugged in. The power level is so low, the
slightest amount of corrosion kills the signal, so just unplugging them
gives a brand new contact via that scribe pin that will last for a bit.
Same for replacing them, one half just got new.

The best is to clean them with a spray contact cleaner. WD40 will work
in a pinch, but. Then sealing the plug skirt with dielectric grease
also helps keep them clean.

We were told our TPS was dead 4 or 5 years ago now and all it needed was
the spray clean with a fresh clean every couple years or so.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Lee Ayrton wrote:
>
> Which leads me to wonder if the problem is not the CPS, as is so often
> assumed, but really a fault in the computer -- some endless loop
> triggered when inputs line up _just_so_ or something (in my mind I'm
> picturing the old MS-DOS loop of "Printer not found - Abort, Retry or
> Fail? Abort, Retry or Fail?"). After all, the CPS is just a dumb
> sensor, unplugging it shouldn't fix or reset anything in it.
>
> Which then makes me wonder how many CPS have been needlessly replaced
> and paid for either in cash or busted knuckles.
>
> L.W.(Bill) ------ III wrote:
> > Merely unplugging it may bring it back to life, just like many times
> > we are forced to do that via instructions for hand held computers, my
> > phone machine, and my DirecTV satellite decoder.
> > God Bless America, Bill O|||||||O
> > mailto:-------------------- http://www.----------.com/
> >
> > Mike Romain wrote:
> >
> >>They get bad connections easy, some spray contact cleaner in them and
> >>dielectric grease on the seal helps. Just unplugging is still good, the
> >>pin gets scratched enough to make a new contact usually.
> >>
> >>Mike
> >>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >>88 Cherokee 235 BFG AT's

Re: Need help in troubleshooting ignition problem
 

They are computer signal pins. The socket has a point that scribes the
pin every time it is plugged in. The power level is so low, the
slightest amount of corrosion kills the signal, so just unplugging them
gives a brand new contact via that scribe pin that will last for a bit.
Same for replacing them, one half just got new.

The best is to clean them with a spray contact cleaner. WD40 will work
in a pinch, but. Then sealing the plug skirt with dielectric grease
also helps keep them clean.

We were told our TPS was dead 4 or 5 years ago now and all it needed was
the spray clean with a fresh clean every couple years or so.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Lee Ayrton wrote:
>
> Which leads me to wonder if the problem is not the CPS, as is so often
> assumed, but really a fault in the computer -- some endless loop
> triggered when inputs line up _just_so_ or something (in my mind I'm
> picturing the old MS-DOS loop of "Printer not found - Abort, Retry or
> Fail? Abort, Retry or Fail?"). After all, the CPS is just a dumb
> sensor, unplugging it shouldn't fix or reset anything in it.
>
> Which then makes me wonder how many CPS have been needlessly replaced
> and paid for either in cash or busted knuckles.
>
> L.W.(Bill) ------ III wrote:
> > Merely unplugging it may bring it back to life, just like many times
> > we are forced to do that via instructions for hand held computers, my
> > phone machine, and my DirecTV satellite decoder.
> > God Bless America, Bill O|||||||O
> > mailto:-------------------- http://www.----------.com/
> >
> > Mike Romain wrote:
> >
> >>They get bad connections easy, some spray contact cleaner in them and
> >>dielectric grease on the seal helps. Just unplugging is still good, the
> >>pin gets scratched enough to make a new contact usually.
> >>
> >>Mike
> >>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >>88 Cherokee 235 BFG AT's

Re: Need help in troubleshooting ignition problem
 

They are computer signal pins. The socket has a point that scribes the
pin every time it is plugged in. The power level is so low, the
slightest amount of corrosion kills the signal, so just unplugging them
gives a brand new contact via that scribe pin that will last for a bit.
Same for replacing them, one half just got new.

The best is to clean them with a spray contact cleaner. WD40 will work
in a pinch, but. Then sealing the plug skirt with dielectric grease
also helps keep them clean.

We were told our TPS was dead 4 or 5 years ago now and all it needed was
the spray clean with a fresh clean every couple years or so.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Lee Ayrton wrote:
>
> Which leads me to wonder if the problem is not the CPS, as is so often
> assumed, but really a fault in the computer -- some endless loop
> triggered when inputs line up _just_so_ or something (in my mind I'm
> picturing the old MS-DOS loop of "Printer not found - Abort, Retry or
> Fail? Abort, Retry or Fail?"). After all, the CPS is just a dumb
> sensor, unplugging it shouldn't fix or reset anything in it.
>
> Which then makes me wonder how many CPS have been needlessly replaced
> and paid for either in cash or busted knuckles.
>
> L.W.(Bill) ------ III wrote:
> > Merely unplugging it may bring it back to life, just like many times
> > we are forced to do that via instructions for hand held computers, my
> > phone machine, and my DirecTV satellite decoder.
> > God Bless America, Bill O|||||||O
> > mailto:-------------------- http://www.----------.com/
> >
> > Mike Romain wrote:
> >
> >>They get bad connections easy, some spray contact cleaner in them and
> >>dielectric grease on the seal helps. Just unplugging is still good, the
> >>pin gets scratched enough to make a new contact usually.
> >>
> >>Mike
> >>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >>88 Cherokee 235 BFG AT's

Re: Need help in troubleshooting ignition problem
 

needs a crank sensor very common failure

Steve Smith wrote:

> My 95 Grand Cherokee would not start today. It is not getting any ignition.
> The engine turns over fine but there is no spark from spark plug wires or
> from the coil. I've tested the coil with a ohmmeter and it checked out fine.
> I replaced the distributor cap and rotor button, but that didn't help. I
> fear it might be the Powertrain Control Module(PCM). My Haynes repair manual
> does not explain how to test this. Does anyone here know? Is there something
> else I should check? I have a 4.0L V6 motor.
>
> Any suggestions would be greatly appreciated.
>
> BTW- If it is the Powertrain Control Module, is it possible to purchase an
> after-market PCM that is better? I saw this on Ebay:
> http://cgi.ebay.com/ebaymotors/ws/eB...category=33597
> but I don't know if it a PCM replacement or just an add on.
>
> Steve Smith

Re: Need help in troubleshooting ignition problem
 

needs a crank sensor very common failure

Steve Smith wrote:

> My 95 Grand Cherokee would not start today. It is not getting any ignition.
> The engine turns over fine but there is no spark from spark plug wires or
> from the coil. I've tested the coil with a ohmmeter and it checked out fine.
> I replaced the distributor cap and rotor button, but that didn't help. I
> fear it might be the Powertrain Control Module(PCM). My Haynes repair manual
> does not explain how to test this. Does anyone here know? Is there something
> else I should check? I have a 4.0L V6 motor.
>
> Any suggestions would be greatly appreciated.
>
> BTW- If it is the Powertrain Control Module, is it possible to purchase an
> after-market PCM that is better? I saw this on Ebay:
> http://cgi.ebay.com/ebaymotors/ws/eB...category=33597
> but I don't know if it a PCM replacement or just an add on.
>
> Steve Smith

Re: Need help in troubleshooting ignition problem
 

needs a crank sensor very common failure

Steve Smith wrote:

> My 95 Grand Cherokee would not start today. It is not getting any ignition.
> The engine turns over fine but there is no spark from spark plug wires or
> from the coil. I've tested the coil with a ohmmeter and it checked out fine.
> I replaced the distributor cap and rotor button, but that didn't help. I
> fear it might be the Powertrain Control Module(PCM). My Haynes repair manual
> does not explain how to test this. Does anyone here know? Is there something
> else I should check? I have a 4.0L V6 motor.
>
> Any suggestions would be greatly appreciated.
>
> BTW- If it is the Powertrain Control Module, is it possible to purchase an
> after-market PCM that is better? I saw this on Ebay:
> http://cgi.ebay.com/ebaymotors/ws/eB...category=33597
> but I don't know if it a PCM replacement or just an add on.
>
> Steve Smith

Re: Need help in troubleshooting ignition problem
 

needs a crank sensor very common failure

Steve Smith wrote:

> My 95 Grand Cherokee would not start today. It is not getting any ignition.
> The engine turns over fine but there is no spark from spark plug wires or
> from the coil. I've tested the coil with a ohmmeter and it checked out fine.
> I replaced the distributor cap and rotor button, but that didn't help. I
> fear it might be the Powertrain Control Module(PCM). My Haynes repair manual
> does not explain how to test this. Does anyone here know? Is there something
> else I should check? I have a 4.0L V6 motor.
>
> Any suggestions would be greatly appreciated.
>
> BTW- If it is the Powertrain Control Module, is it possible to purchase an
> after-market PCM that is better? I saw this on Ebay:
> http://cgi.ebay.com/ebaymotors/ws/eB...category=33597
> but I don't know if it a PCM replacement or just an add on.
>
> Steve Smith