Problem starting my Jeep Comanche 87
 

Hi I have an 87 Comanche 4X4 I6.

Since almost 2 mounts my Jeep is very hard to start especially in the
morning. (After the first start of the day usually the Jeep is fine.)

The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
attempts of 15-20 seconds each before it starts. Last week I changed the
plugs, wires, cap and rotor and I still have the problem.



This morning I tried to start it but the battery died before it started. So
I had it towed to the garage. They put the charger on the battery and it
started right away. The guy put water on the wires and near the computer,
verified the fire that was going to the cap and the pressure of the gas
(38psi when starting the pump and 33psi when engine is working) He told me
about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
sure it's that.

The guy said that usually sensors would not have intermittent problems.



I checked the Haynes manual and I found nothing.



Can someone help me with that? Or had that problem before?



Thanks a lot



Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The problem with the sensors is the plug and socket. They are low power
units so the slightest corrosion can mess them up. Enough so they still
'look' clean, but just work intermittent.

The CPS is notorious for that, so is the TPS connection. The CPS
connector is at the back on top of the exhaust manifold and the TPS is
on the throttle body.

Another one is the ground strap from the engine head to the firewall.
if it gets dirty or ratty, it can not allow enough juice to pass to fire
up the computer if the starter is cranking.

I use a contact cleaner spray like WD40 for the connections. It does
wonders on our old 88.

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

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The problem with the sensors is the plug and socket. They are low power
units so the slightest corrosion can mess them up. Enough so they still
'look' clean, but just work intermittent.

The CPS is notorious for that, so is the TPS connection. The CPS
connector is at the back on top of the exhaust manifold and the TPS is
on the throttle body.

Another one is the ground strap from the engine head to the firewall.
if it gets dirty or ratty, it can not allow enough juice to pass to fire
up the computer if the starter is cranking.

I use a contact cleaner spray like WD40 for the connections. It does
wonders on our old 88.

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

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The problem with the sensors is the plug and socket. They are low power
units so the slightest corrosion can mess them up. Enough so they still
'look' clean, but just work intermittent.

The CPS is notorious for that, so is the TPS connection. The CPS
connector is at the back on top of the exhaust manifold and the TPS is
on the throttle body.

Another one is the ground strap from the engine head to the firewall.
if it gets dirty or ratty, it can not allow enough juice to pass to fire
up the computer if the starter is cranking.

I use a contact cleaner spray like WD40 for the connections. It does
wonders on our old 88.

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

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The problem with the sensors is the plug and socket. They are low power
units so the slightest corrosion can mess them up. Enough so they still
'look' clean, but just work intermittent.

The CPS is notorious for that, so is the TPS connection. The CPS
connector is at the back on top of the exhaust manifold and the TPS is
on the throttle body.

Another one is the ground strap from the engine head to the firewall.
if it gets dirty or ratty, it can not allow enough juice to pass to fire
up the computer if the starter is cranking.

I use a contact cleaner spray like WD40 for the connections. It does
wonders on our old 88.

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

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The Crankshaft Position Sensor should be replaced just on account.
Next time, try turning the ignition to the on position without
hitting the starter, listen for the fuel pump to shut off, and about
three seconds, then turn the ignition off and back on and do it again
five or more times to pump the gas that has bleed off, back up to the
rails. That if the pressure regulator/check valve is bad:
http://members.cox.net/wilsond/Fixes....html#fuelrail
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The Crankshaft Position Sensor should be replaced just on account.
Next time, try turning the ignition to the on position without
hitting the starter, listen for the fuel pump to shut off, and about
three seconds, then turn the ignition off and back on and do it again
five or more times to pump the gas that has bleed off, back up to the
rails. That if the pressure regulator/check valve is bad:
http://members.cox.net/wilsond/Fixes....html#fuelrail
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The Crankshaft Position Sensor should be replaced just on account.
Next time, try turning the ignition to the on position without
hitting the starter, listen for the fuel pump to shut off, and about
three seconds, then turn the ignition off and back on and do it again
five or more times to pump the gas that has bleed off, back up to the
rails. That if the pressure regulator/check valve is bad:
http://members.cox.net/wilsond/Fixes....html#fuelrail
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

The Crankshaft Position Sensor should be replaced just on account.
Next time, try turning the ignition to the on position without
hitting the starter, listen for the fuel pump to shut off, and about
three seconds, then turn the ignition off and back on and do it again
five or more times to pump the gas that has bleed off, back up to the
rails. That if the pressure regulator/check valve is bad:
http://members.cox.net/wilsond/Fixes....html#fuelrail
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Bruno wrote:
>
> Hi I have an 87 Comanche 4X4 I6.
>
> Since almost 2 mounts my Jeep is very hard to start especially in the
> morning. (After the first start of the day usually the Jeep is fine.)
>
> The engine is cranking but doesn't want to start. Sometimes it takes 2 or 3
> attempts of 15-20 seconds each before it starts. Last week I changed the
> plugs, wires, cap and rotor and I still have the problem.
>
> This morning I tried to start it but the battery died before it started. So
> I had it towed to the garage. They put the charger on the battery and it
> started right away. The guy put water on the wires and near the computer,
> verified the fire that was going to the cap and the pressure of the gas
> (38psi when starting the pump and 33psi when engine is working) He told me
> about the crankshaft positioning sensor (or crank angle sensor) but he's 60%
> sure it's that.
>
> The guy said that usually sensors would not have intermittent problems.
>
> I checked the Haynes manual and I found nothing.
>
> Can someone help me with that? Or had that problem before?
>
> Thanks a lot
>
> Bruno (Gatineau, Québec)

Re: Problem starting my Jeep Comanche 87
 

> The guy said that usually sensors would not have intermittent problems.

What sort of mechanic is he??? any sensor can have intermittent problems.
The CPS on my 93 XJ went intermittent on me, everytime the stealership had
the damn XJ it worked fine. but this thing would just die on me doing 120
kph on the highway. anyways long story short, the stealership finally
changed the sensor (after four trips to visit them) and the intermittent
stalling problem went away.

Snow...93 XJ