philthy

are u in michigan by any chance???

"L.W.(Bill) ------ III" wrote:

> I am a total loss as to how it would run without the Crankshaft
> Position Sensor. It should default into the safe mode, with no spark
> advance. Maybe you have your distributor installed in such a way so that
> it's Cam Position Sensor somehow takes over??????? What's the timing
> light show, initial and total?
> God Bless America, Bill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> jeepinacreek wrote:
> >
> > I recently put a new cam in my 1997 Jeep Wrangler 4.0L. I figured it
> > was a great mod with out totaly stroking the motor. After completing
> > the buildup and starting it for the first time, I thought great it
> > runs. Then I ran up and it starting backfiring at around 1800+ RPM.
> > This has been my battle for the last three months.
> >
> > A little about my Jeep;
> > Doug thorley header
> > bored out 62mm throttle
> > MSD ignition
> > New catalatic convertor, Flowmaster 50 exhaust Cold air intake 4in
> > Curry Enterpise lift 33in tires, 4:10 gears, lockers
> >
> > What I have done to fix this so far;
> > -Took it the dealer, they wouldn't touch it.
> > -I currently have timing chain retarded -5 degree's due to pinging, cut
> > down on backfiring.
> > -I also had it advanced +5 degree's, caused a lot more backfiring.
> > -I also ran the cam at TDC with no advance or timing. This is the
> > original way I built it.
> > -Changed TPS
> > -Changed spark plugs, wires, cap, rotor, and coil. Currently run MSD
> > ignition which I disconnected and the Jeep barely ran. Connected it
> > back up and seems to be the only thing keeping it running. So I know
> > the MSD works -changed O2 sensors -changed fuel pump and filters in
> > tank, gas cap to.
> > -Changed fuel injecters to 21LB injectors, stock is around 23.5LB -Put
> > an air/fuel ratio gauge on it.
> >
> > So my latest attempt to get this thing running right truely has me
> > scratching my head, I left the TPS wire connected disconnected, drove
> > it and it runs fine. No backfire at 1800+ RPM, it doesn't surge,
> > hesitate or ping or miss or run rich. It runs great, I can drive it on
> > the freeway now.
> >
> > I am on my last leg with this thing. Anyone have any ideas or
> > suggestions?????? Please help or i may put the stock cam back in.

philthy

are u in michigan by any chance???

"L.W.(Bill) ------ III" wrote:

> I am a total loss as to how it would run without the Crankshaft
> Position Sensor. It should default into the safe mode, with no spark
> advance. Maybe you have your distributor installed in such a way so that
> it's Cam Position Sensor somehow takes over??????? What's the timing
> light show, initial and total?
> God Bless America, Bill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> jeepinacreek wrote:
> >
> > I recently put a new cam in my 1997 Jeep Wrangler 4.0L. I figured it
> > was a great mod with out totaly stroking the motor. After completing
> > the buildup and starting it for the first time, I thought great it
> > runs. Then I ran up and it starting backfiring at around 1800+ RPM.
> > This has been my battle for the last three months.
> >
> > A little about my Jeep;
> > Doug thorley header
> > bored out 62mm throttle
> > MSD ignition
> > New catalatic convertor, Flowmaster 50 exhaust Cold air intake 4in
> > Curry Enterpise lift 33in tires, 4:10 gears, lockers
> >
> > What I have done to fix this so far;
> > -Took it the dealer, they wouldn't touch it.
> > -I currently have timing chain retarded -5 degree's due to pinging, cut
> > down on backfiring.
> > -I also had it advanced +5 degree's, caused a lot more backfiring.
> > -I also ran the cam at TDC with no advance or timing. This is the
> > original way I built it.
> > -Changed TPS
> > -Changed spark plugs, wires, cap, rotor, and coil. Currently run MSD
> > ignition which I disconnected and the Jeep barely ran. Connected it
> > back up and seems to be the only thing keeping it running. So I know
> > the MSD works -changed O2 sensors -changed fuel pump and filters in
> > tank, gas cap to.
> > -Changed fuel injecters to 21LB injectors, stock is around 23.5LB -Put
> > an air/fuel ratio gauge on it.
> >
> > So my latest attempt to get this thing running right truely has me
> > scratching my head, I left the TPS wire connected disconnected, drove
> > it and it runs fine. No backfire at 1800+ RPM, it doesn't surge,
> > hesitate or ping or miss or run rich. It runs great, I can drive it on
> > the freeway now.
> >
> > I am on my last leg with this thing. Anyone have any ideas or
> > suggestions?????? Please help or i may put the stock cam back in.

philthy

with the tps unplugged on that year the pcm goes into a default setting
and takes readings from the map sensor to mathmaticly calculate the
throttle position it will run but not right but it will get you home
resync the dist and get timing gears set and all will be good

DougW wrote:

> Jeffrey DeWitt wrote:
> > It seems at least as likely as the thing running with the TPS
> > unplugged! THAT one I don't understand at all.
>
> The TPS is not a critical doodad. If it goes missing the computer
> will adjust based on the O2 sensor.
>
> What you do loose is the WOT (Wide Open Trottle) signal.
>
> My 93 will run without the TPS. I know this because I left
> the darn thing disconnected. :] heh. oops.
>
> --
> DougW

philthy

with the tps unplugged on that year the pcm goes into a default setting
and takes readings from the map sensor to mathmaticly calculate the
throttle position it will run but not right but it will get you home
resync the dist and get timing gears set and all will be good

DougW wrote:

> Jeffrey DeWitt wrote:
> > It seems at least as likely as the thing running with the TPS
> > unplugged! THAT one I don't understand at all.
>
> The TPS is not a critical doodad. If it goes missing the computer
> will adjust based on the O2 sensor.
>
> What you do loose is the WOT (Wide Open Trottle) signal.
>
> My 93 will run without the TPS. I know this because I left
> the darn thing disconnected. :] heh. oops.
>
> --
> DougW

philthy

with the tps unplugged on that year the pcm goes into a default setting
and takes readings from the map sensor to mathmaticly calculate the
throttle position it will run but not right but it will get you home
resync the dist and get timing gears set and all will be good

DougW wrote:

> Jeffrey DeWitt wrote:
> > It seems at least as likely as the thing running with the TPS
> > unplugged! THAT one I don't understand at all.
>
> The TPS is not a critical doodad. If it goes missing the computer
> will adjust based on the O2 sensor.
>
> What you do loose is the WOT (Wide Open Trottle) signal.
>
> My 93 will run without the TPS. I know this because I left
> the darn thing disconnected. :] heh. oops.
>
> --
> DougW

philthy

the pcm has top go into closed loop before it can start learning tps and
other sensors values after a reset is done some vehicles atke as much as
1500 miles to learn it all

DougW wrote:

> Jeffrey DeWitt wrote:
> > Wonder how the engine runs with the WOT signal on all the time?
> >
> > The OP said the sensor was replaced, but maybe the new one was bad or
> > wrong? Is it possible to connect the sensor wrong?
>
> At least on the ZJ it's possible. :) The shaft and tangs have to be
> lined up. Thing is, if they arn't the throttle simply won't open.
> (or at least that's how the ZJ acts) Some vehicles require the TPS
> to be indexed by watching the voltage.
>
> In all cases it's a good idea to reset the computer and reprogram the
> range. Simply pull the battery off (or pull the fuses), have lunch,
> put the battery back on. turn the key to on, (engine not running)
> and slowly move the throttle between closed and wide open about
> five or six times. Holding it at the limits for a few seconds.
> Then turn the key off, start the car, and let it idle, drive it
> normally, and eventually hit the highway.
>
> Easy enough to test the TPS sensor. Just takes a volt meter.
> (backprobe. i.e. don't pierce the wires, just slide a pin/paperclip
> up the back of the connector)
>
> with ignition on, engine not running.
> Measure across the two outer wires. Should have 5 volts.
> Measure between the ground wire and the center wire.
> Throttle closed >200 milliVolts
> Throttle wide open <4.8 Volts
> As the throttle is moved between idle and WOT, the voltage
> should smootly increase with no dropouts or jumps.
>
> --
> DougW

philthy

the pcm has top go into closed loop before it can start learning tps and
other sensors values after a reset is done some vehicles atke as much as
1500 miles to learn it all

DougW wrote:

> Jeffrey DeWitt wrote:
> > Wonder how the engine runs with the WOT signal on all the time?
> >
> > The OP said the sensor was replaced, but maybe the new one was bad or
> > wrong? Is it possible to connect the sensor wrong?
>
> At least on the ZJ it's possible. :) The shaft and tangs have to be
> lined up. Thing is, if they arn't the throttle simply won't open.
> (or at least that's how the ZJ acts) Some vehicles require the TPS
> to be indexed by watching the voltage.
>
> In all cases it's a good idea to reset the computer and reprogram the
> range. Simply pull the battery off (or pull the fuses), have lunch,
> put the battery back on. turn the key to on, (engine not running)
> and slowly move the throttle between closed and wide open about
> five or six times. Holding it at the limits for a few seconds.
> Then turn the key off, start the car, and let it idle, drive it
> normally, and eventually hit the highway.
>
> Easy enough to test the TPS sensor. Just takes a volt meter.
> (backprobe. i.e. don't pierce the wires, just slide a pin/paperclip
> up the back of the connector)
>
> with ignition on, engine not running.
> Measure across the two outer wires. Should have 5 volts.
> Measure between the ground wire and the center wire.
> Throttle closed >200 milliVolts
> Throttle wide open <4.8 Volts
> As the throttle is moved between idle and WOT, the voltage
> should smootly increase with no dropouts or jumps.
>
> --
> DougW

philthy

the pcm has top go into closed loop before it can start learning tps and
other sensors values after a reset is done some vehicles atke as much as
1500 miles to learn it all

DougW wrote:

> Jeffrey DeWitt wrote:
> > Wonder how the engine runs with the WOT signal on all the time?
> >
> > The OP said the sensor was replaced, but maybe the new one was bad or
> > wrong? Is it possible to connect the sensor wrong?
>
> At least on the ZJ it's possible. :) The shaft and tangs have to be
> lined up. Thing is, if they arn't the throttle simply won't open.
> (or at least that's how the ZJ acts) Some vehicles require the TPS
> to be indexed by watching the voltage.
>
> In all cases it's a good idea to reset the computer and reprogram the
> range. Simply pull the battery off (or pull the fuses), have lunch,
> put the battery back on. turn the key to on, (engine not running)
> and slowly move the throttle between closed and wide open about
> five or six times. Holding it at the limits for a few seconds.
> Then turn the key off, start the car, and let it idle, drive it
> normally, and eventually hit the highway.
>
> Easy enough to test the TPS sensor. Just takes a volt meter.
> (backprobe. i.e. don't pierce the wires, just slide a pin/paperclip
> up the back of the connector)
>
> with ignition on, engine not running.
> Measure across the two outer wires. Should have 5 volts.
> Measure between the ground wire and the center wire.
> Throttle closed >200 milliVolts
> Throttle wide open <4.8 Volts
> As the throttle is moved between idle and WOT, the voltage
> should smootly increase with no dropouts or jumps.
>
> --
> DougW

jeepinacreek

I have tried setting the dist in several tooth positions. I've had no
success with, it runs the same regardless if I advance or retard the
crankshaft or the dist. I set the dist the way the mopar performance
Jeep engine guide and the chiltons manual both told me. It runs great
below 1800 RPM, purs like a kitten, but 1800+, it front and backfires
sometimes. From what I understand, the PCM advances and retards the
timing and the fuel.

philthy wrote:
> you have to set the timing gears bac to straight up and then you have to
> properly resync the dist(.need factory manual for procedure) and get the dist
> rotor past #1 cylinder tower of the dist.cap to get it in the correct place
> even if it means spinning oil pump drive a hair and it should drop in
>
> "L.W.(Bill) ------ III" wrote:
>
> > I am a total loss as to how it would run without the Crankshaft
> > Position Sensor. It should default into the safe mode, with no spark
> > advance. Maybe you have your distributor installed in such a way so that
> > it's Cam Position Sensor somehow takes over??????? What's the timing
> > light show, initial and total?
> > God Bless America, Bill O|||||||O
> > mailto:-------------------- http://www.----------.com/
> >
> > jeepinacreek wrote:
> > >
> > > I recently put a new cam in my 1997 Jeep Wrangler 4.0L. I figured it
> > > was a great mod with out totaly stroking the motor. After completing
> > > the buildup and starting it for the first time, I thought great it
> > > runs. Then I ran up and it starting backfiring at around 1800+ RPM.
> > > This has been my battle for the last three months.
> > >
> > > A little about my Jeep;
> > > Doug thorley header
> > > bored out 62mm throttle
> > > MSD ignition
> > > New catalatic convertor, Flowmaster 50 exhaust Cold air intake 4in
> > > Curry Enterpise lift 33in tires, 4:10 gears, lockers
> > >
> > > What I have done to fix this so far;
> > > -Took it the dealer, they wouldn't touch it.
> > > -I currently have timing chain retarded -5 degree's due to pinging, cut
> > > down on backfiring.
> > > -I also had it advanced +5 degree's, caused a lot more backfiring.
> > > -I also ran the cam at TDC with no advance or timing. This is the
> > > original way I built it.
> > > -Changed TPS
> > > -Changed spark plugs, wires, cap, rotor, and coil. Currently run MSD
> > > ignition which I disconnected and the Jeep barely ran. Connected it
> > > back up and seems to be the only thing keeping it running. So I know
> > > the MSD works -changed O2 sensors -changed fuel pump and filters in
> > > tank, gas cap to.
> > > -Changed fuel injecters to 21LB injectors, stock is around 23.5LB -Put
> > > an air/fuel ratio gauge on it.
> > >
> > > So my latest attempt to get this thing running right truely has me
> > > scratching my head, I left the TPS wire connected disconnected, drove
> > > it and it runs fine. No backfire at 1800+ RPM, it doesn't surge,
> > > hesitate or ping or miss or run rich. It runs great, I can drive it on
> > > the freeway now.
> > >
> > > I am on my last leg with this thing. Anyone have any ideas or
> > > suggestions?????? Please help or i may put the stock cam back in.

jeepinacreek

I have tried setting the dist in several tooth positions. I've had no
success with, it runs the same regardless if I advance or retard the
crankshaft or the dist. I set the dist the way the mopar performance
Jeep engine guide and the chiltons manual both told me. It runs great
below 1800 RPM, purs like a kitten, but 1800+, it front and backfires
sometimes. From what I understand, the PCM advances and retards the
timing and the fuel.

philthy wrote:
> you have to set the timing gears bac to straight up and then you have to
> properly resync the dist(.need factory manual for procedure) and get the dist
> rotor past #1 cylinder tower of the dist.cap to get it in the correct place
> even if it means spinning oil pump drive a hair and it should drop in
>
> "L.W.(Bill) ------ III" wrote:
>
> > I am a total loss as to how it would run without the Crankshaft
> > Position Sensor. It should default into the safe mode, with no spark
> > advance. Maybe you have your distributor installed in such a way so that
> > it's Cam Position Sensor somehow takes over??????? What's the timing
> > light show, initial and total?
> > God Bless America, Bill O|||||||O
> > mailto:-------------------- http://www.----------.com/
> >
> > jeepinacreek wrote:
> > >
> > > I recently put a new cam in my 1997 Jeep Wrangler 4.0L. I figured it
> > > was a great mod with out totaly stroking the motor. After completing
> > > the buildup and starting it for the first time, I thought great it
> > > runs. Then I ran up and it starting backfiring at around 1800+ RPM.
> > > This has been my battle for the last three months.
> > >
> > > A little about my Jeep;
> > > Doug thorley header
> > > bored out 62mm throttle
> > > MSD ignition
> > > New catalatic convertor, Flowmaster 50 exhaust Cold air intake 4in
> > > Curry Enterpise lift 33in tires, 4:10 gears, lockers
> > >
> > > What I have done to fix this so far;
> > > -Took it the dealer, they wouldn't touch it.
> > > -I currently have timing chain retarded -5 degree's due to pinging, cut
> > > down on backfiring.
> > > -I also had it advanced +5 degree's, caused a lot more backfiring.
> > > -I also ran the cam at TDC with no advance or timing. This is the
> > > original way I built it.
> > > -Changed TPS
> > > -Changed spark plugs, wires, cap, rotor, and coil. Currently run MSD
> > > ignition which I disconnected and the Jeep barely ran. Connected it
> > > back up and seems to be the only thing keeping it running. So I know
> > > the MSD works -changed O2 sensors -changed fuel pump and filters in
> > > tank, gas cap to.
> > > -Changed fuel injecters to 21LB injectors, stock is around 23.5LB -Put
> > > an air/fuel ratio gauge on it.
> > >
> > > So my latest attempt to get this thing running right truely has me
> > > scratching my head, I left the TPS wire connected disconnected, drove
> > > it and it runs fine. No backfire at 1800+ RPM, it doesn't surge,
> > > hesitate or ping or miss or run rich. It runs great, I can drive it on
> > > the freeway now.
> > >
> > > I am on my last leg with this thing. Anyone have any ideas or
> > > suggestions?????? Please help or i may put the stock cam back in.