Re: Lost top end power in 88 Cherokee 4.0.
 

Mike Romain wrote:

> Ok, I am on a fishing expedition for likely things to check.
>
> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> goes fine up to that point, then just bogs, no matter what gear it is
> in. It has been neglected for 4 years as far as tuning goes due to me
> not being up to it.
>
> I first changed out the 'very' dirty distributor cap and rotor which
> made starting 'much' faster and smoother.
>
> I then changed the gas filter because it was once again rusted to the
> rot point after about 8 years.
>
> Air filter is new.
>
> I cleaned the connections on the TPS and IAC and verified the TPS
> doesn't have any 'dead' spots with my meter.
>
> I cleaned the CPS and coil connections also.
>
> No joy on any of that.
>
> I have been having some cold idle issues and have been thinking on
> cleaning the IAC, but don't know if that will have a top end effect or
> not.
>
> I am also thinking on unplugging the EGR just to make sure it isn't
> blown vacuum wise because it only bogs under throttle when things like
> the EGR are active.
>
> Any other ideas?

I've had this situation twice. First time was a dying fuel pump - and it
progressed to dead pretty quickly. Second was a shorted cable to the CPS.
Didn't tie it back properly and the exhaust got it. Same symptoms, except
my max RPM was 1000-1200 RPM, period. Crept home at idle <g>.
--
Will Honea

Re: Lost top end power in 88 Cherokee 4.0.
 

Mike, it really sounds like a fuel delivery problem. Because you
changed the fuel filter, I would suspect the fuel line is pinched or
you have had a piece of rubber fuel line come loose and restrict the
flow. It also could be a fuel pump on the way out.

The other obvious thing would be a collapsed baffle in your muffler
restricting exhaust flow. I've had that happen to me.

Either the fuel is not getting in or the exhaust is not getting out. I
wouldn't suspect ignition because it doesn't miss or backfire.

Merrill

On May 27, 3:23 pm, Mike Romain <roma...@sympatico.ca> wrote:
> stilllearning wrote:
> > On May 27, 11:20 am, Mike Romain <roma...@sympatico.ca> wrote:
> >> Ok, I am on a fishing expedition for likely things to check.
>
> >> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> >> goes fine up to that point, then just bogs, no matter what gear it is
> >> in. It has been neglected for 4 years as far as tuning goes due to me
> >> not being up to it.
>
> >> I first changed out the 'very' dirty distributor cap and rotor which
> >> made starting 'much' faster and smoother.
>
> >> I then changed the gas filter because it was once again rusted to the
> >> rot point after about 8 years.
>
> >> Air filter is new.
>
> >> I cleaned the connections on the TPS and IAC and verified the TPS
> >> doesn't have any 'dead' spots with my meter.
>
> >> I cleaned the CPS and coil connections also.
>
> >> No joy on any of that.
>
> >> I have been having some cold idle issues and have been thinking on
> >> cleaning the IAC, but don't know if that will have a top end effect or not.
>
> >> I am also thinking on unplugging the EGR just to make sure it isn't
> >> blown vacuum wise because it only bogs under throttle when things like
> >> the EGR are active.
>
> >> Any other ideas?
>
> >> Mike
> >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> 88 Cherokee 235 BFG AT's
> >> Canadian Off Road Trips Photos: Non members can still view!
> >> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
> >> (More Off Road album links at bottom of the view page)
>
> > What does exactly "then just bogs" mean? The Jeep does not go any
> > faster, or it stalls and stops? What precise noises/knocks and
> > symptoms, etc?
>
> Stalls and stops and sputters until the gas pedal is let up on.
>
> No backfires.
>
> EGR now unplugged.
>
>
>
> > On idle, what happens if you press accelerator until above half
> > throttle? Is there a loss of power?
>
> If I go fast on the pedal, there is a dead spot. No load and smooth
> pedal seems to work.
>
>
>
> > If the fuel pressure is low, the engine can run fine upto a point,
> > until the demand for fuel exceeds the supply due to low pressure.
>
> I knew there was a reason that filter was the second thing I went after.
> ;-) I don't have a pressure gauge other than a compression gauge though.
>
> I also have verified the coil wire still has a connection with the ohm
> meter. It is a bit higher per foot in resistance than the plug wires,
> but only a bit, .7K vs .5K. Hmm the others I have around seem the same
> too....
>
> I made sure the main power had good connections also.
>
> Mike- Hide quoted text -
>
> - Show quoted text -

Re: Lost top end power in 88 Cherokee 4.0.
 

Mike, it really sounds like a fuel delivery problem. Because you
changed the fuel filter, I would suspect the fuel line is pinched or
you have had a piece of rubber fuel line come loose and restrict the
flow. It also could be a fuel pump on the way out.

The other obvious thing would be a collapsed baffle in your muffler
restricting exhaust flow. I've had that happen to me.

Either the fuel is not getting in or the exhaust is not getting out. I
wouldn't suspect ignition because it doesn't miss or backfire.

Merrill

On May 27, 3:23 pm, Mike Romain <roma...@sympatico.ca> wrote:
> stilllearning wrote:
> > On May 27, 11:20 am, Mike Romain <roma...@sympatico.ca> wrote:
> >> Ok, I am on a fishing expedition for likely things to check.
>
> >> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> >> goes fine up to that point, then just bogs, no matter what gear it is
> >> in. It has been neglected for 4 years as far as tuning goes due to me
> >> not being up to it.
>
> >> I first changed out the 'very' dirty distributor cap and rotor which
> >> made starting 'much' faster and smoother.
>
> >> I then changed the gas filter because it was once again rusted to the
> >> rot point after about 8 years.
>
> >> Air filter is new.
>
> >> I cleaned the connections on the TPS and IAC and verified the TPS
> >> doesn't have any 'dead' spots with my meter.
>
> >> I cleaned the CPS and coil connections also.
>
> >> No joy on any of that.
>
> >> I have been having some cold idle issues and have been thinking on
> >> cleaning the IAC, but don't know if that will have a top end effect or not.
>
> >> I am also thinking on unplugging the EGR just to make sure it isn't
> >> blown vacuum wise because it only bogs under throttle when things like
> >> the EGR are active.
>
> >> Any other ideas?
>
> >> Mike
> >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> 88 Cherokee 235 BFG AT's
> >> Canadian Off Road Trips Photos: Non members can still view!
> >> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
> >> (More Off Road album links at bottom of the view page)
>
> > What does exactly "then just bogs" mean? The Jeep does not go any
> > faster, or it stalls and stops? What precise noises/knocks and
> > symptoms, etc?
>
> Stalls and stops and sputters until the gas pedal is let up on.
>
> No backfires.
>
> EGR now unplugged.
>
>
>
> > On idle, what happens if you press accelerator until above half
> > throttle? Is there a loss of power?
>
> If I go fast on the pedal, there is a dead spot. No load and smooth
> pedal seems to work.
>
>
>
> > If the fuel pressure is low, the engine can run fine upto a point,
> > until the demand for fuel exceeds the supply due to low pressure.
>
> I knew there was a reason that filter was the second thing I went after.
> ;-) I don't have a pressure gauge other than a compression gauge though.
>
> I also have verified the coil wire still has a connection with the ohm
> meter. It is a bit higher per foot in resistance than the plug wires,
> but only a bit, .7K vs .5K. Hmm the others I have around seem the same
> too....
>
> I made sure the main power had good connections also.
>
> Mike- Hide quoted text -
>
> - Show quoted text -

Re: Lost top end power in 88 Cherokee 4.0.
 

Mike, it really sounds like a fuel delivery problem. Because you
changed the fuel filter, I would suspect the fuel line is pinched or
you have had a piece of rubber fuel line come loose and restrict the
flow. It also could be a fuel pump on the way out.

The other obvious thing would be a collapsed baffle in your muffler
restricting exhaust flow. I've had that happen to me.

Either the fuel is not getting in or the exhaust is not getting out. I
wouldn't suspect ignition because it doesn't miss or backfire.

Merrill

On May 27, 3:23 pm, Mike Romain <roma...@sympatico.ca> wrote:
> stilllearning wrote:
> > On May 27, 11:20 am, Mike Romain <roma...@sympatico.ca> wrote:
> >> Ok, I am on a fishing expedition for likely things to check.
>
> >> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> >> goes fine up to that point, then just bogs, no matter what gear it is
> >> in. It has been neglected for 4 years as far as tuning goes due to me
> >> not being up to it.
>
> >> I first changed out the 'very' dirty distributor cap and rotor which
> >> made starting 'much' faster and smoother.
>
> >> I then changed the gas filter because it was once again rusted to the
> >> rot point after about 8 years.
>
> >> Air filter is new.
>
> >> I cleaned the connections on the TPS and IAC and verified the TPS
> >> doesn't have any 'dead' spots with my meter.
>
> >> I cleaned the CPS and coil connections also.
>
> >> No joy on any of that.
>
> >> I have been having some cold idle issues and have been thinking on
> >> cleaning the IAC, but don't know if that will have a top end effect or not.
>
> >> I am also thinking on unplugging the EGR just to make sure it isn't
> >> blown vacuum wise because it only bogs under throttle when things like
> >> the EGR are active.
>
> >> Any other ideas?
>
> >> Mike
> >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> 88 Cherokee 235 BFG AT's
> >> Canadian Off Road Trips Photos: Non members can still view!
> >> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
> >> (More Off Road album links at bottom of the view page)
>
> > What does exactly "then just bogs" mean? The Jeep does not go any
> > faster, or it stalls and stops? What precise noises/knocks and
> > symptoms, etc?
>
> Stalls and stops and sputters until the gas pedal is let up on.
>
> No backfires.
>
> EGR now unplugged.
>
>
>
> > On idle, what happens if you press accelerator until above half
> > throttle? Is there a loss of power?
>
> If I go fast on the pedal, there is a dead spot. No load and smooth
> pedal seems to work.
>
>
>
> > If the fuel pressure is low, the engine can run fine upto a point,
> > until the demand for fuel exceeds the supply due to low pressure.
>
> I knew there was a reason that filter was the second thing I went after.
> ;-) I don't have a pressure gauge other than a compression gauge though.
>
> I also have verified the coil wire still has a connection with the ohm
> meter. It is a bit higher per foot in resistance than the plug wires,
> but only a bit, .7K vs .5K. Hmm the others I have around seem the same
> too....
>
> I made sure the main power had good connections also.
>
> Mike- Hide quoted text -
>
> - Show quoted text -

Re: Lost top end power in 88 Cherokee 4.0.
 

Mike, it really sounds like a fuel delivery problem. Because you
changed the fuel filter, I would suspect the fuel line is pinched or
you have had a piece of rubber fuel line come loose and restrict the
flow. It also could be a fuel pump on the way out.

The other obvious thing would be a collapsed baffle in your muffler
restricting exhaust flow. I've had that happen to me.

Either the fuel is not getting in or the exhaust is not getting out. I
wouldn't suspect ignition because it doesn't miss or backfire.

Merrill

On May 27, 3:23 pm, Mike Romain <roma...@sympatico.ca> wrote:
> stilllearning wrote:
> > On May 27, 11:20 am, Mike Romain <roma...@sympatico.ca> wrote:
> >> Ok, I am on a fishing expedition for likely things to check.
>
> >> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> >> goes fine up to that point, then just bogs, no matter what gear it is
> >> in. It has been neglected for 4 years as far as tuning goes due to me
> >> not being up to it.
>
> >> I first changed out the 'very' dirty distributor cap and rotor which
> >> made starting 'much' faster and smoother.
>
> >> I then changed the gas filter because it was once again rusted to the
> >> rot point after about 8 years.
>
> >> Air filter is new.
>
> >> I cleaned the connections on the TPS and IAC and verified the TPS
> >> doesn't have any 'dead' spots with my meter.
>
> >> I cleaned the CPS and coil connections also.
>
> >> No joy on any of that.
>
> >> I have been having some cold idle issues and have been thinking on
> >> cleaning the IAC, but don't know if that will have a top end effect or not.
>
> >> I am also thinking on unplugging the EGR just to make sure it isn't
> >> blown vacuum wise because it only bogs under throttle when things like
> >> the EGR are active.
>
> >> Any other ideas?
>
> >> Mike
> >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> 88 Cherokee 235 BFG AT's
> >> Canadian Off Road Trips Photos: Non members can still view!
> >> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
> >> (More Off Road album links at bottom of the view page)
>
> > What does exactly "then just bogs" mean? The Jeep does not go any
> > faster, or it stalls and stops? What precise noises/knocks and
> > symptoms, etc?
>
> Stalls and stops and sputters until the gas pedal is let up on.
>
> No backfires.
>
> EGR now unplugged.
>
>
>
> > On idle, what happens if you press accelerator until above half
> > throttle? Is there a loss of power?
>
> If I go fast on the pedal, there is a dead spot. No load and smooth
> pedal seems to work.
>
>
>
> > If the fuel pressure is low, the engine can run fine upto a point,
> > until the demand for fuel exceeds the supply due to low pressure.
>
> I knew there was a reason that filter was the second thing I went after.
> ;-) I don't have a pressure gauge other than a compression gauge though.
>
> I also have verified the coil wire still has a connection with the ohm
> meter. It is a bit higher per foot in resistance than the plug wires,
> but only a bit, .7K vs .5K. Hmm the others I have around seem the same
> too....
>
> I made sure the main power had good connections also.
>
> Mike- Hide quoted text -
>
> - Show quoted text -

Re: Lost top end power in 88 Cherokee 4.0.
 

Water in your float bowl.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4659a194$0$3020$9a6e19ea@unlimited.newshostin g.com...
> Ok, I am on a fishing expedition for likely things to check.
>
> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> goes fine up to that point, then just bogs, no matter what gear it is
> in. It has been neglected for 4 years as far as tuning goes due to me
> not being up to it.
>
> I first changed out the 'very' dirty distributor cap and rotor which
> made starting 'much' faster and smoother.
>
> I then changed the gas filter because it was once again rusted to the
> rot point after about 8 years.
>
> Air filter is new.
>
> I cleaned the connections on the TPS and IAC and verified the TPS
> doesn't have any 'dead' spots with my meter.
>
> I cleaned the CPS and coil connections also.
>
> No joy on any of that.
>
> I have been having some cold idle issues and have been thinking on
> cleaning the IAC, but don't know if that will have a top end effect or
not.
>
> I am also thinking on unplugging the EGR just to make sure it isn't
> blown vacuum wise because it only bogs under throttle when things like
> the EGR are active.
>
> Any other ideas?
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)



--
Posted via a free Usenet account from http://www.teranews.com

Re: Lost top end power in 88 Cherokee 4.0.
 

Water in your float bowl.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4659a194$0$3020$9a6e19ea@unlimited.newshostin g.com...
> Ok, I am on a fishing expedition for likely things to check.
>
> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> goes fine up to that point, then just bogs, no matter what gear it is
> in. It has been neglected for 4 years as far as tuning goes due to me
> not being up to it.
>
> I first changed out the 'very' dirty distributor cap and rotor which
> made starting 'much' faster and smoother.
>
> I then changed the gas filter because it was once again rusted to the
> rot point after about 8 years.
>
> Air filter is new.
>
> I cleaned the connections on the TPS and IAC and verified the TPS
> doesn't have any 'dead' spots with my meter.
>
> I cleaned the CPS and coil connections also.
>
> No joy on any of that.
>
> I have been having some cold idle issues and have been thinking on
> cleaning the IAC, but don't know if that will have a top end effect or
not.
>
> I am also thinking on unplugging the EGR just to make sure it isn't
> blown vacuum wise because it only bogs under throttle when things like
> the EGR are active.
>
> Any other ideas?
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)



--
Posted via a free Usenet account from http://www.teranews.com

Re: Lost top end power in 88 Cherokee 4.0.
 

Water in your float bowl.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4659a194$0$3020$9a6e19ea@unlimited.newshostin g.com...
> Ok, I am on a fishing expedition for likely things to check.
>
> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> goes fine up to that point, then just bogs, no matter what gear it is
> in. It has been neglected for 4 years as far as tuning goes due to me
> not being up to it.
>
> I first changed out the 'very' dirty distributor cap and rotor which
> made starting 'much' faster and smoother.
>
> I then changed the gas filter because it was once again rusted to the
> rot point after about 8 years.
>
> Air filter is new.
>
> I cleaned the connections on the TPS and IAC and verified the TPS
> doesn't have any 'dead' spots with my meter.
>
> I cleaned the CPS and coil connections also.
>
> No joy on any of that.
>
> I have been having some cold idle issues and have been thinking on
> cleaning the IAC, but don't know if that will have a top end effect or
not.
>
> I am also thinking on unplugging the EGR just to make sure it isn't
> blown vacuum wise because it only bogs under throttle when things like
> the EGR are active.
>
> Any other ideas?
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)



--
Posted via a free Usenet account from http://www.teranews.com

Re: Lost top end power in 88 Cherokee 4.0.
 

Water in your float bowl.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4659a194$0$3020$9a6e19ea@unlimited.newshostin g.com...
> Ok, I am on a fishing expedition for likely things to check.
>
> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> goes fine up to that point, then just bogs, no matter what gear it is
> in. It has been neglected for 4 years as far as tuning goes due to me
> not being up to it.
>
> I first changed out the 'very' dirty distributor cap and rotor which
> made starting 'much' faster and smoother.
>
> I then changed the gas filter because it was once again rusted to the
> rot point after about 8 years.
>
> Air filter is new.
>
> I cleaned the connections on the TPS and IAC and verified the TPS
> doesn't have any 'dead' spots with my meter.
>
> I cleaned the CPS and coil connections also.
>
> No joy on any of that.
>
> I have been having some cold idle issues and have been thinking on
> cleaning the IAC, but don't know if that will have a top end effect or
not.
>
> I am also thinking on unplugging the EGR just to make sure it isn't
> blown vacuum wise because it only bogs under throttle when things like
> the EGR are active.
>
> Any other ideas?
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)



--
Posted via a free Usenet account from http://www.teranews.com

Re: Lost top end power in 88 Cherokee 4.0.
 

On May 27, 11:20 am, Mike Romain <roma...@sympatico.ca> wrote:
> Ok, I am on a fishing expedition for likely things to check.
>
> Our 88 Cherokee with the 4.0 has lost power above half throttle. It
> goes fine up to that point, then just bogs, no matter what gear it is
> in. It has been neglected for 4 years as far as tuning goes due to me
> not being up to it.
>
> I first changed out the 'very' dirty distributor cap and rotor which
> made starting 'much' faster and smoother.
>
> I then changed the gas filter because it was once again rusted to the
> rot point after about 8 years.
>
> Air filter is new.
>
> I cleaned the connections on the TPS and IAC and verified the TPS
> doesn't have any 'dead' spots with my meter.
>
> I cleaned the CPS and coil connections also.
>
> No joy on any of that.
>
> I have been having some cold idle issues and have been thinking on
> cleaning the IAC, but don't know if that will have a top end effect or not.
>
> I am also thinking on unplugging the EGR just to make sure it isn't
> blown vacuum wise because it only bogs under throttle when things like
> the EGR are active.
>
> Any other ideas?
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
> (More Off Road album links at bottom of the view page)

Since you are just fishing... check the ignition coil input/output
coil voltages and the capacitor. Verify spark can jump a large gap
when engine is not running. Check this article:

http://mgaguru.com/mgtech/ignition/ig108.htm

Do you sense that there are "misses"?

I would still check the fuel pressure and the fuel presssure
regulator.