Davey did pass the time by typing:
> This Idle Air Passage (IAP), is it small channel in throttle body with
> something like solenoid on it? It has connection also, just near TPS?

Exactly,

That connection is a solinoid that adjusts the flow of air and sets
your idle. The internal passages get crud and dirt buildup that keeps
the little pintle from moving smoothly. If you take the solinoid off
do not.. do not.. pull the pintle out, that will kill it.

That's why it is easier to just spray some cleaner through the slot.

--
DougW

 

On Sat, 18 Dec 2004 22:39:41 UTC "DougW"
<post.replies@invalid.address> wrote:

> Davey did pass the time by typing:
> > This Idle Air Passage (IAP), is it small channel in throttle body with
> > something like solenoid on it? It has connection also, just near TPS?
>
> Exactly,
>
> That connection is a solinoid that adjusts the flow of air and sets
> your idle. The internal passages get crud and dirt buildup that keeps
> the little pintle from moving smoothly. If you take the solinoid off
> do not.. do not.. pull the pintle out, that will kill it.
>
> That's why it is easier to just spray some cleaner through the slot.

Same advice goes for turning the igniton on while it's out - that
sucker will shoot the length of a garage. I did get one back together
- once - but it's a fight and you have to know what you are doing.
Picking nits, it isn't a solenoid but a stepper motor.

If the throttle body is pretty dirty and you can see caking in the
idle bypass port you would be better off pulling the IAC and cleaning
the pintle (cone shaped tip) and the shaft. Use a small amount of
grease like the spray on white lithium grease on the shaft after it
dries. Then, before you put it back on, take a tooth brush and
solvent to clean the port the IAC came out of really well. That
sucker will gum up so badly the IAC can't seat and you really can't
clean it from the top. I've got the older Renix system, but I'm
pretty sure that the Mopar tb has the same setup. There should be a
hole from the top surface of the tb, probably a quarter of the way
around from the IAC. If so, it will be about a 1/4 inch hole running
straight down to the manifold. At the bottom of the tb there will be
a cover over a needle valve. You shouldn't have to touch the needle
valve unless that hole is plugged solid like mine was when I got the
truck. If it's plugged and doesn't open up with cleaner from the top,
you'll have to pull the needle valve (count the turns it takes to
screw it all the way down, then take it out. Put it back to the same
position when you are done). Mine had a cap over the valve that had
to be pried off with an ice pick. Use a 16-18 guage solid copper wire
and tb cleaner to get the passage clean then replace the needle valve.
That's a minimum idle air flow setting and on my older truck it made
a lot of difference in the idle and low RPM/light load performance.
You may not have the minimum flow port in your 91, but it's something
to look for. A gummed up IAC/bypass setup will cause all sorts of
surges and hesitation under light to moderate acceleration.

I'm pretty sure they remove the EGR valve in the 91, but if it has one
that could also be causing problems if it's caked up.

--
Will Honea

 

On Sat, 18 Dec 2004 22:39:41 UTC "DougW"
<post.replies@invalid.address> wrote:

> Davey did pass the time by typing:
> > This Idle Air Passage (IAP), is it small channel in throttle body with
> > something like solenoid on it? It has connection also, just near TPS?
>
> Exactly,
>
> That connection is a solinoid that adjusts the flow of air and sets
> your idle. The internal passages get crud and dirt buildup that keeps
> the little pintle from moving smoothly. If you take the solinoid off
> do not.. do not.. pull the pintle out, that will kill it.
>
> That's why it is easier to just spray some cleaner through the slot.

Same advice goes for turning the igniton on while it's out - that
sucker will shoot the length of a garage. I did get one back together
- once - but it's a fight and you have to know what you are doing.
Picking nits, it isn't a solenoid but a stepper motor.

If the throttle body is pretty dirty and you can see caking in the
idle bypass port you would be better off pulling the IAC and cleaning
the pintle (cone shaped tip) and the shaft. Use a small amount of
grease like the spray on white lithium grease on the shaft after it
dries. Then, before you put it back on, take a tooth brush and
solvent to clean the port the IAC came out of really well. That
sucker will gum up so badly the IAC can't seat and you really can't
clean it from the top. I've got the older Renix system, but I'm
pretty sure that the Mopar tb has the same setup. There should be a
hole from the top surface of the tb, probably a quarter of the way
around from the IAC. If so, it will be about a 1/4 inch hole running
straight down to the manifold. At the bottom of the tb there will be
a cover over a needle valve. You shouldn't have to touch the needle
valve unless that hole is plugged solid like mine was when I got the
truck. If it's plugged and doesn't open up with cleaner from the top,
you'll have to pull the needle valve (count the turns it takes to
screw it all the way down, then take it out. Put it back to the same
position when you are done). Mine had a cap over the valve that had
to be pried off with an ice pick. Use a 16-18 guage solid copper wire
and tb cleaner to get the passage clean then replace the needle valve.
That's a minimum idle air flow setting and on my older truck it made
a lot of difference in the idle and low RPM/light load performance.
You may not have the minimum flow port in your 91, but it's something
to look for. A gummed up IAC/bypass setup will cause all sorts of
surges and hesitation under light to moderate acceleration.

I'm pretty sure they remove the EGR valve in the 91, but if it has one
that could also be causing problems if it's caked up.

--
Will Honea

 

On Sat, 18 Dec 2004 22:39:41 UTC "DougW"
<post.replies@invalid.address> wrote:

> Davey did pass the time by typing:
> > This Idle Air Passage (IAP), is it small channel in throttle body with
> > something like solenoid on it? It has connection also, just near TPS?
>
> Exactly,
>
> That connection is a solinoid that adjusts the flow of air and sets
> your idle. The internal passages get crud and dirt buildup that keeps
> the little pintle from moving smoothly. If you take the solinoid off
> do not.. do not.. pull the pintle out, that will kill it.
>
> That's why it is easier to just spray some cleaner through the slot.

Same advice goes for turning the igniton on while it's out - that
sucker will shoot the length of a garage. I did get one back together
- once - but it's a fight and you have to know what you are doing.
Picking nits, it isn't a solenoid but a stepper motor.

If the throttle body is pretty dirty and you can see caking in the
idle bypass port you would be better off pulling the IAC and cleaning
the pintle (cone shaped tip) and the shaft. Use a small amount of
grease like the spray on white lithium grease on the shaft after it
dries. Then, before you put it back on, take a tooth brush and
solvent to clean the port the IAC came out of really well. That
sucker will gum up so badly the IAC can't seat and you really can't
clean it from the top. I've got the older Renix system, but I'm
pretty sure that the Mopar tb has the same setup. There should be a
hole from the top surface of the tb, probably a quarter of the way
around from the IAC. If so, it will be about a 1/4 inch hole running
straight down to the manifold. At the bottom of the tb there will be
a cover over a needle valve. You shouldn't have to touch the needle
valve unless that hole is plugged solid like mine was when I got the
truck. If it's plugged and doesn't open up with cleaner from the top,
you'll have to pull the needle valve (count the turns it takes to
screw it all the way down, then take it out. Put it back to the same
position when you are done). Mine had a cap over the valve that had
to be pried off with an ice pick. Use a 16-18 guage solid copper wire
and tb cleaner to get the passage clean then replace the needle valve.
That's a minimum idle air flow setting and on my older truck it made
a lot of difference in the idle and low RPM/light load performance.
You may not have the minimum flow port in your 91, but it's something
to look for. A gummed up IAC/bypass setup will cause all sorts of
surges and hesitation under light to moderate acceleration.

I'm pretty sure they remove the EGR valve in the 91, but if it has one
that could also be causing problems if it's caked up.

--
Will Honea