High Idle 4500 RPM

We have just replaced the distributor in my wife's 1996 Sebring
Convertible.

Now when we start it up, it goes to 4500 RPM on the idle. I am not sure
what our mph speed is at idle, as we have no Speedometer (it's dead), but I
would estimate it at around 40mph or so.

Any assistance would be most appreciated. Email is good w/o the obvious.

Thanx


Michale

 

I would hope your MPH at ide is equal to "0", That distributor will go in 2
ways, 180 degrees out, or the correct way, if it was out 180 the engine
wouldnt run, start with looking for a vacuum leak, possible the brake
booster/supply line
Glenn Beasley
Chrysler tech

 

Touche'

What I meant was is that when I am am drive and and not giving it any
gas, I estimate my speed at approx 40mph hehehehehe

Would a single leak cause the excessive idle? Or would it be more likely
several leaks?


Thanx for the assist.

Michale

 

depending on the size of leak, keep in mind that when you open the throttle
blade, it is the same as making a vacumm leak, alittle open a higher rpm,
alot open alot more RPMs

 

Except that opening the throttle also calls for more gas to be injected.
Adding air alone will only lean the mixture. You might get a little
bump in RPM, but you shouldn't get 4500 unless way too much fuel is also
being injected along with the air leak.

It sounds like something more fundamental than an air leak is involved
with his problem. Beats me what, though.

Have you checked for a malfunction code in the ECM?


Matt

 

Why on earth would you put the car in Drive with it idling that fast?
The lurch in to drive could easily break motor/trans mounts or worse.
Stopping the car with the engine running that fast will burn up your
transmission in short order.

The brake booster is one large vacuum hose. With your idle speed I
dont have a beter suggestion for you on where to start looking for the
leak, but wherever it is it is one heck of a leak and should be pretty
easy to find. Also make sure that you haven't somehow blocked the
throttle partially open. If you can look down in the throttle body
the blades should be almost closed.

Steve B.

 

it is the same thing regardless if it is the throttle blade opening or a
huge vacuum leak, the MAP sensor determines how much fuel to give it, not
the throttle blade. if you disconnected the TPS sensor and opened the
throttle blade, the map sensor would compensate for it, thus causing a high
RPM The throttle blade does not have anything to do with giving more gas, a
carburator would but not this vehicle

 

Last I knew, the TPS sensor was also factored into the fuel map for ECM
controlled vehicles. Maybe Chrysler was really stupid with their ECM,
but I doubt it. If the throttle is closed as indicated by the TPS, then
I'd be really surprised if the MAP input alone would be enough to
command fuel be added. If that is the case, then the TPS is completely
unnecessary.


Matt

 

Your right it isnt that nessassary. more of a reference point of open and
closed throtlle, u can unhook the tps sensor and the engine will run, it
will give a hesitation on take off but will run because the MAP sensor
determines load and how much fuel to deliver

 

I don't think Chrysler publishes its ECM algorithms, but I've be very
surprised if the TPS is used only to sense closed and WOT. If that were
the case, they would use two cheap switches rather than a relatively
expensive rheostat sensor. I'd also be very surprised if they don't
make a check for closed throttle when the MAP is indicating low pressure
and thus calling for more fuel and not rev the engine wildly with a
closed throttle. Maybe the Chrysler engineers aren't that smart, but
I'm betting they are.

Have you ever seen a Chrysler engine have a vacuum leak that made it run
4,500 RPM with the throttle closed?


Matt

 

~Excluding transmission/transaxle functions~
Rate of change in order to increase the injector pulse width when
the throttle is opened.
Idle air control valve diagnostics (fault sensing)
The TPS is the least important of all the input sensors, its
biggest effect on fuel delivery is when the PCM is receiving a
changing voltage from it indicating throttle movement.

Some manufactures have been known to do this.

Closed throttle low MAP pressure is a heavy decel, which is a
whole different situation from the potential mass vacuum leak
being discussed.
A vacuum leak that can/does add hundreds of RPM to idle speed
-raises- manifold absolute pressure, raising manifold pressure is
usually responded to by the PCM by as an increased injector pulse
width.

Some things are beyond the limits of control of the system.

You've got a minivan or two at your disposal...
Hook up your scanner, pull the PCV or brake booster hose off,
start the engine and report back with the results, i.e., RPM
changes, MAP changes, pulse width changes.
You may not see 4500 RPM exactly, but you will experience the
causes and effect.

 

yup

 

Also, with switches, it is a mechanical adjustment (provisions for
adjustment and the labor of doing so) to calibrate the closed and WOT
positions - cost would more than offset the cost of the rheostat. With
a rheostat, the calibrations for the two points are software functions,
and possibly 100% automatic (I would think it would be easy for the
computer, during the learning phase to tell where the throttle closed
position - i.e., the point below which the rheostat never goes), and the
WOT position could be delta'd off of that with acceptable tolerance
stack and variations - though not sure if they actually incorporate such
an Al-Gore-ithm).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

Much obliged for all the information and tips.


Little more information. The RPMS have settled down into the 3000-3500
range.

There is an opening in the EGR hose that I still need to get fixed.


ERROR CODES:

12- No biggie on this one, the battery was recently disconnected and re-
connected.

24- Throttle Position Sensor

25- Idle Air Control Valve Circuits

I have an Ohm Meter and can check the voltages on them if possible. Not
sure the general procedure or readings, though.

Thanx again.

 

opening in the EGR hose is a vacuum leak!!!!......keep in mind if this were
a mass air flow system, the vehicle would stall and not run

 

now factor in the job the i.a.c does

 

hmm could that neil nelson sure types like him

 

??