I just bought a beautiful 1999 black GS, automatic, with 28K miles on the clock. I've never fooled with a Chrysler or a import before, so I'm a little curious. I'm not new to cars, engines, turbos, superchargers, or fuel injection, as I've been tuning DFI, burning PROM's, and building high horsepower engines for a few years now, so don't hold back on saying anything you think may sound complicated/confusing.

-Does my car have an IAC or ISC?

-Every time I put the car into gear from park or neutral, the IAC/ISC clicks very rapidly (almost like a buzzing)and the RPMs hang simultaneously(approximately 1-2 seconds), and then it drops down to the appropriate RPMs. It also does this while coming to a stop, which is also a period when the IAC/ISC adjusts itself to keep the engine from stalling. And finally, when first starting the engine, it jumps up to about 2K RPMs. I know it's supposed to jump higher than normal and stay higher when cold to help warm up faster/reduce emissions, but this seems kind of high. Also, when starting the engine after sitting for a few hours, and in the cold, after idling for about 30 seconds fine, it will start to surge from 900-1200-900-1200-1000-1500-1000-1600-back to normal in a period of about 10 seconds. Other than that it idles almost perfect in closed loop. All these symptons sound like a stuck/malfunctioning IAC, or a failed ISC motor(depending on which it has). What do you think?

-My EGR valve and or EGR vacuum switch right next to it, is clicking/popping rapidly at all times. You can hear it from inside the car, and I originally thought it was a rod knock or the cams/followers till I investigated further. It's definately coming from this. Is this a normal functioning sound on this vehicle?

-What's the recommended oil weight on a stock 420a equipped Eclipse? The dealer neglected to include a damn owner's manual for the car. Also, what kind of ATF do these things take?

-Is there an A.I.R. system, or a Chrysler equivalent on this vehicle? It's difficult to see in there, and all I see is a power steering pump, A/C compressor, and the alternator.

-Where is the MAP? I'm assuming it's the sensor with 3 wires on the passenger side of the upper intake manifold, all by itself. Is the IAT/ACT sensor located on the back side of the upper intake manifold, next to the vacuum port? If not, what is that?

-Does the TPS receive a 5.0 reference voltage, and use a typical potentiometer-type switch to send a variable voltage signal back for the ECU to determine throttle position? Is it a 3 blade oval or rectangular connector?

Well, that's all I can think of at the moment. Sorry for being so long! ANY help is appreciated!

-Mike

1999 GS

1991 Mustang GT

>-Does my car have an IAC or ISC?

Yes is has an IAC.
>
>-Every time I put the car into gear from park or neutral,
>the IAC/ISC clicks very rapidly (almost like a buzzing)and
>the RPMs hang simultaneously(approximately 1-2 seconds), and
>then it drops down to the appropriate RPMs. It also does
>this while coming to a stop, which is also a period when the
>IAC/ISC adjusts itself to keep the engine from stalling.
>And finally, when first starting the engine, it jumps up to
>about 2K RPMs. I know it's supposed to jump higher than
>normal and stay higher when cold to help warm up
>faster/reduce emissions, but this seems kind of high. Also,
>when starting the engine after sitting for a few hours, and
>in the cold, after idling for about 30 seconds fine, it will
>start to surge from
>900-1200-900-1200-1000-1500-1000-1600-back to normal in a
>period of about 10 seconds. Other than that it idles almost
>perfect in closed loop. All these symptons sound like a
>stuck/malfunctioning IAC, or a failed ISC motor(depending on
>which it has). What do you think?

This is completely normal, i thought it was the solenoid packs
for the Automatic tranny. Mine does that exact thing start it up RPMs jump to 2000 then back down, and everyone gets the clicking

>
>-My EGR valve and or EGR vacuum switch right next to it, is
>clicking/popping rapidly at all times. You can hear it from
>inside the car, and I originally thought it was a rod knock
>or the cams/followers till I investigated further. It's
>definately coming from this. Is this a normal functioning
>sound on this vehicle?

Yes this is normal too, some people have completely removed the egr system from their cars, mitsu even had a recall/removal for like the 95's but if you remove it you will get a check engine light from it that no one has really figured out how to remove.
>
>-What's the recommended oil weight on a stock 420a equipped
>Eclipse? The dealer neglected to include a damn owner's
>manual for the car. Also, what kind of ATF do these things
>take?

i use 5w-30
>
>-Is there an A.I.R. system, or a Chrysler equivalent on this
>vehicle? It's difficult to see in there, and all I see is a
>power steering pump, A/C compressor, and the alternator.
>
not sure what you mean on this A.I.R?

>-Where is the MAP? I'm assuming it's the sensor with 3
>wires on the passenger side of the upper intake manifold,
>all by itself. Is the IAT/ACT sensor located on the back
>side of the upper intake manifold, next to the vacuum port?
>If not, what is that?

your correct with all the above
>
>-Does the TPS receive a 5.0 reference voltage, and use a
>typical potentiometer-type switch to send a variable voltage
>signal back for the ECU to determine throttle position? Is
>it a 3 blade oval or rectangular connector?

yea it gets 5 volts reference, some people have improved throttle response by adjusting the TPS to get the highest output voltage at W.O.T something like 4.0V WOT
>
>Well, that's all I can think of at the moment. Sorry for
>being so long! ANY help is appreciated!
>
no prob thats the best I can do

you might also want to register for www.asog.net its for avengers/sebrings but the 4cyl 420A engine is the same, as well as suspension components (with the exception of springs/shocks) tranny, etc.. check under the V-howto section for the TPS mod as well as various other easy modifications

1998 dodge avenger 4 cyl AT
Mods are:
Not enough

>I just bought a beautiful 1999 black GS, automatic, with 28K
>miles on the clock. I've never fooled with a Chrysler or a
>import before, so I'm a little curious. I'm not new to
>cars, engines, turbos, superchargers, or fuel injection, as
>I've been tuning DFI, burning PROM's, and building high
>horsepower engines for a few years now, so don't hold back
>on saying anything you think may sound
>complicated/confusing.
>
>-Does my car have an IAC or ISC?

ISC.

>
>-Every time I put the car into gear from park or neutral,
>the IAC/ISC clicks very rapidly (almost like a buzzing)and
>the RPMs hang simultaneously(approximately 1-2 seconds), and
>then it drops down to the appropriate RPMs. It also does
>this while coming to a stop, which is also a period when the
>IAC/ISC adjusts itself to keep the engine from stalling.
>And finally, when first starting the engine, it jumps up to
>about 2K RPMs. I know it's supposed to jump higher than
>normal and stay higher when cold to help warm up
>faster/reduce emissions, but this seems kind of high. Also,
>when starting the engine after sitting for a few hours, and
>in the cold, after idling for about 30 seconds fine, it will
>start to surge from
>900-1200-900-1200-1000-1500-1000-1600-back to normal in a
>period of about 10 seconds. Other than that it idles almost
>perfect in closed loop. All these symptons sound like a
>stuck/malfunctioning IAC, or a failed ISC motor(depending on
>which it has). What do you think?

I hear the auto's do that. i have a stick, so i can't say for sure.

>
>-My EGR valve and or EGR vacuum switch right next to it, is
>clicking/popping rapidly at all times. You can hear it from
>inside the car, and I originally thought it was a rod knock
>or the cams/followers till I investigated further. It's
>definately coming from this. Is this a normal functioning
>sound on this vehicle?

Mine didn't do that before i removed it. Doesn't sound right. take it out or replace it. Possibly a busted diaphram. (Note: mine clicks if the vacuum switch is disconnected from the valve)

>
>-What's the recommended oil weight on a stock 420a equipped
>Eclipse? The dealer neglected to include a damn owner's
>manual for the car. Also, what kind of ATF do these things
>take?

I use 10x30 Mobil 1. There's a bunch of stuff from the owners manual on the main page in the Info&Specs section, check it out.

>
>-Is there an A.I.R. system, or a Chrysler equivalent on this
>vehicle? It's difficult to see in there, and all I see is a
>power steering pump, A/C compressor, and the alternator.

No AIR system.

>
>-Where is the MAP? I'm assuming it's the sensor with 3
>wires on the passenger side of the upper intake manifold,
>all by itself. Is the IAT/ACT sensor located on the back
>side of the upper intake manifold, next to the vacuum port?
>If not, what is that?

Right on both counts.

>
>-Does the TPS receive a 5.0 reference voltage, and use a
>typical potentiometer-type switch to send a variable voltage
>signal back for the ECU to determine throttle position? Is
>it a 3 blade oval or rectangular connector?

Yes. It has a rectangular connector, and i believe it is three pronged.

>
>Well, that's all I can think of at the moment. Sorry for
>being so long! ANY help is appreciated!
>
>-Mike

S'what we're here for. Got any more questions?

BTW: Welcome to the club!

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'95 Eclipse TurboGS (garage deco)
'95 TSi AWD (restoring a survivor)
'97 Talon ESi-T (poor impulse control)
'99 Eclipse RS-T (daily beater)
'13 Evo X (mostly stock)
'17 Sienna (Middle Aged Dad Mobile)



Factory Service Manuals: http://nawdu.de/files/

For those who dont know what an A.I.R. system is: Not too sure this is on fuel injected cars, but mostly found on older computer controlled carburated cars. I used to have a 1981, and a 1987 GM cars that had comp controlled carbs, and what it does is it injects air into the exaust gases to help burn off any left over fuel to help emmisions. I havent seen this set up on the newer fuel inj cars, but someone correct me if i am wrong. That was the first thing to come off the motor!! I'm not sure if this is what you mean by an A.I.R. system, but on the older cars, thats what it's called...

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Thanks for the replies!

And yes, A.I.R. stands for Air Injection Reaction, and it dumps air upstream of the O2 during open loop, downstream into the converter during closed loop, and bypasses when decelerating/engine braking. Ford's version is called the Thermactor system. They used both these systems up until at least 1996.

1999 GS

1991 Mustang GT