[ds968]

After parked in tne garage for about four weeks the battery did not have enough juice to start the car, but with a little help from the jumper cables and my conveniently adjacent MBZ , it turned over right away , although it started " racing " at around 2500 rpm...which I expected would drop down and settle to normal idle in half a minute or so. But no such thing ; after more than 20 minutes of running the engine the idle is still hovering around 1800 rpm ! If I shift it in R or D gears , it comes down to where it always hs been ( in those gears ) so that's normal, but in P or N it still races like crazy . What in the world could be causing that ?

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[flash]

see if the throttle cable is hung up

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[ds968]

Ok, will check that .

Uh, wait - if that was the case wouldn't also keep the rpms high when I shift it in a driving gear ? ( Which it doesn't - in gear it drops to where it should be )

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[ds968]

cable seems ok, just the right amount of slack in it, there's nothing stuck between the lever and the adjustment screw either, and after a whole one hour drive to work this morning the, idle is even higher -  about 2100 rpm.   so what could be some of the other culprits  ?    the ICV  ? ( fell asleep with its mouth open for a month, and got stuck in lockjaw  mode ?! )   some other sensor ?   is there an air/fuel mixture control device ?    this happened while the car was parked for four weeks - wtf ?     

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[banditsc]

You could try pinching off the ICV hose that goes into the elbow, I would expect the revs would drop. Also could try unplugging the ICV and see if anything changes. 

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[ds968]

thanks. considering i have a SC, i wonder if  the ICV still hose goes into the elbow , or it's relocated to one of the SC connections ?   flash ??   also, if I follow along the ICV hose i presume it'll lead to that plug i can disconnect  ? 

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[banditsc]

Yes, the ICV is on the elbow in front of the SC, it's the middle hose. And yes if you follow it back you will find the ICV attached to the underside of the intake, it has a spring clip connector that you just squeeze to pull off.

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[ds968]

cool, will try that.   btw, also just did a blink test - it appears to read 1-1-2-3  ( " oxygen regulation " )  - not oxygen sensor .   does that lead to any additional clues ? 

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[banditsc]

Yep, that would indicate a air leak somewhere in the system. Is the middle cap on the throttle body still on and tight and not leaking? Also check all the other hoses and couplers from the MAF back to the throttle body for tightness. I got that when I popped the cap off the middle port on the throttle body.

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[ds968]

will do !  thanks.  

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[ds968]

ok, checked all the caps, the hoses and the clamps, looked for any kinks, unplugged /re-plugged the ICV  connector, al other vacuum hoses going to the FPR, the o-ring of the oil cap, and anything else i could see where an air leak could be present .  all appears to be ok.    however, i was informed there is a possibility that having jumped the car while the good one ( "donor car" ) had the engine running might have created a surge which carries a risk of messing up the electronics in the receiving car.   huh ?    i have always had the donor car engine running while jumping other cars, including the 968s,  dozens of times and never had an issue with surge.  i also do not connect the negative cable to the engine block or some part of the frame, but pace the cables terminal to corresponding terminal on both batteries, though i connect the positives first and then the negatives, and remove in reverse.  never had sparks during this process either.. so the question is : am i doing this wrong, and if so is there a possibility or probability ( there is always a possibility for anything, but looking at how plausible this may be.. ) the electronic "surge" could have messed up the ICV function ?         

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[flash]

it says right in the owner's manual not to jump these cars.  yes, i've done it in nearly every car i've ever had.  no, i've never had a problem.  however, none of them said not to jump it.

 

that being said, i'm not sure what they were afraid of, but it's possible you buggered something

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[ds968]

if anything , it' s usually the donor car's alternator that is at risk for some damage, particularly if its not in the greatest shape to begin with,  but if i somehow buggered anything what potential component(s) might it be that could have been affected by the jump and which would result in a sustained higher rpm ?   a relay ?   the ICV itself ?  the ECU / DME  chip ??        

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[flash]

possibly the ECU.  you could try resetting it.  here's the fun part.  you'll love this.  to reset it, you have to remove it, pull the main connector, and then put it back together.

 

i doubt it though.  i presume the problem still exists.

 

i am still trying to remember what caused a similar problem in my car.  it would do what you are saying, but then reset itself after i shut down the car.  i fixed it, but for the life of me i can't remember what it was.

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[ds968]

maybe if I give the car a  " Fonzie hitting the jukebox "  adjustment ...a solid pound on the fuse box should do the trick, if not kicking the tire might work and reset everything back to normal  :whine:   

 

ugh, unless there is a 99% probability that the ECU is the cause and unplugging / plugging it back would solve the problem, i'd hate to go through the fun of that job.   especially with a bad back !

 

well, if you remember what the fix was..i probably wont do anything to the car at least until the weekend.   does not bother me at all when I drive it, as I said in driving gears it's relatively "normal".

and for the few seconds that it's in P, i can live with that for a  few days ..       

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[banditsc]

Maybe pull the battery cable for a bit. Would like to see if the air regulation code comes back.

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[ds968]

Started it for the drive home and it's as if nothing had happened earlier - it simply returned to normal all by itself. As I stopped at a couple of lights on the way, I shifted it in N, in P, and it's just fine - right where it should be, no fluctuations, nothing ! Crazy, I did not touch a single thing since lunchtime when I ran it for a bit, and when it still had the symptoms, and then half a day later - all is right with the world again . So if any of your cars exhibit anything of the sort, maybe allow it at least two start/stop cycles half a day or a day apart, and perhaps the gremlin will run away from the engine bay .

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