cold starting prob...

this just started happening this week:

when i first start in the morning, ignition surges and then dies. this happens several times before finally starting. then it will start, but continually surge/bounce for about 8 seconds before stabilizing like it should.

if i 'help' it with the gas a little upon first ignition (i.e. barely press on the gas pedal, hold for a second, and then let off), it smooths out immediately.

i think i read something about this earlier, but i can't find it now. thanks-

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Adam Nitti
ajnitti@mindspring.com
www.adamnitti.com
'85 911 Carrera Coupe

i know it sounds obvious, but have you checked your battery terminals? yeah, i KNOW it is the last thing that 99.9% of people consider, but it might be just enough corrosion on the terminals to cause a rough start.

EXACT same thing has happened to me in several different cars. doesn't matter whether it is K-Jetronic, motronic, or other.

good luck

obin

Adam,

You may want to check the Air mass meter (flow meter) with an ohm meter. You will have to look up which terminals and what ohm reading. A bad flow meter will often cause idle bounce in your FI system, esp when cold.
Your system also has a temp sensor somewhere on the engine that tells the computer what the engine temp is. YOu may want to test this as well. (sorry I dont know where, I have an SC with CIS)

You may also want to look at the idle regulator. This will usually cause stall when cold and strange idle behavior all the time, however, can act like what you are experiencing when it first starts to go.

The battery terminals and alternator are also suspect since your system is pretty much totally electronic. The voltage drop which occurs at cold start up can make the FI system behave strangely and if there is some other prob that compromises the voltage already, this can cause such a problem.
Make sure you are running light enough oil for the cold starts (if its really cold), as oil that is too heavy when cold will accentuate this voltage drop.

Hope this helps.
Nick.

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Nick Shumaker
1982 911SC Coupe

i checked both the temp sensor and the intake air sensor in the air flow meter with an ohmmeter, and both were in spec according to the bentley manual...

but, i took off the idle speed regulator, and the piston in it seems to be frozen, cause i don't hear it sliding back and forth when i shake it. also, bentley says the resistance should be 40k at the outer pins, and 20k at the inner... i'm getting a 1k reading for both.

sound like it has failed to you guys? (this is a $150 part!!!!)

thanks-

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Adam Nitti
ajnitti@mindspring.com
www.adamnitti.com
'85 911 Carrera Coupe
'89 Jeep Cherokee (very, very tired...)

Sounds like the idle speed regulator/idle control valve, based on your symptoms.

Your tests seem to have confirmed it.

Can you move the piston back and forth manually? Doesn't Bentley have a visual test for it, where you take it off the car, but leave it plugged in, and observe it with the ignition on?

Anyways, it sounds like your problem.

P.S. You can sometimes clean it up by taking it off the car, running carb cleaner/WD40 through it, while moving the piston back and forth. You can sometimes get additional life out of it, if it is only a "freezing"/mechanical problem, and not an internal electrical problem.

[This message has been edited by Jim T (edited 02-09-2001).]

jim t:

no, i can't move the piston back and forth. it appears to be really stuck. i tried to put a screw driver on the end and push... wouldn't budge.

i plugged it in with the key turned on, and it hums and vibrates like it's supposed to, but the piston just 'twitches' every 2 seconds while sitting there.

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Adam Nitti
ajnitti@mindspring.com
www.adamnitti.com
'85 911 Carrera Coupe
'89 Jeep Cherokee (very, very tired...)

oops... double post.

[This message has been edited by adamnitti (edited 02-09-2001).]

i ordered the new idle speed regulator, and when i went to pick it up, i got cold feet and didn't buy it. i couldn't hear the piston in it sliding around any more than the one that's on my car now when i shook it. i had an overwhelming feeling that it wasn't going to fix my problem, and then i wouldn't be able to return it. i would have checked the one at the shop with an ohmmeter to compare, but the guy behind the counter said he didn't have one there. i'm thinking maybe this isn't my problem.

so, a question: after i start the car in the morning, i only have to hold the gas for about 2 seconds to stabilize it and keep it from dying, and then it's stable as ever. also, it starts fine the rest of the day. could this be as simple a problem as too lean or too rich a mixture in my CO setting? what do you guys think?

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Adam Nitti
ajnitti@mindspring.com
www.adamnitti.com
'85 911 Carrera Coupe