[Bruckner]

What's the normal fast idle speed on cold startup? Mine always starts right up but at a hair over 1000rpm the fast idle doesn't seem a whole lot faster than the 850rpm fully warmed up. Wondering if this is indicative of other issues.

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[ds968]

I believe that’s perfectly normal .   

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[94SilverCab]

Sounds normal to me too...

 

Jay

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[Bruckner]

Ah! Thanks.

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[Waylander]

Yes perfectly normal, all controlled by the blue sensor under the top hose, and the fuel map for cold starts in the ecu, the idle speed is controlled by the ICV

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[Bruckner]

I took the car out for a long drive, logged about 800 miles in a week, the car was great fun and flawless all along. However now it struggles a bit to start, fires right up but takes 2-3 seconds to reach high idle.



https://youtu.be/yen5LeQfBHs



I'm thinking either ICV or fuel pressure related?

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[Waylander]

Sounds about normal to me, it takes a few seconds for the ecu to sort it all out

This is 30 year old tech

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[Bruckner]

Thanks for that, but I still feel like something isn't right. It never behaved that way for years, and now it does it consistently on every cold start. Something must have happened... 

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[ds968]

If it hesitates about 2-3 seconds at start,  I can only speculate one of these issues may be in play :

 

Sticky ICV 

Fuel check valve or FPR

A small vacuum hose leak

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[94SilverCab]

If it hesitates about 2-3 seconds at start,  I can only speculate one of these issues may be in play :

 

Sticky ICV 

Fuel check valve or FPR

A small vacuum hose leak

 

At nearly 10,000 posts, you have finally posted your very first "Technical" response.

 

Bravo!!!

 

Jay

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[Waylander]

Lol

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[ds968]

 

At nearly 10,000 posts, you have finally posted your very first "Technical" response.

 

Bravo!!!

 

Jay

 

Huh ?     

 

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[Rap]

Clueless. Jay I’m glad you’re tallying types of responses.

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[94SilverCab]

Dan prides himself on "Technical Content Free" posting...I was just pulling his leg

 

Jay

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[ds968]

Haha, when you wrote “very first”  I thought maybe you had one too many glasses of that fine PA wine… So what’s the actual split  ?   Designations such as “most active in”  a given forum category could simply mean a 51-49 split .. 

 

 

Anyway, unlike some other folks, unless my cars have had a mechanical issue for which I was seeking some guidance / troubleshooting ideas , prior to taking them to my mechanic for repair , and subsequently posting the result ..the rest of the “technical” arena is simply informative reading ..for the most part.. 

 

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[Roboman]

I'M BACK!!!!!!!! And what a great little theme to join

 

Sorry to be AWOL, it's been a difficult and involving few months .... but as they say "if it doesn't kill you it makes you stronger!"

 

Technically .....hmmm, I think one shouldn't expect too much from a 25 yr old car on cold start up, all sorts of things can be a little sticky early on, but if it works through that and runs well when warmed up then I would be too critical.  I'm not sure (cf 1 human year + 7 cat years) how the human to car aging is calculated .... but if we consider the planned depreciation for many cars is around 10 years and that equates to 3 score and 10 human years, then our cars are about 150 human years old .... I hate to think about my own cold start at that age!!

 

Culturally .....  it's great to see the usual suspects having a dig at each other .... long live 968 forum

 

Now I have to look through the other themes to see where I can contribute.

 

Have a good day/week/meal,

 

Robo

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[Bruckner]

Alright alright! Suck it up it's an old car!



Fair enough, but it is a fairly simple set of devices working together, no reason this particular issue couldn't be addressed, what's the fun of owning these cars if we can't keep them running well?



Thanks to those who supplied useful info. I'll keep looking, testing and report back.

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[Roboman]

I entirely agree, and yes part of the fun of ownership is keeping them running well, and in my case, bring them up to their original condition. However one thing certainly leads to another, and the "while you're in there" urge is very strong. Last year I needed to change the brake booster which lead to .... brake MC, clutch MC, most of the vacuum lines and rubbers, many of the electrical plug/socket covers, and a few other details. I'm very glad I did that work, the engine bay now looks great, the car runs well, and I have enjoyed many a drive this Summer. But I'm retired and have time....

But if you're determined to chase this down you might do well to order a couple of metres/yards of vacuum hose and assorted rubber junctions, because they might be part of this problem and you will anyway need them over time. And then follow Dan's advice with a can of WD40. The air/fuel mix is computer regulated, but it relies on getting correct signals and so dirty terminals, bad connections, wrong air feed, will mess with the input values and sticking sliders will mess with the output response.

Good luck.

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