Engine Question

[blue2004STi]

Hey yall!
I am sort of new to Porsches. Well really new... my dad has owned several and my brother currently owns a silver 1981 911SC. My bro moved to Portland, Oregon from Denver, Colorado and had to leave the car at my folks house. Since I come home from college every weekend(CU-boulder) I like to learn about his car. I got the opportunity to replace his alternator and such and that was a hoot.

Now you've gotten a BIT of a background on to the question. I drive a 2004 Subaru WRX STi. Obviously since it's a new car, whenever you turn the key the engine cranks right on up. Well with my bro's 911 you have to pump the gas and then once it's started you have to hold the gas on because it doesn't idle. My question is why would the car not want to idle from the start? Is it just due to the age of the engine and such and the technology in the car? Spark plugs? Fuel Injectors? I don't know what it is but I have no experience with older cars so any help is appreciated.

Thanks,
Matt

PS. I don't know if it's a big deal here but on my site NASIOC they make sure you searched first. And I did, to no avail.lol

[haycait911]

could be a myriad of things. best bet, get a manual, turn to troubleshooting section and get to work. is the car driven regularily?

[Facey]

well
i can start by telling you a few things about your brothers 911.

it's engine is an 3L, air (oil) cooled alum flat-6. It prodcues 180hp at 5900rpm and 265lb-ft @4200rpm. Really not bad numbers, and they can be easily bumped (search will yeild results).

fuel/air is fed to the engine via an early bosch fuel injection system called CIS. this is the limiting factor of the engine. What your talking about (IMO) sounds like the cold start valve, which is also a very commong failure.

if you do a search on that you will also find results point you in the best direction

there is no reason why in good condition these engines should not fire right up and run smooth. They are an old desgin however it lasted a long time because it was a good one.

cheers
Nick

[yelcab1]

Something is wrong with the car. My 80sc starts right up, holds idle at 1800 and then drops down to 1000 when warm. No help from me is needed.

There are many possible reasons for these, but let's start with the basic. And you will probably need a CIS pressure tester to really do justice on the car's ignition system. You can try swapping things out but it gets expensive quick.

Cold start injector valve
WUR (checking rather than replacing, it's really expensive)
Air box leaks (hard to fix inside the car)
thermal switch
Overall tune up

[Rich76_911s]

Matt,

As a CU-Boulder grad (2001), I have a question for you:
Why are you going home on weekends, the weekends are the best time to be in College.

Send me an email at:
rmshaner(at)hotmail(dot)com I can send you something that might be able to help with your problems.

Also if you like working on the car, there is a small collection of books that you will enjoy reading:
1. 101 Projects for your 911 by Wayne Dempsey (there is one for sale in the used parts section for $10) Porsche parts for sale
2. Porsche 911 Performance Handbook by Bruce Anderson
3. Bentley Manual for 78-83 911SC (pricey but if you like working on the car it is worth the price 10 times over)
4. How to rebuid and Modify Porsche 911 Engines by Wayne Dempsey

Cheers, and start hanging out in Boulder on the weekends.
Rich

[Nine9six]

BTW,
WUR=Warm Up Regulator=Another common problem.

[blue2004STi]

Originally posted by Facey
well
It prodcues 180hp at 5900rpm and 265lb-ft @4200rpm. Really not bad numbers, and they can be easily bumped (search will yeild results).

Nick

You have to understand though. I'm coming from a forced induction 400whp Beast that has 300 ft/lb.lol That's why I never got into the Porsches, is it's too easy to modify the new cars. I will start searching, no clue what my brother will allow me/want me to do but I'll at least start gathering info.

Could it be from the car being tuned to idle too low for when it first starts up? I don't know how well you can exactly tune a 1980's porsche but....

Thanks and keep the info coming,
Matt

[Facey]

there are many members here on the forum who drive seriosuly fast cars... 911's are not that heavy. remember you have* 400 turbo charged horses...naturally aspirated is a different story, and much of the love of porsche is feel and driver envolvment.

if you check over on the 911 turbo side of the forum (the older ones, 930's) you will see MANY 400+hp cars, and a making into the 500's.... you wanna see how far a 911 can be taken search "IF2", follow that thread if you got a sti somewhere that you'd put head to head with that thing i'd be interested in seeing it.


i really think it sounds like the WUR or cold start valve...especially if its doing fine once warmed up (10min)....