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-   -   A few issues on my SC (http://forums.pelicanparts.com/porsche-911-technical-forum/579886-few-issues-my-sc.html)

magnumpi 12-12-2010 08:43 AM

A few issues on my SC
 
CIS newbie just trying to sort through some apparent issues on my 'new to me' 1980 Euro SC.

First off, when turning the key to the "ON" position, before cranking, there is a loud noise from the motor area. It sounds like fuel pump whine? Is this normal? Doing a search I read that some people say this is, others say it's not.

Also, with the air filter off, and the car off with the key in "on" position, I slide my hand into the airbox and lift the 'plate' and then on top of this loud humming noise, I can hear the fuel injectors activating. My question here is when I do this, does fuel actually 'squirt' into the injector/cylinder? Does fuel actually run through the system?

I can see on the closest passenger side injector that it is 'wet' and appears very loose. Could this explain the poor performance (car feels like it's running on 5 cylinders) and hard starting that I'm getting?

Thanks
Dan

vash 12-12-2010 08:50 AM

euro car. dunno about your first question. my car will not whine simply in the on position. yes it is the fuel pump. there is a plug behind that alien head looking thing. check to see if it is plugged in. if not, my car will turn the pump on without ignition.

yes the injectors are spraying when you lift that bar. dont do it too much, you will flood the motor.

and yes, you probably have a vacumn leak at that injector. you should change all the seals.

Gogar 12-12-2010 09:12 AM

1. Is the "loud noise" a very high-pitched, electronic sound? Then YES, that's the CD box doing it's thing, on the left wall of the engine bay.

2. Yes.

3. Take a 12mm and 14mm fitting wrench and undo the metal fuel line from the injector, and pull the injector out. There are two 'pieces', the injector itself, and the sleeve the injector goes into. Sometimes the sleeve will come out with the injector, sometimes not. No big deal.

There is a rubber seal for the 'sleeve', and a rubber seal that holds the injector into the sleeve. Get some new ones and replace the sleeve first, and then the injector. Make sure both are in all the way, so they look similar to the other ones.

Then put the line back on. Tighten with firm hand pressure, but not 'gorilla.'

mca 12-12-2010 09:40 AM

Quote:

Originally Posted by Gogar (Post 5722912)
Sometimes the sleeve will come out with the injector, sometimes not. No big deal.

There is a rubber seal for the 'sleeve', and a rubber seal that holds the injector into the sleeve. Get some new ones and replace the sleeve first, and then the injector. Make sure both are in all the way, so they look similar to the other ones.

I'd be a bit cautious about pulling out the sleeve if it is the original. What happens if it crumbles when you try to remove it? What do you do if the sleeves are staked into the intake?

During my rebuild I had the CIS off of the engine. I had to use a dremel to file down the stakes in order to remove the sleeve. And some of the sleeves simply crumbled during removal.

Just saying ... be careful.

boyt911sc 12-12-2010 09:47 AM

CIS troubleshooting.........
 
Quote:

Originally Posted by magnumpi (Post 5722866)
CIS newbie just trying to sort through some apparent issues on my 'new to me' 1980 Euro SC.

First off, when turning the key to the "ON" position, before cranking, there is a loud noise from the motor area. It sounds like fuel pump whine? Is this normal? Doing a search I read that some people say this is, others say it's not.

Also, with the air filter off, and the car off with the key in "on" position, I slide my hand into the airbox and lift the 'plate' and then on top of this loud humming noise, I can hear the fuel injectors activating. My question here is when I do this, does fuel actually 'squirt' into the injector/cylinder? Does fuel actually run through the system?

I can see on the closest passenger side injector that it is 'wet' and appears very loose. Could this explain the poor performance (car feels like it's running on 5 cylinders) and hard starting that I'm getting?

Thanks
Dan



Dan,

Your questions have been answered already by these guys. You have a pretty good understanding how this CIS works. So if I may suggest, get a fuel pressure gauge to complement your CIS troubleshooting work. Your engine poor performance could be caused by several culprits (ignition, timing, vacuum leak, etc.). This will involve a process of elimination and tests to confirm which could be the most likely culprit/s.

Obtain a good reference maintenance manual like Bentley and the like. Keep us posted.

Tony

Gogar 12-12-2010 09:52 AM

Quote:

Originally Posted by mca (Post 5722953)
I'd be a bit cautious about pulling out the sleeve if it is the original. What happens if it crumbles when you try to remove it? What do you do if the sleeves are staked into the intake?

During my rebuild I had the CIS off of the engine. I had to use a dremel to file down the stakes in order to remove the sleeve. And some of the sleeves simply crumbled during removal.

Just saying ... be careful.


That's good to know; my only experience with the sleeves is when I pulled injectors and some of the sleeves came with the injector.

magnumpi 12-12-2010 09:57 AM

Thanks all for the quick turnaround and great advice. I am placing an order for 6 new injector sleeves, seals and o-rings. I will be very careful with the sleeves, knowing that they could crumble on the way out.

Regarding the "alien head" what is this referring to?

pete3799 12-12-2010 11:59 AM

I think "alien head" that Vash speeks of is an extraterrestrial hummer.
Might be mistaken.

mca 12-12-2010 12:51 PM

Quote:

Originally Posted by Gogar (Post 5722978)
That's good to know; my only experience with the sleeves is when I pulled injectors and some of the sleeves came with the injector.

I would be willing to bet that your sleeves had been replaced at some point and they weren't re-staked.

When I reinstalled my sleeves / injectors I didn't re-stake them either.

mca 12-12-2010 12:55 PM

Quote:

Originally Posted by magnumpi (Post 5722986)
Thanks all for the quick turnaround and great advice. I am placing an order for 6 new injector sleeves, seals and o-rings. I will be very careful with the sleeves, knowing that they could crumble on the way out.

Regarding the "alien head" what is this referring to?

Take a look at the top of the sleeves - plastic things that surround the injector. See if they are staked - likely see 3 notches where the intake runner was punched to hold the sleeve in place. If they are staked, I'd ask around in order to find out the best method for removal.

If you ultimately have to remove the entire CIS, go ahead the replace the intake boots too.

tcar 12-12-2010 06:33 PM

Quote:

Originally Posted by vash (Post 5722877)
yes it is the fuel pump.

No, NOT the fuel pump.

The SC fuel pump is in the FRONT of the car, just below the fuel tank.


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