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foxtg557 · Joined: 05 Aug 2007 Posts: 99 Location: Hamilton On

Khal - The engine runs pretty good while idling and reving - very few coughs sputters, almost no shaking... the exhaust is pretty good, smells a slightly rich - i've played with the A/F ratio on the CIS with the 3mm allen key, any adjustments from where it is makes the engine run really rough and if i go to far the engine will stall. I've chased vacuum leaks as best I can. As for grounds, I have cleaned up quite a few of them, but I might have missed some, any key ground locations to check for ?

I'm siding with fuel delivery as well. I have mentioned that I have a new fuel filter and new fuel pump. The only three components that I am aware of that havnt been checked / tested / replaced are the fuel distributor, fuel pressure regulator, and the accumulators... I really wish I could just replace them - but they are expensive parts

.

Also, someone told me to look into Valve lash, anyone familiar with this ?
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77 924, It Drives !

Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

I do not have a clear idea how to help you yet... but a question that might help others and me.

When the engine dies.

Does it just WHAM cut out and RPMS drop to zero in an instant.

Or does it kind of sputter and die?

One is more of an electrical fault... coil cut off, fuel pump off kind of thing. The slow die is another.

Eric
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1992 968
2003 C4S
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foxtg557 · Joined: 05 Aug 2007 Posts: 99 Location: Hamilton On

The dieing only occurs after ive driven for the 20 or so seconds while in gear, when it dies it dies quick. So if im holdin down on the clutch, the car will sit and idle at about 900 or so rmps rather nicely, but when i go let off the clutch pretty instantly RPM's drop to 0, if im fast enough to get back on the clutch I can get it back to idle...
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77 924, It Drives !

Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

Ok does not sound electrical to me. Electrical is a suddent shut off with no clue it is coming.

Hmmmm....

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1982 924
1992 968
2003 C4S
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Chewtoy · Joined: 07 Apr 2007 Posts: 39 Location: Southern Illinois

Ok now that strikes me as odd. It dies only when it is in gear and the clutch is not depressed? (always good to have an optimistic clutch)

Just so I follow right here are the key points:

1. runs fine at idle
2. revs fine when sitting still (in gear or out? parking brake on a presume)
3. does a sudden die not a stalling.
4. only does this when moving and in gear. pushing the clutch in saves the car.

I would assume that when it is idling you are in nuetral with the parking brake on and outside the car. But just to clarify, is this the case?

When it tries to die tdoes the car loose forward momentum? as in tries to stop?
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'77 Yellow 924

Ozzie · Posted: Wed Jun 04, 2008 9:52 am Post subject:

Check there is not a clutch switch above the clutch pedal. (similar to brake switch)
Some cars with cruise control have one fitted.
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Porsche 924 1984 (UK import) NA
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Engineer of Electro/Mechanical Systems Maintenance

Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

Interesting about the cruise control.

Mine 1982 does not have it. It would have to be aftermarket?

Anyway another though if no cruise control.

The 1977 cars had a Vac booster on them right?

It still seems to be that it is an issue when the engine is under load. So not enough vac or maybe it is building up as the engine is allowed to idle and then being released over those 20 sec that the car actually moving.

So... if there is a vac booster I would suspect that might be faulty and or some other lines are.

Can you actually run the car and drive it for 15 sec say and then put it in neutral and let it idle again for 30 sec and then drive for 15 sec and repeat? Would it drive this way? Not that you want to do it but currious to see if it would.

Do not hit the clutch... just push it out of gear and see if that makes a difference. That will eliminate the clutch pedal.
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1982 924
1992 968
2003 C4S
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foxtg557 · Joined: 05 Aug 2007 Posts: 99 Location: Hamilton On

Chewtoy -

correct, it does die only when it is in gear and the clutch is not depressed. As in I'm driving and moving forward while in gear and as im in gear and moving it begins to shake do what has been described.

Key points:
1. Correct
2. Revs fine when sitting still - it is out of gear and the parking brake is on
3. The way it quits is a stall
4. Correct - only does this when moving and in gear. pushing the clutch does save the car.

When it is idling, it is in nuetral and the parking brake is on while im out of the car.

When it tries to die, it has a strong engine break, studdering until either I depress the clutch or it successfully stalls out.

Ozzie - I don't have cruise nor do I see a clutch switch but thanks for the suggestion

Eturbo - The Vac booster is not hooked up, all my vac accessory lines have been plugged up. I have the proper vac lines running for the main hoses - following the diagram which i believe Ozzie supplied earlier in this thread.

I can do the drive for 15 seconds, I know I can turn the car off, wait 20 - 30 seconds, restart the car and I will get good driving capabilities back for a brief time. If after it dies, I restart it right away I will have little to no power.

Ill try the no clutch neutral suggestion tomorrow afternoon

.
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77 924, It Drives !

Chewtoy · Joined: 07 Apr 2007 Posts: 39 Location: Southern Illinois

My first thought was that something could be binding and stalling the engine. Like a brake hang or something along that line.

Not sure now, could be a timing issue, have you check to make sure it is in time?

I am assuming that it does it when you accelerating in the first few seconds of driving. Is there a certain gear that it seems to do it in? Or can you get it to about 5mph and hold a steady pattern? Any rhyme or pattern to when it occurs when driving?

{Edit} lol, sounds just like what my boat is doing and I've been fighting with it for almost 2 years now.
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'77 Yellow 924

Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

Try this

Unplug the WUR electrical circuit. Maybe it has some thing to do with the circuits that would otherwise be used to warm the car up and should shut off in a short period.

Maybe instead it is shorting some thing out after the period it would normally no longer be in use.

Anyway unplug the connection and see if it does anything.
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1982 924
1992 968
2003 C4S
Parts Parts Parts and More parts.
E-mail me for parts you need!
Drive Fast!

Ozzie · Posted: Wed Jun 04, 2008 12:05 pm Post subject:

The reason I asked is that a lot of people could have fitted, then removed items over the years.
Cruise control on manuals have a clutch switch as well as a brake switch.

To me it sounds like a fuel starvation problem, once the pressure drops below a certain level the injectors shut off.
Just like an electrical fault it is almost instant.
How is the fuel pickup in the tank?
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Joes924Racer · Posted: Wed Jun 04, 2008 12:58 pm Post subject:

When you rev it does it rough fast and with power or does it sound weak.
cause it sounds like a fuel delivery issue.. .

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Buwani 931 · Joined: 31 May 2004 Posts: 308 Location: Napa California

I was looking at one of your old posts. Did you get your injectors replaced or cleaned yet? Said you were getting low delivery and bad pattern.
What direction is your fuel filter pointing?

Shawn
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1980 931
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Ozzie · Posted: Wed Jun 04, 2008 5:02 pm Post subject:

One thing- what model pump did you put in your car?
The 924S pump is differnt to the 924 pump but may physically fit.

Other pumps may not give the correct pressure as the 924 operates at higher pressures.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance