924Board.org

paluck · Joined: 25 Mar 2009 Posts: 69 Location: Walnut Creek, CA

Hello,
We're having a problem with our 1979 924. Quick background - car is a California car that has sat undriven for quite some time (5 - 10 years?). Owner always said he had problems getting it to run well consistently after that and he was giving up on it. Its cosmetically junk and we're getting it running for the 24 Hours of Lemons. We had it running o.k. a few weeks ago at idle and cruising speed, but were having problems getting the engine to rev past 4k rpm or so. .. but today it seems as if we've regressed - we're now running on only 3 cylinders (cyl #4 misses). Here are the things we have done since obtaining the car:
* Fixed elec gremlins to get fuel pump running
* new plugs
* new wires
* new fuel filter
* cleaned the flapper (flow measuring door) and verified smooth operation
* taped up the intake hoses
* checked the rotor and cap - looks good
* Reset timing
* Fixed leaking coolant tank

Additionally, these are the things that we have done since this morning (when we went from 4 cylinders down to 3)
* Swapped injectors - problem remains on Cylinder 4
* Swapped spark plugs - problem remains on cylinder 4
* Swapped plug wires - problem remains on cylinder 4
* Checked spray on a couple injectors - honestly not sure what a good spray would look like - but I can't honestly say they look 100% - they're a little janky
* disassembled and cleaned banjo bolts and the CIS fuel distribution block hydra thingamajigger - including the mini plastic fuel filters
* Blew air through the #4 fuel line
* Silicone resealed the intake hoses and silicone taped them up
* Checked compression - its good
* Removed valve cover gasket and watched the #4 cylinder valves actuate
* Checked spark on the #4 wire with a screw driver in it - to ground

Any hints? The #4 plug comes out fouled - apparently with fuel.

-Mike
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paluck(at)hotmail.com
1989 944 S2
1979 924

Ozzie · Posted: Mon Jul 27, 2009 3:57 pm Post subject:

dissy cap and rotor?
Check timing
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Porsche 924 1984 (UK import) NA
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Rich H · Posted: Mon Jul 27, 2009 6:12 pm Post subject:

Dribble cold start injector honkin gfuel into number 4? It's the right end of the intake manifold....

Crank the engine to get fuel pressure up then quickly pull the csv, see if it's leaking.

Pull al the injectors check for leaks and the spray should ideally be a nice conical spray from all the injectors at once. when the fuel plate is lifted, could be some funny bisnies sin the fuel dizzy.

One last thing have any of the fuel lines to the injectors been replaced? They must be hard nylon pipes or the original brained hoses, like hydraulic hose (Covered in rubber hose but that splits and falls off anyway) if it's been repalced with rubber the injectors don't open cleanly.
BTDT....
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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

emoore924 · Joined: 13 Apr 2004 Posts: 2822

I think bad fuel distributor...only thing I can think of that's not changing and that is specific to #4 and that would cause fuel on the plug...

Move not only the #4 injector, but the #4 fuel line as well and see if the problem moves. I think it will. Just swap #3 and #4 and if it is the fuel dizzy (assuming your injectors are ok), the problem will move.

A good spray from the injector would be cone shaped, and fine atomization all the way around the cone without any dripping.

I don't think the refurb work you did on the fuel dizzy would help things much..., sorry. They're pretty hard for the DIY'er to fix.

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

+1 to above.
If that doesn`t move the problem, time for a compression test.

Nobbi · Joined: 24 Aug 2006 Posts: 1396 Location: Germany

I wouldt buy some new rubber o- rings and put them arround the cleaned injectors. also if you have 5 .- $ extra, get some new plastic inserts for them...... Possible that it gets some air-go-by.

The spray pattern in this cars are not making a huge diffrence, as long as you get 750 ml from the injectors within one minute. (minimum)

And check with cold engine that your s-plugs are torqued well,and the seal-rings on your plugs are fine.

Nobbi

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NA 924 - april/1977- 4-speed-audi gearbox.
500.000 km with fun.....and new toy:Porsche 944 S2 Cabriolet.Other car Daimler c-class cabby,brandnew..Plus : DEUTZ 4005 tractor Built 1967

Slam · Posted: Wed Jul 29, 2009 4:36 am Post subject:

Well, you said you DID move the injector and the problem didn't move. I'm with Rich on the CSV as a likely culprit. If not that then the fuel dizzy.
_________________
'84 944 - kid blew motor
'83 944 - resting comfortably. For 12 years
'87 944 - sideswiped by trucker
'80 924 - gone
'78 924 - gone
'77 924 - rusting comfortably

paluck · Joined: 25 Mar 2009 Posts: 69 Location: Walnut Creek, CA

ok - new critical info. - thanks for all the help so far. It took us a while to figure out the way this whole FI system worked, but we're starting to understand.
2 of the guys were over at the shop last night and made the following discovery:
Swapping the fuel lines that feed Injector4 and Injector 3 AT THE POINT of the FUEL Distribution block caused the problem to move to cylinder 3. So I think that means our problem is what everyone is referring to as the fuel dizzy (the distribution block that meters fuel flow depending on air flow and determined by the mechanical intake portal.
My team members report that they they've cleaned and blown out all the places they can and we're still down a cylinder from that port exit.
So.... next steps?

Can we clean this unit successfully with a good solvent soaking if we fully disassemble all that we can first?

We have another dizzy - believed from a 924 turbo. It is similar but not the same - using a metal layer in between the top and lower halves, instead of the rubber (including some other differences). Also - some inlet port differences. It seems this may have metering screws to fine tune flow to each port though.
Swap whole unit? Swap top half only?

Any operational units floating around in internet land? inexpensively, or we may have other parts available for trade

Remember that this is for the 24 hours of lemons and we are on a strict budget, so we are looking for a reliable, yet inexpensive way to resolve our issue. 1979 924
-Mike
_________________
paluck(at)hotmail.com
1989 944 S2
1979 924

!tom · Posted: Wed Jul 29, 2009 6:20 am Post subject:

If the problem moved from 4 to 3 when you swapped fuel lines on the dizzy, this means that the problem followed the fuel line.

This means you've got a toasted fuel line.

Your fuel distributor and injectors sound fine.

You may be able to find a CSV fuel line for some other CIS car (such as '70's vintage Rabbits, etc.) that might fit, if you're trying to do this on the ultra cheap. I can't recall which fittings the injectors for the '79's have -- I believe there were two different types of fittings on the 924 throughout the years, one shared the same fitting as CSV's, and the other type didn't.
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78 924 NA
5-lug

emoore924 · Joined: 13 Apr 2004 Posts: 2822

Just to clarify, sounds like he switched the feed lines at the dizzy and the problem moved (#3 line was now <not> getting the fuel from where the #4 line had been attached...), so that would be the dizzy, not the line..., right?

Dizzys are out there. I think JJadzak had a couple out there recently. Post a WTB on the parts forum and see what happens.

You might be able to "blow things out" and make the one you have work but I doubt it. They don't take kindly to air pressure or disassembly by a DIY technician (I know this because...)

I don't think the turbo unit will work. Although, if it is operational, you might be able to sell it and get more than it would cost to buy a n/a unit.

You need to find on that has the same numbers on the dizzy as you have now, ends in "005" I think? Look for a post by me a few weeks ago and I think the numbers for the dizzys that will work are in there.

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

Scorpio · Posted: Wed Jul 29, 2009 12:01 pm Post subject:

..It sits between the third cylinder and the firewall...

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dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

Sounds like it could be one of two possible problems with the fuel distributor. If it is putting out too little fuel, there is a blockage in the metering slits or valve body. To clear it the dist should be removed and the piston taken out of the cylinder then spray injector cleaner through the outlet line to see if that will clear the blockage. Also spraying the cleaner through the metering slits in the cylinder may help dislodge it.

If the distributor is putting out too much fuel to the injector, the internal o ring is toast and will require a rebuild or replacement.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

DOCO · Posted: Wed Jul 29, 2009 11:34 pm Post subject:

i have a 79 california fuel dissy off my 79 na what kinda parts ya got to trade?only thing is im in canada an a fuel dissy is heavy.anyway let me know
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79 924 N/A "Webster"
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924RACR · Posted: Thu Jul 30, 2009 1:27 am Post subject:

With all that debugging... sure hope your trans is up to the task too, given that it's a '79... or you can line up a solid Audi box, even better...
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