924Board.org

[Jakkq]

Just today I finished putting back together some parts I had taken off. Today, though, as I tried to fire the car up, it wouldn't do anything. After about my third try I waited a little and it came to life, but it would not hold, and then would die. After trying later on, I started it up and there was a loud BANG! and a puff of white smoke came from somewhere near the Intake Boots.

I took an Intake Boot off to see a bunch of white smoke pour out from it. Normally this loud bang has happened before and it was when my Intake Boots had swollen just enough to not grip right, and when I gave it gas, one of the boots would pop off. They are secure enough this time, though.
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1979 Porsche 924- Snailshell
http://porsche924workblog.blogspot.com/

[Ozzie]

what did you take off.
sounds like a backfire caused by incorrect timing.
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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

[stevekat]

That was the mouse being sucked into the cylinder from its nest in the intake manifold.
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"Never get out of the boat. Absolutely goddamn right. Unless you are goin' all the way."

Gone to new home: '81 924T, US version, CGT Intercooler, UTCIS-PT, Euro DITC, Greddy Trust MBC, Forged Fuchs Flat Dish 6's, Factory Recaro's.

[emoore924]

Did you take the plug wires off? Probably got them back on in the wrong order...

[Jakkq]

I did not take the Plug Wires out. This is all I did:

Removed all 3 Intake Boots
Removed Air Filter Cabin and Air Filter
Removed Coolant Expansion Reservoir
Removed Coolant Hoses leading from Radiator to Thermostat Housing
Replaced Coolant Hose attatched to Thermostat Housing with one that has a Bleeder Hole (there was not one on the hose before)

I then replaced all of the parts as I had them before.

The Fuel Injector Banjo Bolts that connect to the Cylinder Head have bits of oil in the sockets, but the Banjo Bolt Plugs will not come out of the sockets.
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1979 Porsche 924- Snailshell
http://porsche924workblog.blogspot.com/

[emoore924]

Ok, I'm thinking you have something going on with the CIS that loaded up the intake runners with fuel (cold start valve perhaps). Then when it did fire, bango. I had that happen with one of my cars that had a manual override for the CSV. Son sprayed, then cranked, and it went bang.

I think you have a problem of which the bang is a symptom. Reason I'm saying that is it sounds like you had something going on before you did the work.

At this point I'd start by confirming the basics. Make sure static timing is right. Check CIS for vacuum and fuel leaks. Make sure your injectors aren't leaking fuel. Check spark... Be methodical and thorough or this could drive you crazy.

[Paul]

How old is your timing belt?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[Jakkq]

I found out that one of the Injector Fuel Lines had snapped from the circular hook that connects to the Fuel Injector. It broke off a little in the hose, and left a small tip on the circular piece.

I was thinking that the pieces separated when I fired the car up, or is what caused the loud pop... But then wouldn't there at least be a little fuel that would have shot out of the hose?

Another thing is that when I removed the little sleeve from the end of the line, there was oil in it, and on the line. Oil had come through, and spilled from the top? Oil had also been in the Intake Boots earlier on. This was when oil had spilled from the side of the Cylinder Head Valve Cover, as the gasket was snapped.

I'm thinking it would have snapped beforehand, since I removed and was messing with the Air Filter Cabin. Could have snapped from old age and movement, then finished off when I fired up?

Would this have caused backfire, and white smoke to puff out, and through the Intake Boots?

PICTURES: http://porsche924workblog.blogspot.com/2011/09/fuel-injector-oil.html
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1979 Porsche 924- Snailshell
http://porsche924workblog.blogspot.com/

[Jakkq]

Okay, well I have been reading up on a book on Fuel Injection I took from my automotive shop class. One thing I noticed is oil has eaten away at the electrical component connected to the Air Regulator. Is oil going to damage electricals if it makes contact?
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1979 Porsche 924- Snailshell
http://porsche924workblog.blogspot.com/

[Jakkq]

Yeah, I think it is more than likely a timing issue. Put everything back together after installing a new Fuel Injector Line. After I turn the key, nothing will happen. If I give it gas, then it begins to go, and after about 5 seconds will fire up. Then I need to keep giving it gas for it to stay alive. Once it stays put and I let it idle, there is a lot of rumble as if it want's to die off. If I give it too much more gas it will make a loud pop from the bottom and then die off.

Guess I should have mentioned before that I added about 2 gallons of gas to the car before the POP symptom started up. Could the gas be too rich or something? It's the same as I always use.

Would anyone be able to explain how to go about setting the correct timing, and what tools I will need? Haynes is a little confusing about it.
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1979 Porsche 924- Snailshell
http://porsche924workblog.blogspot.com/

[Ozzie]

If you use the search function it will give you lots of timing advice.

First off check your valve timing.
Crank Pulley, Flywheel and cam pulley should all line up at TDC.

Distributor rotor should be pointing to no.1 plug lead.
Check leads are correct. 1-3-4-2 clockwise on dissy cap.

If you have a multimeter check resistance of all leads- should be less than 6K ohms. Longest = highest resistance and reduces with length.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance