924Board.org

[timstar92404]

Ok I just changed my 4 spark plugs with new bosch ones and I screwed around with setting the gaps and I'm not really sure if the gaps are too small or too big.

I have the little circular gap setter and I put it between the gap at the lowest setting and move it to the .028 mm -.032mm range and make it a bit bigger by bending the tool and then you had to push it in and pull it out.

the old plugs aI took out were NGK plugs and have a diff looking smaller tip.....

My engine started up but then I noticed there was alot of vibration in the engine and exhaust more than usual and then it started getting worse then my engine rpm started dropping to like 800 then to 600and it was bouncing up and down..... and souded like it might stall soon.


what is the most likely thing that is wrong??



also while changing my spark plugs on of the white plastic hoses (think hoses that are connected to the vaccuum amplifier (next to the battery area) the hose came out from a connector (half way in the middle of the hose there is a connector thing) I just put it back together.

I doubt it has to do with that.




I also used spark plug grease on the threads and dialectic grease on the ends where the wires plug into....


I''m pretty sure its either the wrong gap or maybe they gave me wrong plugs.....




I have to get it fixed by tom afternoon...... as I have to go to school and then work.
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78 924 sold.
85.5 944

[Codyboy]

Double check your gap.

Did u make sure u didnt mix up the plug wires? and put the same plug wire back on the same cyclinder.

U Tighten the plugs enough? common mistake with some people since they affraid to break them.
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Go hard or go home

[timstar92404]

thanks codboy


there is three things I guess could be wrong the gap,

how tight should i make the spark plugs....... I think they are pretty tight I just turn the ratchet until it was pretty hard to move it .


and during changing the plugs one of the vaccuum amplifier hoses came off the hose4 is cut halfway and it is connected by a connector thing

I can take a pic in the dark to show you.

I just stuck it back into the connector could it be due to this.



as I just noticed again. the car starts easily and it seems to run okay for like 30-40 secs and then it gets worse and worse and stays like that the rpm drops to like 800 or less before changing the plugs it ran at 1000 rpm usually and the engine starts shaking.

but for the first 30 sec the rpm is at like 11000 and the engine runs ok it seems and it revs fine.....


if I shut it off and wait for a while then start it again , it again runs fine for like 30 sec then the rpm drops too much and runs very rough....


it doesn't sound like its the spark plug gaps to me as it starts and runs fine for the first 30 secs or so.....
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78 924 sold.
85.5 944

[timstar92404]

No i'm pretty positive that I didn't mix up the wires i was careful noi to do that.
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78 924 sold.
85.5 944

[timstar92404]

and would this problem be more likely due to a too small gap or too large?
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78 924 sold.
85.5 944

[MunkPuppy]

well if it's running pretty good for 30-40 secs and then getting bad, then it seems like your aux air valve could be a factor. However, I would first make absolutely sure that you've got your plug wires on right, the gap is set properly, and that your cap & rotor are in good shape.

To set your gap (which should be 0.028 in or 0.7 mm), the plug should fit snug at the appropriate gap mark with NO pressure needed to get it there. If it goes PAST the mark, then your gap is too wide (you could be overheating your ignition coil). Obviously, if you have to push it to get it to the right gap mark, then you need to widen it a bit (spark is weak).

Your spark plugs should be of the gasket type, so the rule of thumb is this:
screw the spark plugs in finger-tight with your hand (otherwise you could cross-thread your plugs seats and then you're looking at a visit to the mechanic) and then use your ratchet to turn the plug an extra 1/8 turn. Hayes says spark plugs should be torqued to 21 ft/Lb. (if you have a torque wrench).

Another thing to remember is that when you are removing your plugs, you should screw them almost all the way out, and then use compressed air to clean dirt and gunk out of the plug seat. If you don't have compressed air, wipe with a cloth and then use a vacuum with straw attachment to suck out the dirt before you completely remove the plugs. This will keep dirt from getting into the threads when you install your new plugs, preventing exhaust gases from escaping through the side of the plug and causing some nasty damage.

Hope this helps
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'80 931 FOR SALE

"It's a shame that stupidity isn't painful"
-Anton Szandor LaVey

[timstar92404]

the car was running fine before the spark plug change so it is very unlikely something went wrong with it.


I"m pretty sure the spark plugs are tight enough and the gap may be a bit to small as I had to use a bit of pressure to get it in the .028 mark but I could still get it in the .030 mark by pushing it in......



what about that vacuum ampifier hose.

I'm looking at haynes and there are 4 vaccuum amplifier hoses connected to the vaccuum amplifier and one of the hoses (which is broken in the middlee, and then connected by a middle connecter) came off when I was replacing the plugs and I just stuck it back into the connector.

NOt sure what this does but it might be leaking and causing the drop in idle and rough engine after 30 secs.


should i try taping around the connector part which the hoses go into with electrical tap to make sure it doesn't leak?
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78 924 sold.
85.5 944

[MunkPuppy]

personally, I would take that piece of vacuum hose to Lordco or some other auto place, and get a new length of hose, it's only a few bucks.
_________________
'80 931 FOR SALE

"It's a shame that stupidity isn't painful"
-Anton Szandor LaVey

[timstar92404]

yeah I know but I want to know if that could be causing my problem.

I want to electrical tape around the part where the hose goes into the connector to see if that stops the problem


I'm not sure what teh vacuum amplifier does though...

there are 4 hoses coming off of it and I forgot where this one hose goes too
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78 924 sold.
85.5 944

[timstar92404]

if it was the spark plugs wouldn't it run rough right when you start it?
_________________
78 924 sold.
85.5 944

[MunkPuppy]

[timstar92404]

oh sorry I didn't mean I didn't know where to attach the hose....

I'm pretty sure I attached the hosse to the right connector....

what I meant to say I don't remember right now which hose this was that came off at the middle connector.


I'll post a pic tom morning to show what I mean and what came off.


the hose can easiily be pulled out of the connector.


I looked at pg 107 and I'm pretty sure it was the hose that goes to the throttle valve housing.....

I'll check tom.

the hose is broken into two seperat parts in the middle and the two seperate parts are connected by this bigger cloth like tube.... and end of the hose came out of this and I just stuck it back inside.
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78 924 sold.
85.5 944

[Ozzie]

Sounds like a bad vacuum leak to me.
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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

[timstar92404]

I think the car runs right now.....

I took the plugs out again and made the gaps a bit bigger to about .030 to .o31 haynes says you can make it up to .032 mm

and I made them tighter incase they were leaking.

the car started idline rough again by shaking too much but I drove it for 5 mins and it drives good and actually seems a bit quicker but i'm probably just imagining that.

and now when I start it it idles around 900-1000 and the engine just shakes like usual.....

I think when it was cold it was idling a bit lower and that was causing it to shake too much.

I was probably just worrying too much.....
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78 924 sold.
85.5 944

[tj924]