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Spark Misfire? ANY advice please!!!
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tylercle  



Joined: 17 Aug 2012
Posts: 27
Location: Denton

PostPosted: Thu Aug 23, 2012 9:12 am    Post subject: Spark Misfire? ANY advice please!!! Reply with quote

(77.5 924) Okay, so after fiddling with my timing belt during WP change, replacing spark plugs, dist. and rotor, the car starts but idles low with low volt meter in car, so after a few starts, it won't even turn over. Needed a jump. Did I just drain the battery? It tested fine before the repairs. My main question is how to properly resolve the spark/dist/engine timing. How can I start over here?

Any possible causes to the puttering engine during my procedure?

First changed dist. cap/rotor, but didn't set TDC beforehand. plugs are in proper 1-3-4-2 clockwise order
Changed plugs
Set TDC for timing belt, but when tried to remove without lock, i turned the flywheel (so I rotated it back to TDC and replaced timing)
Changed pump and refilled with coolant.

After poor starts:

I dbl checked engine at TDC and rotor wasn't "pointed" to #1 plug for some reason, although it's wider backend was. So I tried switching it around but car wouldn't start and I heard 2 low thumping sounds coming from the engine so I switched it back.

After jump, engine continued to bounce around with low idle and volt. Now battery appears dead.
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'77 924 "Penelope Cruz" all stock n/a, 70K.

"...actually, ambition won't get you that far. You'll shift gears. You'll see something that's shinier. But if you believe... then you're the long-distance runner." - Sam Abell
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ideola  



Joined: 01 Oct 2004
Posts: 15506
Location: Woodstock IL

PostPosted: Thu Aug 23, 2012 9:32 am    Post subject: Reply with quote

OK, slow down and take a deep breath.

There.

Now. First things first. Using a multi-meter...and NOT your in cockpit voltmeter...what voltage does your battery show with the car not running? If it doesn't show 12.6V (or very close), then charge it first.

Second, if you interrupt ground between the battery and chassis while the car is running, you WILL wipe out the voltage regulator on the alternator. We'll check the voltage on the alt output later once we get the car started...but do you recall at any point removing the negative cable while the car was running???

Third, let's confirm you have your crank, cam, and dizzy all set to TDC. Here's how.

ideola wrote:
You will need a 13mm wrench (for loosening the ignition distributor hold-down clamp), a flat head screw driver (helps with popping off the distributor cap spring-clamps), and a 24mm socket with a 1/2" ratchet and short extension (for rotating the crank).

Using the 24mm socket/ratchet, rotate the crank around to TDC. This is easiest to check by watching for the dimple on the back side of the cam sprocket, and bringing that dimple into alignment with the pointer on the end of the cam cover. (Side note: make sure the cam sprocket is on correctly...it has dimples on both sides, and it is a common mistake during timing belt service to put the cam sprocket on backwards. The sprocket has a shallow side and a deep side. The deep side with the VW/Audi symbol and other writing should face the windshield, the shallow side should face the front of the car. If you find the sprocket is on backwards, fix that NOW before going any further. Once you've verified proper installation of the cam sprocket, use the dimple on the deep side to align with the cam cover pointer. This is TDC).

Pop the distributor cap off and set it aside (no need to disconnect wires unless you think they may be on incorrectly).

Remove the 13mm nut on the distributor hold-down clamp, remove the clamp, and remove the distributor.

Carefully inspect the lip of the distributor. Just to the right of the electrical connection you should see a tiny scribe mark on the lip of the distributor. This is the TDC mark. When you insert the distributor, you want the rotor to point directly to this scribe mark. This is a little tricky because the helical drive gear will cause the rotor to rotate slightly as you re-insert the distributor. Before inserting, rotate the rotor slightly clockwise away from the scribe mark (about 1/8th to 1/6th of a turn). When you insert the distributor, the rotor should rotate back to the TDC scribe mark.

If your distributor has the vac advance/retard housing on it (most of them do), there are only a couple of positions that will allow the distributor to be freely rotated for final timing correction without interfering with the cam cover. What I usually do is have the vac housing oriented as depicted in the following photo:

Just make sure that when you insert the distributor that the rotor ends up pointing to the scribe mark. Once you have it back in place, you can fine tune the distributor rotation until it points EXACTLY at the scribe mark. Then torque down the clamp with the 13mm nut.

Reinstall the distributor cap. The ignition terminal on the cap that is directly above or inline with the rotor (now that it and the engine are all oriented to TDC) is the #1 lead. The firing order should be 1-3-4-2 in a CLOCKWISE rotation. So check the leads to make sure that they are connected in this fashion to the distributor and the correct spark plug. Correct as necessary. Again: CLOCKWISE rotation!!! If you put the leads on for counter-clockwise rotation, the car will fire, but it will only run on cylinders 1 and 4 because 2 and 3 will be exactly 180 degrees out of phase! The car will run this way (ask me how I know) but VERY poorly!!!

The car should now start with relative ease. Now you can break out your timing light and dial in the precise ignition timing you want.


Now, I want you to note a few things from the above post:
1. Orientation of the cam sprocket. Make sure you didn't install it backwards. Even if you didn't remove the sprocket, don't ASSume it's on correctly. Verify using above instructions.
2. If you have the rotor 180 degrees out of phase (which your above post indicates is so), then the car will only run on two cylinders which would explain the puttering.

Get your dizzy inserted correctly and MAKE ABSOLUTELY CERTAIN you have the cam sprocket on correctly, the rotor pointing to #1 with the cam and crank at TDC, and that your leads are connected in CLOCKWISE order 1-3-4-2.

Start the car.

Now with the car running, put your multi-meter on the battery. If you're getting anything less than 13.6V, your alternator is not charging correctly either due to an internal fault, a blown voltage regulator, or a wiring fault between the battery, starter, and alternator.

I presume this is on a normally aspirated car...if so, the main starter/alternator harness from the battery passes under the hot exhaust manifold. These are known to fail from heat stress, and in some cases, the insulation will be completely gone and the harness will short out on the block. This will interfere with proper running (possibly puttering) and as noted above, will interrupt the charging circuit, wiping out the voltage regulator in the process.

Be thorough, systematic, and methodical. Do not make the mistake of ASSuming anything...including that there is only one problem. There may be a multitude of things wrong, so you need to verify from one step to the next as laid out above that things are connected and configured correctly.
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tylercle  



Joined: 17 Aug 2012
Posts: 27
Location: Denton

PostPosted: Thu Aug 23, 2012 9:48 am    Post subject: Plug order Reply with quote

Found the numbers 1342 stamped along the top of the engine - does that mean the front plug (one nearest the radiator) is #1, with #3 behind it and so on? This would make sense in regard to my distributor appearing backwards.
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'77 924 "Penelope Cruz" all stock n/a, 70K.

"...actually, ambition won't get you that far. You'll shift gears. You'll see something that's shinier. But if you believe... then you're the long-distance runner." - Sam Abell
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ideola  



Joined: 01 Oct 2004
Posts: 15506
Location: Woodstock IL

PostPosted: Thu Aug 23, 2012 10:07 am    Post subject: Reply with quote

1-3-4-2 means the firing order.

Once you've identified TDC on the ignition distributor, and have the rotor pointing to the correct location, put the cap on, and note which terminal on the cap corresponds to the small end of the rotor. This is the #1 lead. Connect your plug wire to this terminal, and then connect that to the FIRST spark plug at the front of engine.

Now, the next terminal around on the distributor cap in CLOCKWISE direction; this is the #3 lead. Connect your plug wire to this terminal, and then connect that to the THIRD spark plug, counting back from the front of the engine.

Go to the next terminal on the cap in CLOCKWISE direction; this is the #4 lead. Connect your plug wire to this terminal, and then connect it to the FOURTH spark plug at the back of the head.

Then the final terminal should be connected to the SECOND spark plug.

So in summary, the SPARK PLUGS should be numbered 1-2-3-4 from the front to the back; the plug terminals should be numbered 1-3-4-2 in CLOCKWISE orientation. Then you connect the wires matching the numbers. Make sense???
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tylercle  



Joined: 17 Aug 2012
Posts: 27
Location: Denton

PostPosted: Thu Aug 23, 2012 11:30 am    Post subject: Reply with quote

Yeah, thank you for the clarification. I'm gonna charge the battery and have a go again!
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'77 924 "Penelope Cruz" all stock n/a, 70K.

"...actually, ambition won't get you that far. You'll shift gears. You'll see something that's shinier. But if you believe... then you're the long-distance runner." - Sam Abell
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tylercle  



Joined: 17 Aug 2012
Posts: 27
Location: Denton

PostPosted: Thu Aug 23, 2012 1:29 pm    Post subject: Reply with quote

No cigar...charged the battery and dbl checked the dist/rotor/plugs, all is the same.

Is it strange for 924 spark plugs to omit the top screw-on thingys? my plug wire harnesses are simply pushed onto the threaded portion.
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'77 924 "Penelope Cruz" all stock n/a, 70K.

"...actually, ambition won't get you that far. You'll shift gears. You'll see something that's shinier. But if you believe... then you're the long-distance runner." - Sam Abell
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Paul  



Joined: 02 Nov 2002
Posts: 9451
Location: Southeast Wisconsin

PostPosted: Thu Aug 23, 2012 1:58 pm    Post subject: Reply with quote

Check to make sure the ground wire from the alternator to the block is intact and free of corrosion.
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tylercle  



Joined: 17 Aug 2012
Posts: 27
Location: Denton

PostPosted: Thu Aug 23, 2012 2:11 pm    Post subject: Reply with quote

The battery drained thankx to newb here leaving it off the plugs for 3 days. My alternator ground is in good shape. I DID take off my camshaft cover briefly while trying to remove timing pulley, but no tool so back on it went. I don't think that affected anything though...
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'77 924 "Penelope Cruz" all stock n/a, 70K.

"...actually, ambition won't get you that far. You'll shift gears. You'll see something that's shinier. But if you believe... then you're the long-distance runner." - Sam Abell
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ideola  



Joined: 01 Oct 2004
Posts: 15506
Location: Woodstock IL

PostPosted: Thu Aug 23, 2012 4:28 pm    Post subject: Reply with quote

IF the timing and all is set up correctly (which I'm not convinced it is if you didn't change anything from the way it was...), then it's time to go back to basics. We can't solve the battery dying issue until you get the car running, unless you take the alternator in to your local FLAPS for testing.

As for the basics: spark, fuel, timing.

Spark.
Get a spark tester. Remove the primary coil lead from the dizzy cap. Test to make sure you're getting good spark from the coil. If that checks out, then one by one, disconnect each spark plug lead (at the spark plug end) and make sure you're getting good blue spark at each lead. If that checks out, you can (for now) eliminate spark as the issue.

Fuel.
Can you get the car to catch on starter fluid? Is the fuel pump running? Is the fuel filter installed in the correct orientation and not plugged? Disconnect the main feed line from the fuel filter to the fuel distributor at the fuel dizzy end, put the line in a glass bottle, and use the procedure in Haynes to verify that you're getting fuel to the dizzy (this involves jumpering the fuel pump relay contacts and lifting the air plate in the air metering unit). If that checks out, reconnect it, and remove all four fuel injectors, placing them into glass jars or bottles. Follow the procedure in Haynes to check for fuel flow and pattern at each injector. If that all checks out, then fuel is not your issue.

If both spark and fuel check out OK, then go back to my first post and re-check EVERYTHING on the list for proper timing. Are you absolutely certain you have the cam and crank both timed and properly set to TDC? Are you certain the cam sprocket is on correctly? Re-index the ignition distributor, and double verify the connection of the plug leads.

It's not that complicated. If you have spark and fuel, and your timing is even marginally close, the car should run. So you must be missing something.
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staticsan  



Joined: 19 Jan 2009
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PostPosted: Thu Aug 23, 2012 6:15 pm    Post subject: Reply with quote

tylercle wrote:
Is it strange for 924 spark plugs to omit the top screw-on thingys? my plug wire harnesses are simply pushed onto the threaded portion.


That is strange. I'd be looking in the plugs to see if they've stuck up in there.

Wade.
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!tom  



Joined: 28 Aug 2006
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PostPosted: Thu Aug 23, 2012 7:15 pm    Post subject: Reply with quote

tylercle wrote:
Is it strange for 924 spark plugs to omit the top screw-on thingys? my plug wire harnesses are simply pushed onto the threaded portion.

Nope. Not strange.
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ideola  



Joined: 01 Oct 2004
Posts: 15506
Location: Woodstock IL

PostPosted: Fri Aug 24, 2012 1:55 am    Post subject: Reply with quote

It all depends what plug wires you have. I've had plug wires that need them, and plug wires that don't.

So no, it's not strange.
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jim kleyh  



Joined: 24 Apr 2012
Posts: 55
Location: pine falls, manitoba, canada

PostPosted: Fri Aug 24, 2012 9:28 am    Post subject: poor run Reply with quote

Hi, just to stick my nose in here, how long has the fuel been in the tank. This unleaded crap breaks down very fast. I've had cars that sat for a month barely run on the gas until drained and refilled. I've also started cars that have been sitting for 20 year with very old gas fire up and run with only pouring a bit of gas in the carb. Listen to what Dan is telling you and follow it to the letter and that motor should run. JIM
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tylercle  



Joined: 17 Aug 2012
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Location: Denton

PostPosted: Fri Aug 24, 2012 9:29 am    Post subject: Think I found the problem Reply with quote

Ok, so I realized I never dbl checked the camshaft TDC marker...I can't find the darn thing. I need a dumb-downed version of where to find it.

What I think is going on here is that since I removed the timing belt only with the crank set at TDC, and replaced it only with the crank. (plus a bunch of extra crank-only turns to correct flywheel turning without lock), I could be a bunch of notches off on the cam-crank TDC marriage.

I understand that it takes 2 cycles of the crank to equal one of the cam.


Can anyone give me a clear description on where the heck this cam peering hole is?!


T
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'77 924 "Penelope Cruz" all stock n/a, 70K.

"...actually, ambition won't get you that far. You'll shift gears. You'll see something that's shinier. But if you believe... then you're the long-distance runner." - Sam Abell
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tylercle  



Joined: 17 Aug 2012
Posts: 27
Location: Denton

PostPosted: Fri Aug 24, 2012 9:31 am    Post subject: Reply with quote

And I'm learning a ton-load from you ideola...thanks for all the info.
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'77 924 "Penelope Cruz" all stock n/a, 70K.

"...actually, ambition won't get you that far. You'll shift gears. You'll see something that's shinier. But if you believe... then you're the long-distance runner." - Sam Abell
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