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Pike · Joined: 19 Mar 2003 Posts: 44

_ Ok, I have the car running again, only on 3 cylinders. I have swapped both the plugs and the wires and the problem stays at the same cylinder. Next I bought a new cap and rotor, this did not solve the problem either.

_ The spark getting to #1 is weak and/or nonexistant. The new cap and rotor should have taken car of this. The car is also backfiring, which would indicate that it is recieving gas as well. Why is the spark not hot? It can't be the coil because the other cylinders are working great. Where do I check next?
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positivesale · Joined: 12 Nov 2002 Posts: 126

check the coil anyway... they are easy to test. HOWEVER do not rely on the haynes manual, it is WRONG in one or more places about the reading.

Is your plug bad? just a silly suggestion (switch plugs?plugs can be bad inside). How did you test the spark? holding it to ground? Make sure the cap isn't on a bit lopsided (not clipped in all the way, causing the rotor to miss the contact). I don't know what it could be.
Check continuity everywhere - not just wires but everywhere liek plugs cap, rotor, (even if it's new, could be bad spring/grpahite/lead peice near spring) etc.
Flakey wires that are about to rip at the joint, that only work sometimes?
Melted wires from exhaust, that have continuity but not enough?
Oily and grungy grounds? (could be easily tested just holding it to a good ground)
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82 931

78porsche924 · Posted: Sun Jul 13, 2003 3:02 pm Post subject:

Is the spark always weak/gone? could be your valves because that makes no sense the problem you are having. Is the spark only weak on that cylinder?
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90 944 S2
78 924 NA <---now sold and killed by new owner
snailshell trans
Bae turbo kit
to check out my 944 S2 http://www.cardomain.com/member_pages/view_page.pl?page_id=388139

Pike · Joined: 19 Mar 2003 Posts: 44

I may have a spark to all of the cylinders now. well, at least three again. #1 has a strong spark, as do 2 and 4. but 1 and 3 are also not firing now, and I can't tell if 3 has got spark or not. I am going to clean #1's plug again to see if that improves things, but I am getting really screwed up. The wires all tested ok for resistance. I am back using the old cap and rotor. Also, the car runs with the wires in either of two of the possible places on the disributor?!?!?!
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Lizard · Posted: Sun Jul 13, 2003 3:55 pm Post subject:

ok I will attack this 1,

#1 start from sratch with placement of the wires,

put cyl #1 to TDC using either a screwdriver in the spark plug hole and watch the cam lobes through the oil fill hole to make sure it is on a compression stroke, or follow 78924N/a way of finger over the spark plug hole feel for compression and use the timing marks to see that it is at TDC, then with cyl #1 at TDC of compression stroke pull the cap and see where the rotour is pointing and then run the spark plug wire from that location to cyl #1 and plug the wires in a cw rotation corisponding to the firing order of the engine 1-3-4-2, then try and start it, also to check spark go to a parts store and get a little tool that plugs in and claps to a ground point and watch for spark, or you could put fuel on the end of the spark plug ground it out and if it catches fire you know you have spark there
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3 928s,

MunkPuppy · Posted: Sun Jul 13, 2003 5:03 pm Post subject:

Just a thought, but as we all know, your system uses a hall-effect sensor to trigger the ignition system. I would check that your distributor does not have any play in the bearings, and then make sure that all 4 gaps are aligned properly. With a set of feeler guages and a bending tool that is usually included with said feelers, you should be able to do this in a few minutes. If there is excessive play in the distributor, either rebuild or replace it.
If all of this fails, go to a mechanic and have them put your ignition system onto the oscilliscope (they will know how to do this, I did it in mechanics in Junior high often). This usually takes about 10 minutes to complete the diagnosis, but I will not quote prices as I usually do this myself with my brother's help (and scope.. too bad he's 2000km away now). Believe it or not, you can learn alot from these tests.
If you're really hardcore, you can get a used oscilliscope in online auctions for reasonable prices, and this is a tool that you can use with pretty much any car that doesn't have its own advanced computer.
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CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

Just a thought...hooking up your timing light to each lead will confirm you are getting spark. If the strobe fires, you've got juice. The only thing left would be the actual plug or it's connection to the lead.
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'79 Eurospec 931

Pike · Joined: 19 Mar 2003 Posts: 44

Thanks, I had not thought of that. The problem is sorted out, but I will remember that for next time.

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78porsche924 · Posted: Thu Jul 17, 2003 1:29 pm Post subject:

what was wrong? how did u fix it. i am just curious.
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90 944 S2
78 924 NA <---now sold and killed by new owner
snailshell trans
Bae turbo kit
to check out my 944 S2 http://www.cardomain.com/member_pages/view_page.pl?page_id=388139

Pike · Joined: 19 Mar 2003 Posts: 44

_ I am not sure what the main problem was but there where several contributing factors:

_ The firing order was wrong, that fouled the plugs and the injectors.

_ For whatever reason (I did not touch it to my knowledge) my timing got moved by 45 degrees (I am not kidding, the car woud run with the wires on two of the four possible positions on the distributor) That solved the no spark problem. For starters I timed it by ear.

_ So then I tested the injectors and two had really bad spray patterns. I ran them at high output for a bit out of the engine (killed a lot of grass) and that helped one and fixed the other. A full can of BG in half a tank of gas cleaned them out the rest of the way. In the next week I may run another bottle of injector cleaner though, unless it is too expensive then I will just shell the $120 for new ones.

_ Cleaned and gapped the plugs and had a shop adjust the timing and the idle speed, and it runs like new!! I am still running the brutalized plugs (had to file them to unfoul), and may change that soon, but not before the road trip I am going on. It is running too well to spoil. If any of you in Washington see a blue 924, a blue Checker Marithon, a silver Z3, a black LeBaron, and maybe a rabbit or two, that is us!!! Beep and we may honk and flash lights back.
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78porsche924 · Posted: Fri Jul 18, 2003 1:07 am Post subject:

Go to napa and ask them for the carb cleaner. The heavy duty stuff that will burn your skin. I used that on my injectors and it cleaned them out really well. They were completely clogged with crap and had almost no spray. Rinse it in this stuff which is like $20 a gallon and then rinse in acetone then gasoline. Almost good as new. The early year uses all metal injectors so u can use this stuff. Don't let it contact platic, it will eat it.
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90 944 S2
78 924 NA <---now sold and killed by new owner
snailshell trans
Bae turbo kit
to check out my 944 S2 http://www.cardomain.com/member_pages/view_page.pl?page_id=388139

Pike · Joined: 19 Mar 2003 Posts: 44

_ I made sure that they where clean on the outside. What was needed was one of the cleaners that goes through the unit, besides, I have heard the these also clean the rest of the fueal system and the chamber too.

_ Brakleen is wonderful stuff. It makes most soot come off and even kills weeds in the front yard. I try to use it as little as possible because of how nasty it is.
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Sleykin · Posted: Fri Jul 18, 2003 10:39 am Post subject:

I don't know for sure if it will work on a Porsche injector system but on the XJ6 Jag injectors we pulled them all and connected to a spare pump and pumped straight alcohol through them. Just recirculated it into a pan. IIRC the injectors ran on about 3-5 volts though so you may need to check that out before you try to turn em on. Of course if you are talking mechanical injectors ... never mind

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87' 924S

positivesale · Joined: 12 Nov 2002 Posts: 126

What is the ingredient in the carb cleaner that works? I've never been able to find something that's strong enough to burn my skin or remove black carbon. I need something like that. i always have trouble cleaning parts and wasting money on the diluted crap that doesn't work!

Is it just plain and simple carb cleaner, or is it a special one with different ingredients? Any brand name?

Thank you.
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Pike · Joined: 19 Mar 2003 Posts: 44

Get brakleen. Enough said.

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