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-   -   no spark, won't start (http://forums.pelicanparts.com/porsche-911-technical-forum/85307-no-spark-wont-start.html)

tomt 10-24-2002 09:12 PM

no spark, won't start
 
It all started with a dry and smelly battery... it was 7 years old and dry, but not over charged (13.8 volts). I figured that I might was well replace it.

So, I drop a new battery into the otherwise perfectly reliable car, and now it won't start. The engine turns over fine, but it won't start.

As far as I can tell, all the fuses are OK, including the small panel in on the left side of the engine compartment.

With the key in the on position the fuel pump doesn't run, so I was thinking DME relay... replaced that and it still won't start. Note that the fuel pump runs fine when jumpering its fuse to the adjascent fuse.

Also, I guess I'm supposed to hear a whining sound from the CDI box in the engine compartment when the key is in the on position? I don't hear anything, but to tell you the truth, I don't know what a CDI box it, where it is located, or what it is supposed to sound like.

I'm not getting any spark either, but I did learn about the very cool Klein tool that I had right there in the factory tool kit. I removed aplug, inserted it in the wire and held it near the engine while my wife cranked a bit. No spark.

I'm not all that familiar with these or any cars, and am at somewhat of a loss. All I can think of is that somehow something blew when the new battery was installed (maybe the DME itself?), or I've somehow lost a ground somewhere.

Any help appreciated. Thanks.
Rgds,
TT

---------

85 Carrera Targa

Rot 911 10-25-2002 05:53 AM

Not sure I have the answer, but I want to bump your post back up to the top. Couple of things that come to mind though. First, are you sure you connected all the hot wires back to the positive terminal on the battery. You should have one very thick main red wire that goes to you starter and then a not so thick (I think 10 gauge) wire that goes to your fuse box. There may even be a second 12 gauge wire that also is connected to the battery. As for the CDI, you don't have one. The DME controls the spark.

Botman 10-25-2002 06:49 AM

Do you have an alarm system installed?

tomt 10-25-2002 07:08 AM

Thanks for the pointer on the CDI... If I don't have one it can't be broken! ;)

I didn't disasemble the positive battery cable... there's several thick wires attached to it and I've had the old battery out a time or 2 for recharging and have never had a problem.

Yes, I do have a factory alarm, but no key for it. Possible I blew a fuse or relay for that thing?
Rgds,
TT

Rot 911 10-25-2002 10:54 AM

Botman has found your problem. You will need to disable your alarm to get your car to start. This appears to be a common problem and a quick search should turn up several threads to tell you what you need to do.

tomt 10-25-2002 04:39 PM

How to disable factory Carrera alarm?
 
I ran a few searches, and folks definitely point to the alarm as a potential culprit... however I haven't uncovered any pointers as to how to disable the thing.

Any clues on how to disable the factory Carrera alarm?

Jeff 10-25-2002 05:24 PM

From what I read you can jumper (bypass) the two #61 terminals on the alarm control unit and this disables it and is OK to drive that way.

I will be doing that this weekend if my no start problem isn't fixed by replacing the speed and reference sensors.

tomt 10-25-2002 05:57 PM

Thank Jeff... sorry to be such an idiot, but where's this located?

tomt 10-25-2002 07:20 PM

Thank Jeff... sorry to be such an idiot, but where's this located?

Botman 10-26-2002 05:11 AM

Maybe this will help:

Alarm Thread


Another Alarm thread

You may need to ask for "BELL" or "Randy P" or "Early_S_Man". Any of them should be able to help you more.

Jeff 10-26-2002 07:27 AM

Tom, There are no stupid questions here. The alarm module is located behind the fresh air handler in the front trunk. It takes a little while to get it out (the air handler) but is fairly straight forward (I can give you step by step if you need it [ may even be able to provide pictures if I have to do mine today]).

The alarm is located on the left side of the trunk (looking from the front of the car into the trunk). It has an 10 wire harness coming out of it and a relay next to it. The BLUE wire and the BLUE/RED wire are the two #61 terminals.

Hope this helps. Let us know how you do.

tomt 10-26-2002 09:28 PM

Thanks Botman for the threads...

And thanks CU for the pointers and the offer on the instructions. I'd love a few instructions and pictures on the dreaded 3hr fresh air box removal!

Do you think this no-start problem is really the alarm??
Rgds,
TT

Botman 10-27-2002 04:02 AM

It was running fine before changing out the battery, right?

Did you do anything else besides changing the battery?

Were the doors locked or unlocked when you disconnected the battery?

Jeff 10-27-2002 07:04 AM

Tom,

I did have to bypass my alarm yesterday. Car runs now! YAAAAA!!!!.

There is a way to see if your alarm is the problem without removing your air handler. You can run a wire from the black wire on the dme relay connection (#86) to the backup light/ rear turnsignal fuse (#8 on your car I think)[thanks marcesq]. Connect it to the bottom of fuse terminal. Then try to start the car. if it starts you have found your problem.

You will have to see if your alternator is charging the battery (if it is not you will have to remove the air handler and bypass the alarm. but you will know it is the alarm at this point). To do this have a friend hold the RPMs at 1500 and put a mutimeter on the battery (+ to +, - to -) and look for DC voltage between 13.5 and 14.2. If your voltage is between these marks you are charging fine. If it is above 14.2 you may have a faulty voltage regulator.Below not charging.

Hope this helps. The airhandler isn't that big of a deal (15 to 20 mins.). Send me a PM with your Phone # and I can walk you through it or I can post pictures and procedures.

Let me know.

tomt 10-27-2002 10:04 PM

Bypassed alarm... still won't start
 
Jeff -- glad to hear you got your car started! Unfortunately my luck hasn't been as good.

I "think" I bypassed the alarm. Under the air accumulator there was a cigarette-box sized unit with 1 8-pin connector and 1 2-pin connector -- these both went in the front of the unit next to each other. Immediately to the right, there was a relay with an 8 pin connector.

As I removed the connectors for what I think is the alarm, the horn sounded briefly, so I guess I got the right one. The markings on the top of the unit indicated 2 # 61 terminals, so I jumpered them via the female harness connector and left both connectors out.

It still wouldn't start. Still turning over, but not starting.

Assuming I actually bypassed the alarm, I am at a dead end again.

Any ideas? Coil maybe? Mine isn't leaking anything, and I have never had any starting problems whatsoever prior to changing the freaking battery. Arrgh! :mad: \

I guess I am going to have to get it towed in to the shop... crap.

StanChung 10-27-2002 11:53 PM

This may be really dumb of me to ask but have you considered taking the battery back to where you got it and having it checked? Sometimes it's possible to get a bad one.

Jeff 10-28-2002 11:56 AM

Tom,

Here is what I did/ found. I took the alarm unit apart. I had a burnt connection that triggers one of the two relays in the alarm unit. I cut the two #61 wires and connected them together (the ends that lead away from the alarm) and capped off the other ends. I also cut the black wire and connected it with a wire I ran to the bottom of the #8 (rear turn signal/ back-up lights) fuse. Once again this was the end leading away from the alarm unit, and capped off the other end. Started the car and check alternator and voltage regulator function as mentioned above.

Tom, Did you run the black wire from the alarm (or you could run it from the DME relay plug) to the #8 fuse?

I also replaced my coil, as my thinking was like yours, but that did no good. Although my coil now matches my fuel filter:D

Also when you get your car started it will probably run like crap. Just go out and drive it. The DME just needs to reset itself (takes about 10 minutes).

Let us know if this helps.

Jeff 10-28-2002 12:13 PM

Tom I just re-read your post. Did you jumper the connections on the alarm unit or did you jumper ( splice ) the two #61 wires together. You need to splice the wires together (so they never reach the alarm unit).

Also if you never plan on using the alarm unit again you may want to run the black wire to the fuse box now so you won't go thru this again down the road (or worse yet on the road).

tomt 10-28-2002 08:38 PM

Splice method
 
Jeff,
Here's what I did:
I removed both female connectors to the alarm, and then inserted a small length of wire into the 2 #61 slots on the 8-wire connector (with the ends doubled up so they would make good contact with the female blade connectors). BTW, the wires on 2 #61 connectors are blue and blue/purple.

When I attempted to start the car, both alarm connectors were unplugged with the 2 #61 connectors jumpered.

If this worked, I was going to make a heavier gauge jumper wire with male blade connectors to ensure a solid connection, and then tape off the alarm and connectors and secure them down soemhow.

Did I do this correctly? Was I supposed to splice the wires AND plug the connectors back into the alarm?

I did not try to wire from the DME to the fuse block or from the back of the alarm to the fuse block.
Rgds,
TT

Jeff 10-29-2002 08:48 AM

Tom,

Yes you were suppose to splice the wires and plug them back into the connectors. I just cut the wires and spliced them together to bypass the alarm all together (meaning they never reach the alarm unit). You won't have to run the black wire from the DME to the fuse box if this works. I did on mine because I found a bad connection in the alarm unit. You may want to also, to avoid future problems (your alarm unit is 17 yrs old).

If you are worried about loosing a way to cut off fuel and spark you can unplug your DME relay for a make shift alarm, or put a toggle switch some where along the black wire.


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