PorscheMD

If everything has been checked properly that he stated in his posts I would bet on the alarm. The alarm box is behind the fresh air assembly on the passenger side. You have to remove the fresh air assembly to get to it. It looks like a daunting task but really isn't that difficult. If memory serves me correctly, you can unplug the box and the car will start. I know you need to jump two wires to make the alternator charge which I will need to look at the wiring diagram to tell you the colors of the wires. I know it is terminal 61 and 61a which I believe is written on the side of the alarm control unit.

theiceman

I mean for it to be totally deas like that it would definitely point to this type of thing.

pingman

Thanks again for the intrest. To Doyle, I live in Dublin. As for the terms I am using I will try to be more helpful. The starter will engage and turn the engine over and over. When I turn the key to the right, I can hear the fuel pump running. Yes I have gas in the car. All the gauges light up and the altinator light comes on. Someone had a post about the tach staying still when trying to turn the engine over, my tach will move but does not bounce around. as for testing for spark I connected an alligator clip to the ground on a known good plug, ( I tested the plug in my leaf blower in the dark). I tried several different locations in the engine compartment for grounding the plug including the 3rd fuel rail ground point, to also check the ground stap to the engine. One of the tests that Systems Consultants gave me to try verified (I think) that all the grounds were making it to the ECM. By the way I found Sys. Cons. through a rennlist member, top notch group who were very helpful, thanks. I tried cylinder one and two to test for spark by first removing #1 plug from the engine and trying to see spark, then by using said known good plug and #2 cylinder plug wire at a different ground point.
As far as a lojack, no, I only have the Porsche installed anti-theft, and when I bought the car in 2000,
I checked to see if it worked, it did, and I never used it again. I will look in my manual and see what it has to say about checking this unit out. I am using the Bently publishers Porsche 911 Carrera service for 1984 to 1989 ( the good years), just kidding!!! Thank ya'll again for taking the time, I appreciate it more than you know. Drive on, Mark ( me too soon!)

Mike Murphy

OK, here's what I would do. Take a multimeter to the ignition system and go nuts. Start with checking the coil resistance. Check 12+ to the coil as well when the ignition is on. If you have 12V, now, check the ultra-high voltage side of the coil both with the coil plug wire on and off. Check the resistance on the coil and plug wires. Check the resistance on the plug when grounded and bridge the gap on the plug when doing so (if left open, you'll get 1 million ohms!).

Basically, use that multimeter all over the place, and you're going to end up finding something that doesn't make sense. The problem could be as simple as a bad coil wire from the distributor cap, and the multimeter will show that.

pingman

Thanks murphyslaw. I don't know a lot about electronics as I stated. I have checked to see that I have 12 volts to the coil with the key on, but right now can't remember if I had it when the key was off. Some of the things you suggest I'm not sure of, but I will learn! I did check continuity of the coil wire, it was okay. I replaced the coil with a Bosch coil, checked the ohms with the old coil and they were pretty close to the same with the new coil slightly higher. But honestly I don't know what this means. I know it all has to be connected, and if your butt is in the the connection your gonna' feel it!
Thank you! Mark

Mike Murphy

12V to the coil is a good sign, but now you need to see what the voltage is on the other side" of the coil. A coil has 2 sides, the low voltage side and the high voltage side. The high voltage side give you that 10,000-50,000 voltage needed to spark the spark plug. If your multimeter cannot handle very high voltages (and most cannot) you're going to have to find a way to test the coil.

If the coil produces voltage on the high side, then you now need to check to see why the trigger isn't occurring. The trigger comes from the sensors & DME, and since you checked those, I would suspect that you have bad wiring somewhere.

To check bad wiring, all you really need to do is check the basics, and these are:

1.) Conductivity. With the multimeter set to measure OHMS, checking a good wire usually results in less than .10 ohms per foot of wire. Basically, for a length of 10 feet of wire, you should have only about 1-2 ohms max. Anything higher than that needs to be discussed further.

2.) Voltage. Any 12V sourced wire should read 12V with the multimeter. If it's anything less, there is a bad ground or bad wire.

3.) Grounding. Any good ground usually has less than 1 ohm of resistance. The meter should read full conductivity on grounds. Anything higher could be a problem.

PorscheMD

With the key in the on position, see if you have 12volts at pin number 86 at the DME relay. If you do not you will need to disable the alarm. To do that you disconnect the alarm box, bridge terminals 61 and 61 together and bridge term 15 and 87a together with jumper wires.

theiceman

From what I have read I would summize the car is not firing because it is not being told to fire. From that I mean the secondary ignition components sound okay . Coil, leads, disributor, plugs etc. The fact the coil was replaced makes it okay I would imagine and you can deinitely kill a Voltmeter ( and yourself ) messing with the high side of the coil.
I think the advice above is the place to start. make sure that darn alarm is not interfering. Once you have elliminated that go back to wha the DME is looking for in order to fire. There are things it must see in order to fire and I believe you are missing one of them, either reference sensors or cam sensors .. whatever. You said you have replaced the sensors . Do they plug riht into the dme or do they go through wiring harneses ! can you check the pins at the dme for input from these sensors ? The DME relay . is the wiring harness okay for that ? wouldn't it really suck if you just had a grounded or broken wire in the harness?

Good luck and let us know what you find.

pingman

Thanks murphslaw1978, Porschemd, and theiceman. This information will be very helpful. I cannot look at the car right now due to having to work for a living. Mom and dad cut me off a long time ago.
Just a little humor. To answer theiceman on a couple of things, the speed and reference sensors have their own wires in the wiring harness which are terminated at the male pin junction for the ECM. Each wire has a three pin connector, one is a black wire, one is a white wire and the last is a brown wire which I believe is the ground wire. I have checked continuity on both sensor wires to the ECM connector according to the instructions from Systems Consultants and they checked okay. I will recheck these wire using the info that murphslaw has given me on the ohms. The DME relay is located right next to the ECM. It has a four pin connector. Once I replaced the DME relay I did not look at it much more. I did rig up an elaborate jumper harness in the early stages of this journey to test the fuel pump, but as you already know the fuel was not the problem, and again I have replaced the fuel pump and the relay. I will definetly check the alarm points that porschemd has suggested on Saturday. I will let everyone know what happens when I get a chance to look at it. I noticed another thread where someone is having very similar problems. Thanks again, Mark