Greg

I have a 1983 944. I got it and it was missing an ignition coil but the engine did turn over fine. As of now I have an ignition coil in the car but i am not gettin sparks at the plugs. I have gone about testing for 12volts at the wires that lead to terminals 1 and 15 of the coil and i do have 12 volts when the wires are not connected to teh coil. When i connect them to the coil it registers up as 0, but to the any ground on teh vehicle both terminals 1 and 15 register 12 V. . . this is when i started getting confused. Is there any other way of testing the coil besides resistance. On primary resistance i get .6 ohms which is witin the levels, i have no way of testing the primary resistance because i have no meters which read up to that high of a resistance. I have gone through and checked other things such as the wires to teh distrubutor and they all seem to be fine, i have used multiple plugs and still no spark. The cap and rotor are a little worn but seem to all be in working condtion, my rotor does turn. . . HELP please!! also is there anything to do with the alarm system? I dont have a key that fits the alarm system but i belive that it is disengaged in the position that it is in. Does anyone have any idea what my problem could be?

Thanks in Advance
Greg

velns

Heh.... Greg.. I know how it is... when you're stuck ( wish you all the best and luck

SidViscous2

Greg. Is it a new cool. If so it`s probably fine. Is there any aftermarket alarm system. Could be an interrupt.

If your reading 12 volts each terminal your probably reading through the coil, and there is a round interrupt going.

_________________

Sid Viscous in Montreal.

CHECK YOUR NUTS!

special tool

You have checked the DME relay and the crank sensors??????

<img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" />

Tom Carson

Sid is right...with key on, you would read +12volts on each terminal (from the black wire and/or from the green wire) to the chassis...but 0 volts across the 2 terminals...that normal as the 12 volts is just feeding through the coil.

When cranking, the green wire should be getting a ground 'pulse' from the DME box. That should produce about 20,000volts at the high voltage wire into the distributor cap.

With the key on, you can 'rig' a wire from chassis or neg. battery (ground) & simulate a pulse by tapping it to the green coil wire. If you have the HV lead pulled out of the distributor and held about a 1/16 inch from the motor or chassis you will see a spark telling you the coil is ok.

Don’t let that HV wire near any other wires/harness (like the injectors!) when you do this cuz you will fry your DME if the 20,000 volts arcs over to it.

btw..don’t hold it with your bare hand either cuz you could break your arm as you ram it into the fender…20k volts can hurt!

Alarms may ‘open’ one of the coil leads. If you put your voltmeter on a low voltage AC scale and put 1 meter lead on green coil wire and the other meter lead on chassis or neg. battery terminal you should see a small AC voltage while cranking which means the DME is doing some kind of ‘pulsing’. Report back...

Greg

the coil is not new. . . and i do not have an aftermarket alarm, just the standard porsche alarm with they keyhole on the driverside right of the door. I dont have a key for the alarm. . its not the same as the ignition key apparently, but i do believe the alarm is disengaged, when i open the doors and stuff the alarm does not go off, but if i pull one of the wires off of the alarm keylock, the alarm goes crazy when i open the doors, try to start the car etc... Which relay would the DME relay be. . . maybe those missing relays might be a problem eh? Does anyone have something like a reference chart for the relays so i can figure out what i need? As for crank sensor, i have not checked that, but i will look in to it. TOM - I do get those exact symptoms with the 12v going through the coil and I figured that, but i do not think that my green wire is sending a pulse. . . this leads me back to the DME relay, so i will check that out.

Greg

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Tom Carson:
<strong>Alarms may ‘open’ one of the coil leads. If you put your voltmeter on a low voltage AC scale and put 1 meter lead on green coil wire and the other meter lead on chassis or neg. battery terminal you should see a small AC voltage while cranking which means the DME is doing some kind of ‘pulsing’. Report back...</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yea, I do have a low voltage AC reading of about .13 when i cranking, so if my DME is doing some kind of pulsing, does that mean my DME relay is probably good, or can that not yet be eliminated, I still dont know which relay is what, and I do have a couple empty slots, i would say 3 or 4 relays were missing when i got it, so i need to find out what goes in those slots.

Greg

SidViscous

I'm sure you can find it on Clark's garage or one of my other links

go to <a href="http://www.sidv.org." target="_blank">www.sidv.org.</a> look under the Porsche button.

Tom Carson

Can’t see how the DME relay would effect the spark...’no gas’ yes...that’s why they call it the fuel pump relay, but spark?...dunno how

The 12 volts to the DME unit and the coil comes from the ignition key.

Now the reference sensor definitely can cause a ‘no spark’ condition

Greg

hmm, Clarks Garage says that the DME relay is only found in 85.5 and up. . . i have an 83, but it does say somehing about my fuel pump relay... and i do have that because my fuel pumps nice and fine... any other ideas now? when it stops raining i will have to try the ground tapping on the coil to see if i can get a spark, but for now i guess all i can do is banter

SidViscous

Fuel Pimp relay and DME relay are the same. It's like top upper left and one over if I remember. It's a tall one.

Greg

if my fuel is pumping with the relay in, does that mean its in good workin order?

Tom Carson

yeah, that's a good sign. the DME unit controls the DME/fuel relay.

the AC voltage you read across the coil input sounds like you are getting some kind of pulse and the alarm is not the problem.

mine read less then 2 volts while cranking but I don't remember if it was as low as 1.3 volts.

2 questions:

when you crank it over, do you see the tach pulsing slightly?

from my 1st post yesterday (posted 04-21-2003 17:30) did you try "With the key on, you can 'rig' a wire from..." ?

Greg

i do not get any tach pull at all. . . , it was raining yesterday so i didnt get a chance to try the wire, didnt think rain would be very friendly with electricity. will try today if it clears up and keep ya posted.

Tom Carson

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Greg:
<strong>Clarks Garage says that the DME relay is only found in 85.5 and up. . . i have an 83, but it does say somehing about my fuel pump relay... </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">it looks like the 944 early series 'relay' only effects the fuel pump.

any spark yet?