weak current on coil

juVius · 06-17-2006, 08:11 PM

hello all. I've been trying to tackle the no spark problem on my 84 944. Been reading all the "no spark" posts and have tried everything. Been through 3 dme's, 3 dme relays, 5 reference/speed sensors, 3 coils, bypassed the alarm, checked the timing belt, but still no spark. And now, for some reason the power going to the coil is very weak. It barely lights the test light. I've went through the 5 minute check by Socal. Today I ordered a new ignition switch. Am i missing something?

also, how can i tell if the flywheel setscrew is there and ok?

I'm about to give up, but i'd rather be driving.

SoCal Driver · SoCal Driver's Garage

Clean the positive terminal connections. All of them. Clean the main ground to the engine-chassis. If any of these terminals are aftermarket tinned crip on and not a decent copper lug crimped and soldered change them. You should have battery voltage at the black wire at the coil (this is terminal 15 on the coil) with the key on. You will have some voltage on terminal 1 that goes to the DME.

What year and model is your car? The 'S' models have an ignition trigger module that can flake out.

juVius · 06-18-2006, 10:19 AM

I'll clean them now. it's an 84 porsche 944.

juVius · 06-18-2006, 11:08 AM

well i got the battery cables cleaned off. they were pretty dirty and had some rust on em, but i won't know if that helped until i get my ignition switch in from the autoparts store. The old one fell apart when i took it out.

juVius · 06-19-2006, 07:48 AM

I guess while i'm waiting on my ignition switch to come in, does anyone have an answere to this question?

how can i tell if the flywheel setscrew is there and ok?

thanks in advance,
steve

SoCal Driver · SoCal Driver's Garage

Take the cover off of the bottom of the bell housing and slowly lever the flywheel around.

juVius · 06-20-2006, 06:46 AM

Thanks again SoCal. I'm back in DC now so i'll have to wait til this weekend to get to look at it. It's parked in my parents garage until i get it running.

juVius · 06-20-2006, 06:48 AM

oh.. by the way. is that the same area i will see the flywheel pin, or is it the same thing?

SoCal Driver · SoCal Driver's Garage

Some where after the 83's Porsche added a third sensor to the pair for factory/dealer testing. This third sensor, closest to the engine, looks at two pins. So you will find three pins on later flywheels and only one pin on early flywheels where there are just two sensors.

As you have an electrical problem with the switch I suggest getting that replaced (instructions on www.clarks-garage.com or www.frwilk.com) first. Then completing the five minute test plan. Don't try to fix what ain't broken.

juVius · 06-21-2006, 02:50 AM

thanks again for the good info

juVius · 06-22-2006, 02:48 AM

I'm goin crazy with this car. My dad put on the new ignition switch yesterday and still the power to the coil is very faint. What would you suggest I do? I would really like to get this car running before I lose the rest of my hair.

thanks in advance.

juVius · 06-22-2006, 07:47 AM

somebody, please help me.....

SoCal Driver · SoCal Driver's Garage

Did you clean all of the wires at the battery? Is the battery charged? Is the battery grounded? How are you testing the voltage at the coil? Should be from the terminal to ground.

Run a jumper from the battery positive to terminal 15 (black wire) on the coil and see if you get spark during cranking.

Could be the connectors for the sensors. Could be the sensors are out of adjustment of have a load of metal filings on their tips. Could be the DME is dying.

juVius · 06-22-2006, 09:30 AM

I did clean the battery terminals and the ground where entering the chassy, the battery is charged. My dad looked at the current on the coil with both a test light and a multimeter. the speed/reference sensors are both new and it adjusted it with the .8mm washer trick. and i have three dme's i've been switching between ( i know at least one is good, it was taken out of a running car that was wrecked.), 3 dme relays and i've switched different combos between them. as far as the jumper, last weekend my dad and i did that, but made no spark. i had swapped the sensor connectors back and forth but no change. this weekend i'm going to check all the ground on the car and trace wires as best i can. i've read a lot of electrical/no start posts and tried following all the advise/knowledge. I don't know what else to do.

SoCal Driver · SoCal Driver's Garage

Try the jumper from the battery positive to the #15 terminal on the coil. If you get spark you will know that the circuit between the coil and the ignition switch is open (not connecting). If you still don't get spark directly out of the coil then this circuit needs to be checked at all points. Note that the power for this circuit comes from the ten gauge wires coming off of the batteries positive terminal.

juVius · 06-23-2006, 07:11 PM

got it running, but still no power to coil. I did the jumper from the battery to coil. at first it didn't work, so i started looking at the fuse panel and relays. i noticed that when i jiggled the fuse box it made a click. it was pretty messy down there so i took some pictures and disasembled, cleaned out and reasembled. then i tried the jump from the battery to the coil again.. it started.

i followed the coil wires as far as i could but didn't see any problems. i looked at the wires from the ignition switch as far as i could see and saw no problems there. I do know that when i first got the car and we did the 5 minute check there was power at the coil and i don't know what happened for it to stop. i checked all the grounds on the car today and cleaned them up.

any ideas on where i should start on getting this coil its power?

SoCal Driver · SoCal Driver's Garage

You've covered most of the wiring. May have a loose connection at the fuse/relay board. It's definately a mass of wires behind it. Comes stock that way so don't think that the previous owner did it.

If you turn the key on and the fresh air blower works and the gauges work then the power is getting to the #15 circuit/buss and should be getting to the coil. There are several square multi pin connectors on the fire wall. Might be worth it to take them apart and clean the pins and receivers.

juVius · 06-23-2006, 08:17 PM

yup, fresh air blower and the guages work, i'll have a look at the multi pin connectores on the fire wall. This probable don't apply here, but i noticed on the dme relay diagram there is something labeled ignition, if that particular set was bad would that prevent power to the coil?
but i'll check on the connectors tomorrow morning and keep ya updated. i really appreciate your help here. you don't know how happy i was to finally here it running.

juVius · 06-24-2006, 04:36 PM

I was able to trace the coil wire to the fuse box. it turns out that the fuse box itself is the problem. the problem is at the large white connector in the back. the pins that it plugs into on the fuse box are loose and lose connection. Now it starts as long as i apply extra pressure on that connection to keep it still. Next weekend i'm gonna hit the junkyard and grab another fuse box. thanks for all your help Socal. Woohoo i got to drive it down the road for the first time....

SoCal Driver · SoCal Driver's Garage

Don't forget to change the timing belt.