78 SC Starting issues

rpo420 · 04-09-2017, 02:28 PM

I have a 1978 SC. the car was running well for a while, and then it would die and not run.. then run again, and on and off. I first replaced the fuel filter.. and the old one was clogged, you couldnt even blow air through it.. changed that and she ran great for a few weeks.. So i say to myself, you need Air, you need fuel and you need spark.

On Fuel. I bought the bosch book on CIS. Tested all my pressures. Control 74psi. Cold System 14 psi. Plunger moves freely. Blew out return line to the Tank. WUR has power to it when the car is turning over, but I didnt check the WUR and time it to change system pressure, but i pulled all the injectors and when you lift the arm the fuel pump runs and and the injectors have a nice spray pattern and each bottom had the same amount of fuel.. i was amazed how much fuel comes out in like 20 seconds.. So i say to myself you have to have enough fuel to start the car.. but still no start. Also before this all happened it was running really nice. it would cut out and come back sometimes while still rolling..

Ignition. So i think I have no spark.. I have a permatune CD box, put it in many years ago after stock CDI went bad. I have ready many call it permadoom. I called Lonnie and who is the guy in Long island who is the company guy who i actually bought it from but his voice mail box has not been set up and he didnt answer my e mails on how to actually test the Permatue.. Coil is american made permatune too. So today i took off the coil and bought a multimeter. I am not genius with electronics to note. When i looked inside the big hole of the coil i saw some blue type residue in there, cleaned it out with a dremil, cleaned all contacts to the connecting wire to the distributor as well. Distributer is immaculate inside as well. Tested the coil, outside 2 poles pos and neg i get .6 ohm.. i read thats what its supposed to be. When i test the ground and the inside circle i get 10ohms.. tech article said 600ohms.. tried to start it and she started for maybe 7 seconds. my excitement lasted so short! uggghhh....would have been too easy that just to clean a wire could have done this.. so i want to ask someone who knows 2 things.
1) i still have a spark if i take the wire coming off the coil and put it by a ground.
So can you still have a spark off the coil if the Permatue CDI box went bad?

2) Is the coil not producing a hot enough spark?

3) does anyone know if the permatune can be tested and if so how do i do it?

I need some wisdom here, and i will methodically go through anything that you think i should and will post shots and be quick about it.

any help would be greatly appreciated.

rpo420 · 04-09-2017, 02:30 PM

i also did get an e mail from Lonnie at Permatune and i am sending the unit and coil out tomorrow for them to test it.

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by rpo420

Tested all my pressures. Control 74psi. Cold System 14 psi.

Tell us how you arrived at these pressures. If 74psi is control pressure, you have a blockage at or downstream of the WUR.

If you mean system pressure, it seems high. Edit: just checked, it's not high if system pressure. It's at the high end of the ok range.

14 psi could pass as cold control pressure. A bit low, but car should run with that number.

Do you have the factory graph of pressures?

rpo420 · 04-09-2017, 04:31 PM

Thanks for the response.. When i run the guage from the top of the fuel distributor to the WUR, with the valve on the guage on the WUR side i get 70psi to maybe 74psi with the valve closed. I thought that was the control pressure. i ready that System pressure is with the guage opened, and that was around 14psi.. maybe a tad shy of that. I agree that it should be sufficient pressure to start the car. So my real concern at this point is to find out if my spark is hot enough. I listed info on that in my first post. Since i wrote this i did get an e mail from Lonnie at Permatune to send my box out with the coil tomorrow for testing. i still dont understand how i could have some type of spark, maybe its not hot enough though, from the coil and not get the car running. Maybe as i said its not hot enough, and or you can have spark without the permatune working properly?

Porscher · Porscher's Garage

I also have a 78sc and also ran in to some problems, both running and start problems. I have a thread about it, we replaced the accumulator and renovated the WUR and the thing ran exactly like it should after that.

boyt911sc · boyt911sc's Garage

PM sent.

Tony

rpo420 · 04-13-2017, 01:03 PM

Update, sent the Permatune CD box and coil to Lonnie.. he got back to me that the coil had no oil in it. i have been trying to fix this intermittent problem for over a year, and always thought it had to be fuel because i had spark. So he said no oil in the coil, and I said i am always working on the car and there would have to be some sign of leakage.. the coil looked brand new. it was a permatune coil. I just cant believe that oil could have leaked out and and i never saw it.. i say impossible.. further more since the coil died so did the Permatune CD box.. so now i need new stuff. At least I now know.. needless to say permatune will never be in the car again. Thanks for the help guys.

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by rpo420

I thought that was the control pressure. i ready that System pressure is with the guage opened, and that was around 14psi.. maybe a tad shy of that. I agree that it should be sufficient pressure to start the car.

All good. Gauge open allows the fuel to run the full circuit through the control pressure regulator (WUR). Shut off with FP running = system pressure.

Do you have the pressure graph for the 78SC? If not, I can find it for you.

If control pressure needs tweaking, Tony (boyt911sc) is a wiz at dialing them back in.

zelrik911 · zelrik911's Garage

Quote:

Originally Posted by rpo420

it was a permatune coil. I just cant believe that oil could have leaked out and and i never saw it.. i say impossible.. further more since the coil died so did the Permatune CD box.. so now i need new stuff. At least I now know.. needless to say permatune will never be in the car again. Thanks for the help guys.

Oil will gradually leak out of coils - so slowly that you wont notice unless you feel it & its slippery.
I used a MSD Steetfire CDI in my SC WITH a 'Blaster' coil that can run upside down.
Its been great - I got lots of advice from researching this forum. I recommend this as an effective & economical solution.

T77911S · 04-14-2017, 04:16 AM

why do you have 2 threads on the same subject!!!

rpo420 · 04-14-2017, 07:29 AM

Thats Exactly what i am doing.. thanks for the heads up!

rpo420 · 04-14-2017, 07:32 AM

I posted it once and i went to find it and it wasnt there.. so i did it again. sorry about that T77911S. Should i delete it? I find this forum a bit weird to navigate.. sorry about that.

T77911S · 04-14-2017, 08:58 AM

you can go to the "user cp" at the top and that will show the threads that you are currently active that have a response to them.
you can also look under subscribed threads.

also, if you just want to subscribe to a thread you can click on the "thread tools" and select subscribe. that way you don't have to clutter up a thread with "subd" like so many do.

there is also an option for email notification when someone replies to a thread you are subscribed to.

your subscribed threads will also have a check mark over on the right.

this is a great site. not a lot of advertising like a lot of forums. the only ad is the banner at the top.
its too bad its there, we support this business quite well so I don't see the need for the ad.

rpo420 · 04-14-2017, 10:34 AM

thanks T77911s for the help.. i dont post adds.. never. just keeping the 911 happy.

Dmitry at Pelican Parts · 04-14-2017, 10:44 AM

In case you need additional info to troubleshoot for starter system, please take a look at the link below!

Porsche 911 Starter System Troubleshooting | 911 (1965-89) - 930 Turbo (1975-89) | Pelican Parts DIY Maintenance Article

-Dmitry

Zacman · 04-14-2017, 10:48 AM

You might check the wiring to the distributor. There is a ground the goes around the green signal wire. If the green wire has insulation problems the ground may contact, and loss of spark.

rpo420 · 04-14-2017, 11:06 AM

Guys,
thanks for all the advice, after testing the Coil and not liking the numbers i sent the Permatune CD box and coil back to Lonnie who is in ohio now.. PM me if you need the address.. At any rate he called me yesterday and said my coil had no oil in it and it must have leaked out. I say impossible. no way i wouldnt have noticed that. no no way! no residue, nothing.. totally clean coil, unless it can evaporate i dont buy it. He followed that since the coil went it cooked the CD box too.. i dont know much about the inners of them, so i said ok.. Just ordered a MSD for it. I will have it next week and report back.. Also going to redo all the ground straps as well just in case. i will report back as soon as i hear that fab speed exhaust ringing again!

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by rpo420

Just ordered a MSD for it.

Your nightmares are coming to a rapid close.

A guy named Steve here told me in 2003 to buy myself insurance and get the MSD box/coil. I was asking his thoughts after my 2nd legacy silver P-Tune box bit the dust.

He stated to become "anal retentive" on the grounds with those serrated washers that dig into metal.

I placed my box under the drivers seat. Took me two weekends with family stuff and traveling through the week. Newer boxes are smaller than the 6AL. Engine bay mount is a little easier.

12+ years of no issues.

Side note, Lonnie spent a boat load of time with me on the phone in the early 90's. I got a lot of time for him.

P-Tunes website has lots of information as well.

rpo420 · 04-14-2017, 01:44 PM

Bob thanks for the note.. yea man it will be nice to hear her gurgle.. the weather is getting nice!! i will report back when i get it all dialed.

Bob Kontak · Bob Kontak's Garage

You know, it may have just been my coil that cooked both boxes. If it can snuff the box, if bad, how does a regular guy know? I replaced the coil with the MSD change out in the way back. As noted, no probs. You did the right thing sending it to him.

Lonnie said that the old boxes are mighty when all is well. (Some guys are still going strong after decades of use. From the 1970's.) But when there is an electrical anomaly they don't fare well.

Keep us posted.