Starting Issues with 79 SC-Need advice

[Blk95993]

Fellas-

Trying to help a friend identify a starting issue he is having with his 79 SC. Today his car started acting up on the way over to my house. Basically he first noticed a smell coming from the trunk (acid). 5 minutes later the windshield wipers freaked out on him, and at the same time the engine shut off. After leaving him on the road for dead, the car continued to not turn over. The battery was scorching hot to the touch-may have been the culprit of the smell. I picked him up and headed to walmart. We installed the new battery, car turned over, could smell fuel (almost like it may have flooded), but would not fire up..all electrical components worked (lights, sunroof, radio, etc).

Suggestions appreciated on helping isolate the problem. Hoping that it may be a relay or something mildly electrical.

Additionally, in the past when he has parked his car on a hill, it usually takes him a couple of times to get the car started..the fuel pump does not whine and I believe has been replaced recently.

[Flieger]

My guess would be a bad ground somewhere in an electrical wire carrying a significant portion of the car's battery power. Check the terminals for corrosion and make sure all of the brown wires you can find are securely connected to clean metal like the tub at their screw ends. These are the ground wires.

It is a little hard to tell from your description but the bad ground may have led to the battery shorting out after grounding through the windshield wiper circuit. This would cause a hot battery and some hydrogen, maybe a little spilled acid.

Does the car run strong otherwise, when it is not shutting off? Or does it sputter, surg, and want to die?

[Forte]

Electrical problem is always fun to diagnose. I suspect you have a short from the positive side to the ground. The short may be a direct short, like an exposed wire or device/component going bad. I suggest you take an ohm meter to check the all the circuits...probably from the fuse box.

What the voltage level at the battery if everything is turned off?
What's the level when the ignition key is turned to accessory (Engine not running), but leave everything turned off (like radio, wiper, head lights, etc)?
You can also check the current flow with an AMP meter for the above two conditions. Be sure you have a hi-amp meter (10 AMP should work if you're not cranking the engine or running any of accessory devices.)
Check all of the fuses too, there might be one that's too high and passing too much current.
It's also possible that your alternator (gone bad) is overcharging your battery. An scope would be helpful here.

Good luck,
Jim

[Blk95993]

Thanks for the response. Couple of questions:

1.) The car was running fine up until yesterday's event. Did not sputter, surg, or want to die before yesterday. Once the windsheild wipers started freaking out, everything died from there. Perhaps this is the indicator for the bad ground? Should I start here?

2.) The old battery, as you discribed, had a little over flow of acid and was hot to the touch (you can still smell the pungent odor). My friend loaded up his trunk with parts, maybe something nuged something out of place? Is this possible with all carpet and protective covers in tact? I know, anything is possible. Maybe its was just a coencidence...

3.) Can anyone send some pics of all the brown ground wires I should be checking? Will most be in the trunk, or are any on the under-side (I know of the ground strap on the tranny)? Sorry, I hate dealing with electrical issues and am not comfortable. Very challenged in this area. Also, please recommend a meter to use to check the circuits.

4.) I removed the old battery and replaced it with a new one, so there is no issues with corrosion, etc. Everything electrical turns on (radio, wipers, windows, etc), but I can not get the car to fire up..with the new battery, the car is getting juice to the starter; however, it will not fire up. Just turns over and over and over. I tried again this AM, still no luck.

5.) Fuse panel & relays, any pointers on what to look for on how to identify a problem?

6.) In my SC, I could hear my fuel pump whine, in his I hear nothing, but we do smell the distinct scent of fuel after several starting attempts..

I found this post, which shares similar problems minus the electrical event with the windsheild wipers:

fuel problem...I think!!!

Thanks again for all the help. Curry

[Gunter]

You'll need an electrical diagram; I suggest to get the Bentley SC Repair Manual and study.
Very difficult from a distance to diagnose; since it turns over without firing, it could be fuel or ignition.
Battery shortening is no good and may have done some damage to the Bosch CDI module.
The Bentley will tell you how to check the 6-pin module and the fuel pump and shows you where the ground connections are.
If the car hasn't received a lot of TLC, or a good tune-up for a while, it's not easy to pin-point problems and a long-distance quick-fix is not very likely.
To check for fuel, remove the airfilter, ignition ON, reach into the airbox and lift the air sensor plate briefly. You should hear the injectors squeeling.
To check for a spark on the plugs do the standard test: Use an extra plug, remove the ignition wire from any plug and connect it to the extra plug, ignition ON, have someone crank the engine while you ground the plug on the engine case and watch for a nice spark best observed in a dark corner of the garage.
You might get sapped, so, don't do it if your'e not comfortable with this.

[stormcrow]

Sounds as if the battery is being overcharged. Check the alternator to see if that's whats causing the problem.

A hot battery with the smell of acid boiling out indicates one thing - overcharging

A hot battery without the smell of acid boiling out indicates one thing - battery + terminal shorted to ground causing so much of a current draw it will get the battery hot.

Steve

"A Porsche does more then just go fast in a straight line"

[Blk95993]

How bout a hot battery with a possessed windshield wiper?

Even if the alternator was bad, wouldnt the car start based off the juice from the new battery I installed?


Thanks for the help.

[Blk95993]

Gunter-

Good points, where is the Bosch CDI module? Additionally, if the car was starting correctly without any issues previous to the event that happened yesterday, would a short in a ground or overcharging the battery have caused this sort of an effect on the ignition system?

[Gunter]

Originally Posted by Blk95993

Gunter-

Good points, where is the Bosch CDI module? Additionally, if the car was starting correctly without any issues previous to the event that happened yesterday, would a short in a ground or overcharging the battery have caused this sort of an effect on the ignition system?

Do you have the Bentley or are planning to get one?
It's a must-have for any SC owner.

Do the tests for spark and fuel as suggested above, then report back and let us know the results.

[Blk95993]

I don't have a bently for an SC. Just 101 projects from our fearless leader...


Just checked pelican, saw the diagram for the CDI unit-this makes sense that there may be an issue with this module, as the car does not whine when the ignition is turned. Is there anyway that I can test it- or is the spark plug exercise the test?

If it is the CDI unit is a result of the shorted battery, what do I need to do to ensure that the battery does not short again, which result in another CDI failure?

[Gunter]

Not all modules whine.
The spark test confirms that the CDI works.
The fuel test confirms that the pump works.

Do both tests and let us know.

[Blk95993]

Gunter and the forum-

We called pelican this week regards the CDI. We were considering purchasing a unit and returning in the event the CDI was not the issue, as I dont have much time to work on the car. The salesman that we spoke to stated that he has had 10+ SC's and never once had an issue with the CDI unit. Additionally, he mentioned that Pelican rarely ever sells CDI units. He talked us out of buying anything for now, rather requested that we check the relays first.

The salesman at pelican suggested that we pull the red relay, tap it a couple of times, re-install, and then see if she fires up.

I pulled the red relay and one of the prongs looks a little bent. Is there another black relay that I can borrow from the bank to swap in place of the red relay? If so, which one?

I have not had a chance to pull a plug and run the suggested above test. That will be next in the event that the relay does not work.

Additionally, I checked all the brown ground wires running to the nut in the front of the tub. Everything was secure and did not look exposed.

The car does not make any whining noise with the key turned before inj. My instict supports Gunters above regards to the CDI unit. Would the red relay have an effect on the CDI unit or is does the CDI unit draw power directly from the battery?

[Blk95993]

Still looking to see if I can borrow/swap one of the black relay in place of the red one. If so, which one?? Want to check the relay off the list.

[Gunter]

Good advise on NOT buying a new CDI module.
Some observations:
Sounds like you have very little time to fix this; not good.
Fixing stuff on the fly, especially with limited knowledge, doesn't really work.

You need the Bentley to do it right because it explains so nicely, with pictures, how to test the pump and check for spark.
Ask your friend to invest in the Bentley; it also shows you the relays and what they do.
All black relays have the same configuration and can be interchanged.

Why don't you do the test I suggested above by reaching into the airbox, lift the Air Sensor Plate with ignition ON and listen for the squeel from the injectors?

People can only help you if you follow their advise; going all over the place and wild guessing is not going to do it.

Trouble shooting is a process of elimination; you find the components that work and go on to the next step.

If you don't want to do it, how can we help?
Do the suggested steps or ask your friend to take it to a shop.

Best wishes.

[Formerly Steve Wilkinson]

subscribed.

[Blk95993]

Injectors squeelin' like a pig on the Chatuga River...

Spark plug test next...will have to wait until I can get the car on some jacks. Maybe next weekend's project.

Anyways, with the injectors working, is it safe to assume that the relay and fuel pump be checked off or eliminated from the list? Sorry guys, you're gonna have to be patient with me...I can't stand electrical trouble shooting...just trying to help a brother from another mother.

More to come and thanks for keeping me in a straight line.

I have asked my friend to get a bently. I believe he has purchased..

[Gunter]

Yes, squeeling means that the pump is running.
Don't let them squeel too long or else the cylinders are flooded.

No need to take a plug out, just get an extra one, disconnect any ignition wire that's convenient and ground the extra plug as described in the Bentley.
Pull the red relay to disconnect the pump when checking for spark; you don't want to flood the engine.
When ready, have someone crank while you look for the spark on the properly grounded plug.
A dark place is best to see the spark.
Make sure nothing gets caught when the engine cranks.
Also, the ignition is high Voltage; if you get zapped it means it's working.

As preventive electrical maintenance, buy some dielectric grease, then pull each relay and grease the pins.
Do the same with the 6-pin Bosch CDI module.
Pull the connector-plug off the bottom of the module, get some grease into the 6 connectors and reinstall.
Read up on some of the above when the Bentley arrives.
If you don't get a spark, we'll do some more.

[jtfreels]

Not really hijacking as I'm having apparently the same problem.
Last night the car started up and ran (I hate this random aspect of the problem), for about a minute and then died, no sputter just cut off.
So I tried the fuel check... fuel pump runs, get the injector squeal etc.
Then hooked up an old spark plug, cranked again, no spark. I want to try this again, as honestly I hate getting zapped so I'm not sure I grounded it well enough. But I'm going to go on the no spark theory.
Gunther provides some hints on pulling relays, using dielectric grease etc. So assuming all this gets done and still no spark, what is next in line to check?

Thanks and good luck.

Jay

[Blk95993]

Fellas-

Ran Gunther's spark plug test....no sparks....(grounded on engine mount and cross member).

I have pulled the CDI unit and am going to send off to Pelican for a rebuilt exchange.

Or is there another step I need to address?

Regards the Alternator, if it is overcharging the battery, wouldn't the voltage regulator need replacing vs. the entire Alt. unit?


Thanks again for all the help! Curry

[Blk95993]

Also, I have cranked this thing a couple of times prior to this post and Gunter's advice. If the car is flooded, is there anyway I can unflood the car?? Or will it unflood itself? Sorry, seems like a stupied question, but last time a checked...this is what a forum is all about. Smart people helping people like me....