outbackgeorgia

Brian,
Sounds like a good plan. If I were there I would connect a good battery + to the " jumper post" (which should now have a good cable to the battery). Connect the - to a good solid piece of the engine like the lift loop or a good bolt.
I am just adverse to crawling under a car if not necessary!
Your plan is fine too.
Dave

medipedicman

Thanks Dave. Crawling under the car is the only form of bonding that I have any more. I used to enjoy driving, pushing the car to the limits, cornering hard and fast. Now........ I just look at the underside, dreaming of what the car will be like when I have her back.

ps. I armor-all'd the interior the other day. No reason, I just wanted to sit in the cockpit for a while.

82Porsche928

Careful with the armor all! It has alcohol in it which will dry out and crack rubber/leather. I learned this from an old guy who owned a tire shop. Best thing for rubber is lemon pledge, and for leather, get furniture wipes that are good for antique furniture, and conditioner! Just my $.02

medipedicman

Battery reading 12.58

Reading at starter post 12.58

I am assuming that takes the lead from the battery positive post to the starter off the table as an issue. Please correct me if I am wrong.

The other battery has 12.77 but I didn't feel like swapping them for this experiment.

I will try to get down there tonight and install the battery from my DD and see if that leads to crank or helps clear up the cca issue with the two batteries that I have been using.

Thank you for all of your help. On one hand I would love to install the DD battery and have it crank right up. Problem solved, minimal $ to buy a new battery. But on the other hand I would feel kind of dumb chasing all of these issues and have it just be a tired battery.

Next step?? I guess I could pull the harness and check and/or redo all of the connections I have previously made. No $, but a huge PIA.

medipedicman

Another thought before pulling the harness back out..... Can I get a reading from the alternator with the key in the on position?

medipedicman

I have installed the battery from my DD. No start.
I have reinstalled the fully charged battery and hooked up a charger and used the 200 amp "Start" setting. No start.

Just to summarize:
18 months ago pulled the interior for complete replacement.
Replaced slave and master cylinder, replaced clutch discs.
Replaced transmission. Shorted starter and wiring while removing lower bell housing during this process.
Replaced ignition switch to try to remedy car constant running with out key.
Drive 5 minutes-no power-tow home
repair wiring between the starter and alternator (half-assed)
Drive 6 minutes-no power-tow home
replace 30" of wiring between the starter and alternator. New connectors. Used butt connectors, vice, heat shrink tubes, electrical tape and new sleeve/tube.
Starts right up. Idles well. Runs 7-10 minutes in driveway. Then cuts off with no fanfare at all.

Current situation: Key on, lights work fine, dash lights up, turn key to start and absolutely nothing happens. No sound, only the dimming of lights. Several tests to eliminate issues. Power strap from battery works as I get reading at the starter post. Used several batteries and a charger to eliminate battery.

My question is: What would cause a running car to shut down electronically after 10 minutes? I am assuming that I have addressed issues that caused the previous shut downs but at this point the only thing that has changed is I have quit test driving the car. The end result is no different.

Perplexed EDIT: After further research I am leaning towards ignition coil. I have a new old stock coil at the house and will swap it out and clean this weekend. If this fails to remedy my issue I will move to the distributor, wires and plugs.

medipedicman

Two weeks later....... I have had my starter rebuilt locally. They said it was toast. The only thing salvageable was the housing. I have installed the new starter and a new ignition coil. I was able to get her started today, albeit on lift bars. She cranked good and eventually started and idled well. Once the car warmed up (6-7 mins) and the rpms started to drop to normal levels, 30 seconds later compete shut down.

Does that sound like fuel starvation? Running off of the WUR until warm and then cut off? PLEASE keep in mind that I am not a mechanic and have no experience measuring fuel pressure and such.

The cutoff symptoms are identical to the previous issues described over the last two months EXCEPT now I can hop back in the car and crank it. The battery, starter and wiring repairs appear to be holding strong.

I can replace the fuel pump and filter fairly easily as I just did this on the 85 back in the fall while trouble shooting.

Any advice on actions to take prior to buying the fuel pump???

Thank you in advance

The Deputy

So.......when it stalls and you crank it over again...does it start right up?

Personally, I would not think it was the fuel pump. Normally, once an electric fuel pump is running, it stays running. Usually, if a fuel pump goes bad, it doesn't run. Sometimes you can give the fuel tank a good wack, while someone is turning it over and it will take off. The vibration is usually enough to give the fuel pump a "jump start" so to speak. You could check for voltage at the pump with a test-light or voltmeter. On most cars, you have voltage to the fuel pump for six or seven seconds when you first turn the key on, then you don't, unless the crank sensors acknowledges the engine turning over. If the engine is turning over or running, then the fuel pump will have a voltage to its electrical connection constantly.

Me, I'd lean more towards the fuel pump relay or something electrical (poor connection at fuse). And, if it doesn't start immediately after quitting, how long do you have to wait before it does?

If I remember correctly...you already had the starter tested before...and they said it was good. Then you re-did some wiring and it started, ran for a bit, then stalled and never restarted, until now. However, this stalling issue has been going on since the clutch replacement, correct?

Another thing...

I'm a little confused about your alternator connections, by the picture supplied early. Do you have every wire connected to the one large terminal? If so...I'm confused about which wire you are using the read the condition of your battery or excite the alternators windings?

Brian.

medipedicman

Good memory Brian, After it stalls it will crank but not start unless 1. The engine cools off or 2. I floor the gas.
The starter was tested by a parts store. First try did not work. He then cleaned the terminals and it worked the second time. After the most recent troubles the starter would not turn over at all. One of my buddies has a shop and recommended his guy for starters and alternators. They completely rebuilt the starter using all bosch parts.

The alternator pictured was an aftermarket unit that was replaced with stock.


The 1979 has two fuel pumps and a fuel accumulator. It also has a Warm Up Regulator. The WUR controls fuel pressure while warming up.?.?.? Once car warms up the car dies. Perhaps a Fuel Pressure Regulator.?.?.? Sometimes I get the terminology from different model years mixed up. I don't even know if the 79 has an FPR.

Thanks for your interest. Maybe I can get some more input and resolve this issue soon.

The Deputy

Interesting, about the two fuel pumps. I'm relatively new to these 928's and that is why my reply to your problem were so general in nature. These beast sure are weird in a lot of respects...lol

Anyhow, sounds like you may be onto something with the secondary fuel pump theory.

Good luck, and at least you have it turning over now. It can be a son-of-a-gun when multiple problems exists.

Brian.

outbackgeorgia

Brian,
Sounds like it is going very rich after warmup, based on your comment "I floor the gas" which would clear out a over rich "flooded" condition.
Dave

medipedicman

I am diving back in after six weeks of inaction. Spoke with Jim Doerr for advice, spoke with Roger about possible parts needed and ended up with additional solid advice.

I may have lots of love for these cars and all the tools needed to tinker with them and swap parts out etc......., but none of that adds up to mechanical knowledge. I used to be blissfully ignorant but now I am just plain ignorant.

Straycat (Bill) has agreed to come up to the house today and help me out and is bringing all of his diagnostic equipment to hopefully get me back on the road.

I hope to post a video this weekend of the results.

jwillman

just has something that sounds very similar.

Turned out to be a clogged catalytic converter.

Had been struggling with odd idling and hot start issues for a few months. Last week it got to the point where it started immediately but within a few minutes would not stay running at stop lights unless I kept the idle high with the gas pedal. On its own it would drop to near zero and engine would die. I could only start after that with the pedal to the floor. I also had some intermittent rattling like rocks in a can from under the shifter.

Got it on jacks and replicated the noise when banging on the CAT. Had it replaced even though we don't have emissions testing and problems are gone. I still need to fine tune AF mixture as I had jacked it all around trying to keep the car running with the bad CAT.

medipedicman

No video yet, but I am happy to say that she starts and drives fine. We traced a fault in the wiring between the 14 pin connecter and the starter. (I could have never done that by myself, thanks Bill).

As it turns out the previous wiring done between the starter and the alternator held fine. The problem was that after the wiring repairs had been made I routed the wiring harness incorrectly back to the starter. It was resting squarely on the exhaust header. Dumb mistake, but nothing time and more wiring couldn't fix.

Once the wiring was in place properly, Bill set the air/fuel mixture and the front idle screw to a much better setting. It sounds great and we took it for a two mile test drive with no issues. The new trans shifts perfectly and the synchros allow for smooth downshifts at reasonable RPM's.

Big victory and allows me to focus on some of the smaller known issues that I have wanted to take care of. It will also help to justify going ahead and tagging the car for use on the actual road. This thing has been torn apart for two years just taking up space. It has suddenly gone from a conversation piece to functional part of our household.

outbackgeorgia

OK,
Great news. Ready for SITM?
Dave