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My problem finally solved!


Alex

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Hi to all!

 

I just thought that I would pass this on to all older (pre 964) 911 owners.....I learned a valuable lesson for sure!

 

For some 4-5 years now, I have been having ongoing issues with my '80 SC 3.0L. Above 3500RPM I would get a lot of hesitation and then bucking if I would try to drive the car "hard". I was never able to get her anywhere near redline. I was also getting a fair amount of exhaust backfire. My now former mechanic couldn't figure it out either!

 

I found out that the problem was that above 3500RPM, my AFR would drop like a stone....into the low 9.0's for sure. So, after doing much research (PelicanParts forums, etc.) I thought that it must be fuel supply/injection or ignition related....I then started "digging"...replacing some components, falsely adjusting others.... all to no avail!....I was getting more and more PO'd in the meantime!....I was just about ready to "launch her off a cliff somewhere"! I decided to post one more plea for help on the PelicanParts 911 technical forum...this time in CAPITAL LETTERS!

 

A "pelican" by the name of Lonewolf responded and after I had explained, in detail, what was going on he told me that it was probably my battery. I thought how could it possibly be the battery, as the car starts up fine and when the vehicle is in storage I've always got it on a trickle charger? The battery was only (duh!) about 4-5 years old. So I did some tests on it as he recommended and, sure enough, it wasn't able to keep a descent enough charge! So, essentially, I was getting a weak spark, which, inturn caused a low AFR reading as I was getting incomplete combustion. This would also explain the exhaust backfire, as there would be unburnt fuel in the exhaust.

 

I installed a new battery and BANG, what a difference! The old girl is back! I'll also be doing some tests on the alternator as well, just to rule that out. Lonewolf seems to think that trickle chargers, over time, reduce the amperage output of a battery, however there is no real way of checking that. So, imagine that! After all my trials, tribulations, mechanic consults, and, of course, $$$... it was all due to a....stooooooopid battery....$165.00!!!

 

So if any of you are having intermittent, what appear to be, "ignition" issues....check your battery first!!!

 

From now on, my $0.02 worth on to you!

 

Alex

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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Guest RJ911SC

Alex,

Nice to hear you found your fix, while my 79 SC has not shown any of your problems, I did however change to an Optima battery, and really noticed the cranking power on startup, huge difference, I did this more so for the Alpine system I put in the car, but really noticed the difference when starting the car. I absolutely agree that boards like Pelican, Rennlist, are absolutely Valuable, Even some of the Canadian Porsche Club forums, are great for help from local enthusiasts who work on their own vehicles and enjoy passing on helpful tips and information.

I personally would like to see more of the local members of this board do the same, having said that I should put my "money where my mouth is" so to speak, if the members have no problems I will start by posting all my projects needed to get my 79 SC up and running again please see my post of "CV Joint Failure Carnage" I have already done some of the work, replaced E Brake, heater box cables, SS Brake lines, but still need to replace Bell Crank linkage, paint brake calipers, new shift bushings, short shift kit, CV axels re build and install, all new interior lighting, and a long list of other things.

 

I guess what I am saying is it would be nice to have what Pelican, and Rennlist have in way of help more on a local level, everyone post what the are working on! It helps us all! Ok for what that is worth, that’s my 2 cents worth, wait one more thing, the "What to Sell" forum on this site is excellent, I have bought several parts from members in Calgary at very reasonable pricing, even free, Well done!, Once I have finished all my projects I hope to return the favor, my garage is getting full, and will need to clear it out soon.

 

Share your knowledge!!

 

Rob

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Rob:

 

Sounds great! By all means, do keep us informed by posting some pictures of your upcoming upgrade projects! I posted some last year when I performed my Carrera tensioner upgrade...and all went well...actually it was fun. I am planning on the following in the near future:

(1) Bleeding brakes

(2) Short shift kit and Seine gate install

(3) Replace the steering wheel

(4) Upgrade pedals and floor mats

(5) Turbo tie rods

(6) maybe doing an engine drop next fall/winter to fix a couple of small oil leaks, etc.

 

Anything else I should do?

 

Alex

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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Rob:

 

Which Optima battery did you buy....what are the specs? Btw, have you checked your AFRs under load? It's a great way to see "where things are at" with tuning and possibly fine-tuning your vehicle. I bought an Innovate LM-2 for this purpose and it has served me well. It helped diagnose my ongoing problem. Im still "tweaking" things but you're welcome to borrow it once I'm done.

 

Alex

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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Thanks Brodie!

 

But, as many of us can attest to.....older 911s are definitely a "work in progess"....it really never ends!

 

Cheers!

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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Alex, great report and finding's.

In my previous life, I sold many batteries do to the use of trickle chargers. Cheap trickle chargers are giving a constant current and don't jolt the battery to life. With a cheap trickle charger the battery sulfates and shortens out the battery plates.

With a good charger and the odd jolt of current the sulfate deposit is blown of the plates and it will keep the battery charged to proper voltage.

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Fritz, thanks for the info.....I may be guilty of that as I am using a Motomaster unit from CT. Can you recommend a good brand that I should switch to?

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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Hi Alex

 

Glad you got to the root of your problem. More often than not, trouble shooting involves clearing your mind of the complex assumptions and starting with fundamentals. Your scenario is good evidence of this philosophy. My earlier suggestion of fouled waste gate is an example of the former.

 

Look forward to seeing you and your Targa at one of the drives this summer.

 

cheers!

 

Rick

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Guest RJ911SC
Rob:

 

Which Optima battery did you buy....what are the specs? Btw, have you checked your AFRs under load? It's a great way to see "where things are at" with tuning and possibly fine-tuning your vehicle. I bought an Innovate LM-2 for this purpose and it has served me well. It helped diagnose my ongoing problem. Im still "tweaking" things but you're welcome to borrow it once I'm done.

 

Alex

 

I went with the Optima Red Top 34/78 1000 amps of crank at 32F Walmart had a sale on the Red Tops at 40% off, i little bit of an upgrade compaired to the old interstate i originally had.

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Guest RJ911SC
Rob:

 

Sounds great! By all means, do keep us informed by posting some pictures of your upcoming upgrade projects! I posted some last year when I performed my Carrera tensioner upgrade...and all went well...actually it was fun. I am planning on the following in the near future:

(1) Bleeding brakes

(2) Short shift kit and Seine gate install

(3) Replace the steering wheel

(4) Upgrade pedals and floor mats

(5) Turbo tie rods

(6) maybe doing an engine drop next fall/winter to fix a couple of small oil leaks, etc.

 

Anything else I should do?

 

Alex

If your doing the Turbo Tie Rod kits, i would do all the front end bushings at the same time,

Please post your Wheel change, its one thing i want to do down the raod, Also when you get a round to your engine drop and you need a hand, willing to help

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