1980 SC Newbie - Help Needed!
 

Hello everyone, after a long time lurking I finally took the air cooled plunge and purchased a 1980 911 SC Targa with roughly 121k miles. Would love your expertise in diagnosing some problems with the car. I took delivery of the car yesterday and these are the problems I am already having.. http://forums.pelicanparts.com/support/smileys/sad2.gif

Problem #1. Car starts right up when cold and idles for about 3-4 min then dies. I can start it back up then it dies again in about 15-30 seconds. I can keep it running after this by giving it a little gas and keeping the rpms up.

Problem# 2. After the car has started to warm up while driving it will die when when I come to a stop or the car is in neutral for more than a couple seconds. Starts right up and I can continue on my way.

Problem #3. I drove car yesterday around the neighborhood for about 7 min then let it idle in front of my house for another 5 min. Shut it off and came back out 15 min later and the car would not start. Also seemed like it was cranking a little slow.

I pushed the car in the garage, put it on a trickle charge for an hour, let the engine cool down then it started again but problem #1 surfaced again..

Here is what I tested:
It seemed odd the engine was turning slowly during problem #3 because the battery is only 3 days old so I tested to see if it could be the alternator. Battery was at 12.7v with key off and 12.7v with car running. Could this be attributed to an alternator? I also have a suspicion a Fuel Accumulator could be to blame but that just from reading on here.


Other items to note:
The car got out of the shop 5 days ago from the Previous Owner and this is what was done..
1. Battery and ground cable
2. New distributor cap, rotor, spark plugs and ignition wires
3. Replace belts
4. Replace broken vacuum line @ throttle body
4. Shop set enrichment and idle @ shop (idles at 900 rpm)


**Finally if any of you are from the St Pete, Fl area I would love to meet you and learn all I can about these cars. Free beer is always available to anyone that wants to swing by and check it out. :D

Hi - suggest to get acquainted with CIS by thoroughly reading the below thread - no quick answers to your various issues. Buy a set of gauges immediately, and get to work.

https://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies.html

Good luck!

Oh, and pics of your new purchase are imperative.

Jason

Thanks Jason! I will read up some more

Here is a picture of the new to me Targa

Attachment 10493


Sent from my iPhone using Tapatalk

^^^ Nice ! ^^^

Nice SC!

Seems to me that if it just got out of the shop 5 days ago, maybe you could take the car back to them and see if they will do some diagnostics for free. 5 days is really short time from the shop, no matter that it changed hands in the meantime. It doesn't sound like you have done anything to it but drive it.

Craig

Welcome to the club !

The same voltage when running indicates the alternator is not charging. I would fix that first. Was it working prior ?

If you can keep it running by giving it gas, it may be a vacuum leak. That has happened to me several times and it always turned out to be a vac leak. Also since they replaced a vac line on the throttle body, you may want to start there. Or bring it back to whoever replace the line.

Nice!!!

Wish I could, Unfortunately the shop was in South Carolina and the car is now located in Florida. Yep the only thing I have done is drive it about .5 miles around a circle in my neighborhood.

No clue if it was working prior, I took ownership of the car yesterday. It might have been bad before and thats why they replaced the battery thinking that was the culprit. I am going to try testing the voltage above 2500 RPM tonight just to double check.

I wish I could take it back but the shop was in SC and im now in FL. I will look into the vac lines. That does seem to make sense.

Kills me as I just took delivery of the car yesterday and it was supposed to be all sorted and ready to go upon arrival, but I guess thats air cooled ownership from what everyone is telling me.

Charge issue could be the ground strap under the car by the transmission.
To check if it's a grounding issue, grab you jumper cables and connect one end of the black wire to the fan shroud. Connect the other end of the black wire to the chassis somewhere that's metal. Check your voltage with the motor running before and after the black wire is connected to the chassis.
It's a very common problem the ground strap gets too much resistance and battery won't charge as a result. Just one of many things you can check for free.
Good luck!

I wouldn't sweat the problems you have listed.

It's an old car, probably seldom driven by the PO hence will have accumulated its share of minor issues !

Once you get the few annoyances sorted these old tubs will give an Accord a run for the money as to reliability.

Check your grounds and then replace the alternator if no improvement.

It does not have to be the squillion amp $600 version. FLAPS (Friendly Local Auto Parts Store) sell them for a couple hundred bucks.

These cars like juice. I would nail this first.

Agree with the prior posts...Check basic stuff before you move onto to bigger ticket items...I agree to check the tightening the ground strap, but first make sure that there is a metal to metal connection at the strap to the chassis. Sometimes paint or debris gets in the way. I would disconnect and clean and reconnect with a new clean washer.

Check the battery connections, make sure they are tight. Sometimes very old battery cable connectors may appear tight but there is still room to tighten further. I had this happen to me for fear i'd snap the clamp,...it was just too loose and caused intermittent issues..Also, make sure the ground end at the battery is connected to a solid chassis ground. Like the ground strap at the transmission, make sure it is metal to metal. Use a new washer.

On the vacuum leak, check hoses for connection, but I have seen shops use the wrong size hoses in some instances that were too large and created a leak...so check that the hoses are not only in-place & connected, but are tight.

When the car is idling, are you getting a steady 900-950RPM? Idle may be set too low.

If there are still low voltage readings at idle, may need a new alternator.
Good luck...let us know what you find out and how issues were ultimately resolved.

Ryoder,

Congrats! Great looking car.

A few thoughts...

Problem #1: The time is interesting. From cold start 3-4 minutes is the approximate amount of time that it takes to transition from cold running to warm (normal) operation. Could be that it is running too rich or too lean at that point and that is the reason for it stalling. This is just a hunch based on your description. Need to gather some more facts before drawing a conclusion. When initially started did the engine idle at 1200-1400 rpms and then slowly settle to ~950?

Problem 2: Consistant with theory that warmed up engine AFR is not right. Sudden stalls could be CDI box but I wouldn’t go there until ruling out fuel/air issues.

Problem 3: Again, consistent with incorrect AFR. Could be a component but best to be methodical and not jump to random part swapping.

I see you’re on the path of checking alternator/battery/groud strap. Suggest you conclude those tests first. Next step would be to get a set of fuel pressure gauges and do the tests in CIS for Dummies thread.

A quick and easy test is once the car is warmed up and idling in the driveway, take the oil fill cap off. You should hear rpms change. If not you have a good sized vac leak somewhere.

Good luck!

Nice car and you have plenty of correct advise above to start with.
I just wanted to welcome you to the "Yes honey; I spent $$,$$$.$$ for a car that needs work" club.

I will check the ground strap tonight, thanks!

Looking forward to sorting out the small stuff and getting on the road!

Perfect, I will look into the grounds then move to alternator. Thanks for the recommendation on the alternator as well.

Yea its steady at 900-950 at idle, it isnt much higher while warming up though. I would have to see the idle process of one thats really dialed in to see how far off mine is from normal..

This is all great advice. I will also be checking the oil fill cap tonight to see if I hear a change in RPM. In addition I have been reading through your CIS for dummies thread.. Verrry insightful.

Fortunately she is fully on board with my hobbies and all the money they seem to suck up! I think she is just as excited as I am for our first longer drive along the beach.

I cannot help write this note since this is a new purchase.

If you bought this from a Dealer, I would insist on a credit to cover the cost that you ultimately spend to get this car right. I would insist on this even if you bought the car "AS IS, WHERE IS"...A Dealer has got to stand behind the sale. If he/she tells you to go pound sand, I'd write to the State's BBB and post a nasty note about the Dealer on Google. The entire world will see it when they search that Seller's name in the future....Just sayin'.....

If this was a private purchase, I think you also have recourse to the Seller. He should honor the cost of the repair. He should understand the issues you're facing and want to help right them. Admittedly you have less recourse with a Private Seller than a Dealer. If he/she tells you to go pound sand, you have less leverage.

In addition, I'd call the shop where the latest most recent work was done. Look over their invoice. Talk to the shop owner. I realize it is 2 States away, but you can also contact that State's BBB and write a nasty rating on Google if you get no satisfaction or worse, they refuse to even talk with you. That would tell me volumes...Perhaps they will tell you that they told the Seller of these issues and the Seller ignored them.

Sorry. I think there is no excuse for selling a car that has issues UNLESS THESE WERE EXPLAINED AND YOU KNEW THIS WHEN YOU BOUGHT IT...Really have no patience for Seller's who just stick you with their problem, unless of course, you knew what you were buying. From your opening post, it sure sounds like a surprise to you.

Caveat Emptor.....

Sorry, I don’t see thing the way you do. I agree the seller/shop/dealer should help make things right but ultimately the responsibility is on the buyer.

Yes, agree, it's ultimately the Buyer who needs to investigate and know what they are buying...But not if the issues were known and not revealed and especially this is so in the case of a Dealer who wants to keep his/her reputation.

If this was a dealer I do agree with you about reaching out to see if they can help resolve the issue.

In my case I purchased this from a private seller.. i believe he is also active on this forum but I do not know his username. He and I have been in contact since I took delivery, and he has been helpful but there has not been any offer to help money wise to resolve the issues.

To answer your question about what is normal idle process, think of it this way. Any engine goes through several states. Cranking. Cold start. Warm start. Idle. Cruise. Wide open throttle.

When you're troubleshooting CIS, think about what state you're having the problem in. What is supposed to be happening in that state? If you understand that, the reason for the tests in the Bentley and the CIS thread make a lot more sense.

On a cold start, the WUR and the AAR add more air and fuel because you need a richer mixture for a cold engine. The two components together act like a choke. What that means for us is that once you start the car, rpms should rise to ~1200-1400. As the engine temp increases, the rpms will gradually come back down to normal idle at +/- 950 rpm. It usually takes 2-4 minutes and depends on the outside ambient air temp.

Once the engine is warmed up, the WUR and the AAR have done their cold start job and the AFR is leaned out to normal.

New CIS car owner.........
 

Ryoder,

Welcome to the CIS club. Since you already bought the car and own it now, the previous owner has been relieved of his responsibility to this car. Have you tried to contact the PO? Even if you did, I doubt things will change. The car has some minor problems and could be fixed by any DIYer like you or me. And if you enjoy working on your car and like to learn about CIS troubleshooting, this the right forum to start. Or would you rather send it to a shop and just pay them for their services?

On the brighter side, you own a very nice looking red car and I bet you have been staring at this car with a big grin on your face. This is like the feeling you had when you first met your partner. Love at first sight.

Let’s get back to business. If I were in your shoes, I will have the fuel pressures tested and check for unmetered air. If you don’t know where to begin and get started, you are not alone. We all started like you and with the help from the other members, you will find your way home.

Tony

Cool, I had a 944 that color - quintessential 80's Porsche :D

Don't start the car until you're ready to drive it, then drive away - keep motor spinning comfortably (light load) and RPMs reasonable until the oil is up to temp (or at least has some heat in it). Says that in the owner's handbook.

Idling from cold; when the oil is at its thickest - giving the lowest amount of oil flow. Factory explicitly says not to do that.

Prolonged hot idle isn't ideal either; air flow from the fan is directly related to RPM.

Listen to those who know CIS and work through it methodically; it'll work out..

Idle speed shouldn't have been set with the motor cold, but you never know... Once you get charging sorted out, I'd raise the idle so it at least keeps running while you figure things out.

Should get right around 14V at the battery with motor running, just like any other 12V vehicle. Sounds like alternator or voltage regulator not working, or something disturbed and not (re-)connected that should be. Possibly when the shop was working on it.

Does the alternator warning light (in the oil temp/pressure combo gauge) come on when you turn the key to Run, before you hit start?

Is it a bulb - e.g. hasn't been replaced with an LED?

That bulb - and the resistance it provides, in both directions - is part of the alternator exciter circuit; if that bulb blows/replaced with an LED/not connected, there will be no output from the alternator.

If the warning light does come on, it should go out immediately the motor starts. If it doesn't, not charging.

Fan belt was replaced? Check the tension and/or the # of shims fitted; if the belt is slipping, no charge & insufficient airflow from the fan....

Not charging/low voltage won't help anything; CDI box needs good voltage, and many of the CIS doo-dads have heating coils too...

Fuel accumulator keeps pressure up in the injector lines after the motor & pump stops running; to prevent the fuel boiling from heat soak after stopping.

The usual symptom of that being defective (unless it's leaking everywhere) is that hot re-starts - e.g. drive for an hour, leave car for 20 minutes, go to leave again - are problematic. It takes at least 15 minutes of driving the car to get the motor up to temperature, BTW.

It's fairly unusual for these to fail. Most often if they do, they simply don't hold pressure, or it bleeds off too fast. Can't check residual system pressure without a set of CIS gauges though...

Cold idle should be higher, then drop as it warms up and whatever air valves are fitted do whatever they do.



If it were me, I'd probably sort the charging out, tweak up the cold idle 200- RPM and take it for a drive to see what it does when its up to temperature with the correct voltage...

Good luck!

If it is actually a bad alternator it can be rebuilt locally by an auto, Marine electrical shop, they can test it on the bench rebuild it and you know it will fit.

Hi!
I got my 1980 Targa from a private dealer too in 2006.
It sounds me curious to read that a shop has "set enrichment and idle": In twelve years I never set anyting in my K-Jetronic, nor in the four Audi 5 cyllinders equipped with the same ignition. I turn the key on and it fires.
I would check fuel filter + accumulator and the fuel pump relay (in the fuse box) looking for bad contacts. Tirvin gave you a good suggestion on removing the oil cap to see if the idle changes.
No changes means vacuum leaks

http://forums.pelicanparts.com/uploa...1549031045.JPG

Gently enlarge the fins with a blade and spray deoxy to have a good contact in all five pins

Vapor lock in CIS.......
 

Spuggy,

I agree with most of the things you mentioned in your original post but disagree with this one. The vapor lock in a CIS is a myth that came about from carbureted systems that operate at very low system pressure (5 psi. or less). A typical normally aspirated CIS has a system pressure between 65~75 psi. and the 930/turbo has a system pressure between 95~105 psi. As you can see the disparity in the system pressures between a CIS and a carbureted system.

Secondly, gasoline is an incompressible fluid. No amount of vapor lock in the fuel line could prevent the “fluid” from being expelled at 70 psi. system pressure (turbo @ 100 psi.). Have you actually seen or witnessed a vapor lock in a CIS?

If vapor lock is actually occurring in a CIS, then why did the engineers switch from the plastic fuel lines to the metal fuel lines in later models? The metal fuel lines have a much greater heat transfer capacity than the plastic materials.

I did some testing and experiments applying heat to the metal fuel line in a CIS to create a “vapor lock” many years ago to investigate it. This was a very risky experiment that involved heating a combustible and flammable liquid like gasoline. My objective was to create a condition (vapor lock) that would prevent the liquid from being injected. At a much warmer conditions, heating the fuel line under test was able to deliver fuel once the FD plunger was raised or elevated from its rest point.

If someone could safely demonstrate a vapor lock exists in a CIS, I will be a convert. I will be forever grateful if someone could prove or demonstrate the existence of vapor lock in a CIS. This is a technical discussion in the Technical Forum and nothing personal. Thanks.

Tony

I don't agree the seller has any responsibility here - we are talking about a nearly 40 year old car, not a CPO camry. The most I would ask from the seller is to give me any information on what recent changes/behaviour they had seen. You're wasting mental energy trying to get anything from a previous owner except advice and information. Better to suck it up and put the energy and time into making it right. Chances are the PO sold it because they couldn't fix it. CIS cars need special care if they aren't running right and not many shops or owners have the knowledge or patience to do it.

Have you done the 'oil cap off at idle' check? This is a very simple test for gross vacuum leaks. If it doesn't drop at idle then you have a big vacuum leak.

Having said that, I seem to recall every person that has problems with hot starting or difficulties transitioning from cold run to warm run need to pay attention to the WUR. But you can also unplug/replug the AAV and AAR and see if that makes a difference. Best thing to do is start reading because you need to start developing knowledge on CIS or a check writing habit.

So this weekend I was able to get the car warmed up to the point it would drive. The cold start issue is still the main problem. I also took off the oil cap and the car died immediately which I guess means there are no significant vacuum leaks.

Here is a video of the car about 1 min after starting. It stalled shortly after I ended the video.

https://youtu.be/bi39NC6KCTI

Basic tests.........
 

Ryoder,

Buy or borrow a CIS pressure gauge kit and check your cold, warm, residual, and system fuel pressures. This is a mandatory tool for any fuel injection system troubleshooting. Without one, you are wasting your time and effort trying to fix your problem/s.

Test for sources of unmetered air. Until you have confirmed and verified the absence of unmetered air, I will bet my money that you have vacuum leaks. A smoke test will take a few mins. to evaluate the integrity of your vacuum system. Keep us posted.

Tony

Your engine sounds like something... messy.
A 911 cold engine has to fire without touching the throttle

I read the list of the works done by the PO

I wondered why those particular jobs were made at the time of selling the vehicle. I'd never done this, unless the car was unused for a long time even in the wet. This is not something to do to a KJetronic.

Consider the possibility of injectors stall. Removing it is very simple and washing it wit ultrasounds can tell you a lot on their condition.

https://get.google.com/albumarchive/106799704896439228817/album/AF1QipOyu_dfGEAlFMuaRFxLR3YeUClly-suFD-vppzG

Have a look too to airbox straps: A slack airbox changes the balance air/fuel

Thanks for all your suggestions so far.. I love the car but it is quite frustrating to have it stall every time the car is in neutral the first 10 min of driving..

The Previous Owner said he knew this was an issue but thought it was addressed. Oh well I am moving forward. I bought the car and will not continue to bug him..

I purchased a fuel pressure tester kit and once that arrives I plan on going through and checking everything. I think I am going to ask a local PP member to come over and assist since he said he has been through this before.

Another (probably dumb) question:
If the air box was cracked would the car always run rough like this or would the problem go away when warmed up like mine is?

Interesting thread

I take my 83 to a very good shop and i ve mentioned the possibility of vacuum leaks based on the oil cap test..but they poo poo d that notion? I ve happen to have the car at the shop now for valve work and will again repeat my request re vacuum leaks since the cis will be out and easy to test. My car runs and idles great (in high temp the idle may climb 100 rpm over time..but nothing like hunting..just gradual

When i had a charging issue..measured voltage at battery with and without engine running and i discovered that...

1 I need to be at 1500 RPM to get charger excited which produces 13.6 or so at the battery
2 The idiot light on the dial needs to be correct in order for the exciter to get the juice needed to be excited and start charging (replaced LED with standard bulb..all fixed)

Just my thoughts..any comments on the oil cap situation? The garage seemed to think this was not ALL years this would ocur...but i can go back and insist on full test for leaks and then have them pull cap to see after corrections are made?

A few posts back "TIRWIN" raises the possibility that it might be the CDI box. Indeed, the start/die/restart is a common symptom of one that is just barely hanging on by the skin of its teeth. This is a typical situation when the discharge capacitor inside has degraded to the point of providing barely enough energy to make spark. At that point, everything comes into play. Battery voltage, heat, leaning fuel mixture, and run-time all can be factors. Normally, a good CDI box will tolerate low battery voltage (down to 8V or so) just fine, but not when they are degraded. 12.7V should be fine, however I'm surprised you measured that low with the engine running. Normally, revving up the engine to, say 2000rpm or so, should result in a charge voltage of around 13.5 - 14V. So the charging system may also be part of this problem.

Admittedly, I do have a dog in this hunt, since I routinely repair & service those boxes. But like TIRWIN said, rule out the other stuff first to see if the problem points in the ignition direction. If it turns out you suspect your CDI unit is flaky, I can lend you a temporary test unit to plug in so you can determine if that is the problem or not. At least that way you will have scratched another possible suspect off the list. And, if it turns out your box needs repair, Pelican offers my service.

Can't help you with your other issues but the car dying upon removing the oil cap typically means the oil tank breather hose restrictor is missing. You need to be able to take the oil cap off while at idle so you can check the oil level.

Here's a thread about it.

http://forums.pelicanparts.com/porsche-911-technical-forum/674216-oil-breather-hose-restrictor-idle-issue-update.html

My first post! Congrats on the new car. I just picked up a 74 a couple weeks ago but it’s not nearly as nice as your car.
I have been playing with CIS for years on Rabbits. Here’s a couple links that I found helpful. You are in the right place I found this forum searching CIS issues and the knowledge here is incredible. Getting that pressure gauge is the first step.

https://youtu.be/a4fJAfXYxWk

The Bad Habit Rabbit - Volkswagen Rabbit Page - Fuel Pressure Gauge

The 1980s didn't come with these.

Are you sure? The thread I linked was for an 81. I have an 82 and it required one. And the OP has an 80 that dies upon removal of the oil cap.

^^^ 80 has the "restrictor", a screen, on the angle connector at the back of the "pope's hat".

I know because I ordered one for my oil line and it doesn't fit....

http://forums.pelicanparts.com/uploa...1549647927.png

http://forums.pelicanparts.com/uploa...1549647927.png