911 doesn't start! Advice please!

[Piko22]

Hey guys, i have been having this problem for a couple weeks now. I have a 1977 911S. It was working perfectly fine a couple weeks back but one day for some reason it didn't want to start. It's been sitting in the garage for about a month now and i have tried every trick in the book and still, no spark. I have replaced the CDI with a new one from Perma-tune, replaced all the spark plugs, replaced the rotor, replaced the breaker point, replaced the distributor cap and still no spark. I have been getting 11.98v from the CDI yet it still leaves me scratching my head. When i measure the pins from A to D on the CDI, on A +15 i get no voltage. When i measure the red wire of the Perma-tune wire i get 11.98v. The yellow wire of the perma-tune i get 11.98v as well. I have also measured the voltage that comes from the electric fuel pump in which i got 9.98v when i try to start the car. When i measure the voltage from the ignition switch and the breaker point i get 11.98v yet the car still doesn't start. I have also replaced the ignition coil when i installed the new CDI. When i measure the high tension from the distributor to the engine case there is still no spark. When i installed the new CDI from Perma-tune, i read the troubleshooting section thoroughly. I did all the bench checks of the ignition box and got all the numbers i was suppose to. I did the ground circuit test using a multimeter going from the battery to the chassi that goes back into the engine and the continuity is less than 0.5ohms. I cleaned all the grounds, fuses, fusable links, and most importantly the ground from the chassi to the CDI. I was hoping you guys can give me your inputs. This situation has become very frustrating and hopefully i can get some helpful information from you all. Thank you and i apologize for the inconvenience of reading this this entire essay.

[Walter_Middie]

Pik022,

Welcome to the best website - Porsche or otherwise.

What makes you think you have no spark? Have you connected a timing light to see if it flashes? I ask because these cars won’t start if the cold start valve doesn’t spray extra fuel into the intake.

Have you done the Telegraph Test on your CDI? You can’t measure voltage at pin “A”. Your CDI should be a 3 pin model originally. Perma-Doom does not have a good reputation here, so don’t assume the new CDI is any good. Although, I think the more recent Perma-Dooms are better. Do you still have the original Bosch unit?

The CDI has a +12V power input to the middle terminal “B”. Then the CDI has a +460V power output directly to the ignition coil on pin “A”. Finally, and very important is the CDI ground, this is usually a metal tab on the case. A way to remember is "B" for Battery, "C" for contact (the points), and "A" for ACHTUNG, don't electrocute yourself!

In general the Bosch 3pin CDI releases a spark every time you ground pin C. The wire to the distributor does the same thing: Every time the points inside the distributor close they ground the wire that runs to pin C of the CDI box. And that makes the box generate a spark.

To troubeshoot you need to check if the points close, and if the wire from the points to the CDI box shows continuity to GND when the points are closed.

Next connect a spare spark plug with a high-tension wire straight to the coil (grounding the threaded portion of the plug). This removes the rotor and cap from the equation. Once the points close it should produce a spark.

Once you have gotten to the point where a turning distributor produces sparks with a single spark plug connected to the coil you can add the distributor to the equation.

[Piko22]

Walter, thank you so much for your advice. I did all your test methods and found out there was a spark. I was reading other threads mentioning why the car doesn't start and have a strong feeling that it is a fuel problem. Although the other tests have been successful and have been a sigh of relief, the car still does not start. I found it weird that i am only getting 9.98v from the electric fuel pump when the book is telling me i should be getting 11.5 and above volts. If there is anyone else out there, including you walter, that can give me more advice to this problem i would be very grateful. Thank you again!

[ossiblue]

If you've confirmed spark, then try a simple fuel pump/fuel delivery test.

Remove the air cleaner and turn on the ignition switch. Go to the engine compartment and gently push up on the plunger inside the intake. You should hear the fuel pump begin to run and you should hear the injectors begin to "squeal" within a couple of seconds. If either one of those things fails to occur, there is a problem with the fuel delivery. If they both occur, immediately let go of the plunger (never hold it up for more than 5-10 seconds if you hear the "squeal") and try to start your engine. Report your results.

The fact you have only 9.98 volts at the fuel pump is a concern, but try the above test first. You may wish to pull the fuel pump relay, clean the contact and check the voltage again, or replace the relay temporarily with a black one and retest the voltage.

[Piko22]

Hey ossi, here is what i got after doing what everyone else has been advising me to do. I have checked for the spark using a timing light, and i have confirmed that there is a spark. I also did the spare spark plug test that Walter advised me to do. They both showed me that there was a spark. I also cleaned the contact point of the relay and checked the voltage in which i got normal numbers from the relay. I also temporarily replaced the relay with the black one and also got normal numbers. I did however make a mistake saying that i was only receiving 9.98v at the fuel pump when i really meant to say that i got 9.98v when i try to start the car, and not when it is actually on. My apologies for the confusion. I then continued to do the fuel delivery test in which i pressed the plunger and heard the "squeal" noise you mentioned. After all of this, the car still refuses to start. It has left me very frustrated and confused as to why my car will not start. If there are any more tricks anyone can tell me i would greatly appreciate it! Thank you again!

Here are my relay switch numbers that i got when i removed the relay:
Fuel Pressure Relay Socket Check
A. Ignition Switch Off
87A - no power
87- no power
86 - no power
85 - no power this should be a ground reading
30 - no power this should be a ground reading
B. Ignition On
87A - Has power
87 - no power
86 - has power
85 - no power this should have a ground reading
30 - no power this should have a ground reading
Fuel Relay Test
87A - 30 - Has continuity (normal closed)
87 - 30 - No continuity (normal open)
86 - 85 - has continuity (connected) When power is applied to these terminals, the coil is energized resulting 87A - 30 to open and 87 - 30 to close.

[timmy2]

Pull all 6 injectors and put them each in a baby jar. Have someone turn it over and make sure you are getting good fuel flow through each one. If you have spark and fuel then all that is left is compression....Assuming the spark is being delivered to the correct cylinder when fueled and compressed.
You didn't happen to pull the distributor and move it a tooth did you?
Pully at TDC and rotor centered on dist case mark for cylinder #1, wires run to correct cylinders ?

[Mia911]

Play with the fuses by the purmatune box....they sometime get corroded by sitting...just rub your fingers on them....

[T77911S]

no need to pull injectors yet.

remove the air filter, turn the key on, reach inside and lift the air sensor plate. you should hear a loud squeal from the injectors and feel resistance from the sensor plate as you lift it.
now go start the car. you may also have someone start it as you lift up on the sensor plate to help it start.

if it starts, check out the cold start circuit.

if you have gages, check control pressures. if you do not, remove the warm up regulator and check the inlet screen and clean it if it is dirty. this can raise your control pressures making it hard to start.

check for air leaks.

[boyt911sc]

Originally Posted by Piko22

Hey ossi, here is what i got after doing what everyone else has been advising me to do. I have checked for the spark using a timing light, and i have confirmed that there is a spark. I also did the spare spark plug test that Walter advised me to do. They both showed me that there was a spark. I also cleaned the contact point of the relay and checked the voltage in which i got normal numbers from the relay. I also temporarily replaced the relay with the black one and also got normal numbers. I did however make a mistake saying that i was only receiving 9.98v at the fuel pump when i really meant to say that i got 9.98v when i try to start the car, and not when it is actually on. My apologies for the confusion. I then continued to do the fuel delivery test in which i pressed the plunger and heard the "squeal" noise you mentioned. After all of this, the car still refuses to start. It has left me very frustrated and confused as to why my car will not start. If there are any more tricks anyone can tell me i would greatly appreciate it! Thank you again!

Here are my relay switch numbers that i got when i removed the relay:
Fuel Pressure Relay Socket Check
A. Ignition Switch Off
87A - no power
87- no power
86 - no power
85 - no power this should be a ground reading
30 - no power this should be a ground reading
B. Ignition On
87A - Has power
87 - no power
86 - has power
85 - no power this should have a ground reading
30 - no power this should have a ground reading
Fuel Relay Test
87A - 30 - Has continuity (normal closed)
87 - 30 - No continuity (normal open)
86 - 85 - has continuity (connected) When power is applied to these terminals, the coil is energized resulting 87A - 30 to open and 87 - 30 to close.

Piko22,

This was a very organized and systematic way of troubleshooting. I'm impressed!!!! The tests show that the FP relay is working. Test the fuel pressures (system, control, and residual). If you don't have a fuel pressure gauge kit handy, you could do the volumetric flow rate test to estimate the delivery fuel pressure. Goal: minimum flow rate @ 2 liter per minute.

If you are getting less 10 volts reading to the FP, this would be a problem. Are you familiar with the FP test run using 87a-30 jumper set-up (ignition switch @ ON)? Since you have confirmed the presence of ignition sparks during start, I would suggest to test the fuel pressures. If all the seven (7) injectors are spraying consistent mist pattern/s and still fails to start, I would bet you have a significant vacuum/air leak causing this LEAN condition during cold start.

What ever you decide to do, do not tinker the air mixture screw setting at this point!!!!!! You'll be making a bad situation worst. You could make the engine start/run without disturbing this setting. Keep us posted.

Tony

[Lorenfb]

"If you are getting less 10 volts reading to the FP, this would be a problem"

Not really! Remember, there are very cold conditions, e.g. in Europe, where the
temp can result in a battery voltage of 9 - 10 volts (even 8) while cranking and
the engine starts, i.e. the pump supplies fuel to both the injectors and the
cold start valve.

Read the many posts on how simple it is to isolate the no-start to fuel or ignition
and also check here for more info: Diagnostic

[ossiblue]

Originally Posted by boyt911sc

Piko22,

This was a very organized and systematic way of troubleshooting. I'm impressed!!!! The tests show that the FP relay is working. Test the fuel pressures (system, control, and residual). If you don't have a fuel pressure gauge kit handy, you could do the volumetric flow rate test to estimate the delivery fuel pressure. Goal: minimum flow rate @ 2 liter per minute.

If you are getting less 10 volts reading to the FP, this would be a problem. Are you familiar with the FP test run using 87a-30 jumper set-up (ignition switch @ ON)? Since you have confirmed the presence of ignition sparks during start, I would suggest to test the fuel pressures. If all the seven (7) injectors are spraying consistent mist pattern/s and still fails to start, I would bet you have a significant vacuum/air leak causing this LEAN condition during cold start.

What ever you decide to do, do not tinker the air mixture screw setting at this point!!!!!! You'll be making a bad situation worst. You could make the engine start/run without disturbing this setting. Keep us posted.

Tony

+1 on the highlighted, above.

If you've confirmed you have spark during start and the injectors are spraying, you should get the engine to fire even if the cold start valve is malfunctioning after you lift the plunger to prime the system and shoot fuel into the cylinders. The fact that your car wouldn't start even after hearing the injectors squeal, would lead me to believe in an extremely condition as Tony indicated, either from too high fuel pressure or massive air leak, or both. A sudden drop in outside temps will amplify starting problems in a system that is marginally lean to a point where no start is possible.

Do a pressure test and report results but double check that you do have spark when the starter is turning over the engine.

[Lorenfb]

"If you've confirmed you have spark during start and the injectors are spraying, you should get the engine to fire even if the cold start valve is malfunctioning after you lift the plunger to prime the system and shoot fuel into the cylinders."

Which assumes:

1. An adequate spark (> 10-15mm), and
2. Spark plugs/cylinders that aren't flooded.

Simple solution:

1. Pull the plugs and check for flooding.
2. Pull the fuel pump fuse and crank the engine without the plugs to remove any excess fuel.
3. Re-install the plugs without installing the fuel pump fuse.
4. Crank the engine while carefully spraying carb/brake cleaner into the intake.
5. If still no-start, then time to check for engine mechanical problem, e.g. distributor timing,
plug wire placement in the cap, & etc.

[davidva930]

Spark, Fuel, Compression. You have spark/fuel from what you`ve described.
This is what I do, I keep a new spark plug in my tool box, I remove the plug wire
from the engine, insert my loose plug and have someone turn the engine over. It does not need to be grounded to spark when engine is being turned over. Even in the day light you will see the arc and hear a repetitive ticking/zapping sound as the engine turns over. Do that on all six wires. If all of your wires are similar in brightness/arcing and sound then remove and replace the plugs. You did not do anything to change timing or confuse the location of the wires on the cap from what I gather. I have had New Porsche OEM wires not work as well as Bosch plugs that were defective. It can happen. It`s rare though. If you have good spark at all the end of all six wires, new plugs installed and have proper fuel delivery to each cylinder, there is no reason why your car will not start, backfire or run for a second or two unless your engine has a major loss of compression.

Are you interested in selling me your old CDI unit? I have a car sitting that needs one.

[Piko22]

Hey everyone! I just wanted to thank everyone for their advice they have given me. I have done every test in the book thanks to all of you! I just wanted you all to know that thanks to you guys my car is up and running again! I seriously cannot thank you guys enough for everything you've all done. Thank you for all the tests you suggested to me and many solutions that have helped me every step of the way. Thank you again! Godbless!

[timmy2]

The suspense is killing me...What was your cure?
What was it that you did (out of all of the ideas posted) to get it running?

[boyt911sc]

Originally Posted by timmy2

The suspense is killing me...What was your cure?
What was it that you did (out of all of the ideas posted) to get it running?

timmy2,

I got a phone call from Willie (aka Piko22) about the problem/s and asked him more detail information. A test was suggested to check the fuel pressures and it turned out that the FP was not delivering the required fuel pressures. The FP was running but not capable of delivering the correct flow rate. FP was replaced and the engine started right away based from the feed back I received after the test. CIS troubleshooting is easy and simple. Avoid guess-work and you'll know the culprit/s. End of story.

Tony

[ossiblue]

Originally Posted by boyt911sc

timmy2,

I got a phone call from Willie (aka Piko22) about the problem/s and asked him more detail information. A test was suggested to check the fuel pressures and it turned out that the FP was not delivering the required fuel pressures. The FP was running but not capable of delivering the correct flow rate. FP was replaced and the engine started right away based from the feed back I received after the test. CIS troubleshooting is easy and simple. Avoid guess-work and you'll know the culprit/s. End of story.

Tony

A special "Thanks" to Tony for being the surrogate OP!

The "Thank you" from Piko22 is appreciated but it is important to let all who read these threads know the results of our communal efforts or we would never learn a thing. From the simplest problem to the highly complex, it benefits the entire community to simply add one last post which pinpoints the solution.

Piko22, congratulations and welcome, again, to the best forum on the net.

[Walter_Middie]

Congratulations Piko22 - I'm glad you got it running, and I am very impressed with your systematic and detailed troubleshooting. You saved yourself lots of wasted money by not just replacing parts until it worked, and you probably learned a lot about your car.

And thank you Tony (boyt911sc) for helping out and providing the critical information needed.

[timmy2]

+100 thanks to Tony for answering for Piko22 and providing the solution for us all.
The threads that just stop with an "I got it!" don't help the rest of the community.

[boyt911sc]

This is a copy of the email Willie sent to me last week:

Tony,

Thank you so much for the advice you gave! It turns out, it really was like you said, the fuel pump. I went to a local shop that i have been going to for parts and ended up getting a brand new fuel pump. With that being said, after installing the new FP, and 6 weeks of endless stress, she finally started. It was such a sigh of relief! Without you saying we should use a CIS pressure test guage, i would have never been able to diagnose it the way we have. Thank you again for all the help and may I wish you happy holidays!! Attached is a picture of how i connected the pressure guage! And Thank you again!!

-Willie

--- On Sun, 11/20/11, tony donato wrote:

From: tony donato
Subject: RE: Hey it's Piko22!
To: papercutsz25@yahoo.com
Date: Sunday, November 20, 2011, 6:12 PM

Willie,

A typical CIS FP could deliver up to 100 psi. The system pressure is usually around 70 psi and the excess fuel is returned to the tank. So if the FP could not deliver 2 liters of fuel per minute, the FP is considered deficient and won't be able to deliver the correct fuel pressure.

You'll need a replacement fuel pump!!!!! If you decide to buy a used FP, ask the seller for a guarantee that it could deliver 2 liters per min. Otherwise, you might end up with another bad unit. Not until you could achieve a system pressure of 65-70 psi, the fuel delivery system is questionable. A running pump does not mean it could deliver the correct fuel pressure. Connecting a pressure gauge will tell you if the FP is delivering the CORRECT pressure.

Question for you:
Is the 21.5 psi fuel pressure control or system fuel pressure? How did you connect the pressure gauge with respect to the shut-off valve (if any). Do you have a picture of how the gauge is hook-up to the engine? This is very critical. If the gauge is not installed the correct way, you won't be able to measure the system pressure.

Tony