Need help getting it started
 

Car turns over, I have spark, but car wont start.

I have a 1977 911S I am trying to turn into a track car. Electrical was hacked pretty bad so I am basically starting over with a Painless panel. I thought I had reconnected all the critical wires to power, but since the car wont start, I think I am forgetting something.

In the rear of the car I have done a number of Wayne projects - swapped the 5 blade for an 11 blade fan, changed out the CDI for the MSD units. I checked for spark per the MSD instructions, and have a good strong spark.

Thoughts?

Brad

What fuel system is currently on the car?

Do you have adequate fuel pressure?

Ronnie - Not sure I can answer your question without more information.

Part of the wiring problem was that the red lead in the fuel pump relay had been soldered to the black lead and was running without a relay. I cleaned up the wiring and got the correct (red) relay. In starting with the relay, I dont hear the fuel pump running (might be why they spliced the two?). So I pulled the relay and jumpered between the red and black ports in the relay. Now with starting, I can hear the fuel pump running, but it still wont start.

Brad

Where is the best place to check for fuel flow, fuel pressure?

If still running CIS, you will need fuel pressure gauges. Giving it a shot of ether/kwik start will confirm spark and lack of fuel.....if it coughs and tries to start.....you HAVE spark and a fuel issue.

The fuel rails have ports to hook up gauges.

Do you smell Fuel when you try to start, after attempt jump to the tail pipe to check for fuel smell.

I bet it is the fuel pump.

Porsche is a new platform for me. I switched over from Fords a couple of years ago.

Draco - thats a good idea. I am thinking I didnt smell any gas after trying to start, although I can hear the fuel pump running when I jumper the relay.

I have some concern about some other weird add on (read not 1977 original on a original 1977 engine) - connects to an extra box - wires run to an sensor in the exhaust, and some sort of valve in the fuel ine.

Fuel pump relay socket test.........
 

Brad,

Go check your FP relay socket. Search for DKLever48's thread re:FP relay. I posted a detail test how to check the FP relay socket's terminals. The FP may be not running because it is not getting power at the right time. Or the relay is bad (??). This might help you get started. Keep us posted.

Tony

google Jim CIS primer and you can read how to do the fuel pressure checks (need CIS pressure test kit). you will be able to solve the problem with a test kit.

Tony, I will look for the thread and test it. I think there was something wrong with it as they fused the red and black leads and the relay was missing. I separated the red and black leads, reinsulated them independently and got the red relay from Pelican parts. The FP does not run on the relay. When I pull the relay and jumper red to black, it runs.

Schumicat - will look for the post and test.

Thanks all!

Troubleshooting........
 

Brad,

It would be very helpful if your feedback to us is more definitive. For example: What terminal numbers are involve for the red and black wires? I don't know where these wires are connected in your set-up and I would be just guessing to give you an advise without positively knowing where these wires are connected.

The wiring connections for the FP relay socket is very simple and if you have any question about it, just ask. But do read the post I suggested to give you a better perspective of the troubleshooting. Once we have established that the wiring connections for the socket is correct, the rest of the troubleshooting is easy and simple. Let's get this thing resolve first. Keep us posted.

Tony

I found the test instructions to DKLever and tested mine. I got the same results as DKLever as noted below:


1). Pull out the FP relay and do the test (ignition switch @ OFF position) for the individual terminal at the socket:
87...........no power - yes
87a.........no power - yes
86...........no power (87a 86 are bridged) - yes
85...........no power (should be grounded at this point) - yes
30...........no power (has ground contact?) - yes

2). Turn ignition switch @ ON position (not start):
87............no power - yes
87a..........has power - yes
86...........has power - yes
85...........no power, presence of ground contact - yes
30...........no power, presence of ground contact - yes

3). Next, insert the FP relay into the socket and turn the ignition SW @ ON position (not start):

I partially inserted the relay so I could check the terminals
87...........has power - No power
87a.........no power - Has power
86...........no power - Has power
85...........should have ground contact - Ok
30...........no power but exhibit ground contact. - Ok

With the FP relay in place and the key turned to Start, the FP does not run. If I pull the relay and jumper 87a to 30, I can hear the FP running when i turn the key to start. The car turns over, but will not start.

Brad

Reading more, I felt better about the results I got:

"I made a big mistake in giving you the wrong information. Test#3 should have the same results as test #2. Surprised nobody noticed the blunder!!!!!

For test#3: FP relay installed, ignition SW @ RUN.
87...........no power
87a.........has power
86...........has power
85...........should have ground
30...........no power

Test I. Remove the air filter and lift the AFS plate to activate the FP for a second or two (no longer). Ignition SW @ RUN."

I removed the air filter, moved the key to run, and lifted up on the AFS. Low and behold I heard the FP run and fuel squirting!

I went back and tried to start the car. Again, it turns over but wont start. We read more on the DKLever thread, but wanted to post findings.

Brad

FP relay test.........
 

Brad,

When I was reading your post #13, I could not believe what I was reading and it didn't make sense unless something was very wrong in the test procedure. Anyway, the following post #14 explained the reason for it. Your tests showed that the FP relay is working.

This is just the beginning, you need to determine your fuel pressures. The control fuel pressure might be too high for cold start. We don't know. Or you have a significant air/vacuum leak affecting the fuel mixture. Before going any further investigation, confirm that you have ignition spark. Test will tell you if the ignition spark is present during cranking of the starter.

When was the last time this engine ran? Keep us posted.

Tony

Tony, all,

The car hasnt ran for awhile (months) as I deal with some electrical issues. It is garaged here in Northern California so cold really isnt an issue. Previously it ran fine.

I swapped out the CDI for the MSD unit, to include the tach adapter and the Blaster MSD coil. Using the MSD instructions, I was able to verify a spark with the white wire.

I had to disconnect the old fuse panel, and I have been in the process of cleaning up and reconnecting a hacked up system to a Painless fuse box. I am thinking I have not connected a key wire, but am at a loss as to what it might be.

Car is a 1977 911S with the stock motor and trans.

Brad

Any ideas on the best way to get fuel pressures?

Brad

As I mentioned....CIS gauges......a kwik way to see if your pressure is too low or a failing fuel pump is to use ether directly into the intake. If it coughs and tries to start....it's a fuel pressure issue.

ASSUMING you have spark at the plugs.....

There are MANY threads on this board discussing fuel pressure diagnosis for CIS.....all involve using gauges.

Get a pressure tester from pelican.
http://forums.pelicanparts.com/uploa...1335033236.jpg

I had a similar problem, for me it was several problems that needed to be sorted. My guess the problem is a broken vacuum line. Here is my troubleshooting if you are interested, it is several pages.

http://forums.pelicanparts.com/porsche-911-technical-forum/664950-1976-911s-garage-find-road-4.html#post6702074

I can hear the fuel pump running, but it still wont start.http://www.rragam.info/h.jpg

Fuel PRESSURE and spark.....got that? If not it won't run....

I have spark. I will test the fuel pressure but am pretty sure that isnt the issue. I have a wire off the fusebox somewhere that I think is causing this.

I had a problem that my pump was working but the return back to the tank wasn't. The amount of fuel that moves the the system is MUCH bigger than the fuel that is used by the engine, most fuel goes through the pump through the system and back into the fuel tank.

There are quite a number of places where this could screw up, having the fuel pressures are a good place to start.

Spark plus (adequate) fuel plus air....what does a loose wire do?