no spark

[quattrorunner]

I have a 77 911 and it just want start. It ran yesterday but wouldn't refire an hour later after running well. it was kinda slow to start the time before now, which i attributed it to worm start and a worm day (70 degree). Car has a permatune and a crane xr700. Any ideas what I should do first? I already swapped the rotor just to do something. Cap looks fine too. Thanks, BA

[Joe Bob]

Perma Tune Technical Support for Porsche 911

Read the trouble shooting tips at Permatune. If you truly have nos spark, it's likely the module.

[Gunter]

I'd go back to the 3-pin Bosch with maybe a Petronix pointless set-up in the distributor.

Too many people having trouble with Permatune.

[quattrorunner]

Well, I think I was wrong. I got it running with manipulation of the fuel pump fuse and it ran but not normal. Then it just started to deteriorate and would only idle but stumble and backfire on anything other than idle. I'm pretty sure it's the fuel pump. I'm going to get a fuel filter, pump, and whatever else I should replace there and try it out. I'm getting an 044 bosch pump and then add another when the 930 engine goes in in a couple months.

[Joe Bob]

CIS needs a specific fuel pressure to run correctly. You need gauges to fix it without tearing your hair out....

[quattrorunner]

I'd like to get some gauges. Does our host have some?

[Charlie V]

Perma tune box might be cooked.....

Before:



After:



Rewired from permatune box to coil and distributor:

[Gunter]

Your profile doesn't really show what you have.
Turbo?
What year?
Bosch 044 pump may be the wrong inlet size plus has no internal check valve.
Besides, how do you know which of the 2 pumps is good and which is NFG?
Before just guessing and buying parts, a fuel pressure check is in order.
And, how did this engine get a Permatune instead of Bosch?
A clear desription of what type/year your engine is and pictures would surely help.

Originally Posted by quattrorunner

Well, I think I was wrong. I got it running with manipulation of the fuel pump fuse and it ran but not normal. Then it just started to deteriorate and would only idle but stumble and backfire on anything other than idle. I'm pretty sure it's the fuel pump. I'm going to get a fuel filter, pump, and whatever else I should replace there and try it out. I'm getting an 044 bosch pump and then add another when the 930 engine goes in in a couple months.

[quattrorunner]

Sorry, this car is currently running the 77' 2.7 with cis and upgraded to the perma tune and crane xr700. I will have the 77 3.0 930 engine in this car soon. I want the ignition sorted first though. The 044 pumps should be applicable with the 930. One should be applicable for the 2.7 I think. I might be wrong. I do need the CIS gauges though. And maybe I should consider an ignition change?

[Gunter]

Permatune is a downgrade, IMHO.
Why do you think the 044 is compatible?
You'll need to check the sizes of inlet and outlet on your existing lines and verify if you have an external check valve. If not, you may need a pump with internal check valve like the 984.
But then you'll need a 2nd pump later anyway.

The 77 930 may have too much power for the small CV-axles on a '77 and/or even the existing transmission and clutch.
Definitelly a change to Bosch CDI.
Is a professional doing the turbo engine install and start-up?

[quattrorunner]

I'm a professional...........but not at wrenching. I'm a jeweler. I'll be doing it. The car had these things done when I got it. It's still new to me(2 months). Car has sc flares and 8 inch rears running 245 rubber. I know it's a lot of power for the trans/axles. I'm keeping it under 340hp or whatever it is. Of its too powerful, I can just lower the boost. I'm resolve to have replacement 915's hanging around. Mine is the mag 915/61. It's a good 915.

[Perma-Tune]

Hi Brando,

It looks like you have an original equipment Perma-Tune there.

Since you are having ignition and fuel pump problems the ground between the engine/transmission bolt to the body is suspect. Perform this check from our web site:

There are many ways to troubleshoot ground connections; here is a fast way to do it on a 911. Use a digital Ohm meter set to its most sensitive setting, an analogue meter is not sensitive enough to use this technique. To reduce the chance of misdiagnosis, tug on the wire being tested while watching the meter and perform the test in the order as follows: Stab the black lead of the meter directly into the lead of the battery minus terminal and connect the red lead to the chassis of the car, do not connect the red lead to the battery ground connection. The resistance should read less than 0.5 Ohms, any more than that indicates a bad connection. Move to the back of the car and connect the black lead of the meter to the chassis of the car and the red lead to the engine case, again the meter should read less than 0.5 Ohms. Disconnect the ground wire from the ignition box. Connect the black lead of the meter to the engine case and the red lead to the ignition box ground wire, again the meter should read less than 0.5 Ohms. Connect the black lead of the meter to the engine case and the red lead to the aluminum relay panel that the Perma-Tune is connected to. Again the meter should read less than 0.5 Ohms. Reconnect the ground wire to the ignition box.

WARNING: To avoid the possibility of fire, do not install additional ground wires on the vehicle and replace defective ground wires using only wires of the same gage.

[quattrorunner]

I'll check it out, BA

[Perma-Tune]

If you need help, feel free to call me.

631.909.1011

Lonnie

[quattrorunner]

Tonight I went out to do some trouble shooting. Mostly just fiddling. I unplugged each sparkplug wire from the plugs while running to see I'd any were not firing. They all seemed to be firing but I started to feel it run more smoothly as I moved things around. Then I took it for a ride. It stumbled and popped till 3000rpm them went like hell from 3k on. Pretty consistently. I still don't have the gauges and didn't check ground issues yet. But I'm thinking tune up. I feel I need wires at least. Next thing I'll do is check the plugs and order wires. I got the duel 044 pumps and an msd to throw at the new powerplant later. Mostly I need some gauges and some other tools that I'll need for the cis. I can't believe I don't have that already.