No Start

[bob thibodeuax]

Gentlemen, I am hoping you'll can help me with my problem. I am rebuilding a 1972 911T. Just put engine in with a MSD 6AL. Only thing done to internal of engine is a mechanic installed new chain tensioners. I removed MFI cleaned it up and installed back making sure that instructions where followed in setting the timing with TDC.
Here is the situation I have now: Plenty fuel from pump, good spark from coil when following MSD directions, NO SPARK AT PLUGS My problem I think is with the distributor, but have new plug wires, new cap, new points.
CANNOT GET ENGINE TO FIRE AT ALL EVEN USING STARTED FLUID.
Any suggestions on where I should check?
Thank you in advance for your help.

[Dmitry at Pelican Parts]

Hey Bob....check out the tech articles below from our site. It'll definitely help you troubleshoot the issue; which you're correct about sounding like a distributor issue. Best of luck and let us know what you find.

Porsche 911/914 Distributor Trouble Overview | 1965-1989 | Pelican Parts DIY Maitenance Article

Porsche 911 Setting Distributor Static Timing | 911 (1965-89) - 930 Turbo (1975-89) | Pelican Parts DIY Maintenance Article


-Dmitry

[David E. Clark]

Assuming you have correct voltage at the coil but are not getting spark at the plug you have a problem with your rotor or distributor cap or your wires are improperly seated. It's extremely unlikely that all six wires are bad.

I know you said your cap and rotor are new so I'd start by making double sure you have installed the correct cap and rotor. If you are certain you've got the correct cap and rotor, check the cap for hairline cracks. Make sure the cap and rotor are properly seated. Finally, confirm that the ground wire at the vacuum advance plate is connected.

Let us know if any of this helps.

[911obgyn]

A quick check for spark or where the spark stops is with an inductive timing light, use it on the coil wire to see if you have spark from the coil, then test each lead to spark plugs. Make sure the wires are firmly clipped onto spark plugs and you have the little screw on tips on the plugs.

[bob thibodeuax]

Thanks everyone for info. David Clark you said to make sure distributor is grounded.Question do I need a ground on distributor with a MSD system?

[David E. Clark]

Originally Posted by bob thibodeuax

Thanks everyone for info. David Clark you said to make sure distributor is grounded.Question do I need a ground on distributor with a MSD system?

Yes! This could very well explain your symptoms. The ground wire grounding the advance plate to the distributor body gets brittle with age and heat and sometimes breaks. When this happens the car will normally shut down because no (or very weak) spark is leaving the distributor cap to the plugs. If the wire on your distributor plate is not connected or broken, that would definitely explain your no spark symptoms. Good luck.

P.S. The ground wire is “tack welded” at both ends and is very difficult to fix properly at home. The best fix is to replace the advance place and ground wire with new parts.

P.P.S. Here's a picture of the ground wire.

[bob thibodeuax]

David, my ground inside distributor is OK. Does the distributor housing need to be grounded on outside or is it grounded when setting in its place?

[David E. Clark]

Originally Posted by bob thibodeuax

David, my ground inside distributor is OK. Does the distributor housing need to be grounded on outside or is it grounded when setting in its place?

The distributor body grounds to the engine block when installed, no separate grounding wire. The heavy black wire from the MDS unit must be grounded to the body.

I'm running out of ideas. Have you confirmed that your points are properly gapped and not completely shut closed? Same with your spark plugs? It's sometimes hard to properly seat the spark plug wires on our cars. Do you feel the wire "snap" in place when you push the wire down on to the plugs? Long-shot but if the wires are not properly connected - no spark, no start.

[bob thibodeuax]

I know that with the standard CDI unit for 1972 911T requires a ground for distributor on outside attached to vacuum advance and then to good ground point. Would this ground harm MDS if I installed?

[David E. Clark]

I'm not at home now but I do not recall any separate ground wire/strap for the distributor body to engine block on my '73. If you have a condenser you may be thinking of the condenser lead wire?

[bob thibodeuax]

Discovered points were corroded although they were new, the engine has been sitting up a couple years with them installed. The engine was sitting out of car till 2 weeks ago.
Engine will now fire but not run. Will bring to mechanic to have MFI checked out. Thanks for everyone help.

[David E. Clark]

MFI is a very tricky system and very few mechanics know what they are doing with MFI cars. I'd recommend you learn a least the basics about the system before you throw a lot of money at a mechanic - unless you know your mechanic has experience with MFI and knows what he/she is doing.

I'd start by reviewing the links under my signature. My rule number 1: It's probably not the pump. Don't mess with the pump until you've gone through all the steps, in order, in the CMA manual. Good luck.