73 911e no start

benzboy · benzboy's Garage

im having trouble figuring this one out. a few weekends ago i had my 911e out for a nice drive. it began to backfire and stumble, then just shout off. it wouldnt start back up, cranked over by no start. had the car towed. i looked at the rotor. here the rotor actually cracked. so i replaced the cap and rotor. plugs and wires are new too. still wouldnt start. just didnt sound like it wanted to start. i smell gas. so i think its not a fuel problem. i have juice to the points with key on, but no juice when the car is cranked over. what is my problem?? is it a bad ignition switch? . coil is also good too. any help???

Flat6pac · 08-17-2012, 06:06 PM

911.613.017.01
This is the ignition starter switch, they do go bad.
Bruce

wasserkuhl · wasserkuhl's Garage

Check the Plugs for fouling?

Does it still have the original MFI? Are there any fuel leaks on or around the MFI?(You can smell fuel)

Double Check Fuel pressure?

Points not loose and still gapped correctly? Distributor hasn't slipped?

Do you have an alarm/immobiliser installed?

Ignition Starter switch check this...... *Edit, Bruce you got there first!!

benzboy · benzboy's Garage

iwas leaning towards the switch. there is no alarm no fuel leaks. if it was the mfi pump, i should still get juice to the points when the car is cranked by the keys right?

RSTarga · 08-18-2012, 05:15 AM

classical points problem. Your points closed up. put a new set in gap them properly and retime.

benzboy · benzboy's Garage

anyone has the proper way to install and gap points? i never had a car with points before. would really like to get this car running

tobluforu · tobluforu's Garage

There has to be a post with a how to some where on this board? Take cap off, pull rotor, crank engine over by hand. While looking down into dizzy, you will see the six lobes on the dizzy, crank it over until the little block that rides on the dizzy is at tdc of one of those lobes. Take feeler gauge, slide it into where the points open, then take screw driver and loosen points. You will see a notch in the dizzy where you will put a screw driver into, this will allow you to open and close the gap of the points. When you have the right gap, tighten screw and re-check.

frank edwards · 08-18-2012, 04:08 PM

hi,i never gap my dizzy in the car, turn engine to t.d.c. on #1,make sure fire stroke,rotor should point to #1 on cap.take out distributor and replace new points and gap them in comfort,i put bolt through clamp hole snug up,and clamp bolt in bench vice, dont clamp dizzy in vice.might be worth taking the plugs out and let them dry out also any gas will evaporate from inside the cylinders,hope this helps,good luck.

benzboy · benzboy's Garage

thanks for the advice. my concern is, i get no juice to the points when key is on the on position, or when i crank the car over. i should get juice to the points right? i changed out the switch, from another one of my cars. i know the switch works. and i get no juice again. is there some relay of fuse that could have blown?

RSTarga · 08-19-2012, 05:59 AM

so you fixed the points and the ignition switch, both new?

mobius911 · 08-19-2012, 06:08 AM

Could also be a dead CD box. Listen for the whine, or swap in a known good one.

benzboy · benzboy's Garage

i have not gotten to swithing out the points yet. where would the cd box be located?

mobius911 · 08-19-2012, 05:36 PM

Left hand side of the engine compartment, just behind the fuel filter. At least that's the setup in the 72/73 models and I believe the earlier years are similar. It's a finned aluminum box about 5 inches tall, 4 inches wide, 3 inches deep. The original brand is Bosch, but there versions available from others. They all can have problems.

Mine went when it heated up. Cold it was fine. There are other failure modes as well.

Best option is to borrow one that is known to work.

Porboynz · Porboynz's Garage

Another possible fault is the plug that connects the engine to the fuse/relay panel. Easy to disconnect it and check for corrosion and reconnect. If the points are closed up then you will not measure any voltage at the distributor as it will be a hard short to earth, but easy to pull the wire off and recheck with voltmeter. Check that the CDI is whistling, no noise, no go. Same with fuel pump, you can not miss these noises with the lid up and looking listening at the engine end. These are simple engines compared to later models but if you are uncertain about gapping points then maybe get some help and learn from someone, much easier to watch it being done.

benzboy · benzboy's Garage

im pretty sure it s the points. will be having them put in the next few day. have my fingers crossed. i did switch out the cd box, and im really glad its not that. are they really $2600?? btw what does the cd box do, and what does it stand for? always nice to get more info on these cars.

47silver · 47silver's Garage

stands for capacitive discharge ignition. allows a higher voltage to be sent to the coil, result higher voltage to the plugs. Also I think it recharges the coil quicker.

when the points close the cdi charges the coil, when the points open the coil circuit collapses and sends the resultant energy to the only place it can go and that is to the spark plug via the rotor/distributor.

tobluforu · tobluforu's Garage

The cd can be rebuilt.