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> Ot 74 911 no spark help..
mb911
post Apr 9 2017, 02:29 PM
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So a while ago I posted about taking on a basket case 911 project that had the engine out for a long time..

Well engine is in everything is hooked up but trying to fire this thing up and am having very intermittent spark.. The cdi box was a no go and hooked up a used msd box and now I see spark every once and a while. Looking for a little advice.. What should I check next.. Points hanging up ?
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Dave_Darling
post Apr 9 2017, 04:15 PM
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Definitely check for the points opening and closing. Make sure you have a good ground path for them, as well as for the spark.

--DD
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infraredcalvin
post Apr 9 2017, 09:31 PM
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QUOTE(Dave_Darling @ Apr 9 2017, 03:15 PM) *

Definitely check for the points opening and closing. Make sure you have a good ground path for them, as well as for the spark.

--DD


EDIT: looks like you have points per Dave mentions above, I'll leave my comments below for posterity in case you have a later dizzy...


Im guessing, but, does that have the star magnetic pickup inside the dizzy? If so check that the arms aren't bent, it happens pretty easy if the cap clips get caught up inside.

Then check the signal wire (green wire). Those are known cause weird issues.
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mb911
post Apr 10 2017, 01:54 PM
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Ok have decent enough spark now and got it to fire up.. Really didn't get it to run longer then about 15 seconds before it dies. Thinking points are a bit of an issue still and considering pertronix as I want to be done with this car.. And then it's tweaking the fuel injection..
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Jeffs9146
post Apr 10 2017, 03:17 PM
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FI or Carbs?
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mb911
post Apr 10 2017, 04:27 PM
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QUOTE(Jeffs9146 @ Apr 10 2017, 01:17 PM) *

FI or Carbs?



Cis..
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Jeffs9146
post Apr 11 2017, 12:06 AM
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Check for vacuum leaks. When I installed my motor it would use the cold start injector to run for a few seconds and the more leaks the shorter it would run!

The vacuum lifts the AFR plate to increase the fuel to the injectors.
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mb911
post Apr 11 2017, 07:22 PM
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QUOTE(Jeffs9146 @ Apr 10 2017, 10:06 PM) *

Check for vacuum leaks. When I installed my motor it would use the cold start injector to run for a few seconds and the more leaks the shorter it would run!

The vacuum lifts the AFR plate to increase the fuel to the injectors.




I was manually lifting the plate etc but I still think I have air to bleed out.
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Jeffs9146
post Apr 11 2017, 08:03 PM
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QUOTE(mb911 @ Apr 11 2017, 06:22 PM) *

QUOTE(Jeffs9146 @ Apr 10 2017, 10:06 PM) *

Check for vacuum leaks. When I installed my motor it would use the cold start injector to run for a few seconds and the more leaks the shorter it would run!

The vacuum lifts the AFR plate to increase the fuel to the injectors.




I was manually lifting the plate etc but I still think I have air to bleed out.


Check the fuel pressures.
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mepstein
post Apr 11 2017, 08:15 PM
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Tony Danato (on pelican) will rebuild a WUR and fuel dist but it costs about $800. Text me if you need his number.
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mb911
post Apr 12 2017, 06:52 AM
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QUOTE(mepstein @ Apr 11 2017, 06:15 PM) *

Tony Danato (on pelican) will rebuild a WUR and fuel dist but it costs about $800. Text me if you need his number.



Hoping I won't need him.. I will get fuel pressures this weekend. Gotta get this car out of my pole barn.
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mb911
post Jun 17 2017, 05:45 AM
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So update on this project is that finally got it running well.. Excited to get it out of my shop.. Will be leaving at the end of the month. Currently try to figure out why there is no voltage regulator, and why the silicone valve cover gaskets on passenger side are leaking..

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Mark Henry
post Jun 17 2017, 06:23 AM
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QUOTE(mb911 @ Jun 17 2017, 07:45 AM) *

Currently try to figure out why there is no voltage regulator, and why the silicone valve cover gaskets on passenger side are leaking..

No voltage regulator or the VR is not working?
There is internal and external VR's
No idiot light is a big cause of issues as it needs the idiot light to excite the field in the alternator. Some of the Bosch 911 alternator's are very sensitive to having the correct matching Bosch VR.

Other causes are wiring connections, ground issues, brushes, dead VR, wrong VR.

Silicone valve cover gaskets, I bet they are cranked on too hard. You have to use nyloc nuts and less than factory torque, almost half.
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mb911
post Jun 17 2017, 07:29 AM
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QUOTE(Mark Henry @ Jun 17 2017, 04:23 AM) *

QUOTE(mb911 @ Jun 17 2017, 07:45 AM) *

Currently try to figure out why there is no voltage regulator, and why the silicone valve cover gaskets on passenger side are leaking..

No voltage regulator or the VR is not working?
There is internal and external VR's
No idiot light is a big cause of issues as it needs the idiot light to excite the field in the alternator. Some of the Bosch 911 alternator's are very sensitive to having the correct matching Bosch VR.

Other causes are wiring connections, ground issues, brushes, dead VR, wrong VR.

Silicone valve cover gaskets, I bet they are cranked on too hard. You have to use nyloc nuts and less than factory torque, almost half.



Yup no voltage regulator.. I see the wires double blue, black , and brown. I have an extra regulator so i will have to try it..

I will try to loosen the valve covers a bit and see what happens.
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