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Ideas on next try for a solution for subtle engine surge / misfire.

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Old 02-02-2020, 03:00 PM
  #16  
wopfe
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Hmm, i understand your point They back in already (wanted to test today if in some "magically" way the car would run better....not... So i amateuristic photoshopped this:



Old 02-02-2020, 03:07 PM
  #17  
wopfe
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Hi, thanks for your suggestion, i have been questioning the module already, moving towards 41 years, i suspect this "computer" to miss a beat sometimes...Good idea. I am making a shortlist of options, my first impression is that the sparks look pretty ok... But i think i will first check the sparkwires, i can't find my multimeter, will get a new one tomorrow....

Shortlist:
- Fuel distributor refurbish.
- New sparkwire(s)
- ignition module
- Fuel accumulator

Originally Posted by hacker-pschorr
I had a random surge / misfire in my 81 years ago, happened while cruising under half - 3/4 throttle. The culprit ended up being the ignition module which sits below the jump post terminal. If you know anyone with a proper running 78-84 (all CIS & L-Jet cars have these) do a swap and see if the issue carries over to their car and / or fixes yours.

Might be worth simply removing it and checking the connection. I've seen these connections with bad corrosion, could be as simple as cleaning up the plug and connections with some DeOxit or similar contact cleaner.

The green wire connector goes straight to this module. Any ignition issue that could be related to the green wire could also be this item or the connections between them.

Question for the group, does anyone still rebuild / refurbish these? @Mark Anderson - do you offer an exchange service on these like the L-Jet barn door?

Looks like this:


Old 02-02-2020, 05:38 PM
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Speedtoys
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Did you ohm out the wires yet?6.6.0
Old 02-02-2020, 05:52 PM
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Probably tomorrow, i couldn't find my multimeter today, so i am getting a new one tomorrow
Sorry i am not familiar with the code 6.6.0? I guess i should simply measure them and see if i see a peak or low in resistance?

Originally Posted by Speedtoys
Did you ohm out the wires yet?6.6.0
Old 02-02-2020, 07:47 PM
  #20  
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Originally Posted by wopfe
Probably tomorrow, i couldn't find my multimeter today, so i am getting a new one tomorrow
Sorry i am not familiar with the code 6.6.0? I guess i should simply measure them and see if i see a peak or low in resistance?
No idea what in my browser is doing it...I gave up.


I dont know the spec offhand, just test and list em.


Found it..this is what I found:
https://rennlist.com/forums/928-foru...-found-it.html
Old 02-03-2020, 02:45 AM
  #21  
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Thanks for the info, i will check that out when making the overview!

Originally Posted by Speedtoys
No idea what in my browser is doing it...I gave up.


I dont know the spec offhand, just test and list em.


Found it..this is what I found:
https://rennlist.com/forums/928-foru...-found-it.html
Old 02-04-2020, 12:21 PM
  #22  
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Have you checked the timing with a timing light. 3000rpm with vacuum removed from distributor should be at 31° BTDC
Old 02-04-2020, 04:35 PM
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Thanks for your reply, no i did not after we did the timing a while ago. Thanks i will put it on the list...

Originally Posted by giddyupp
Have you checked the timing with a timing light. 3000rpm with vacuum removed from distributor should be at 31° BTDC
Old 02-04-2020, 05:02 PM
  #24  
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Update:
So i bought myself a multimeter yesterday, took off the sparkplugwires and tried to measure them.

The result is quite strange:
- I tried to measure plugwire 1-4 and 5-8. Put on the 20k Ohm selector and started with the wire between from the coil to the distributor: 1.12. Then i measured for 4: 2,86 3: 2,78 2: 2,63 1: no measurement and 5-8 same story: i can't get any result, whatever i do. Bend the wires, with and without the sparkplug connector, change setting on the multimeter etc etc.

I am bafled, are these wires crap or could something else be wrong? If i return to plug 4,3,2 it give the same measurement right away. So the multimeter looks to work correctly?
I am curious if people have encountered this "new" problem before, but i think i am going to order a fresh set of Beru wires really soon. The result looks like it could cause the problems i mentioned with the Engine. The solution could be close (and yes could be so far away...(but having fun, interested in your ideas...)

Last edited by wopfe; 02-05-2020 at 02:14 AM.
Old 02-04-2020, 08:52 PM
  #25  
karl ruiter
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I think there is someone on the list who can take your WUR and FD and rebuild or evaluate them. My '79 also has some running issues, the biggest being an intermittent huge loss of power, that feels electrical, as if I am loosing voltage to my fuel pump or ignition module.
Old 02-05-2020, 02:17 AM
  #26  
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Thanks for the reply! Wur has been rebuild 2 weeks ago, FD is next on the list after plugwires...

Originally Posted by karl ruiter
I think there is someone on the list who can take your WUR and FD and rebuild or evaluate them. My '79 also has some running issues, the biggest being an intermittent huge loss of power, that feels electrical, as if I am loosing voltage to my fuel pump or ignition module.
Old 02-05-2020, 10:05 AM
  #27  
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Originally Posted by wopfe
Update:
So i bought myself a multimeter yesterday, took off the sparkplugwires and tried to measure them.

The result is quite strange:
- I tried to measure plugwire 1-4 and 5-8. Put on the 20k Ohm selector and started with the wire between from the coil to the distributor: 1.12. Then i measured for 4: 2,86 3: 2,78 2: 2,63 1: no measurement and 5-8 same story: i can't get any result, whatever i do. Bend the wires, with and without the sparkplug connector, change setting on the multimeter etc etc.

I am bafled, are these wires crap or could something else be wrong? If i return to plug 4,3,2 it give the same measurement right away. So the multimeter looks to work correctly?
I am curious if people have encountered this "new" problem before, but i think i am going to order a fresh set of Beru wires really soon. The result looks like it could cause the problems i mentioned with the Engine. The solution could be close (and yes could be so far away...(but having fun, interested in your ideas...)
Wow, sounds like you found something, that is good news! The resistance is in the spark plug end, wires should be zero, I don't think I've ever measured a spark plug end that was zero ohms. I've had bad ones what were out of spec, but not zero

Very interesting.
Old 02-05-2020, 10:57 AM
  #28  
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Yeah, i have tried it over and over again but really it is what it is Ordered a new set, i am going to test it saturday, btw i also bought a working second hand ignition module for a nice price, like you mentioned. Thats next on the option i am going to try, if it does not help: after that refurbish the fuel distributor.

Originally Posted by hacker-pschorr
Wow, sounds like you found something, that is good news! The resistance is in the spark plug end, wires should be zero, I don't think I've ever measured a spark plug end that was zero ohms. I've had bad ones what were out of spec, but not zero

Very interesting.
The following 2 users liked this post by wopfe:
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Old 02-10-2020, 04:30 PM
  #29  
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Finally got my new sparkplugwires delivered, busy week so probably i will have to wait until the weekend to get them on the engine. I did measure them right away, i was wondering if i could see the difference: 8 out of 8: +/3.05 kOhm. So this could really be it.

Last edited by wopfe; 02-10-2020 at 06:13 PM.
Old 02-16-2020, 11:17 AM
  #30  
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Good news, i put on the new sparkplugwires and with good result: engine runs smooth, feels like 20 horses more and not the misfire like feeling in the engine anymore! Thanks for all the suggestions! There is a but: it now iddles a bit strange, like it is searching for the right rpm. It goes up and down between 400-1000 rpm. I suspect my thinkering with the air flow. So diving into this next!



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