Ideas on next try for a solution for subtle engine surge / misfire.
#1
Rennlist Member
Thread Starter
Update: Ideas on next try for a solution for subtle engine surge / misfire.
Hi Everybody,
After two years on working on the Engine (a lot of renewals i wanted to do) i am still not completely happy with how the engine runs. Basically i am running out of options i think, so i hope people have experience with a problem like this and have advice.
Problem:
- Around 2000rpm there is a something in the engine that i would describe like a misfire in the engine. So when you drive around 30mph in a low gear (manual) you feel a very subtile shake in your bottom irregular moments. If i put it in a higher gear / lower rpm you can't feel it.
- When idling i feel/hear it too. Its sound something like: tu du tu du tu du tu du tu du ...tu du...tu du tu du. Again very subtile.
- When i rev up to about 2000 you notice the same but then more clear it sort of misses a beat sometimes.
What did i already replace/try:
- I did an engine out overhaul of the engine 2 year ago.
- I replaced fuelpump, rotor, sparkplugs, injectors, spark coil, vacuüm hoses, battery.
- I overhauled the WUR last week by a specialist (was my last gues).
My next gues: fuel accumulator or my 10 year old sparkwires.
I hope for a good idea Thanks in advance!
Cheers,
Arjan
'79 manual euro.
After two years on working on the Engine (a lot of renewals i wanted to do) i am still not completely happy with how the engine runs. Basically i am running out of options i think, so i hope people have experience with a problem like this and have advice.
Problem:
- Around 2000rpm there is a something in the engine that i would describe like a misfire in the engine. So when you drive around 30mph in a low gear (manual) you feel a very subtile shake in your bottom irregular moments. If i put it in a higher gear / lower rpm you can't feel it.
- When idling i feel/hear it too. Its sound something like: tu du tu du tu du tu du tu du ...tu du...tu du tu du. Again very subtile.
- When i rev up to about 2000 you notice the same but then more clear it sort of misses a beat sometimes.
What did i already replace/try:
- I did an engine out overhaul of the engine 2 year ago.
- I replaced fuelpump, rotor, sparkplugs, injectors, spark coil, vacuüm hoses, battery.
- I overhauled the WUR last week by a specialist (was my last gues).
My next gues: fuel accumulator or my 10 year old sparkwires.
I hope for a good idea Thanks in advance!
Cheers,
Arjan
'79 manual euro.
Last edited by wopfe; 02-01-2020 at 03:13 PM. Reason: Added pictures and movies.
#2
My knowledge of the 79 is somewhat limited, but...
Does it have a green wire and has it been replaced?
Are you running ported vacuum or direct vacuum to the distributor?
Cap, rotor and wires are obvious candidates.
Does it have a green wire and has it been replaced?
Are you running ported vacuum or direct vacuum to the distributor?
Cap, rotor and wires are obvious candidates.
#3
Rennlist Member
Thread Starter
I replaced ithe green wire when working on the engine, about 2 years old!
How do i know if i run it ported or direct? Added a picture this was yesterday just before i punt in the refurbished wur:
How do i know if i run it ported or direct? Added a picture this was yesterday just before i punt in the refurbished wur:
Last edited by wopfe; 01-26-2020 at 04:46 PM.
#6
Rennlist Member
Yes, will also assume the proper plugs and gaps are set. But a misfire is a huge lack of fuel, or way too much...that wont fire, or spark is being blown out by too much gap, too little, or spark is too weak or missing from something between the coil and the end of the plug.
Coil is good, no green corrosion in the end, or leaking oil?
#7
Former Vendor
Your '79 Euro is a CIS (mechanical) injected engine. This injection system is very prone to age/fuel/moisture deterioration of the injectors, the fuel distributor, and the warm-up regulator.
Go drive it around, normally (for 15 minutes or so), let it cool down, and pull the spark plugs. If there is a "funky" running cylinder/cylinders, the plugs should show it.
Keep them in order and take a picture of each "side" of the engine, for us to see.
Go drive it around, normally (for 15 minutes or so), let it cool down, and pull the spark plugs. If there is a "funky" running cylinder/cylinders, the plugs should show it.
Keep them in order and take a picture of each "side" of the engine, for us to see.
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Speedtoys (01-26-2020)
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#8
Rennlist Member
Thread Starter
I bought 8 new plugs, i asumed they where with the right gaps when new...i could check that. Coil is also brand new...
6.5.0
Yes, will also assume the proper plugs and gaps are set. But a misfire is a huge lack of fuel, or way too much...that wont fire, or spark is being blown out by too much gap, too little, or spark is too weak or missing from something between the coil and the end of the plug.
Coil is good, no green corrosion in the end, or leaking oil?
Yes, will also assume the proper plugs and gaps are set. But a misfire is a huge lack of fuel, or way too much...that wont fire, or spark is being blown out by too much gap, too little, or spark is too weak or missing from something between the coil and the end of the plug.
Coil is good, no green corrosion in the end, or leaking oil?
#10
Former Vendor
I don't care about the gap...I want to see if there is a difference in color from one cylinder to the next....to see if there is anything obvious occurring.
#12
Rennlist Member
Thread Starter
So i followed your advice here is the overview in gaps per plugs (nothing special i think):
Then the pictures per plug:
1: One
2: Two
3: three
4: Four
5: five
6: Six
7: Seven
8: Eight
I also made some movies to show the shake te engine makes:
and:
Then the pictures per plug:
1: One
2: Two
3: three
4: Four
5: five
6: Six
7: Seven
8: Eight
I also made some movies to show the shake te engine makes:
and:
#14
Team Owner
its easier to see the plug differences if you lay them all next to each other then take a picture
#15
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
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:
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: