wopfe

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.

Billu

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.

wopfe

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:

Speedtoys

Cap an rotor not replaced is an easy an obvious "do it", if not already new'ish.

When you do, Ohm out your wires from conductor to conductor as well.6.5.06.5.0

wopfe

Cap and rotor where also replaced (new). Check the wires for resistance you mean?

Speedtoys

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?

GregBBRD

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.

wopfe

I bought 8 new plugs, i asumed they where with the right gaps when new...i could check that. Coil is also brand new...

Speedtoys

6.5.0

Ya, drive it, and photos. Never trust pre-gapped plugs. 1 in 50 will be WAY WAY off. The other 49 will be +/- a RCH or two.

GregBBRD

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.

wopfe

Ok thanks guys. I will probably have time saturday to do the 15 minutes drive and then remove them, i will return with the photo's and results.

wopfe

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:

wopfe

Any plug whisperer in the house?

Mrmerlin

its easier to see the plug differences if you lay them all next to each other then take a picture

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: