Blackish smoke on wot

[s3irios]

Hello again dear 5 maniacs!
I had to change my engine for a rebuilt one, as mine had a huge crack on the block and the piston rings had went fishing...
So i still encounter a same issue as before changing my engine.
On wide open throtlle (when giving it the beans) i had + still have a kinda hugie blackish smoke poping from exhaust whilke cars kinda stalls for a moment then just freely revs up.

Spark plugs are new ngk ones, spark cables are new Magnecor and dizzy +rotor arm is clean and a-ok.

The only 2 issues i have are:
*Prior to the engine change i had to change my aei unit for another used one as i broke the small pipe connection.
*Car IS and was running super rich (afrt 10's) so that kinda explains the blackish smoke.

The final question is, is this caused from the super rich mixture ONLY? Or the coil on the aei unit might have weakened too?

Well just in need of "opinions" rather than definite answers ofc, i mean weakened coil is it something usual and could produce this effect only and work ok rest?

[Nick k]

Just sounds to me like a general over fueling issue, Are you running a solex 32 carb?? Any jet changes?

[SCHWARTZ]

What carb jets you got in there?

[s3irios]

As i just changed the whole engine it had a newly serviced carb 32dis on but the fella didn't know exact specs of jets, just that theyre changed to allow more fuel MEANING that some smartass just put a larger main jet as usual... Well my aem goes from 14ish on stand, on FULL flat 10's on even the slightest throttle so obvioysly it consumes fuel like a biitch.

I'm going to open it and adjust jets accordingly, not going to let it like that ofcourse, it's just it's only been like a week from the engine swap so i was taking my time with it

[michael tierney]

u should be aiming for 12's.....a standard carb will give u 12.5

[s3irios]

u should be aiming for 12's.....a standard carb will give u 12.5

I totally agree but as i said it was obviously treated by a "i put a 1,9 main jet and i'm fueling like a pro" kinda person

[Scoff]

It will be the carburettor only, don't worry about the coil. A weak spark would mean a misfire, it can't affect AFR

[s3irios]

Can't get a straighter answer from that!
Thanks m8!

[s3irios]

Ok so back again! Stripped thoroughly cleaned carb, it had a 122.5 main and rest OE.
I changed main to 120, drilled second stage to 1.1 since i had lean wots at 16 psi, well still not rich enough i got high 13s so i prob need to redrill the second to 1.2 and see. I put a new air 0.95 on too. Put new gaskets and stuff, put sealant on base gaskets too. I have a quite good idle afr at 900 rpm 13.8 to 14.7 and it purrs just fine.

B U T i still got same issue with too rich slight and mid throttle and i get still black smoke on wot.
Engine has a phase 1 (whatever that means) cam on.

This is the exact issues i had prior swaping engines wtih carb too. So it's something that wasn't changed in fault? Like the fuel pressure regulator? Could it produce something like this? Honestly i can't think of anything else to fault anymore. AS i said whole engine with defferent carb on was put on the car but still same exact problems like before.

(yes i'm that depressed about this problem now that i spam silly smilies)

[Brigsy]

Small air corrector could be causing super rich fuelling. On my setup a .9 a/c will put enough fuel in for 20+ psi... go back to the standard air corrector and enlarge the 2nd stage.

[s3irios]

I agree but Air corrector was OE before changing it with same silly rich readings and i changed it just to help the wot lean issue, which still needs to be richer than now.
I can change it back to oe but nothing will change for some reason

[Brigsy]

Has the venturi been bored out? aka grp a carb body?

[s3irios]

that's a good question. i honestly don't know. the jets werent group a jets though.

Still with different smaller jets it should be even leaner if it has a bigger venturi, since more air group A > fuel of a std carb ???

[Brigsy]

Bored out venturi's are renowned for super rich afr's on cruise and lean at wot. If it is bored out get it changed

[s3irios]

Damn gotta find out, totally bored to deal with thye carb for the 40th time....

[gttjames]

Small air corrector could be causing super rich fuelling. On my setup a .9 a/c will put enough fuel in for 20+ psi... go back to the standard air corrector and enlarge the 2nd stage.

Jumping in here. My carb fuelled perfectly at 13psi (standard carb) - and im talking
idle 14 area
light throttle 13.8 area
on boost 12 - it ran smooth, no smoke, think i took for granted how well it ran.

I then played about, 20psi. 1.2mm 2nd stage and put a 1mm ac in -
idle - terrible, up and down, get it set to 14.5ish with screw wound right out - then it will go upto 16 - and cant wind idle screw out any more or il loose it
light throttle 14-16
on boost was fine 11's (bit rich really)

Going by what youv just said brigsy if i put standard ac in it will be better?
If running 20+psi is having a poor idle and off boost driving something we just have to live with?

[Brigsy]

Idle should be Ok with a smaller a/c matey, id say you have an air leak or blocked idle jet if its hunting.

[gttjames]

argh right ok, does ac jet affect the whole carb idle and cruise? Or will it only affect when on boost? Cheers

[Nottswoody]

i run 20psi daily standard carb just 2nd stage at 1.3mm no probs yet AFRs good till 100mph just need to look into that..

[Brigsy]

argh right ok, does ac jet affect the whole carb idle and cruise? Or will it only affect when on boost? Cheers

A/c richens up the on boost fuelling and cruise. The only jet that affects idle is the idle jet.

[s3irios]

A/c richens up the on boost fuelling and cruise. The only jet that affects idle is the idle jet.

I have to disagree here, whenever i changed the ac jet and on this and on prevous carb, idle needed reajdustment but then it would be ok. Form there i saw difference only on WOT conditions.


Also i must say that i don;t knw what happened but tonight on 16 psi WOT i had high 12s AFRs. I don't know how i can only suppose that when i first drilled the second stage some swarf must go left inside and took it's time till they pass through.