Ok listen up out there! Car still runs a bit rough. (recap - ZS carb
leaked gas and ran rough - then rebuilt carb and no gas leaks but still runs
fairly rough. Did the following today:
1. compression check - All cyl. at 109lbs.
2. Ensured timing was correct and operates smoothly. Discovered advance
vacuum pipe was melted and replaced.
3. Attached a vacuum gauge. Reads steadily and changes smoothly.
Discovered vacuum port for EGR - (top rear section of carb nearest manifold)
appears to be dead (checked good when carb was on the bench). No vacuum (or
pressure) measured. I remember wondering which way the carb-to-manifold
gasket should be since it has a notch. I put it where the old was which was
pointed to the front of car and downward. THIS CORRECT????????????
4. Ran engine from new gas in gas can instead of cars gas which may be old.
5. pinched off temporarily various vacuum hoses while engine ran to see if
there was any change. Virtually nil on all of them. Discovered large
crankcase breather pipes leaking and replaced with new hoses.
6. Ensured Choke control operated properly.
7. Replaced dashpot oil with 3-in-one.
8. Used ColorTune. NO color changes when turning idle mixture screw. Can
see/hear no difference at all despite many turns. Always slightly
blue/white.
9. Ensured Lucas distributor had gap as specified in manual. Noticed dist.
shaft seems to move somewhat preventing decent measurement. Cap and rotor
are new.
10. HT plug wires all measured 6-10 ohms.
11. Plugs cleaned and regapped to 25 thou. Splitfire plugs.
What am I missing? All of the changes had little or no effect to the
running of the car though the new vacuum advance pipe does appear to give a
little more power than before.
----- Original Message -----
From: Reed Mideke <rmideke@interbase.com>
To: Peter S. <alfapete@pacbell.net>
Cc: Spit-LIST <spitfires@autox.team.net>
Sent: Friday, June 25, 1999 3:16 PM
Subject: carb [ex Re: alternator diagnosis]
>
>
>
> "Peter S." wrote:
> >
> > > You should be able to tell extreme rich from lean by smell,
> > > and sooty smoke from the exhaust. Proper mix should barely smell at
all.
> > > (don't sniff it for too long ;-)
> > >
> >
> > It smells alright. Not super bad but noticeable. Turning the mixture
screw
> > clockwise (in) does what?
> >
> Don't know off the top of my head. I think in is leaner (on DGVs), but
> I'm
> dylsexic, so it might be out. Somebody on this list must know for sure.
> My point though, was that you can turn the screw in one direction,
> counting
> the turns so you can get back to where you were, until it runs really
> bad.
> If thats the rich direction, it will smoke and smell bad. If it's the
> lean
> direction, it will just run bad. Then you turn other way, until it runs
> bad
> again. If everything else is working right, there should be a nice
> smooth zone
> in between. I usually turn it to the rich extreme, and then turn it back
> a
> turn or so past where it starts to run nice. Of course if it doesn't
> run smooth in any position, you have to fix that first.
>
> Hmmm, I noticed that in your original post you say 'idle mixture
> adjust',
> wheras when I wrote the above I was thinking about main
> mixture (on a DGV or SU). Not knowing anything about the ZS carb,
> I don't really know what this means ;-( I know there are
> lots of ZS owners out there, so I'll shut up now.
>
> > > If you EGR vacuum diaphragm doesn't hold vacuum, it could be causing
> > > a vacuum leak, which will mess up your idle. If it's old/original,
> > > its probably dead. Even if the diaphragm of the vacuum parts is ok,
> > > the actual valve is probably clogged with soot. My datsun motor
> > > was so clogged that I ran it for a week with the EGR stuff completly
> > > removed (and no plate or anything) until it backfired out the
> > > carb and blew out the blocks of soot that had been sealing it
> > > up. Then it didn't run at all.
> >
> > If I operate the valve manually with my fingers its definately flowing
> > exhaust. It just wont hold vacuum. The plate idea is very tempting.
> > Ps
> >
> Right. So it's not clogged. If the control doesn't hold vacuum, you
> intake
> is probably sucking in air. The plate wont help this, but you
> could invisbly plug the vacuum line too. If you go the plate route,
> try to find a "pass or don't pay" smog check place (they're common
> in CA, don't know where you're located), because they might
> notice that it's not functioning.
>
>
> --
> Reed Mideke rmideke@interbase.com
>
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