[DML] Brass Manifold Screws vs Centralized Idle

["content22207" <brobertson@xxxxxxxxxxxx>]

If I'm not mistaken the whole purpose of idling off the manifold
screws, vs simply cracking the throttle plates like an old fashioned
carburetor, is to take some of the rock & roll out of the odd firing
sequence. If so:

There is no way to properly balance a PRV with CIS only. The idle
speed motor meters both banks equally through the centrally located
cold start tube. Net effect is exactly the same as *VARIABLY* cracking
the throttle plates. 

Nearly all my Renault & Volvo literature is dated 1983 - earlier, so I
may indeed be mistaken Re: late decade blocks. Z7V's and B27E's were
100% manually tuned.

I've yet to find any acronym for fuel injection in my early Renault
literature. Did they later adopt Volvo nomenclature (CI)?

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, Martin Gutkowski <webmaster@xxxx> wrote:
> You're half right. Renault certainly DID employ CIS on later models of 
> their PRVs, my "bible" is the Renault K-Jet manual describing all
manner 
> of permutations of different forms of the PRV's Injection, ignition, 
> fuel and idlespeed systems. I have fantastically thorough fault 
> diagnosis pages (eg proper pin-outs on idlespeed computer), cutaway 
> views of the metering head and full explanations of all the system
parts 
> and how to adjust them _properly_.
> 
> The brass screws on the Volvo 760 are not shear type, the engine has
CIS 
> and the Volvos were set up correctly allowing proper balancing of the 
> banks. Renault also describe the procedure. The DeLorean manual is a 
> simplified system but does not give as much flexibility as is sometimes 
> needed when factory tolerances are not quite spot on (eg centre
position 
> of idlespeed valve). As well as preventing the engine from ever being 
> proerly "fine tuned". The ports are there o the exhaust to achieve it.
> 
> Continued blind acceptance of the DeLorean manual as gospel regarding 
> the idlespeed screws is quite simply wrong. The fine adjustment is so 
> fine in most cases that it makes no noticable difference, but for one 
> car in five, a proper set up of the screws results in a smoother more 
> reliable idle.
> 
> Martin
> DMUK
> 
> content22207 wrote:
> 
> >Note also that Renault never adopted CIS -- it never used shear head
> >style balancing screws. 
> >
> >Interestingly, last weekend I bought an upper air assembly from a 1989
> >B28F that, although CIS equipped, did NOT have shear head balancing
> >screws. Either Volvo itself or a previous owner had adopted John
> >Hervey's philosophy by the end of the decade.
> >
> >Bill Robertson
> >#5939
> >  
> >
> >  
> >




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