Re: Quad-4 (1228707 ECM) Rough Idle Problem

[Rex Weatherford <rex.weatherford@mentisys.com>]

Will Remaklus wrote:
> 
>
> Here are some new findings on the problem:
> 
> In pursuit of trying to understand my rough idling problem I
> decided that the 2X reference pulses from the ignition module
> did not provide enough resolution.  Therefore, several weeks ago
> I fabricated a 24 slot crank position sensor using an IR LED and
> photodetector.  The .pdf file:
> 
>  ftp://ftp.diy-efi.org/incoming/Quad-4%20Idle%20Miss.pdf
> 
> shows the instantaneous RPM, that is RPM calculated based on the
> time between two adjacent slots in the wheel, versus time.  I also
> included the slot number off the wheel to aid in identifying the
> relative position of the crank.
> 
> 
> Therefore, it appears that the problem is likely caused by
> something in the top end.  When I checked the timing chain
> several weeks ago I verified that at TDC the camshaft alignment
> dowel pins went in easily.  As such, the only things left to
> check are the lifters and the cams.
> 
> Any ideas?
> 
> -Will
> 
> 


AFAIK all W-41 optioned Quads will do this loping.  The cam's have more
duration that the stock HO and do this as an effect of the longer
duration.

Personally I would like to have a set of those cams...


My HO will sometimes slip into this "lope" and a little tap of the gas
will bring it out of it.  The W-41 will settle back into it naturally.

Rex Weatherford
92 Beretta GTZ HO Quad4
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