Re: 86 5kCSQ jerks when deacclerated

[Orin Eman <orin@WOLFENET.com>]

I'd say it's the nature of the beast.  Mine 'jerks' quite strongly
if I take my foot off the gas quickly, more so at high RPMs.
Using as high a gear as possible without lugging the engine helps.
Usually helps gas mileage too.

Orin.


> I saw another post on the decel shutoff valve ... I'e never run into
> that one, but you could test to see if it was happening in your case by
> not completely removing your foot from the throttle.  The decel bypass
> is only enabled if the RPMs are above a certain value and the Idle
> Switch is closed.  My thoughts were that the effect might be due to a
> high effective compression since you are on boost.  This would be more
> likely to be true if you quickly went from full throttle acceleration to
> foot off the gas.  Normally the turbo engine isn't great for engine
> braking due to the lower compression, but you can get a big spike of
> deceleration when the turbo is angry ... I don't think the '86 has the
> idle dashpot, so it is also possible for you to get a backpressure spike
> in the turbo and t\intercooler when the throttle is closed under high
> boost as well.  I don't know whether or not this will increase engine
> braking though ...

> HTH!
> Steve Buchholz
> San Jose, CA (USA)

> > ----------
> > 	Summary of the problem would be 
> > 	"Is hard engine braking normal to this car"
> > 
> > 	Explanation of the Problem will be like;
> > 	I am not sure if it is a characteristic of the beast or
> > 	if there is something wrong. While in stop and go traffic
> > 	(california), let's say I am in in a low gear, and I just
> > 	took my foot off the gas pedal, without pressing the clutch, 
> > 	the car has a sudden jerk. The jerk is so bad that I get 
> > 	nervous that someone might hit me from behind ( bumper to 
> > 	bumper traffic). I have been driving stick shift for last 
> > 	20 or so years, and don't think that I have to press clutch 
> > 	everytime I take my foot off the gas pedal. The lower the 
> > 	gear the harder the jerk is.
> >