Date: Sun, 19 Aug 2007 13:46:43 -0600
Reply-To: Martin Jagersand <jag@CS.UALBERTA.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Martin Jagersand <jag@CS.UALBERTA.CA>
Subject: Re: A bit rough idle, running. Unbalanced injectors?
In-Reply-To: <0JN000DRYWX3IZZ6@vms046.mailsrvcs.net>
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Hi, thanks for tips so far. Below I'll try to summarize and clarify
the Eurovan I5 engine problem.
> On 8/19/07 scottdaniel@turbovans.com wrote:
> > List all your symptoms.
The most obvious is that the engine sound and vibration. In the previous
post I used the word "rough running", but I realize that this is easily
confusable. This engine is too loud, but unlike many other problems, both
high and low idle RPM's are rock steady, likewise drive ability is fine
(no stumbling).
Hence I'm thinking the problem is more likely due to a problem with
unbalance between cylinders, rather than with EFI control loops. (I'm no
expert on gas engines, but thought that most EFI control loops maladies
affect all cyl's, and manifests itself in other kinds of rough running,
such as difficulty in holding constant idle rpm, sudden loss of power etc
that come and go over seconds or longer periods.)
I have checked compression, and it is fine. (The van has only 100tkm
on it)
Dennis Haynes suggested checking plugs and wires. All plugs fire pretty
bright and blue when I test ran with one out at a time, and I didn't see
any very obvious deposits on plugs. All cylinders seem to fire, since
pulling a plug wire at a time makes it run worse.
However, my theory (right or wrong) is that they fire with unequal
power, making the engine louder, and transmitting more vibration to
the power train than other Eurovan with I5's I've driven.
Motor mounts seem ok. Most of the vibration comes only when in drive.
(Automatic tranny). It is there whether stopped or driving, and fills
the cabin with a low tone drone, so I'm thinking it's transmitted
through the driveshaft
Other than the noise, it has a bit lower fuel economy than expected,
and is sometimes hard to start when warm (especially after long idling
or slow city driving).
As mentioned, both high and low idle is steady, and on cold start
it goes through the expected high idle, until it warms, and then
idle drops to low. (I also verified temps sensor Ohms at both cold and
warm and they are ok) I was wondering if dropping to low idle also means
that it goes into closed loop cycle regulating injection from the O2
sensor? I'm suspecting they may be separate, but don't know how to
tell if it's closed loop. (Other than buying expensive equipment
such as Ross-tech engine program+adaptor or an oscilloscope).
Hence having checked spark plugs, I couldn't think of any other
obvious culprit than injectors.
Pat Dooley suggested injectors are probably on a rail. I indeed
located a plastic rail-looking component inside the bend of the
intake manifold. (It's a lot harder to see and reach things in the
Eurovan engine compartment compared to the Vanagon). I found one
bolt in one end of the rail, and expect that there is another
someplace in the other.
Is it usual that the injector rail assembly sits just with two bolts?
If I take them out, should I just try to wiggle the plastic rail
out? Then do the injectors come with it? How do I do it without risking
breaking the long and slender looking plastic rail?
Assuming I can get them out, how could I test them. Since all cyls
are running, they must all be firing at least some fuel, but I
guess I can try putting 5 tall glasses, one under each, and crank
for a while to see if they deliver the same amount of fuel.
(I tried injector cleaner already, a variety of major brands,
but haven't seen the Lucas brand that Scott at turbovans suggested.)
Everyone says injectors go bad very seldom, but maybe one or two
of mine are among the odd one.
So should I try pulling the injectors? Or try something else before?
Thanks,
Martin
On 8/19/07, pdooley <psdooley@verizon.net> wrote:
>
> Martin,
>
> Unbalanced injectors seem to be a big problem on older CIS systems, not so
> much with EFI injectors. (at least in my experiences) Still, it is worth
> checking.
>
--
Martin Jagersand
University of Alberta
http://www.cs.ualberta.ca/~jag/
