Date: Mon, 18 Oct 1999 22:46:25 -0400
Reply-To: Jeffrey T Cross <jtcross@CDC.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jeffrey T Cross <jtcross@CDC.NET>
Subject: Weird hesitation / power loss in '85
Content-Type: text/plain; charset="us-ascii"; format=flowed
Vanagonians,
I am the proud new owner of an '85 Van (4speed) with only 225,000 on it -
barely broken in! Actually, 60K on a rebuilt engine. It wasn't running too
well when I got it, but I have a friend, Scott, who is my personal mechanic
with an '84 of his own. The biggest problem turned out to be that I was
running on 3/4 an engine (broken injector control wire) - I knew it would
be slow, but NOT THAT SLOW! Anyway, that fixed, we figured everything would
be great. Close, but not quite. Here's what I'm dealing with:
After starting cold or warm, it runs great for at least 10 minutes or so.
After that point, there are three possible symptoms depending on what speed
we're running. (1) At idle, the idle is rough. Holds 800 rpm+/-, but
noticeably rough. (2) Around town, you just can't count on how far you'll
have to push the accelerator to get what you want to happen to happen. At
very low speed (<1800 rpm, i.e. pulling away from a stop) it might have NO
power, requiring clutching up to 2500 or so in order to get going. Cruising
at 35-40 mph, it feels like someone is behind alternately giving you a push
or grabbing your bumper and pulling. Varies between annoying and dangerous
depending on the situation. (3) At highway speeds, 3500+ rpm, you can still
feel the occasional hesitation but it's not usually a problem due to
inertia. BUT, sometimes it gets to an extreme case that seems quite
strange: with the pedal all the way down, the van starts losing speed as if
the engine is losing power altogether, and perhaps in a way it is!
The strangest thing to me is my workaround for the problem: all I have to
do is turn the engine off and back on! It always starts right back up, and
with no waiting period, we're in good shape for at least another 15
minutes, often longer at this point. That's right: (1) smooth idle, (2)
smooth acceleration, (3) 70-75 on the highway with no problem. Am I
"rebooting" my van? I'm a software guy, so maybe this shouldn't surprise me...
More details:
-- The problem is most likely to begin AFTER coasting down a hill in 3rd.
-- While the problem is occuring, it generally responds to having the
accelerator pushed all the way. For example, you're trying to accelerate
and push the gas down halfway. Nothing really happens - just no response at
all. Keep pushing, keep pushing, keep pushing, and when it's pretty much
all the way down, YOW! Full steam ahead!
-- Before the 3-cylinder problem was found, Scott did adjust the timing
(in spite of it "not needing adjustment") as a troubleshooting measure. It
made things worse, and he put it back.
-- We replaced the O2 sensor. No help.
-- I've been using 93 octane gas.
-- California emissions.
-- Fuel mixture has been adjusted.
-- Idle control valve replaced.
The hesitation seems not to be the lurching I'd associate with missing,
i.e. an ignition problem, so it seems to me (a non-mechanic, but
mechanically inclined) that it must be a fuel delivery problem, or maybe
timing. Could some type of grounding problem be causing static in a sensor
or chip somewhere and freaking out the injection system?
I'm not terribly worried - it doesn't seem like anything could be TOO
wrong, and I can have Scott look at it again. However, if anyone has any
really specific suggestions, my wife is out of town with it for the week
and I would kind of like for it to be working better for her coming home.
Thanks to anyone who can help.
JC
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