Yeah, I would have expected the idle switch to fail open, which would seem
to be the more typical failure mode for these sorts of switches. I'm still
hesitant to claim complete success since I can't get the switch to misbehave
on-demand in the garage. But the car runs fine with the switch unhooked, so
we'll see.

$100+ for this switch?! I figured it was a dealer item, but I hadn't yet
checked pricing. I did notice that the idle switch couldn't be replaced
separate from the full-throttle switch and harness. I'll likely just bite
the bullet and spring for the new switch; I'd probably spend more time than
I'd expect looking for a reliable used switch or modifying one from a
different FI system, and my time is worth something.

Thanks for the recommendations though, they're much appreciated.

--
Kent
1987 VW GTI 8V, original owner, 222,000+ miles


"Randolph" <trash (AT) junkmail (DOT) com> wrote

I've replaced the transfer pump at least five times in the almost 20 years
I've owned the car. Definitely a weak point in the design. I think there was
also a recall associated with excessive pressure drop through the screen
filter that would cause the same symptoms of transfer pump failure due to
fuel vaporization on warm days. Similar to a vapor lock effect. This effect
would also overheat the pump and accelerate failure, as a steady flow of
fuel through the pump is required to keep it cool. Some say the VDO pump
offers better longevity than the Piedmont (sp?), but I'm not certain if this
is true. I actually carry a spare one with me for swap out, cause it's not a
matter of "if" it fails, it's a matter of "when". I recognize the symptoms
of transfer pump failure well by now: surging and bucking upon acceleration,
more prominent buzzing from the main pump, etc. My current power loss
problem is definitely a different animal, but as I've postulated (see my
later post in this thread), it is likely still a fuel supply issue.

--
Kent
1987 VW GTI 8V, original owner, 222,000+ miles

"Randolph" <trash (AT) junkmail (DOT) com> wrote

"Kent" <immortala2 (AT) yahoo (DOT) com> wrote

What brand was your replacement? Years ago I remember reading on this group
that the bad OEM one was by VDO and that the Pierburg replacement was the
better one. Did you replace with VDO or Pierburg?

I've owned my A2 since new and it's 14 years old and only replaced the xfer
pump about 2 years ago at most with a Pierburg unit.

Pierburg, and I've heard it's the other way around. I know I saw 'VDO' on
my original one that went bad.

Pierburg, that's right. I don't know why I remembered it as Piedmont. I'm
not sure what type's currently in the car is, but the spare I've been
carrying around is a VDO. It's been quite a while since my transfer pump has
failed, so I don't remember where I bought it. Recently I've been buying all
my parts from Adirondack, and I know they only sell the Pierburg unit with a
new filter screen. My experience has been that the folks at Adirondack know
their stuff, so I'm guessing the Pierburg unit is the best bet, not VDO.
Thanks for straightening me out on this Matt.

Now that I think of it, maybe I've only replaced the transfer pump three or
four times, although the first one or two didn't last as long as the others,
perhaps because of a bad filter screen. I know I did a great deal of hot
weather driving at that time. I recall that my transfer pump failed for the
first time when the car was not very old. I remember replacing it myself
with a unit purchased from a dealer, and it didn't include the filter, so I
just installed the new pump with the original filter. I was moving alot back
then, so I never received notification of the recall associated with the
screen filter. I think the replacement pump failed not too long after, and I
think I did the same thing again: replaced the pump, but used the original
filter again. Dumb ass. I think I finally bought a new screen filter for the
third replacement, and it seems that the pumps have lasted much longer since
then. In the last ten years, I think I've replaced the transfer pump only
once, but I'm not completely certain.

Speaking of recalls, I also wasn't aware of the recall on the heater core
until it failed, stranding me and my girlfriend without coolant. Again, dumb
ass.

--
Kent
1987 VW GTI 8V, original owner, 222,000+ miles


"Matt B." <noway (AT) hellno (DOT) com> wrote

"Kent" <immortala2 (AT) yahoo (DOT) com> wrote

I got mine from Adirondack so yeah it's Pierburg they carry.

The engine (AKA air pump) needs fuel and ignition.
So there is some problem or problems with either:
Fuel
Ignition
Compression (which could mean exhaust also)

Well was it the idle switch?
Yes it could be a fuel pressure problem. Check the fuses and also the
ground wires that might go to the cold start valve bolt. Hooking up a VOM
to the Fuel Pressure Regulator to measure the current might help determine
if you have problems with wiring to it.
BTW I have replaced a couple of CIS-E fuel distributors that were causing
problems like yours even though I tried to clean out the plunger in the
center first.

I was also thinking that it could be some blockage in the exhaust. I had a
problem with my rear muffler restricting the flow of exhaust on my 91
Passat. I could hear the problem though and feel the power loss. If I
slowed down the blockage may open back up but it would soon return. Of
course another rear muffler solved that problem.
You could use a vacuum gauge to help determine if this is your problem.

Oh I remember another Jetta that had too much oil pressure causing the
hydraulic lifters to pump up and actually cause the valves to stay open and
cause a compression loss. Freaky problem that I have never seen before.
8^)
-
later,
dave
(One out of many daves)

"One out of many daves" <vwdoc1NOSPAM (AT) PLEASEhotmail (DOT) com> wrote


Drove it another 50 or so miles yesterday with the throttle switches
unhooked, still no problems. The sluggish performance I referred to in my
original post turned out to be a big leak in the intake system where the
intake pipe connects to the rubber boot on the mixture control unit. My
fault, I took the intake pipe off when I changed my injectors last Sunday
and didn't tighten down the clamp when I replaced it. No question the leak
was enlarging at speed and seriously leaning out the mixture. Feels really
strong now. I'm going to drive around with the throttle switches unhooked
for another week or so before I invest in a new switch. I think I've licked
this one.

--
Kent
1987 VW GTI 8V, original owner, 222,000+ miles

ruimigueldias (AT) gmail (DOT) com wrote:


You don't know what you're talking about.

There is no such thing as a "security mode" on a 1987 KE-Jetronic motor.

Tom Levigne wrote:


His car has only ONE coil, you idiot.

This kind of idiotic misinformation reminds me of why I left this group
5 years ago.

EC wrote:
Good answer, and only 8 days after someone else pointed it out! Glad to
have you back.