Date: Wed, 2 Nov 2005 18:13:37 -0600
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: 88 GLstarts, stalls immediately -- possible solution
In-Reply-To: <000201c5e002$6755f490$50c36bd8@Erik>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Eric, I had problems with my engine running fough on my 88 GL. It was
really bad going down the road when coasting or with the foot lightly
feathered on the gas pedal. I found the vent line from the crankcase
vent to the AFM had rotted through on the underside. It was not obvious
from the top side. Replace it an things were better but not cured.
Finally I disconnected the clip at the end of the Idle Stablizer Valve.
Voila!! No more roughness.
However, my engine won't idle by itself on cold days, and under certain
conditions, if I push the wheel to the stops when moving slow it will
kill the engine. My AC is all apart so that doesn't have any impact.
The idle stabilizer system comes into play on three different occasions.
_Start-up_: While is is not a cold start valve, it does kick the engine
rpm up on a cold start to make it run smooth until the engine warms up
and the O2 sensor gets hot so that the proper signal is sent to the ECU
to keep it running at the correct Idle Rpm after it warms up.
_Air Conditioning:_ The Idle stabilizer system kicks the engine rpm up
when the AC is turned on. This is to keep the AC from loading the engine
down when the engine is idling, such as at a top sign, etc.
_Power Steering:_ When the steering wheel is moved to the limits of its
travel, the Idle stable lizer system kicks up the engine rpm to keep the
PS pump from stalling the engine.
Maybe somewhere in all this there might be clue as to what your engine
problem is.
Contact John Bange off list, and inquire as to the disposition of a
certain PDF about servicing the FI on the vans.
Good Luck,
Regards,
John Rodgers
88 GL Driver
Erik Walker wrote:
>Thanks to the many of you who have been helping me sort through this
>problem. Recapping briefly, van fires up without problem but then
>immediately sputters, stumbles, kicks and dies. Good fuel pressure, no
>vacuum leaks readily apparent, good spark even as it is winding down
>into a stall.
>
>Replaced Temp II sensor, checked and cleaned grounds, etc.
>
>What I have found is that the idle stabilizer control unit has a burnt
>transistor or two. I'm guessing this could be the culprit, though I
>can't say for certain. What I can say for certain is that the price tag
>for a new ISCU caused me to spit a mouthful of miso soup all over my
>computer screen -- so now I have that problem too.
>
>I'm tempted to try to fix this unit or try to find one in a boneyard.
>Does anyone have any kind of schematic for the 251 907 393B? I saw a
>great post on this from Jim Davis, circa 1998; but only limited
>information was available.
>
>Thanks in advance for any further guidance.
>
>Erik Walker
>Lempster, NH
>
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