1988 90Q - bad fuel system or is snow the problem?
#1
12-02-2010, 11:26 AM
1988 90Q - bad fuel system or is snow the problem?
Hi all,
Just picked up a 1988 90 quattro with 271K miles on the clock -- runs remarkably well with one exception I desperately need to figure out as winter sets in.
Twice now the car has developed a massive hesitation, during which the car will die if I'm not at med-full throttle. In both cases it was a temporary affliction, lasting 10-20 minutes. I've been driving in snow/slush both times that the hesitation/stall problem has happened, presumably kicking up a lot of water onto any exposed switches/wiring/sensors under the car. Previous owner reports no problems driving when through puddles, in rain, etc.
In normal driving, I've sometimes noticed a slight hesitation at low rpm & throttle, but nothing like this where the car will die if not at nearly full throttle.
Some background:
* the car apparently sat with bad gas in it for a long time - I changed the fuel filter and run a can of Sea Foam through it.. I thought this had fixed the problem, but I just ran into it again last night
* the fuel pump is sometimes pretty loud, others not -- leads me to believe it may be a suspect, or at least not helping matters.
* I've tried to recreate the problem in the garage by tweaking vacuum lines, spraying electrical connections under the car with water, all without any luck.
Any ideas about where to start with this? The snow bit might be coincidence as it seems reasonable that this car could have clogged filters/strainers/lines, junk floating in the tank, etc. But perhaps those of you with knowledge of this car can think of a sensor or wire that, if shorted out by water, would cause bad things to happen with fuel delivery or fuel/air mixture?
Thank you for any help! Looking forward to lots of miles with this car. Apologies for the vwvortex cross-posting for any of you who are subscribed to both forums. Hope to find more help here!
Nathan
Just picked up a 1988 90 quattro with 271K miles on the clock -- runs remarkably well with one exception I desperately need to figure out as winter sets in.
Twice now the car has developed a massive hesitation, during which the car will die if I'm not at med-full throttle. In both cases it was a temporary affliction, lasting 10-20 minutes. I've been driving in snow/slush both times that the hesitation/stall problem has happened, presumably kicking up a lot of water onto any exposed switches/wiring/sensors under the car. Previous owner reports no problems driving when through puddles, in rain, etc.
In normal driving, I've sometimes noticed a slight hesitation at low rpm & throttle, but nothing like this where the car will die if not at nearly full throttle.
Some background:
* the car apparently sat with bad gas in it for a long time - I changed the fuel filter and run a can of Sea Foam through it.. I thought this had fixed the problem, but I just ran into it again last night
* the fuel pump is sometimes pretty loud, others not -- leads me to believe it may be a suspect, or at least not helping matters.
* I've tried to recreate the problem in the garage by tweaking vacuum lines, spraying electrical connections under the car with water, all without any luck.
Any ideas about where to start with this? The snow bit might be coincidence as it seems reasonable that this car could have clogged filters/strainers/lines, junk floating in the tank, etc. But perhaps those of you with knowledge of this car can think of a sensor or wire that, if shorted out by water, would cause bad things to happen with fuel delivery or fuel/air mixture?
Thank you for any help! Looking forward to lots of miles with this car. Apologies for the vwvortex cross-posting for any of you who are subscribed to both forums. Hope to find more help here!
Nathan
#2
12-05-2010, 10:54 PM
Quick update - I was able to make the car die in the garage by heavily spraying the O2 sensor wires (under the car, not in the engine bay) with water and moving them around a bit. Perhaps just an old sensor and maybe some brittle wires/connections allowing water in during snow driving, shorting out, and messing up the fuel/air mixture?
I've sealed up the wire junction on the sensor with silicone and we'll see if the car still stalls in the snow.
In the meantime, I'm still seeing some substantial hesitation while accelerating, usually around 1800rpm. Seems like it's most common when the engine's cold. Any particular areas to look into?
I've sealed up the wire junction on the sensor with silicone and we'll see if the car still stalls in the snow.
In the meantime, I'm still seeing some substantial hesitation while accelerating, usually around 1800rpm. Seems like it's most common when the engine's cold. Any particular areas to look into?
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