hesitation in the rain ?

[Jerseyj]

Hi all,
I'm far from an expert and hope someone has run across this before.

I have a 1989 Forrester with about 140K miles, regularly serviced. I've
noticed this problem starting several years ago but have not been able
to figure it out.

When there's a heavy rain going on, and I get in the car and start up,
there's severe hesitation. I can add a bit of gas or floor the gas and
the RPM's don't change out of the normal range, I can hear the engine
racing, but the car hardly moves along, or does so slowly with a jerking
motion.

NEVER have this problem in dry weather.

After driving for a while, the hesitation goes away.

Any clue ???

 

[Edward Hayes]

Ignition system. Probably spark plug wires and or connections. When was you
last tune-up??

 

[Carl 1 Lucky Texan]

Classic sign of bad high voltage ignition component(s). You may have a
cracked 'coil' or bad wires. Soemtimes the symptom can be duplicated
(or, in the dark, seen as sparks!) by spraying a mister bottle of water
around under the hood while idling.

Carl
1 Lucky Texan

 

[Jerseyj]

Don't recall, but the car gets serviced as reccomended by Subaru.

Jerry

 

[Jerseyj]

This something that the dealership can diagnose ?

Jerry

p.s. but why would the car engine race but RPM's not go up if it's an
electrical problem ?

 

[Carl 1 Lucky Texan]

manual or auto tranny?

Hi all,
I'm far from an expert and hope someone has run across this before.

I have a 1989 Forrester with about 140K miles, regularly serviced. I've
noticed this problem starting several years ago but have not been able
to figure it out.

When there's a heavy rain going on, and I get in the car and start up,
there's severe hesitation. I can add a bit of gas or floor the gas and
the RPM's don't change out of the normal range, I can hear the engine
racing, but the car hardly moves along, or does so slowly with a jerking
motion.

NEVER have this problem in dry weather.

After driving for a while, the hesitation goes away.

Any clue ???

 

[ismlv]

You know, I have a similar problem on my 99 SUS with 86K miles. It's normally garage kept but we bought another old VW Bug a while back so
the garage is taken up. About a year ago, I started parking the Subby outside and noticed that on wet mornings (rain or dew) when I first
started up, it bucks and chugs like it's going to stall and the RPMs are very low (about 200RPM). I can press the gas a bit and keep it
steady but at a stop light I have to sit on the gas a bit. This happens for only a few miles and then it's fine. I have all the scheduled
maintenence done by my dealer and told him about this on one trip last year not long after it started happening. They said it's likely the
Idle Air Control valve and cleaned it. It MIGHT have helped for a few weeks but then it started happening again. I'll have to check my
records and see when the spark plug wires and such were last looked at. Since I'm approaching 90K miles, I suppose I'll soon be due for
another major tune up.

 

[Jerseyj]

Automatic.

manual or auto tranny?

 

[H]

I had something similar on a VW after a drive in heavy rain. Turned out
it was the connections on the engine computer that were wet/dirty. It
took 1h for my mechanic to diagnose and fix. Cheap !

H

 

[Chris Phillipo]

This something that the dealership can diagnose ?

Jerry

p.s. but why would the car engine race but RPM's not go up if it's an
electrical problem ?

How can the engine race without increasing RPMs? I think maybe you are
hearing the starter motor failing to disengage from the flywheel.

 

[Todd H.]

Hi all,
I'm far from an expert and hope someone has run across this before.

I have a 1989 Forrester with about 140K miles, regularly serviced. I've
noticed this problem starting several years ago but have not been able
to figure it out.

When there's a heavy rain going on, and I get in the car and start up,
there's severe hesitation. I can add a bit of gas or floor the gas and
the RPM's don't change out of the normal range, I can hear the engine
racing, but the car hardly moves along, or does so slowly with a jerking
motion.

NEVER have this problem in dry weather.

After driving for a while, the hesitation goes away.

I had similar problems with a Mazda 626 several times.

Replace the plug wires, and I bet a quarter that yur problem goes
away.

If your car has a distributor, check the cap for cracks, and if it
does have a crack the distributor may be fouled (moisture induced
corrosion of teh contacts). But, given the timing of your issue,
moisture induced arcing caused by worn out plug wire insulation has my
bet.

Best Regards,

 

[Todd H.]

This something that the dealership can diagnose ?

Possibly. Cheaper just to replace the plug wires. If you've never
had that done before it's probably the cause. And they're pretty
cheap and dead simple to replace yourself.

Replace one wire at a time so you don't screw up the firing order.

 

[NitroTrike]

Someone said "why is the motor revving but the rpm's not going up" So the
engine is revving but the tach isnt moving (?) Sounds like a grounding issue
(subaru was pretty cheap whith their grounding straps) Check all the grounding
points. There are even "grounding kits" out there (just check any subaru forum)
Also ive seen a "failing" alternator cause weird things. Remember electrical
components dont like moisture

 

[Guest]

Someone said "why is the motor revving but the rpm's not going up" So the
engine is revving but the tach isnt moving (?) Sounds like a grounding issue
(subaru was pretty cheap whith their grounding straps) Check all the grounding
points. There are even "grounding kits" out there (just check any subaru forum)
Also ive seen a "failing" alternator cause weird things. Remember electrical
components dont like moisture

Hmmm...my Baja takes about 4 Revs to start when cold. If I immediately shut it of and then try again, it fires immediately. Sometimes it will start (4 Rev type) and slowly drop to 0 RPM. No problem re-starting, or otherwise. I wonder if it's a grounding strap problem. Porsche can develop the same problem.

This is a Subaru forum, anyone here know about the straps?
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