Yeah, Yeah, it never rains in So Cal is a bunch of crap. It was pooring for nearly 2 weeks straight in San Diego (flooding) and my Fiero weathered it pretty well except.....

After the rains stopped at the middle of last week the car would stumble pretty bad upon acceleration
and then run normally. It has gotten better over the last few days as everything is drying up, but it still does this a little. I wonder if anyone has ideas as to where has the water flooded to (rear spark plugs) or what should I do? The car was running well after I fixed my ignition problems with new AC Delco ign module, magnetic pick up, and Delco coil. Advice anyone.

Help

You probably have condensation in the distributor cap. If you still have the old metal covers on the end of the wire , remove them as they promote grounding of the wires to the block.

Is it a 4 or 6 banger?I once had a 4, and when it rained water would drip on the neck of the air filter,then fill the air cleaner neck with a load of water on acceleration water could easily get sucked into the motor.

it is a 2.8 V6

Possibly the fuel pump is going out (if it fails to clear up in dry weather)or possibly the pulsater valve is bad (noise surpresser).Both are usually replaced at the same time,but instead of useing a pulsater valve,use a piece of ruber fuel line and a couple of hose clamps.If you have a fuel presure tester you can test the fuel pressure,by attaching it to the schrader valve.

usually, a problem running in rain is ignition related. like someone above said - condensation in the cap is #1.
then bad wires #2 bad coil/coil packs #3

oh, shoudla read the post, not the title....
new cap/rotor - probably got wet, and is now crusty
new wires - probably arced thru, and now has a path to ground

[This message has been edited by Pyrthian (edited 01-21-2005).]

Does this mean I need to replace my spark plug wires? That sucks I just bought MSD wires. And a new cap and rotor too? Thanks for the advice folks. I do still have the metal sleeves for the spark plugs should I first take them off, will it help?

quote Originally posted by blkpearl: Does this mean I need to replace my spark plug wires? That sucks I just bought MSD wires. And a new cap and rotor too? Thanks for the advice folks. I do still have the metal sleeves for the spark plugs should I first take them off, will it help?

Keep the wires! Just pull them off and put some dielectric grease in the ends - that'll seal them off, and make them easier to remove later.

Replace the cap and rotor. What'll happen is you get moisture under there - the water makes a nice easy path for electron flow - it arcs and the car runs crappy - it dries up, but the path that the arcing took leaves a very slight carbon trace - then it keep running crappy while you scratch your head going "but it's dry now?!".

I live in BC. It rains here. A lot. Like, a LOT....

(place right near here recorded 600mm (yes 24") of rain the last week)

If it happens only while it's raining more than likely it's the wires. I've only ever had that problem once on a 91 S-10 Blazer. I replaced the wires no problem after that. I could see the wires arcing to the block at night and it wasn't at the cap or plugs. The wires will break down and weather over time.

quote Originally posted by FieroGT87: The wires will break down and weather over time.

quote Originally posted by Blkpearl: That sucks I just bought MSD wires.

Yeah the wires have less than 2000 miles on them and are about 6 month's old. I will replace the cap and rotor soon and see what happens after that. Thanks for all the help, and that is some serious rain.

Check the little carbon pin inside the disributor cap and make sure it has spring tension. Sometimes that spring can get hot and lose it's ability to rebound. when it does it arks inside and can bounce.
Check for a spark leak at night in dark area. If it,s jumping spark you may be able to see where.
Sometimes it can be as simple as twisting the plug connector so the wire is not laying against a ground.

[This message has been edited by Wolfhound (edited 01-22-2005).]

Spray the wires, junctions and cap with silicone spray after it's dry. Really prevents moisture from getting into the wiring system.

Now that the rain has stopped here I have tried to fix the problem.

I noticed when the weather clears and the engine dries up the problem is eliminiated by about 65%. At low rpm and when the car first moves from a stop it will sputter a little and stumble (jerk, jerk, jerk, then go). It seems like water or something is choking it. You can hear a little sputtering before it moves smoothly.

I did check at night to see any arching and saw nothing. I have since replaced the cap & rotor plus the spark plugs. I saw some crustiness (not in my shorts!) on the connection from the coil to the distributer. But everything else looked normal. I am begining to think maybe it is the fuel pump or something like it. Even though it seems like it would be electrical/spark related because once the rain falls the damn car turns into a bucking bronco. Literally.

Anyone care to chime in?

personally .. i've seen a lot of aftermarker performance wires not like wet weather - id' try swapping on some fresh cheapo wires
i really doubt its anything internal beyond a watery-failed sensor..

its not the fuel pump - if the pump wasn't working you'd have no top end - it'd be starving the engine

Another thing to check....I get this occasionally with a downpour...check the air filter to see if its soaking wet. If it is, replace it with a K&N. They dont clog up when wet nearly as bad, and it will dry itself out where the paper ones dont.

aair filter or (possibly vaccum leak?)

A few things to check:
Remove distributor cap and on the base of the distributor you'll see two circle's with screens in them. Make sure they are clean.
If clogged/blocked will cause condensation inside the distributor.
Check electrical connectors to the coil, distributor, the O2 sensor, Injectors, and the map sensor.
Check all your electrical grounds. There are some braided wire grounds from the engine to the chassis. If corroded could cause all kinds of problems.
Check connections at the starter for corrosion.
Buy some Gumout Throttle Body Cleaner spray. If you have some carbon in the TB, this can retain moisture and swell blocking/restricting vacuum ports and the IAC port.

Thanks for the input guys. I will work on these things this weekend and post my results/findings.

Progress report:

Checked the air filter and it is very dry. I would say that is not the problem, it looks just fine and it also is fairly new.

Checked the throttle body and it does have some carbon buildup. Not horrendous but I will work on cleaning it out.

Distributer is fine the little screens are clean and connections are good.

How do I check the injector connections? and the Map sensor seems good (connections) The Oxygen sensor has carbon buildup at the base of it (near threads). I cleaned that up but otherwise it seemed ok.

Now here is what did help the car. It is running smoother now, and the problem of hesitation is about 85% gone. The grounds near the intake and decklid were cleaned up. And I spent 15 minutes cleaning the braided grounds at the bottom near the battery. This is what I believe helped the car out.

What other grounds should I go after?

Other ideas? I think I'm pretty close to getting this thing worked out.

quote Originally posted by blkpearl: Progress report: Checked the air filter and it is very dry. I would say that is not the problem, it looks just fine and it also is fairly new. Checked the throttle body and it does have some carbon buildup. Not horrendous but I will work on cleaning it out. Distributer is fine the little screens are clean and connections are good. How do I check the injector connections? and the Map sensor seems good (connections) The Oxygen sensor has carbon buildup at the base of it (near threads). I cleaned that up but otherwise it seemed ok. Now here is what did help the car. It is running smoother now, and the problem of hesitation is about 85% gone. The grounds near the intake and decklid were cleaned up. And I spent 15 minutes cleaning the braided grounds at the bottom near the battery. This is what I believe helped the car out. What other grounds should I go after? Other ideas? I think I'm pretty close to getting this thing worked out.

There should be a ground on the firewall side of the trans attaching to the frame rail just under the air cleaner housing to the trans. Some cars have a braided wire and some just have a black wire. This one usually gets forgotten or broken if the cradle has ever been lowered. I have mostly seen them broken/detached on manual trans cars because of the removal during clutch changes.
Have you check the coonections on the back of the starter? There should also be a power block mounted on the paasenger side wall between the battery and the strut tower. These should also be checked. You can also check where the negative battery cable attaches to the engine block as well. Make sure the cable attaches to the engine block or head, Not the timing cover. We had one where they attached it to the timing cover and it caused some problems.

The injector connections to check are first, Just above the water pump/timing cover should be a 6 pin wide connector. This is where the injector harness is attached to the main harness. The individual injector connectors should be OK. They are under the plenum. You should be able to see them. If one looks like it isn't seated all the way, You can reach in wit a flat-bladed screwdriver and push them down. I wouldn't worry about the individual injector connects unless you've had work done recently where they were removed.

Glad to hear it's running better.

[This message has been edited by Oreif (edited 04-10-2005).]