What kind of damage could a MAJOR backfire do to a 3.2?

[efhughes3]

So, I stop at the drive-up atm @ 5:00am this morning in the rain on my way to a wet DE. As I'm driving out from under the awning, I have to go thru a waterfall. It douses the motor thru the ducktail, and the motor dies. No starty.

I push it back under the cover, and try it every couple of minutes. I finally get a couple of signs of life, and then BAM!!! It backfired as loud as I've ever heard. It then starts, and runs a little rough, but smooths out. I hear what I feel to be an exhaust leak underneath, like I blew a header gasket.

I go to the track, as the car's running OK, and do a few sessions in the rain, so no real abuse. I'm driving home, and it seems like it's off power a bit, nothing major, but just doesn't feel the same.

I'll get under it tomorrow, but could a blown gasket cause it to be off pace a bit? What else could've been hurt? It starts, idles and runs "smooth", with the exception of the exhaust leak. At least, what I think is an exhaust leak. I've had enough cars with headers in the past to know what this sounds like, and I'd bet thats what I have here, but wanted to check for other parts that could've gotten hurt in the explosion.

By the way, Clewett wires, which I'd not had any issues with, but others have-that's what killed the motor, I'm sure.

[john walker's workshop]

the airflow meter flap could get bent.

[efhughes3]

Thanks John, I'll pull the air filter and check that.

[stlrj]

The air boot over your throttle could have popped off and there still could be some condensation inside your distributor cap.

Joe

[Quicksilver]

Pouring water into the engine grill shouldn't kill it if everything in the ignition system is seriously up to snuff. Some of your wires might need replacing.

I like to make sure that all the boots are sealed to the cap, plugs, and sealed to the wires with dielectric tuneup grease. If it is going to get seriously wet you can spray the wires down with silicone spray. (you don't want to use much.)

As far as to why it may run rough... In addition to the list above you can check and see if there are any tears in the rubber 'elbow' that hooks the throttle to the airflow meter. Check to see if it popped the hose off that connects on the back.

Also, if the engine was warm a good douse of water can crack the distributor cap, which will make for a permanent miss that gets worse as it gets dirty and carbons up.

[Brother]

Might pull the plugs and see if there is condesation around the base of the wires.

Weird. My duck sat in the south texas rain all the time.

Maybe time to do the yearly maintenance items.


PS - When did the 928 enter the picture?

[stlrj]

Carbon core ignition cables like Cewett are a good choice but you also need to seal your distributor cap to make your ignition system totally waterproof.

After I hosed my engine, it kept right on purring like nothing happened and I was able to take off without the slightest hint of a miss.

Here's the proof:




Cheers,

Joe

[tshih]

you might have sucked water into the air filter and it may be soaked limiting the efficiency of air getting into the intake. Hopefully that's all but I agree with JW on possible AFS damage ($400-500).

[john walker's workshop]

3.2s seem to get lots of condensation in the distributor cap after sitting in the rain, for some reason. the older cars didn't really have this problem.

[efhughes3]

Nothing wrong with the intake. The noise is down on the bottom of the LH side, up near the heads. It sounds like an exhaust leak, but I can't pinpoint its exact location, sounds like either #1 or #2.

I guess my original question should've been: What could make a noise like an exhaust leak after a large back fire? Anything in the valve train, or heaven forbid, a screwed up head?

PS-It's the Clewett wires that killed the motor. They got doused and are not resistant to water.

[john walker's workshop]

a stethoscope with a hose or small tube on the end will find any source of noise. or just use a 3ft length of fuel hose in your ear. pass it around all the exhaust flanges and the area where the heads meet the cylinders. could be a broken heads stud.