Low on power after driving through flood!

[Petros]

Hi all,

Well, after all the massive snow we had in Dec, we then got warmer weather and rain. The results was massive flooding in the state.

Our house is high and dry and perfectly safe, but I had to drive though a flooded creek that was washing over the roadway several times. Mostly this is okay, but one morning it was especially deep, so I crept in slowly but then the engine started to sputter when the water was up to my head lights!! I reved the engine quickly and slammed it into reverse and crawled back out. It appears the wave of water building up against the grill allowed water to block off/fill up the cold air intake tube up by the headlight.

Now here is the odd part, after clearing the water the engine keep reving higher and higher and the throttle was unresponsive. I shut it off real quick, before it reached red line, got out and opened the hood. I had considered this before, that water ahead of the grill would flood into the cold air intake sooner than it would if it did not have the cold air intake connected. So I removed the plastic flex tube (it gave me 6 more inches of freeboard above the grill inlet) and I looked over the throttle linkage/cable, but it seemed okay.

After I restarted it, it seemed to act normal, no over reving and the throttle acted normally. So I slowly crept back into the water, and although it got even deeper, it plowed through it just fine without the cold air intake connected, keeping my daughter and I dry and safe. Water over the roadway was about 200 feet long with as much as 2 feet deep in the middle.

After coming out the other side, the fan belts squealed a little, and the brakes were wet, but after that everything seemed normal. Except now after taking off down the hwy, it seems to be down on power at full throttle. IT is almost like it is not reaching full throttle now, or the secondary throttle is not opening. There is no miss fires or any other symptoms of a problem.

So here is the question: swallowing a little water into the air intake, but not enough to stall it or cause hydro-lock (engine damaging), what would cause it first to get stuck at full throttle, and than be down on power at full throttle?

Once I get a chance I am going to do a compression test (but it runs good so I doubt that will show anything) and get a closer look at the throttle linkage, adjustments, etc. I have driven it several days since then, and nothing has changed: drives normal except I am not getting full throttle power.

Any comments or ideas?

[Neu]

I"m ganna say it managed to get into the vacuum system which is causing some random things.

[sdoan]

Strange. How about water sitting in the exhaust pipe or muffler adding a little extra back-pressure at full flow?

[Petros]

I do not think water in the exhaust is possible, it was running when it went in keeping the water out, and I have since driven it about 200 miles. I would think it would have evaporated out from the hot exhaust by now, if not leaked out all the holes in my mufflers. Would water hurt a catalytic converter?

The vac system seems more likely, I was think something along these lines. There are so many little vac diaphragms, servos and other vac operated widgets on the carb this seems most likely. Yet another reason to switch to EFI.

[Neu]

Just give it a few days and I bet the problem will go away.

[danzo]

I don't think it would be a mechanical prob, most likely it's electrical. If your car did not have any vaccuum leaks then water cannot get it, and if it did it would have been immediatley sucked into the motor and burned up. Water got into a plug or switch and maybe shorted something. I would check all the fuses. If they are good then just wait a few days for things to dry out and I bet it will go away like someone else said.

Good luck, let us know what happens. Next time wait for Moses to help you out when crossing a sea!

[Neu]

I'm pretty sure it's vacuum, I've had it happen to me now that I think about it.

I was in a pretty thin mud hole, and i just kept going through it. Eventually I went through it a lil fast and water went a little bit over my hood.

It revved up pretty high on it's own, so i shut it off. Let it sit a minute, then when I started it back up it seemed kind of fine. when I got home (10 plus miles) it was running pretty hot and didn't want to start at all. I just let it sit overnight and it started just fine.

Weird now that I think back on it.

[Snax]

1 vote for installing a Weber and a Snorkus!

[Petros]

Thanks for the replys, it appears to have returned to normal after a few days of driving. That sounds like normal for this engine after ingesting water.

The really odd thing is, why would it go to an near full throttle condition when it ingests water?

[ARCHINSTL]

This would be kind of a nebulous reply, but - didn't some WWII piston planes (and maybe other vehicles) use water injection of some kind for "emergency" power boosts? It seems like I remember something about that.
Could this be a reason for the full throttle surges? I'd think, however, that this would be sort of a one-shot occurrence, as it would all be sucked up (technical term) at one fell swoop. Not enough to hydrolock, but atomized enough to give it some kind of the aforementioned boost?
Tom M.

[Neu]

I'm still saying it was vacuum related. the water was messing with some of the components.

[Petros]

The water injection on the wwII aircraft was used to cool the pistons when at full axillary power. It did not provide more power, it does not improve efficiency as many mistakenly think. The old air cooled engines were very ping and preignition prone, and they were rather fragile too. The metal and combustion technology was not very advanced as compared with today's average car. so they had two throttle settings, one a normal max power, and the other a "max military" power only to be used for short bursts, and emergencies. Every time it was used they risk doing damage to the engine. The water injection reduced the risk of damage by preventing ping, and keeping the peak combustion temps down. It has the effect of raising the octane rating of the fuel, but is also displaces oxygen. A better design, perhaps even better gasoline, would have not required this, but it was a quick fix that allowed them to use full throttle to escape the enemy for short bursts.

Water in the intake never helps power out put, if it displaces oxygen it will limit the max power output as compared to dry air input. Besides, when my engine was reving up I put my foot down on the throttle to see if tapping it might bring the speed back down, and the throttle felt like it was almost all the way to the floor. So how ever the water caused the engine speed to increase, it appears to have caused it by allowing the throttle to say open.

[Snax]

I have to disagree with you a little there on the water injection Petros. While water itself does not lend extra power to the combustion cycle, the increased effective octane allowed more power to be extracted from the fuel under high boost.

With respect to water in the vacuum system, my guess is that it most likely filled a diaphragm in the system which eliminated the normal compressibility of air that would otherwise be present. How that ties into the idle/throttle speed exactly I couldn't say.

[danzo]

I must also respectfully disagree, esp with your "Water in the intake never helps power out put" statement. Water injection is a common aftermarket mod, esp with the turbo/supercharger crowd. Water injection cools/densifies the intake charge - it does the same as the various types of intercoolers, cold air intakes, rain, cold weather, etc. By the time the charge gets compressed/heated in the cylinders it isn't water anymore. That's why your car makes more power and is more efficient in the spring and fall. You can experience the same effect if you eat at a southern outdoor restaurant in the summer that has the "misters". Patrons never get wet, yet they are cooled by sprayed water.

Concerning your Red Sea Adventure - you are assuming water got into your engine. I don't think this is the case. Since you are mechanically prudent you probably didn't have any vaccuum leaks, so no water got in that way. Even if water was somehow sucked into the intake (and somehow got past the air filter), it would have been a very small amount and would have been burned off quickly. Peeps worldwide pour liquid Sea Foam directly into their engines with no ill effects.

With our 20+ year old T4wds, for the most part the engine management systems are certainly not in tip top shape. When a fault occurs, it's really difficult to pinpoint the cause. Think of all the possible vaccuum leaks, all the emission switches/valves, all the supposedly water/air tight plugs in that system, etc. etc. that could be effected by water around the motor.

I'm glad to hear your car seems like it's back to normal. Hopefully I'm not coming across as a jerk!

[Petros]

I must also respectfully disagree, esp with your "Water in the intake never helps power out put" statement. Water injection is a common aftermarket mod, esp with the turbo/supercharger crowd. Water injection cools/densifies the intake charge - it does the same as the various types of intercoolers, cold air intakes, rain, cold weather, etc. By the time the charge gets compressed/heated in the cylinders it isn't water anymore.

wow, mythology lives on. any water vapor in the intake will reduce the max power out put because it displaces O2. Cooling the air has advantages, but if you used the same temp dry air, as the air cooled by evaporative cooling, the dry air will produce more power. While the cooler air does allow you less ping and more spark advance (higher pressures) and the evapative cooling could produce benefit. You just need to know what you are comparing it to. Same temp cool air dry vs. wet, dry is always better. So it is possible on a high compression engine to get some benefit, it just would not be as high if you had either higher octane fuel or used the same temp dry air.

And water is ALWAYS water, it is either vapor (gas), liquid droplets, or a solid (if it is cold enough). There is not enough energy to turn it into free H2 and 02, at lease not in any significant amounts.

The water injectors are mostly a scam, a number of reliable companies, including Consumers Union and the EPA have tested them, not one has help economy or power out put on a properly running engine.

The only benefit is you might be able to go to regular fuel if your car needs premium because of high compression engine, either due to carbon build up or by engine design.