First off, the water was only about 4-6 inches in height, barely touching the undercarriage of the body. The road was flooded and everyone was crossing fine, but I made it about 1/4 mile across (Half, so total of 1/2 mile flood width) when the car stumbled and died. When I tried to start it, all I got was a click. Something kicked up in the engine compartment and shorted out, so the battery / starter wasn't strong enough to turn the motor over. Well after this happened they closed off the road for a 5 mile radius and my car was stuck in this water for almost 2 complete days. The day after it happened when I went to get my personal belongings from the car, I went ahead and took the battery out to charge it at the families house (I was out on vacation). This battery has given me problems before, and has always been on the weak side, I never got around to replacing it. After putting the battery in and attempting to start it, it still would not turn the motor over. It started to, but something wasn't getting enough juice. At this point someone showed up with a truck and offered to pull me out. We hooked up the chain to the rear axle and pulled her out. We grabbed some jumper cables and after some time of charging it started up. Lots of smoke from being flooded by gas, though. Anyway, car ran pretty decent after that. But when I got home I noticed it was idling very high when first starting it up. I had to romp on the gas pedal a bit to calm it down, and the idle went a bit lower. Well, fast forward to me getting home (10 hour drive, no problems with the car apart from the car idling VERY low and dying once when I got gas) The idle now surges badly when first started in the morning, and the aroma of gas. My tach doesn't work so I can't tell you the RPM but it feels like it jumps from 700-1200 and back down until it warms up. Even then it's erratic sometimes - but for the most part "okay". The big thing is the smell of gas which should hint as some sort of fuel sensor or control device, it sounds like it's feeding it too much gas and then backs itself back down or something. But when it warms up it seems to run fine. Does this ring a bell with anyone? Maybe one of the O2 sensors got wet and needs to be replaced, but would it do that if that were the case? Thanks everyone.

When I get home, I'll get some pictures of my car and the flood on here.

 

hearing that the tach doesn't work points me to the coil.

 

I though the tach got its signal from the opti on our cars. Not 100% sure though.

 

The 93 LT1 tach reads the RPM off the coil, via a filter. 94 and up gets the tach signal from the PCM, which gets RPM from the low resolution pulse from the optical sensor in the Opti.

 

Well I had it half correct for the year I've got

 

Can you get a voltage reading with the car running? Use a digital voltmeter.
Was the car running perfectly(i.e. no intermittent problems) before you got into the water?

 

I've had the tach problem since I replaced the motor in the car. It's a 95 in a 93 body. I won't be able to get ahold of a volt meter very easily. If I can, where would I attach it?

Thanks.

 

i was just curious where you're located b/c i literally just moved from montgomery,al about 2 weeks ago and the past 2days it has flooded and i had alot of friends and family get flood damage 2 there cars, houses, and property. sorry 4 the off subject question.

 

I was wondering if you are getting ~13.5 volts with the car running.

If the car was running fine before the flood, then I think you have some sort of wiring issue. Maybe water trapped in a connector.

 

Well, still having the issue. Any water stuck on a wire would've been dried by now. The motor still has a surging idle that goes up and down from 600rpm to 1000 when warming up in the morning with the smell of fuel. After warming up everything is fine. Although when idleing sometimes you can here the idle is a little off. Anyone have any ideas?

 

Any SES codes? What do the plugs look like? Any of them fouled or wet with excessive fuel?

What is your primed fuel pressure and your fuel pressure at idle? What is the cold(engine completely cold) resistance of the temp. sensor in the water pump?

If you don't have a digital mulitmeter, run down to radio shack and pick up a decent one(I prefer Fluke, but I don't know if you want to spend that much).

 

If it was all the way up to the floor boards I would imagine that your o2s got washed out if the exhaust isn't water proof. If the o2s are bad, that could cause the engine to make the car run rich while it tries to get the proper fuel ratios based off of o2 readings.

Only other cause of a fuel smell could also be the EVAP canister not purging fuel vapors into the intake manifold but I don't know why a car being in water would cause EVAP issues.

Do you by chance see any difference in idle stability between open loop (cold engine) and closed loop (operating temperature)?

 

Thanks for your response guys.

No SES codes. I did do the paper clip trick on the ECU and got codes that read rich. Plugs are fine. I would imagine they are doused with fuel during startup (because of the fuel smell) and they dry up after warmed up.

I haven't tested the fuel pressure yet, I'll have to stop by Autozone and grab a pressure tester. And when you say temp sensor on the water pump, I'm assuming you mean the thermostat? The water pump and thermostat are new(installed a few months ago), so they should be fine.

I actually just replaced both o2 sensors the other day hoping it would fix it, it didn't help any.

Well generally I thought the smell occured when it was running too rich? I think finding the reason for that should lead me to the problem.

That's exactly the problem. When the motor is cold, like when I go to work in the morning and start up the car - the idle is extremely erradic dropping down to 500 or so rpm then jumping back up to 1100'ish RPM (I'm guessing this because my tach doesn't work). During this you also have the smell of fuel. After about 10 minutes of warming up the motor stabilizes and it's running ok. But overall the idle even when warm is still slightly erradic. Hard to notice though.

 

The EVAP canister is located in the rear of the car by the gas filler tube and when under load - if memory serves correct - the EVAP solenoid kicks in and purges vapors from the fuel tank back into the intake manifold. When the EVAP is not working, you'll get a strong smell of gas on the driver's side because the vapors will build up in the charcoal canister and what not. But that said, I do not think that'd cause the issues you're describing.

Honestly your best bet would be to find someone that can do some logging for you with the engine running. I know when my o2 sensor fouled out, it seemed like my open loop fuel trims did not want to reset until I left the battery unplugged for awhile (making the PCM lose power).

 

There are two temp sensors on the LT1. One in the drivers head for the gauge and one in the water pump for the computer. If the one in the water pump is not working properly, it can cause running issues.

I agree with messenation that you are going to have to get someone to log the car or test some of the sensors with a meter.