Redeasysport

Well with several recent ocurrances the subject of what happens when a cylinder gets washed with gasoline has come up.I would like to get everyones heads togther and come up with all the symptoms that could indicate this problem in one post.I will start with the obvious that there may be loss of compression due to wear. But I am really thinking along the lines of an answer like The engine may idle uneven due to compression problems. Can you share what symptoms led to finding this problem and what was needed to repair the damage.

Another question in this area is how long does it take before a gas leak into the cylinder does damage?

bogus

washing in it's own right isn't "damaging". It's running without oil. So the engine is rubbing the bare metal.

Having been the biggest victim of this of late, I don't notice any visable problems with mine at this time.

The best test is either compression or leak down. I prefer leak down. When I get gauges, those are the ones I will get.

Compression is good to show one thing - a huge leak - head gasket failure or hole in piston... otherwise, it's really kinda pointless.

Leak down, now THAT'S a test! There is an air source (compressor) and 2 gauges. On gauge shows the amt of air that had been pumped in, the 2nd, shows the air escaping. The rate of loss (leakage) is the key.

A compression test won't show leaky valves or dubious rings.

If you engine was the victim of a wash down, and you know it, I would suggest you change the oil, remove all the plugs, remove the fuel pump and coil fuses, and crank the motor. Blow out all the gas you can. Then, squirt a shot of motor oil into each cylinder, reinstall the plugs and crank. You don't want to blow the oil out, you want to spread it around.

Then, reinstall the fuses and fire it up. It will smoke like crazy for a few minutes, but otherwise, all should be ok.

BigC4

I don't understand what you mean about gas leaking into the cylinder?

Redeasysport

Well Bogus my car was "washed" for an undetermined amount by the original owner. As I discovered after I bought it the FPR was shot causing hard start problems by flooding the intake(gas leaking into the cylinder) but we know it can occur other ways too I.E. Leaky injectors the bottom line is raw gas in the cylinder. Now in my case not knowing how long this went on bothers me as the original owner let maintenance slip the last year or so as he was racking up 80,000mi in 4 yrs.

So what I am looking foir I guess is how can you tell(leak down test?)when a lot of damage has been done? In what ways will this affect drivability? I still have this ~2K vibration that has become a little intermittant lately. Of course as soon as I got the car the problem was one of the first things I fixed but was the damage done already?I must also add that all electrical and fuel systems parts are new and functional but when I am winding her out and I hit around 70mp-75mph(~2Krpm) I get a significant shudder in the car.I can feel it in the lower gears a little and even at park just reving the engine to that rpm. Now it has improved as the new parts were installed but it is still there most of the time. So I guess I am looking internal right now.

JAKE

Washing down the cylinder walls with gasoline kills the ring seal. Gasoline dilutes the oil that serves as a barrier between the piston rings and the cylinder wall. The rings actually ride on a film of oil which the gasoline will dilute. Without the right amount and viscosity of oil, you'll have ring to wall contact which will kill the seal pretty quickly.

There's really no way to say if damage was done; we'd need to know how long the engine was run, under what conditions and how much oil dilution actually occurred. In any event, it would just be a guess.

The way to determine if, and how much damage was done is with a dual gauge leak-down test. Leakage should be less than 10%.

Sure you can drive the car with more leakage than that, but power will suffer. You'll also see an increase in blow-by out of the PCV hole in the valve cover too.

Remember, too, that oil being diluted by gas hurts more than just ring seal. The gasoline will also dilute the oil in the pan which will effect bearing wear, camshaft/lifter wear, pin oiling, etc.

Jake

Redeasysport

So Jake you say the damage would occur pretty quickly?I assume that would be with a continuous washing but if it happens only on start up due to FPR failure it would take longer. Yes I am worried about the other lubed parts but since my engine runs well,idles well,and still gets good gas milage that any damage must be minimal at this point.Do you agree?

Some symptoms might be rough idling ,decreased gas milage,decreased power correct? Basically ring failure symptoms would be the first indicator that the damge is done right?

Red Tornado

would there also be a certain amount of black smoke out the exhaust as well?

Alvin

You could smell gas in the oil.

You see this alot with people who try to use used injectors. People don't understand that if a injector sits out of a car for a while it will get gummed up, affect spray pattern, fail completely, or probally leak.

I've personally seen them doo all of the above but leak.

One used injector i tested would squirt probally 20 feet like a really awesome squirt gun or something, while anthor delievered a nice 4 inch cloud of fuel just beyond the injector

JAKE

There are many variables involved in this so it's not possible for me to accurately say what, if anything, suffered the most, or if, in fact, anything suffered at all.

The amount of the oil dilution, temperatures, load on the various parts which depend on an oil film, how long the engine ran, RPM, splash, how critical oil is to that particular part, etc., etc.

I suspect the most heavily loaded part(s) would be show the effects first and would be the first to go; weakest link in the chain analogy. Also, all wear/damage may not show up immediately.

Let's say you scuffed the base of a flat tappet/lifter. That probably won't show up for a while. The wear may be gradual, but tends to accelerate over time. Eventually the base will become cupped and will kill the lobe it's riding on.

There are many parts in our engines that owe their very life to a clean, pressurized oil film and they don't take kindly to being deprived. I don't want to sound like the "prophet of doom"; these are just possibilities, not probabilities. Again, it depends on the variables.

All we can do is hope for the best. I've got my fingers crossed!

Jake

JrRifleCoach

Washed Cylinder Walls Symptoms?

Well for one, clean pistons!

Is it me, or do some topics just seem to demand an answer like this?

REDC4CORVETTE

If the FPR was that bad the engine would have locked up and not turned over.
Been there done that.My engine filled to the valve covers with fuel.
Drain the oil ,install new filter.
Just don't use an Accel FPR,They are the worst.
The damage that will result is low oil presure and a spunn rod bearing.
The starter would also need to be replaced soon if not already.
Cylender walls would be nice and shiney and the car would smoke pretty bad.

93 ragtop

Jake, if you dont mind I would like to ask 2 questions on this.
1. do you try to test the engine hot?
2. is the 10% leakage over a set period of time? ie 5 min.

Thanks and I apoligize for barging in on this thread if I am taking it away from its focus point.

Redeasysport

Welcome 93 ragtop your still on topic. It is about diagnosing and fixing. It is turning out like I wanted it to. Some good info coming out,food for thought as I have noticed a lot of FPR problems poping up around here lately. I am still guessing on mine since I have no smoke and hardly any other drivabilty issues that the damage at this time is minor in my engine.What may happen down the road????

Also in ref to the total flooding of the intake with FP failure the answer is not always. If the FPR is not totally fubar it can leak slowly into the intake causing the tell tale " Hard Start" issue.

bogus

when my AFPR started to die (I didn't know the cause yet) it was very slow to start. Once it DID start, there was a light mist of raw fuel out the pipes... and a smell of raw fuel.

Not good at all.

JAKE

Only if you're not the one with the washed walls. Then it's a different story.

Jake

JAKE

the dual gauge tester will come with instructions for it's use, but, yes, the engine should be warmed up first.

This allows for normal expansion from the heat. Piston should be brought to TDC.

The first gauge (the one closest to the compressor) shows the incoming air pressure and has a connection for the hose that runs to the compressor. Most of those have an adjustable **** to allow pressure adjustments.

The second gauge has the connection for the hose that screws into the spark plug hole. That gauge can be of the same type as the first one; just showing psi numbers from, say, 20 psi to 200 psi, or of a different type that reads out directly how much leakage is occurring.

Only takes a few seconds to get a reading. Remember, the longer you take to get your readings, the cooler the engine will become. If you encounter any kind of long delay, it's best to re-fire and re-warm the engine.

What you want is for the engine temp to have as little variance as possible, cylinder to cylinder. So if you start off checking #1 with a coolant temp of 200F, then, preferably, all of the others should be checked at the same temp.

Jake

Jake

REDC4CORVETTE

Also in ref to the total flooding of the intake with FP failure the answer is not always. If the FPR is not totally fubar it can leak slowly into the intake causing the tell tale " Hard Start" issue. Correct
If you push it like I did and believed a new FPR can't fail,well it will only cost you money .
Now I run an Aeromotive FPR.
Starters for a 94 are not cheap eather.(because you are stupid)Join the grind!
I did change my oil 3 times after words ,150 mile between changes.
The second oil change I put durablend in .The last oil change was Mobil 1.
That was 2 years ago and ,no problems since.

JTHVETTE

I fully understand what occurs to cause this problem, but isn't the fuel pump suppose to be off when the engine is turn off? I can see it possible to occur some when a fuel injector(s) is/are leaking while the engine is running, but I would think it wouldn't be enough to pour into the crankcase. I,m curious to know when the dumping of raw gas into the engine occurs , engine on or off? Given, neither is good for any engine.

Thanks,
JTHVETTE

Redeasysport

When the FPR starts leaking the pressure in the rail will pump gas into the intake when the car is shut off. Sure it is not enough to cause Hydrolock but will cause a "flooded" restart. Eventually enough leaks into the oil to ruin it and or it leaks worse and does fill the cylinder with the key on.

Red Tornado

fascinating. i have an accel unit with no problems.