I've replaced OPTISPARK almost 5 months ago and TPS with spark plug wires (TAYLOR 8mm) at the same time, since that time I had no problem with idle and start at all. Up until now...

Hard start with white smoke after start and gas smell started after I filled tank with 2 gallons of Premium (always use premium) from gas station that I don't like. Did it on my way home after work and in the morning it was hard to start. But after it started works fine, was just small hesitation while I was pulling out of the garage.
Same hard start with smoke after work.
Today those 2 gallons almost used up and I went to work. Hard start again. I wanted to fill it up with fresh gas after work.
But IT DID NOT START after work.

I was cranking it for long time and with gas pedal in floor.
Somehow I noticed fuel on my exhaust pipe and it even burst in flames from spark that originated from the cylinder that is closest to driver on the driver-side.

Later I brought 5 gallons of premium and added a 1oz of Lucas to that gas. Still no luck... it cranks but sometimes it even stops like there is resistance. (with main wire from Ignition module to OPTI disconnected I have same sudden stops while I crank).

Wire connected to Ignition module gives strong and steady spark.
Spark-plug from that cylinder that is close to driver on driver-side is clean, but overfilled with gas. And I have spark in cycles.

WHAT IS THIS?
bad fuel or my new DELPHI optispark with original acdelco unit inside saying bye-bye?

What should I look for? and Where?

This might help:
*Always use premium.
*Replaced Opti-Spark with TPS and 8mm Spark plug wires in middle of July 2012.
*Had no problem with start before this gas station.
*Before this gas station on previous fill up I've used few ounces of Lucas, but it was fine.
*Hard start and white puff of smoke with gas smell.
*No start at all when tank was almost empty.
*Strong spark from Ignition module ( before OPTI )
*Strong spark on Spark-plug driver-side closest to driver.
*Fuel pump is working
*Fuel appers on exhaust pipe connection after long cranking
*Spark fires this fuel ( where this spark comes from UNKNOWN)
*Spark plug upon inspection appears normal and clean
*No start at all..

HELP! What to do? where to look?

 

http://www.mainstreamtopics.com/foru...rt-diagnostic/

 

Stop trying to start engine until you go through the guide provided by vetteoz. Based on your description you may have an injector issue that is causing a hydrolock.

 

I had very similar symptom when my OPTI died. I assumed that this is because spark is irregular and this is what stops crank. Never thought of hydrolock.. Thanks. Now I think back then it was same hydrolock and I could've damaged the engine.

Well I didn't crank it today but let it sit.. and it leaked at the end of the day. Seems that it relieved the pressure from lines...

 

UPDATE! (Gas leak?)

Today I was going to do that test following vetteoz guide. But I was charging my battery.
While I was charging the battery vette was always in my sight during the day. And by the end of the day it started to leak fuel from underneath the engine. I've checked high pressure lines on top - all fine. Dry on the back of the engine. It seems like it was leaking from somewhere on the passenger side behind the exhaust.

Car was overnight in the garage without the battery and there was a dry puddle of gas underneath and it started leaking only after ~7 hours standing. Did not touch anything... just let it sit.

What is this? Where it could possibly leak?

I assume that this is the reason of my no start condition.

 

Check the FPR vacuum line and see if it is full of fuel. It could be filling up the manifold with fuel. Also see if the FPR is leaking fuel from any of its seals and running down the engine.

Just turn the key to ON for the 2 second prime to check for leaks. (NO start).

 

Have you looked at your oil? I have heard of a leaking injector dumping alot of gas into the engine in a very short amount of time.

My first thought reading your initial post was the fuel pressure regulator. I had a similar hard start, raw fuel, white smoke episode, and found the FPR was leaking on the manifold. Glad I found it before the Fire Dept would have.

Your fuel filter is located on the passenger side along frame rail just above the cat converter. Possibly it could leak from there, if the canister or the line is compromised.

 

The fuel filter is located under the passengers feet
Because tank is higher than the filter fuel will leak out there if connections on filter or return ( in the same location ) are faulty

Maybe but if hole big enough to leak ( on the supply side ) by gravity only then it should be spraying fuel out with the pump running when it is under pressure
A leak at the join on the return line would not give the problem you are having ( except danger of car catching fire with either leak )

 

I will do tmrw.
But so far there were no leaks whatsoever. When I was cranking I saw gas on exhaust manifold on driver side. But only after long cranking..

 

My oil is OK, but I do need to change it.. Its thin already.. I have change oil light for almost 3 weeks now.

Not the fuel filter for sure. It is dry - I checked. And I replaced it like 9 months ago (such PITA).
It is leaking from the engine itself and not the top part but somewhere behind the exhaust manifold..

 

It is leaking from the engine itself. I will check the filter again tmrw, but it was dry today.

My thoughts exactly.. Unless it just finally bursted..

Actually... when I was cranking car for long time I had fuel on the bottom part of the engine and even on the exhaust pipe itself.. Maybe I didn't look under the engine, at that time I was looking for the solution on the surface. Hmmm... I will do as pcolt94 suggested.

puzzling..

 

My next guess is to check the fuel lines from the filter running up to the rail. There could be a pin hole leak that sprays onto the block when the system is pressured up? Impossible for fuel to leak from the engine block itself. It has to come from the fuel line somewhere.

 

I think it's from the fuel line somewhere.. but i can't find schematic on the fuel rails. 95 corvette.
It seems like there are no fuel lines behind the exhaust manifold.
Haynes manual is no help

 

The fuel lines going to the engine are the two lines coming up along the wheel well on the passenger side. Can't miss them, they run parallel to each other and hook up to the fuel rail. One is the supply and the other is the return. From the engine, they run down along the frame rail to the fuel tank. If you have a leak, it is somewhere in the line from the engine to the tank, nowhere else it could be.

Now, at the fuel rail, the supply line goes to the fuel pressure regulator. It's right there, can't miss it. On mine, I had a leak where the fuel line went into the regulator. The o-ring inside had deteriorated. Found a puddle of gas on the manifold just below it.

Pressure up the system, do not start the car!, and closely follow the fuel lines from the regulator all the way to the tank. Even a pinhole leak will see significant flow as it's at about 42 psi. It is entirely possible that a pinhole at the filter could spray onto the block and make it appear to be leaking from somewhere else.

It is important that you find this leak before attempting to start the car for obvious reasons.

 

What puzzled me that fuel lines are clean and no leak on them.. leak was from engine. Now I know where.. my vacuum system was full of gas under high pressure. So eventually it went inside the engine...

 

I found a leak. It was Fuel Pressure Regulator.

Connected the battery and turn the key to ON and i hear hissss.. but no leak anywhere. So i disconnected the vacuum line from FPR Oooh my, how nice it is to be sprayed with gas all over the EVERYTHING

So it was leaking right into the vacuum line.

FPR replaced. But when i tried to start it.. it turns super slow and something resisting. So i stoped trying.

Checked oil. and OMG i have engine full of gasoline! it is 3 or 4 levels of oil but full of gas.

I'm afraid that something bad happened to the engine and it doesn't turn. But there could be a just simple hydrolock on both sides. triple or quadriple level of liquid inside the engine can cause the engine not to turn.

Any thoughts on what else should i check?

I'll drain everything and add oil with lucas tmrw. Is there are any precautions i should take before trying to start the car?

 

Any thoughts on what could be wrong?

 

Resolve the obvious first then proceed. Change the oil and filter and then see if it cranks properly. If there is still a problem, then next step would be to check/charge the battery.

But don’t go off in a different direction yet, I think there is a good chance the problem will be resolved after the oil pan is drained and a proper level is attained.

 

Well, if you have alot of gas in your engine, your oil is worthless. Gasoline breaks down oil. So I could see why there might be some 'resistance' as the rotating assembly is pretty much metal on metal right now. Thank goodness the engine didn't start.

First thing, as said before, change oil and filter, and buy enough for two oil changes. It might be a good suggestion to change plugs, or at least pull the ones in there to check for hydrolock in the cylinders.

When you change the oil, the first time, pull the coil wire and crank it for a few seconds, starting and stopping intermittantly. This will allow the pump to get the oil where it needs to be without combustion heating up the metal. You can look through the oil fill cap to see that oil has gotten all the way to the heads. Then run it for 15-20 minutes. This will help oil attach to bearings and cylinder walls and flush out any gas deposits. Then change your oil again. Be prepared to change oil in about another 200 miles to be safe.

Is all of this absolutely necceassary? Probably not, but considering what can happen, it's worth it.

 

Changed the oil with filter today added some Lucas. I had 5 gallons of oil/gas mixture in the engine..

So as I changed the oil and tried to crank it.. It was stuck. That was scary.. So I've tried to crank it 3 times with no success I took a wrench and rotated the engine carefully myself in both directions.. there was some resistance at some point and then it was fine. Tried to start it.. It rotates

It cranks but does not start.

So far I have checked:
1. The fuel pressure is 40 psi with some change (close to 41) and holding steady. No gas leaks anywhere now.
2. There is a pulse on fuel injectors. (they spray. don't know quality of the spray, but they do)
3. There is a spark on spark plugs ( didn't get a chance to check all of them though )
4. Spark plugs are wet with gas ( which is what expected at this condition )
5. Engine cranks but doesn't start..
6. I've checked the vacuum hose that goes in OPTI and there is a one way valve so gas didn't get in there. Tried to smell and blow inside of Opti vent tube and no smell or taste of gas. I assume it's clean..

One thing that is strange... spark on the spark plug is not as often as I guess should be.. I always thought it should fire more often when engine cranks. dunno, maybe it's normal.

Battery is right from the charger. (overnight slow charge, test shows that it's good. I think 660 cold cranking amps - test result.)