Well all I can say now is, "it really can happen." My 94 has had leaky injector syndrome ever since it sat for 3-4 months last year when I had it apart for an opti replacement. It sat forever because I was in the process of building a new home and just didn't have time to mess with it. Well at any rate after the long sitting period the car developed one or more leaking injectors. It never caused any great problems, just the occasional hard start (turning over for 5-10 seconds before starting) but it would always start and blow the extra fuel out the pipes and all would be fine. Car ran great otherwise. Well today after going to see a movie at the local theater I get back in to start it and after about 5 seconds of cranking BOOM a very loud explosion is heard under the hood followed by lots of smoke creeping out from under the hood. I immediately pop the hood and check for fire or some other damage. I spend a few minutes blowing at the smoke to clear it up (which I find extra funny since I am a Captain for the Federal Fire Service) the smoke seems to stop after a minute or so and I the only thing I can see out of place is the explosion blew the valve cover gasket out from under the valve cover on the drivers side but only up near the intake side of the head. Oh it also blew my fuel rail cover off on that side as well. So study the situation for a few minutes and decide there is nothing else that I can see wrong so I try to start it again. It fires up and sounds fine so I go back out to check and see if there is oil pouring out of the valve cover. Nothing is leaking since the gasket is still holding at the exhaust side of the head. I weight the cost of calling a tow truck or just trying to limp her back home as it would have been a very expensive tow (well over $100) so I drive her home pulling over to check for oil leaks every 10 miles or so. Made it home without incident somehow.

After reading about a similar incident a few weeks back here on the forum about a leaky injector causing an explosion and thinking NO WAY I guess I was wrong. I guess I will be changing my injectors now. I was just trying to avoind having to by 2 sets. I will be doing some serious modding to the car and I will have to eventually get at least 60# injectors but I suppose I will have to pony up for a set of 22's or 24's to drive it in the meantime or just park it until I start modding.

Moral of the story: Yes it can happen. I am just thankful that it didn't do more damage.

 

Yeah that sounds pretty scary. I'd be worried about the valve train now though if it actually exploded like that. Just hope it didnt do any serious internal damage.

 

Try having them professionally cleaned. Did you change your skivvies?

 

I guess I will say it, and see if it happens to me,
how is that possible?

any idea behind the science of it? it just does not make sense to me.
why the valve cover?

 

I was thinking the same thing.

 

I'd check your oil, I think it has fuel in it. That's why the valve cover blew.

 

 

if fuel is leaking past the rings, and there's gas in the oil, I wouldn't worry too much about it. just get it warm, and go for a lesurely drive, but don't hot foot it.
In the war years, planes were outfitted with fuel dilution systems that added fuel to the oil to make it thinner in extreme cold conditions.
Alll it takes to get the fuel out, is getting it up to operating temps for about 2 hours, and the fuel evaporates.
This even works when the ambient temp is down to -20.
after all, if you were gas, and it was 190 degrees, wouldn't you vaporize and go into the PCV valve?
So the excuse that it's cold outside doesn't make any difference.
But it is a better idea to drain it out and refill with new oil if you are going to let it sit.

 

Dude - if there was enough vapour to cause that to blow, there was enough fuel to cause the oil to loose all lubricating properties.

Do NOT drive that car until the oil is changed.

 

 

You would think that but this leaky injector thing has been going on for a while now, and I just did an oil change maybe 50 miles ago no noticable difference in the oil at all. I will assume that it's just a fluke thing. Either way it's not a biggie to me, I have been just nursing the current engine along until I get some free time to build the low compression short block I need to install the T trim and multiple other parts I have sitting in boxes. Just been a hectic year with building the new house and barn and god knows what else. I didn't contract it out, we actually built it ourselves. So time has been short for some time, but we are at least in the new house and barn is almost complete. So time for the car is coming. If I just start tearing it apart it will force me to install all the new stuff. I just know that if I start tearing mine down before I fix Jens(Vettebabe) car she will be pissed. It did scare the crap out of me though. I thought it was on fire. I could already hear the guys at work...

Lee

 

Interesting... you guys sure are brave! Building your own house? Did you actually pound all the nails?? or did you act as your own GC? It sounds like you literally pounded all the nails! As I said... brave... crazy, sure, but brave.

I still have bastet44's 87 apart, I am off to the parts shop for supplies. Need to get moving on that puppy!!

How is Jen's vette doing? How is Jen doing?

 

Jen is doing fine, her vette on the other hand not so much. When we moved I had to push it up on the car trailer. Nothing major (I think)just no time to troubleshoot the problem. Something electrical. Wiring was all hacked up to put in a fancy alarm by the guy that owned it after she sold it the first time. So I am still in the process of tracing wires and removing alarm and stereo parts. Nice stuff just a **** poor job on the install. And since I am not a fan of aftermarket alarms on C4's it's got to go. As for pounding the nails, yes I pounded the nails. Not all of them on the house, but every last one of them on the barn. It's a 10 stall barn 48 X 86. 81 yards of concrete for the foundation we poured it all in one day. Fun fun....so I need some car time now to say the least.

Lee

 

The trouble with that is the engine seals will rot out as the engine oil is warming up before it evaporates.

 

I would have thought that the PCV valve would have been blown out of the valve cover (and through the hood?) before the gaskets would have moved. Wow. Scary.

 

Yeah, me too. But the PCV is still in place, in fact all the vacuum lines were still in place. I figured the vac lines and the intake boot would have been blown off. Oh well.


Lee

 

With your car being a 94, i dont see why you cant throw the #60 injectors straight in and just recalibrate the tune. You can flash the ECM in a 94 as many times as you like, so i cant see any reason why you couldnt do that.

 

Because if I had the 60's in there right now they would have to be running so low a pressure and small pulse width that it would probably effect driveability to a point. Not to mention that when I do the new motor I want everything to be new at the same time, just a pet peave of mine. I try not to recycle much of anything on a new project, I rather save the old stuff for later or give it away to guys that need stock stuff.

Lee

 

Roger that, no worries.

 

Interesting to see this post. I've been absent from the forum for a while, and I ventured back to discuss a recent problem I've ran across and it seems to fit into this post. I'll try not to ramble on too much.

I think I solved my ultimate problem, but I find it hard to believe it was the real cause. Long story short, the last few times I drove the car it would intermittently run terrible over 2k rpm. Thought I was loosing an opti again, but no codes. With bad weather this fall the car sat in the garage a lot. A few times the starter wouldn't turn the motor over. I finally could get it to turn a few times but not start. Keep in mind the car had probably not been run over a month prior. After trying to start it I realized I had a STREAM of fuel/oil mix coming out of the bellhousing. That's not good. I drained my pan and I estimate I had approx 1 gal of gas in the crank case. I drained 11 qts out of a 7 qt capacity pan. I have no idea when the fuel started dumping in. I immediatly suspect a leaking injector. But I can't find any problems on the top end. I pulled the rails off, the injectors hold pressure fine, and the regulator isn't leaking. The cool thing was after changing the oil I wanted to see how the injectors were spraying when out of motor so I hit the key and the car ran for about 5 seconds with no injectors in it. There was still some fuel in there. Anyway, everything on the fuel side seems to check out, but now I suspect my problem might have been a loose fit of the eprom on the chip piggyback board, and maybe the car was in limp mode the last couple times I drove it. I can't believe a bad tune would be that rich but it's the only thing I can find wrong. I also think the engine wouldn't turn over due to being hydrolocked with fuel. To me that says injectors letting fuel in as it sat over time. Anyway, after fixing the chip the car is running great again. However, now I have an oil leak out the back of the motor. Someone mentioned fuel wrecking the seals. So is my rear main wrecked? The oil leak is bad - lost about 2 qts in 5-10 min of driving. It's inside the bellhousing; causes the clutch to slip when you get on the gas.

So I guess my questions are is it likely that the fuel/oil mix passing by the rear seal ruined it? And also I believe it's possible to change the seal w/o dropping the pan or crank (just remove trans and flywheel). Can anyone verify that? I think the leak has to be either the rear main or the paper gasket between the block and seal carrier. With that much fuel in the pan, I'm glad I didn't have an explosion. Thanks for reading.