Got a new one for you guys. 3800pro wasn't very helpful. 86 3800sc 3.5 pulley, otherwise stock.
I was at a test and tune and got to drag race my buddy in his LT4 Corvette. Fiero was pulling like a freight train as per usual, but after I let off the gas it sounds like I'm down a cylinder or two and it's just bellowing smoke out of the exhaust. I pulled into paddock and shut it off. When I went to restart it, it just STOPS. At the time I thought I was the first man on Earth to blow up a basically stock 3800, but when I got home I pulled the plugs out and an entire cylinder's worth of gas came pouring out of cyl 6..... I disconnected the fuel pump and spun the engine over with nothing in it and it spins super freely, isn't making any odd noises, seems happy. So what happened? Stuck injector comes to mind followed by maybe a bad regulator? What do I test here?
I'll hook a compression tester on it tonight and see if it's done for, I'd have to assume I bent a rod but maybe I got lucky.
I did win the race though.
(A side note: make sure you also unplug the coilpacks when spinning the engine that was just full of gasoline over or you'll set the front exhaust manifold and some of your ignition wiring on fire when the plug wire does what it's supposed to do and sparks. Ask me how I know. Thankfully, I keep a fire extinguisher in the trunk.)
[This message has been edited by Additivewalnut (edited 04-14-2025).]
Got a new one for you guys. 3800pro wasn't very helpful. 86 3800sc 3.5 pulley, otherwise stock.
I was at a test and tune and got to drag race my buddy in his LT4 Corvette. Fiero was pulling like a freight train as per usual, but after I let off the gas it sounds like I'm down a cylinder or two and it's just bellowing smoke out of the exhaust. I pulled into paddock and shut it off. When I went to restart it, it just STOPS. At the time I thought I was the first man on Earth to blow up a basically stock 3800, but when I got home I pulled the plugs out and an entire cylinder's worth of gas came pouring out of cyl 6..... I disconnected the fuel pump and spun the engine over with nothing in it and it spins super freely, isn't making any odd noises, seems happy. So what happened? Stuck injector comes to mind followed by maybe a bad regulator? What do I test here?
I'll hook a compression tester on it tonight and see if it's done for, I'd have to assume I bent a rod but maybe I got lucky.
I did win the race though.
(A side note: make sure you also unplug the coilpacks when spinning the engine that was just full of gasoline over or you'll set the front exhaust manifold and some of your ignition wiring on fire when the plug wire does what it's supposed to do and sparks. Ask me how I know. Thankfully, I keep a fire extinguisher in the trunk.)
ah. try lesving the plug out and cycling the key a few times to see if that injector floods or not. its either that or you lost all spark but thats rather unlikely unless it was hoth cylinders on that pack
ah. try lesving the plug out and cycling the key a few times to see if that injector floods or not. its either that or you lost all spark but thats rather unlikely unless it was hoth cylinders on that pack
Yeah I have complete faith the plug was firing since the other cylinder on that coil was dry. I have no doubts the injector is gonna just DUMP fuel when I cycle the key, I'm assuming it's as easy as just replacing the injector? And doing an oil change.
Yeah I have complete faith the plug was firing since the other cylinder on that coil was dry. I have no doubts the injector is gonna just DUMP fuel when I cycle the key, I'm assuming it's as easy as just replacing the injector? And doing an oil change.
probably. you might have a bent rod but lets hope not. i do enjoy seeing that fiero whip around the track when you post about it it could be a shorted harness but thats fairly unlikely but check anyways
probably. you might have a bent rod but lets hope not. i do enjoy seeing that fiero whip around the track when you post about it it could be a shorted harness but thats fairly unlikely but check anyways
I love whipping it around the track when it decides to be nice to me. Absolute worst case I'll go find another $300 junkyard 3800. Just sucks that I may possibly be the first man in recorded history to blow up a stock(ish) 3800SC
When I winged the engine over without plugs I didn't hear any knocking, but I guess it's probably not going fast enough to hear it if there was any.
Originally posted by cartercarbaficionado: probably. you might have a bent rod but lets hope not.
There is some element of luck involved, depending on the volume of liquid that was in the cylinder.
If the hydrolock occured with the engine near TDC or BDC, then crankshaft had a lot of leverage and ability to split things open. If the crankarm was near "horizontal", then damage is unlikely.
I hydrolocked my engine with a piston at about 48° BTDC, and it was okay after. I knew where it happened because the flywheel's ring gear teeth got damaged where it hydrolocked during the startup attempt.
I pulled the oil pan to have a look at the connecting rods:
I placed a short ruler on each connecting rod (as best as I could with everything still inside the engine block) to detect if any connecting rod had taken a banana shape.
I also wiggled the connecting rods fore-aft to make sure that they weren't binding and had a normal amount of endplay.
I'm curious to see what your investigation reveals.
[This message has been edited by pmbrunelle (edited 04-14-2025).]
I would suggest pulling the heads off and rotating the engine by hand. Compare the heights of the pistons at the very top of travel in the bores. They should be equal. If not a rod bearing let go or a connecting rod has been damaged or bent. Such being the case the engine is probably toast. .
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
There is some element of luck involved, depending on the volume of liquid that was in the cylinder.
If the hydrolock occured with the engine near TDC or BDC, then crankshaft had a lot of leverage and ability to split things open. If the crankarm was near "horizontal", then damage is unlikely.
I hydrolocked my engine with a piston at about 48° BTDC, and it was okay after. I knew where it happened because the flywheel's ring gear teeth got damaged where it hydrolocked during the startup attempt.
That's what I'm counting on here. There was a comical amount of fuel in the cylinder when I took out the plug so I want to say I'm likely in the clear. That and it would crank a couple turns AND THEN stop and hydrolock. I'm subscribing to the plan of just grabbing a used injector or 3 from the junkyard, putting the plugs back in, changing the oil, and listening for a knock.
and fixing the couple of now burnt wires from my stupid, stupid mistake.
