my c4 engine locked up at start up
06-22-2018, 07:02 AM
#1
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my c4 engine locked up at start up
93 C4 87000 mi I tried to start engine turned over 2 times and locked up . Engine ran fine previous day I parked it in my garage got in to start and it just went bang and apparently locked ? has this happened to any one . my guess maybe timing chain
06-22-2018, 07:16 AM
#2
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Serious damage can occur if that happens, especially if you attempt repeatedly to start the motor with a "wet" cylinder.
So, my recommendation would be to pull the sparkplugs and check them each for signs of water (coolant).. And, with the plugs out, spin the starter to see if a cylinder spits water.
Last edited by Paul Workman; 06-22-2018 at 07:18 AM.
06-22-2018, 08:13 AM
#3
Race Director
Are you 100% sure its "locked up" ?
A bad opti can do some crazy stuff. Although a bad fuel injector can easily cause the hydro lock condition being described above.
Either way, the best course of action is probably to pull all the plugs and crank it over again. Do something to disable the ignition system before you do, just in case a cylinder is full of fuel.
A bad opti can do some crazy stuff. Although a bad fuel injector can easily cause the hydro lock condition being described above.
Either way, the best course of action is probably to pull all the plugs and crank it over again. Do something to disable the ignition system before you do, just in case a cylinder is full of fuel.
06-22-2018, 05:44 PM
#4
It turned out to be the fuel pressure regulator.
it has a diaphragm and when it leaks, fuel pours right into the cylinders
good luck
Last edited by llesg; 06-22-2018 at 05:45 PM.
06-22-2018, 06:39 PM
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locked up C4
What you're describing is a classic example of water in a cylinder, aka "hydro lock".
Serious damage can occur if that happens, especially if you attempt repeatedly to start the motor with a "wet" cylinder.
So, my recommendation would be to pull the sparkplugs and check them each for signs of water (coolant).. And, with the plugs out, spin the starter to see if a cylinder spits water.
Serious damage can occur if that happens, especially if you attempt repeatedly to start the motor with a "wet" cylinder.
So, my recommendation would be to pull the sparkplugs and check them each for signs of water (coolant).. And, with the plugs out, spin the starter to see if a cylinder spits water.
06-22-2018, 06:42 PM
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Melting Slicks
06-23-2018, 08:33 AM
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I also vote for injectors, had it happen on a 90 ZR-1. Pulled plugs turned over fine and blew all the fuel out. Be sure to pull the fuel pump fuse first you may also want to place a few rags around as not to get fuel every were. If this works do as others stated drain the oil. replace the injectors or pressure regulator once you find out what is bad.
06-23-2018, 11:11 PM
#11
Melting Slicks
Turning an engine over if you suspect fuel is in it with the starter can be risky. If the fuel blows out all over the place and the loose plug wire sparks it off, you may have a bad day. If you happen to get the fuel blown all over you, THEN the ignition lights it off you will have a REALLY bad day.
If you take all the plugs out, it is fairly easy to bar the engine over with a socket on the alternator pulley. Don't risk fire or a really bad burn.
If you take all the plugs out, it is fairly easy to bar the engine over with a socket on the alternator pulley. Don't risk fire or a really bad burn.
06-23-2018, 11:22 PM
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Or you might put some paper towels near the spark plug holes to catch any fuel "spurts". After all you don't need to crank more than 4-5 revolutions.
BTW, I suggest you pull the injector & FP fuses
You can pull the vac. line off the FPR to see it there is a smell of gas from a bad diaphram.
BTW, I suggest you pull the injector & FP fuses
You can pull the vac. line off the FPR to see it there is a smell of gas from a bad diaphram.
Last edited by 65Z01; 06-23-2018 at 11:23 PM.
06-24-2018, 06:13 AM
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St. Jude Donor '05
hook up a fuel pressure gaue to your shrader valve once the plugs are out you should have your answer.
06-24-2018, 06:57 AM
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I agree with killing the spark, can be done by simply removing the coil wire or unplugging the module . After 24 hours there will be very little fuel left in the cylinder it will leak by the rings into the oil.