hydrolock?

[zedx]

my 93 has/had this very intermittent rough running problem. smelled like it was flooding out. wouldn't do it when I could get someplace to get the codes read.

shutting the truck off and back on would 99% make it run correctly again sometimes it would take 2 to 3 times but it would start every time.

well, it finally wouldn't start so I got a code reader and started testing the truck. cycling the key injects gas which is a good thing if it is metered, not if you have a stuck injector so the cyl was full of gas when I cranked the motor after replacing the MAF and TPS. got that hard thunk you get from hydrolock.

my question is what is the likely hood that I bent the connecting rod with this mess up.
I do not have the space or equipment to do a tare down. I'm figuring I do have the time and most of the tools can rent the rest to replace the motor if I have to.

 

[SixFoFalcon]

Was the engine running at all or were you just cranking it? At cranking speeds, I'm not sure the starter is strong enough to do much damage if the cylinder is hydrolocked. Honestly I wouldn't be too worried. Pull the plugs and crank it over w/ the gas pedal floored (this cuts the injectors) and see if you get a fountain out of one of the cylinders.

FWIW, cycling the key doesn't inject gas. It just runs the fuel pump in order to pressurize the fuel rail. The injectors don't do their thing until you start cranking the engine.

As for the rough running, I don't know what troubleshooting you've done but I almost always start w/ searching for vacuum leaks. The IAC and EGR can mimic a vacuum leak too, although they usually throw a code.

 

[rickcdewitt]

a compression test would show if you bent a rod

 

[289-tiger-]

Chock the tires, put it in neutral, negative off the battery(Keep it safe) Turn the engine with the correct size socket at the crank/balancer to see if the starter has simply locked.

Good luck

 

[zedx]

Was the engine running at all or were you just cranking it? At cranking speeds, I'm not sure the starter is strong enough to do much damage if the cylinder is hydrolocked. Honestly I wouldn't be too worried. Pull the plugs and crank it over w/ the gas pedal floored (this cuts the injectors) and see if you get a fountain out of one of the cylinders.

FWIW, cycling the key doesn't inject gas. It just runs the fuel pump in order to pressurize the fuel rail. The injectors don't do their thing until you start cranking the engine.

As for the rough running, I don't know what troubleshooting you've done but I almost always start w/ searching for vacuum leaks. The IAC and EGR can mimic a vacuum leak too, although they usually throw a code.

it did it at cranking.

the thing that makes me think it's not a vacuum leak is that you can be driving along just fine pull up to a stop light it's fine, pull up to another and it does it. turn it off and re start it and it runs fine. will act up for a few weeks then not do it for months. this time around it did it once and won't run right still.

is the injection system different than the others I have worked with? all the others give it a shot of gas when the key is turned on.

 

[zedx]

a compression test would show if you bent a rod

thought about that too. don't think it would affect compression test unless the valves aren't closing or the rings are bad. the first stroke may not raise the compression as high but after you continue the test to get the reading it would be the same because it is drawing in the extra air to compress.

I'm not figuring that it is bent like a pretzel but maybe enough to cause bearing damage which could cause more damage later and with my luck it would last till november when it's cold/snowing to go out. I'm stuck doing it outside so would rather do it now when all I have to worry about is rain.

 

[zedx]

Chock the tires, put it in neutral, negative off the battery(Keep it safe) Turn the engine with the correct size socket at the crank/balancer to see if the starter has simply locked.

Good luck

I did get it to start after the hydrolock but it ran like crap. same rough running smelling very, very rich.

 

[SixFoFalcon]

is the injection system different than the others I have worked with? all the others give it a shot of gas when the key is turned on.

Not if you have the pedal floored. Every EFI system I've worked on will cut the injectors if you have the pedal floored and you crank the starter. When you turn the key to ON, the fuel pump runs for a second or two to bring the fuel rail up to pressure. Then when you turn the key to START the injectors cycle as you crank. But if you push the pedal to the floor, the PCM senses this via the TPS and it will cut the injectors entirely. So you can crank all day long and the engine will not start. Useful for priming oil systems and clearing the cylinders if they are "flooded".

Off the top of my head, some things you may want to check:
IAC
TPS
CmPS
CkPS

Check the wiring and connector on each of them first, to make sure you don't have damaged wires or a corroded connection.

 

[SixFoFalcon]

thought about that too. don't think it would affect compression test unless the valves aren't closing or the rings are bad. the first stroke may not raise the compression as high but after you continue the test to get the reading it would be the same because it is drawing in the extra air to compress.

I'm not figuring that it is bent like a pretzel but maybe enough to cause bearing damage which could cause more damage later and with my luck it would last till november when it's cold/snowing to go out. I'm stuck doing it outside so would rather do it now when all I have to worry about is rain.

Actually it *should* show up in a compression test. It's not drawing in any extra air because you would be moving both TDC and BDC lower down in the cylinder. The swept area (and hence volume) would remain the same, but compression would be lower because of the extra CC volume. In other words, you'd be drawing the same volume of air/fuel in (you haven't changed the crank, just the rod), but there would be more headspace between piston TDC and the head chamber, so it wouldn't compress as much. Just like "short rodding" an engine. Now whether or not it would be enough of a reduction for it to register noticably during a compression test, I do not know.

 

[zedx]

fuel pressure regulator had a hole in the diaphragm.

figured that the injectors could be weak since the pressure overpowered at least one so I also replaced the injectors.