If I unplug a coil will I hydro lock that cylinder on fuel?

[Jon K]

I want to poll a coil off of a plug, Cyl 1 for instance and hook it up to my other ecu to see if it sparks. I know my engine will not fire on cylinder 1 ( i will leave the spark plug in ) but will it load up with fuel and hydrolock?

[joshua43214]

It will just flood that cylinder out and possibly wash out the rings. put an old junk plug in its place, plugs are never the same after they have been flooded out.

[Gearhead]

Like Josh said, for the little bit of atomized fuel squirted in the cylinder with each pulse, you'll wash the cylinder walls down at most. Hydrolock won't be an issue as most of the unburned atomozed fuel will go out the exhaust valve with each cycle.

[pingu]

Am I right in thinking that what you're planning is equivalent to having a defective coil on cylinder 1? I've never had a duff coil but I presume the engine just runs lumpy rather than smashing itself?

[fkong777]

Injectors will not spray enough gas to fill up the combustion chamber before it gets blown out of the exhaust valve on the combustion cycle. So No it should not hydrolock..

however you will have raw fuel going into the exhaust.. if you have a Cat in the car it can damage it.

[Jon K]

Am I right in thinking that what you're planning is equivalent to having a defective coil on cylinder 1? I've never had a duff coil but I presume the engine just runs lumpy rather than smashing itself?


It runs retardded - i've had it happen by failure.

[Jon K]

What do you guys think of just pulling the fuel pump relay. I just need to crank the engine to see if I am getting spark.

[Gearhead]

Yeah, don't want to damage your cat. Your car might end up doing this:

http://members.cox.net/wdixon27/pussy.gif

[Bill R.]

is capable of adjusting each cylinders fuel needs individually. It monitors the primary ignition circuit so if it see's the coil not firing then it will in theory not open the injector to that cylinder after it sets a code. If it doesn't you won't hydrolock the cylinder or wash out the rings, but you may over load the cat with raw fuel and damage it depending on how long your going to do this.
If you want to run it for a while like this disconnect the injector harness to that cylinder.




I want to poll a coil off of a plug, Cyl 1 for instance and hook it up to my other ecu to see if it sparks. I know my engine will not fire on cylinder 1 ( i will leave the spark plug in ) but will it load up with fuel and hydrolock?

[Morgenster]

What do you guys think of just pulling the fuel pump relay. I just need to crank the engine to see if I am getting spark.

Wouldn't there still be residual pressure on the fuel lines and rail?
It'd still be less messy.

[Jon K]

is capable of adjusting each cylinders fuel needs individually. It monitors the primary ignition circuit so if it see's the coil not firing then it will in theory not open the injector to that cylinder after it sets a code. If it doesn't you won't hydrolock the cylinder or wash out the rings, but you may over load the cat with raw fuel and damage it depending on how long your going to do this.
If you want to run it for a while like this disconnect the injector harness to that cylinder.


Bill is it easier to just pull the fuel pump relay?

Also - if i unplug all the injectors from the stock ECU, does it do anything weird like retard timing a bunch?

[Bill R.]

start the car and allow it to run until it stalls to use up residual pressure in the lines. I don't know if it will retard the timing if you disconnect all the injectors but for testing purposes do you care?



Bill is it easier to just pull the fuel pump relay?

Also - if i unplug all the injectors from the stock ECU, does it do anything weird like retard timing a bunch?

[fkong777]

OH you are just going to crank it a few turn? then it shouldnt be a problem.

[Jon K]

start the car and allow it to run until it stalls to use up residual pressure in the lines. I don't know if it will retard the timing if you disconnect all the injectors but for testing purposes do you care?



Not technically - but I was hoping I could maybe do a fuel map for idle and a little bit off idle by using stock ECU for ignition so when I swap over to ignition control I've got a working fuel map. Hrmph.

[Bill R.]

newer coils used on the m52 if your going to use a standalone ignition system since the m50 coils are 30k volts output and the m52 are 50k volts output.. especially on a turbo or super charged car where the higher cylinder pressure tends to blow the spark out..I'm assuming your standalone would have enough current to handle the higher output coils

[Jon K]

I am pretty sure the higher spec coils wouldn't be a big deal - people run all sorts of crazy coils... the current load can't exceed 7.5A per coil during dwell.. but that would be 100% dwell which the coil will never run.


Got any of those puppies laying around?