I am stumped and at a standstill...

[FastPAt]

Basically the problem is my #4 Cyl is doing nothing. When I run the engine all my other pistons are moving fine, when I disconnect the wiring from the coil on all the other cyl. the engine sounds different, but on #4 nothing happens stays the same.
It causes the car to shake, idle high, then low, makes it sound loud and rough. But the car still drives fine, just not as powerful.

I have tried everything I could. Swapping 2-3 differnt plugs and coils into the cyl. got a brand new wiring harness, new ignition module, coils are brand new Yellowjackets, the plugs only have roughly 5k on them, and they all work fine in my #1, and #6 cyl. compression is 90 - 100lbs in the cyl. when I pull the plug out the tip is damp and has gas on it, and when I look down the top of the piston looks damp, so gas is getting in there.

Now theres one of two posssabilities that I have come to a conclusion and I am not sure if this might be a common problem with RB20 engines, so I might as well give my thoughts out there and see what people think.

When I remove the oil cap and smell the oil (or the dip stick) it has a strong gasoline smell to it, and the oil is extremely thin, even when not hot. So I am thinking maybe the injector has been flooding the #4 cyl. causing gas to seep down the side of the piston and thining my oil, but then why isn't that one cyl. just not running to rich? I don't seem to get a spark at all!

So it brings me to my second theory of why it might not be firing, it might be an electrical problem, everything from the Ignition module to the plugs is pretty much brand new, and works perfectly fine, I have determined that the coil is sending a spark to the plug, as I have lifted it while the engine was running and noticed little archs and 'popping' noises when I did so.
Could this be a ECU problem? If so how would I diagnose a problem with my ECU?

I have yet to change the oil completely to see if that might be the case, I am planning on draining the oil today, and pulling out all my plugs, and one cam cover to let the engine dry out of all gas (let it evaporate) and then put in some new oil maybe tomorrow, but I highly doubt it's a mechanical problem and it's more of an electrical problem...

ANY help will be appreciated, this shaking and lose of power is driving me nuts!

[Skym]

Engine stumbles, splutters when it overfuels and smell of fuel confirms it. It can be injector has failed / leaks internally or problem with injector loom (suffers the same hard as a ironing board problem as coilpack loom and causes problems). Leaking injectors is a common problem with RB engine when they get older or sometimes happens with new injectors. Same with injector loom.

Can check injectors by removing CAS (mark position of CAS with twink or similar on timing belt cover, CAS before removing CAS), turn ignition barrel to 3 (just before turning engine on but supplies power to ECU). Then turn CAS and see if injectors click. But you'll get a CAS error code on ECU, so have to reset ECU by pulling battery cables, stomping on brakes to remove left over charge and reattach battery cables.

[love_boost]

yes like skym said the #4 injector is most likeley the problem.

[MikeRWK]

You shouldnt be running the car with gas in the oil, a malfunctioning injector will be the least of your worries.

[FastPAt]

You shouldnt be running the car with gas in the oil, a malfunctioning injector will be the least of your worries.

If it's been spewing fuel into the cyl constantly it will run down the sides of the piston thinning the oil. It's not a big problem at all... just need to change the injector and the oil.

[MikeRWK]

Alright keep driving it like it is, i look forward to a thread titled "my engine blew up"

[Skym]

If running rich on one cylinder for a long period of time or drive a long distance / alot of km, I would agree that bearings, rings in engine, turbo bearings, etc would be affected. Would be shorter period of time if engine is excessively overfueling on all cylinders and all sparkplugs are getting wet. If black tip on 1x sparkplug (failed coilpack), not a wet tip, probably can get away with it for a little bit longer.

[FastPAt]

I havent been driving it at all. Sitting in my garage and working on it right now ... I'm not dumb lol.

[RixR32]

Replace your injector(s) and harness man.

I would say swap #4 injector to another cyl and check like you do with coils.....but by the time you take the time to do that you'll either:

a) wreck the harness anyway
b) destroy the o-rings on the injectors

So, just get a harness, and either one or a set of injectors and o-rings and be done with it.
I can't think of anything else it would be other than a leaking/stuck open injector.
Good luck...hope you finally lick this problem.


Rick

[FastPAt]

Just a little update, I bought some injectors a while back as it was my initial hunch. Just replaced my number 4, fired her up and it ran smooth like silk, took it for a little test run, and it runs perfectly.
The old injector was clogged with gunk and the mesh filter was very, very dirty. So I am going to replace all my injectors with the new ones.

Now another question. When I start my car it kinda needs to crank a few times before it starts to get going. Would this be due to the fact that I would need to retune my car a little to work well with the new (rebuilt) injectors?

[Joker]

Might want to start with a new fuel filter and go from there :P

[Skym]

^^^ Good idea if injectors are dirty.

Also change your oil, filter if you haven't already.

Sometimes the start up maps are the cause (run too rich) and when you fit mods to car you notice it (smell fuel) and gets worse when cold outside. Or IACV / AACV is sticky and needs cleaning. In some cases it can be the boot light draining battery, so remove the boot light bulb (I had to do this on my car). Or there are airleaks in intake piping.

With engine overfueling, can crank engine longer. Or if really bad, press the throttle while cranking (opens throttle body and allows more air into engine).

[FastPAt]

Oil and oil filter were changed in the process of figuring out my problem haha.

Fuel filter is a good idea! Never thought of that. Thanks for all the help guys, this has been the best news for me in a while haha.

[FastPAt]

Changed fuel filter, ran perfect. So I decided to replace the rest of my injectors, and of course problems are arisen...
At first everything was seemingly perfect, just that I forgot the o ring that goes at the tip of the injector on number 4, and I was hearing what sounded like a hissing, almost like a air leak, I ran the car for a bit and could not find anything, turns out on number 5 the little tiny O ring that is on the top on fuel rail side was all chewed up from I guess putting it back in, O joy! So fuel was spilling out all over the place. But wait theres more ...
Before I actually figured it all out I ran the car fo just a little bit, (after I installed the o ring on number 4) and it would NOT start at all, I tried to crank it and I hear a slight "Thoomp" like something was sucked into a vacume cleaner, needless to say I have yet turn on the car as I need the new o rings for my number 5 Cyl... this is becoming a pain in the ass! haha I should have just left it the way it was working ... o well just a little challenge i guess.

[RixR32]

Kind of in the same boat with injectors right now.
Best to just replace all the o-rings and be done with it if you're doing all the injectors.
Pulling that crap apart more than once is a big PITA.