Ford 2.3 with a dead #2 cylinder

[Mellvis]

So my little 91 LX Mustang dropped the #2 cylinder. New plugs, wires, fuel filter and such. Still dead on #2. So now I go tapping on the fuel injector (#2 plug showed it was lean) because I was thinking it was frozen shut. These are just solenoids is my understanding, and could have not been opening to let fuel spray in. No change after that, #2 is still dead. My next logical step I thought was to spray just a dab of carb cleaner in the intake to see if #2 hits. Still nothing from #2. So as I'm scratching my head I notice that the vent hose from the valve cover to the manifold is old and likely leaking vacuum so I pull it of and plug the port. I'm still not certain what possessed me to do it, but I put my finger over the vent pipe on the valve cover for a few seconds and noticed that it slowly built up vacuum. I can't come up with any reason for the crankcase to build up vacuum instead of building up pressure. Is it feasible that I have run #2 cylinder lean due to a bad injector, causing the piston to burn holes, in turn causing vacuum in the crankcase from the flow of the exhaust when #2 exhaust valve opens and sucks past a hole in the piston????? Does anyone follow me? I think it makes sense but I don't want ti just go assuming. I plan to due a compression check soon, just don't happen to have a tester on hand right now.

[Greg D]

First if it's showing lean then the injector is likely the problem, whether it be the injector itself or the wiring harness.
Burning a hole in a piston doesn't happen overnight on a normally driven car.
Parts from a "pull ur own" are cheap enough to use for swap & check diagnosis - I believe you can check them with an ohms meter too.
There are quite a few things it could be, how long has it had the miss? You would really notice it on a 4 cylinder.
One other thing - did you change all 8 spark plugs?

This site is an excellent resource also;

http://www.oldfuelinjection.com/?p=3

[Mellvis]

Yes, I'm certain that the injector is bad. My big question is why am I getting vacuum in the crankcase? The miss was intermittent at first, which also led me to weak fuel/ignition issues. The car had original plugs and wires and was arcing from the wires to the engine making it drop a cylinder under load, but run well at idle. This is why I started with wires, plugs and fuel filter.

[Toyz]

I'm assuming you still have the PCV system in place. The evacuated crankcase is a GOOD thing! Borrow or buy a "noid light" to check that your injector is getting a signal, or, like Greg said, just swap two injectors and see if the miss follows the suspect injector.
Paul

[Mellvis]

As stated, I'm sure I have a bad injector. I did however get voltage at the injector plug when checked with a test light. The engine was not running. The crankcase vent was only undone to check it for a vacuum leak and the car isn't being operated like that. But my question still remains, why does the crankcase build vacuum rather than pressure as a normal engine does. There really is vacuum building in the crankcase NOT pressure that needs to be evacuated. My only theory is as stated in my original post. Something has gone wrong causing vacuum in the crankcase such as you would find in the intake manifold runner. After more consideration I'm thinking a head gasket blown between a cylinder (#2) and an oil passage. When the piston is on the intake stroke it's sucking in from the oil passage. The only thing wrong in that scenario is I don't find oil fouling on the #2 plug.

[mercuryv8]

It is normal for a pollution controlled engine to run with vacuum in the crankcase. The air from the case is being sucked into the pcv system. Positive crankcase ventilation.

Nic

[Toyz]

Any of the things you have mentioned as suspect will result in PRESSURE at the crankcase! Think about it, if one of your suspects is creating vacuum, on the compression stroke it will thus create pressure. As Mercury and I stated, it is normal to have crankcase vacuum with the PCV system intact. An old car buyers trick is to pull the pcv valve from it's port with the engine idling; if removing the closed vacuum source results in noticeable smoke from the port, the engine is worn, or has problems. 2.3 injectors are much more likely to fail to seat than fail to open, given the correct signal. You stated that introducing fuel externally didn't change the miss
Key wording is "such as you would find in an intake manifold". Given the restricted design of the PCV system, that is EXACTLY what you would find in a "tight" engine, given enough time to build without an inlet air supply from the inlet you are blocking.
Sure it's an injector; like previously mentioned, put a replacement in! If it in fact has strong crankcase vacuum even with a dead cylinder, then you're concerned about a problem that IMO doesn't exist.
BTW, if you can get an exhaust valve to "suck"; I think you have just invented a vast improvement in engine scavenging.
Paul

[Greg D]

I guess I kinda misunderstood - I thought you were baffled by the continued miss.

Like Merc & Paul said - the purpose of the PVC system is to create a vacuum in the crankcase -
it's supposed to evacuate the oil vapor and burn it to keep sludge buildup in the engine to a minimum = longer engine life.
While you are in there replace the air silencer in the intake system (it looks like a plastic muffler) with a piece of aluminum or PVC pipe.
You'll pick up a touch more MPG and a little bit more torque & HP.

[Mellvis]

I know that the engine needs to have the PVC to evacuate the vapors and such from the crankcase. Maybe I was over-zealous with the scavenging effect when the exhaust vale is open. After it's pointed out I can see that not being reasonable. I still can't figure vacuum in the crankcase WITHOUT a PVC system connected. As I said I had it unhooked from the valve cover, unless I overlooked another vent pulling vacuum from the intake system to the crankcase. I have always found that a crankcase build pressure rather than vacuum if there is no PVC system. My FE 352 builds crankcase pressure and blows out of the valve cover if I don't have a PCV valve in place. All of my old motorcycles and any other engine I can think of messing with has produced pressure rather than vacuum in the crankcase. The only thing I may not be consider, as it's new territory for me, is the air pump mentioned above, but I thought the theory on that was that it just pumped air into the exhaust manifold to help burn remaining raw fuel in the exhaust.

Toyz: I wonder if I'm, in fact, plugging the air going INTO the crankcase and the PCV system is pulling vacuum because there is no air getting into the system. That makes sense to me and you may have set it straight for me!

[Toyz]

I know little of the twin plug 2.3s; although that block is the basis of my "big inch, lol" Lima stroker. Maybe Greg will know the answer. On the 2.3 Turbos; the pvc is inline kinda hidden by the intake manifold. If that setup exists on the Mustang/ Ranger twin plugs; you are doing just as you stated, creating a vacuum build-up by restricting the fresh air inlet. If the line runs from the engine air intake before the throttle body, I would say that is the case.

[Mellvis]

Yeah, that's it then. HA! Learn something new every day. There is a reason I like older stuff, Fuel injected newer stuff makes me mad. The F100 doesn't hide parts behind other parts.

Thanks Toyz, now I get it.

[Greg D]

Yes,
the PCV in the valve cover is not the only vacuum source for the crankcase.
It's not it's Grandpa's PVC system, lol. Even my 79 pulls vacuum from more than 1 place for PVC.
Those twin plug 2.3s are really confusing at first - everything looks kinda foreign.
It's actually a very simple setup once you get used to the extra set of plugs & wires and the seemingly odd locations of things.
They are nearly impossible to kill if you take care of them at all - very strong engines.
People get insane amounts of horsepower out of them and retain the reliability - Paul knows.
I have run one 300,000 miles and it still ran fine with 97% of the efficiency it had at 50K,
even the oil consumption was well within limits for a NEW engine.
I have run a few others over 200K without a failure (the vehicles were swapped out for other reasons).

[Toyz]

Yeah, that's it then. HA! Learn something new every day. There is a reason I like older stuff, Fuel injected newer stuff makes me mad. The F100 doesn't hide parts behind other parts.

Thanks Toyz, now I get it.

Thank God Ford chose not to hide any maintenance items below that 352 manifold
Paul

[Toyz]

Yes,
the PCV in the valve cover is not the only vacuum source for the crankcase.
It's not it's Grandpa's PVC system, lol. Even my 79 pulls vacuum from more than 1 place for PVC.
Those twin plug 2.3s are really confusing at first - everything looks kinda foreign.
It's actually a very simple setup once you get used to the extra set of plugs & wires and the seemingly odd locations of things.
They are nearly impossible to kill if you take care of them at all - very strong engines.
People get insane amounts of horsepower out of them and retain the reliability - Paul knows.
I have run one 300,000 miles and it still ran fine with 97% of the efficiency it had at 50K,
even the oil consumption was well within limits for a NEW engine.
I have run a few others over 200K without a failure (the vehicles were swapped out for other reasons).

For a fact! My last engine (stock cubes) dyno'd just south of 400 horsepower. It didn't NEED replacing; I just wanted to up the boost some more and figured I should strengthen things somewhat I supplied a well worn Mustang w/2.3 for a friends 385 build. We thought it would be interesting to see just how much power that 160,000 mile 2.3 would hold. We ran out of nitrous after a 300 shot, never did manage to detonate the engine!

[Mellvis]

I think I'll do the compression check, then the injector and see what' going on after that. If I remember right this engine has 19lb injectors. Should I upgrade to 24lb? Is it overkill? Is it going to make any improvements if I do? As I said, fuel injection is somewhat foreign to me. I understand how it works, just not all of the math and such to determine injector upgrades.

[Toyz]

Unless you have some substantial power adders; the 19's should be fine. I'm not sure the stock 'puter will handle 24's. I keep working upward; currently have 84's but am running an aftermarket system and E85!
Paul

[Mellvis]

Thanks again. Just curious because I've never researched it, can I run E85 in it? What is the difference (short, sweet version) in equipment for E85 V/S Regular gas?

[Toyz]

You'd need bigger injectors and a computer to handle them. With current pricing of E85, I see no reason to run it unless you need the octane. When it was 2/3 the price of gasoline, it might have made sense in the long term, but right now if I didn't need 100+ octane , it would be hard to justify from an economics standpoint.
Paul