PCV installation

[imadv8]

Greetings. Sorry my technical writing skills are not more astute. I am in the process of trying to figure out if I should keep my PCV (Indigo). Since installation I have had an engine that was not as reliable prior to the installation. First a break down of the series of events.. Since I recently installed a MM engine hour meter times are reference the hours on the new meter and not total time on the engine..


6/13/2009 2.9 Hours Installed New Spark Plugs.. Champion RJ12C


6/28/2009 2.9 Hours Installed Indigo PCV Valve. Ran engine for 20 Minutes, no leaks were found. Adjusted idle mixture screw in (clockwise) 2.5 turns. Engine idled smoothly at 1050 RPM. This was about 100 RPM higher than pre PCV install.


7/10/2009 Motored to fuel dock and out of marina, engine ran great, I would guess run time was close to an hour. After a 3 hour sail engine started but sounded like it was “missing” or “running rough”. Meteorological conditions on Lake Superior dictated that we not trouble shoot and get inside the break water, boat made 5 kts at 1200 RPM “running rough”. Made into the slip secured dock lines and engine died. Engine would not start. No further investigation that night.


7/11/2009 Attempted numerous starts. Engine would run for about 10 seconds with the choke full on and than die. From that point I visually checked all connections I had touched with the installation of the PCV kit. Wires to electric fuel pump appeared loose so I pushed them back onto the spade fitting. I also tightened Aluminum spacer. Engine started and ran. I followed the Indigo instructions for adjusting the idle mixture screw. Ran engine @ dock under load (in gear @ 1100 rpm) for 40 minutes. Engine sounded great. And as a bonus there was no smoke thanks to the new PCV valve. After the engine cooled pulled plugs the were black and sooty, cleaned and reinstalled. Cleaned flame arrestor. Engine was hard to start and would die as soon as the alternator began to charge. Once again jiggled the wires on the fuel pump. Engine fired up and ran great under load up to operating temperature.




A lot of information to sort through just to get to my question about the PCV valve. On automobiles the PCV runs through the carb allowing fuel to be added to the Crankcase gases. On the install with a carb spacer the gases go into the manifold after the fuel is added. What are the effects of this unmetered air?
I am also wondering what I accidentally changed during the installation to make A4 less than reliable? Could it be loose fuel pump wires?


Thanks for all the experts that post to this forum. It is one of the few on the Internet that I can actually find useful information !

RRR

[Baltimore Sailor]

Considering that every time you jiggled the fuel pump wires you got the engine running again, I'd focus my efforts there instead of the PCV installation.

[rigspelt]

Not a mechanic, but I'll give a shot at trying to help a bit while more knowledgable folks consider replies. Maybe my meandering here will trigger a more useful response. I'm not good at priorizing the possibilities for this kind of situation. I'll follow your troubleshooting with interest. This will be a good learning experience for me.

My understanding of the PCV kits is that they are pretty innocuous. I think I'd be looking at something else. One option is to give Indigo a call - I found them very helpful.

I'm pondering air (in and out), fuel and electrical supply possibilities. Consider a new problem related to the install (as you are doing) or a pre-existing problem that by coincidence is manifesting now, or a pre-existing problem that the PCV kit is unmasking (is that possible?).

Air supply: Starting with the things that have changed, to install the PCV kit you presumably had to unbolt and rebolt the charb to the manifold. I used new gaskets for the carb/spacer/manifold joints and carefully checked the gasket surfaces prior to reinstalling the kit. A leak in these joints could cause trouble, maybe similar to what you're experiencing (?). That would be an "air-in" problem (too much air, leaking in at the joints?). The new studs to hold these joints together are different from ordinary bolts: I practiced with them when the carb was on the table so I could get a sense for how they work to compress the joints together, watching for possible impact on surrounding structures - the aft stud bottoms out very near the idle mixture screw in our case. You mentioned engine space smoke prior to the PCV kit, and sooty plugs -- any chance the exhaust has a blockage? Is it old? That would be an "air-out" problem with air supply, an example of a pre-existing problem. Or maybe the soot signifies something else?

Fuel supply: You may have disconnected the throttle and choke linkages during the PCV kit install. Any chance they are set differently now? I wonder about the 2.5 turns in on the idle mixture screw -- seems a lot. My understanding is that the usual start point is about 1 turn back from full in? Were you turning the idle mixture screw, or the idle throttle linkage screw?

Electrical supply: As Baltimore Sailor mentioned, you noticed a loose fuel pump electrical connection. Also, running rough makes me wonder about ignition/timing. No harm in cleaning and securing electrical connections at least.

[imadv8]

Rigspelt thanks for the post. All good things to consider as I trouble shoot.

[ghaegele]

Baltimore Sailor said it. The PCV is a red herring.

[roadnsky]

Rigs gave you lots of detective ideas, so I won't repeat.

I'd only add that the sooty plugs could point to a rich setting and/or an exhaust blockage. BUT it is also very common for the first few hours of running with the PCV kit because of oil burning off that used to blow into your cabin.
Keep cleaning them every few hours of running and watch for the sootiness (is that a real word?) to be less each time. IF it doesn't OR even gets worse, look at that exhaust.
As a sidenote to this: I used to use the Champion RJ-12C's and always had a bit of soot, but when I changed to the AUTOLITE 437's, which burn slightly hotter, all sooty residue ceased.

I'll finish by saying that you should really take a look at that wiring to the fuel pump. Maybe even do a temporary NEW wiring to see if the issue is there.

Happy hunting!
-Jerry

[Dave Neptune]

PCV & idle

RRR, I have been using the same PCV set up for about 6 years now with no trouble. Make sure that you add clamps to be sure all is secure. There should be a gasket on both sides of the adaptor. As per the instructions my idle adjustment was exactly what they recommended which was to start at 1/4 clockwise (in) turn on the mixture screw and I reset the idle speed screw to 650 rpm warm. It starts cold fine and after about 3 minutes will idle on the stop just fine.
If you turned your MIXTURE screw in 2 1/2 turns you were already way to rich as far as average idle settings without the PCV which are around 1 1/2turns off the closed position. You could have a preexisting carb problem, since all the PCV does is vent unmetered air from the crankcase to an inlet to the intake just after the carb (exactly like your car) it should lean the mix a bit which is why they said to enrichen the idle mixture 1/4 turn in.
My engine is 39 years old and very tired indeed. I use the J12 series plugs and the color always looks like milk with a tiny bit of chocolate in it never sooty.
I don't think that the PCV is part of your problem, its instalation just pointed out an existing problem. I think the PCV system is the second best thing I have done for my A-4, it really cleans the crankcase and keeps the fumes that you would normally have out of the cabin a good thing indeed.
Check out the wiring and then check the carb's air jets or go ahead and clean the carb.
How old is the exhaust? If it does develop a bit of back-preassure you will have very poor performance and in most cases sooty plugs, from off idle running not idle.

DSave Neptune

[Dave Neptune]

PCV idle correction

That's 2 1/2 turns would be a very lean idle not rich, oops!
Blame it on multi-tasking.
David