Dave WM

prob best to just do one thing at a time, since you already removed the BCCD function I would suggest you follow CO advice the make the block off work. I was just thinking out loud about modification in general. Best thing is not to do a lot of changes at once, too many varibles to keep up with.

think its a non issue, I did more test as well, down to 500 rpm, NO effect and I know the new canister valve is working. So it would seem the minor leakage of a purging system is really not going to be an issue. Not sure why it was deemed it need to open and close the purge valve, seem like it could work just fine perm open. I think a dirty EGR is a more likely thing to cause issues with vacuum leaks regarding the emission control system, much larger possible leak and in a dirty environment as well. Just something to keep in mind if so equipped. My take on the canister is its not a issue, at least as long as it has some restriction from the purge line.

I was thinking he was just chasing a reg vacuum leak. Sometimes on these long threads I just jump in without reading everything. I wonder, do the BCDD fail that often, or is it just folks don't like the way the effects the engine? Mine is hooked up and seems to have somewhat random effects, like between shift rpm, the time it hold open the throttle etc... but it really does not effect my driving since I generally keep the car in gear most of the time, even when decelerating (want to be in the correct gear at all times). Mine will hold the idle up a bit if I coast to a stop in neutral, but its not crazy high, maybe 1500-1800, then it quickly drops as I go below 10mph. I find the best thing you can do for Z cars is drive them. Seems like some problems are not problems at all with time. I think maybe with out computers and sensors galore, the engines do not react the exact same way all the time, as the mechanical aspects of the various systems are not as repeatable as a working computer controlled modern car. I know my lexus starts and runs exactly the same way regardless of temps etc....

I just use a cheap cigar, and a clear plastic tube attached to the brake boost port on the manifold. Then put a stryofoam cup in the TB intake to seal it up. Now stoke up the cigar and start puffing smoke into the manifold. It should resist some the airflow into it. Just keep going and keep your eyes open for smoke leaking out somewhere.

smoke it out.

I will drop the rpm and test again later. maybe get it real low like 500 just to see if I can tell a difference (open purge vs closed purge while idling).

maybe if I lower the rpm may be able to notice better.... I tend to run a bit high like 900-1000.

I think the leakage is pretty minor, but you could just try clamping it off and see if you can tell any difference at idle. I just pulled the line and held my finger over it, listen to idle after it settles, then reattach and listen again. Takes a couple seconds each time for he engine to recover from the momentary open between switching would tell you if its having any effect, even if the performance effects were nil. OCD strikes again...

in one of my early "will not start when cold" phases, blaming the CSV or course.. I installed a 85f thermotime switch. Since its almost always hotter than that it rarely fires (and always starts easy). Well lately its been in the upper 60's and It is firing (I could hear it when I disconnected the solenoid for a fuel pressure test the other day). I plan to test tomorrow with the CSV disconnected, should be in the upper 60's again, will see how starting goes. One thing for sure starting is not always exactly the same. I attribute that to the myriad of mechanical sensors and lack of sophistication of the ECU. It starts and generally easy but just not the exact same every time across different temp ranges. My guess is it does not need the extra fuel for the mild temps, will see tomorrow how it goes. As is the vacuum is only good for the idle for a short time (the extra enrichment period you mentioned perhaps).

I actually tried the pushing down trick not sure if it was working (between the noise of the engine, the balancing of the spare cansister on top of the installed one, and trying to suck on the pipe to activate the purge valve, all the while trying to push down on top of the valve, I just could not be sure if it was working. I could actually hear a click like noise with the new setup as I applied vacuum to the new setup (as well as a slight change in idle). Could not hear anything with the old setup, but that maybe a design issue. The valving while similar its NOT the exact same (I pulled apart a JY valve to investigate).

ok just for fun, after warming up the car, I disconnect the purge line and as expected car runs rough (vacuum leak) Interesting fact, when 1st started, the same vacuum leak allowed the idle to raise quite a bit and still be smooth, so I guess my starting mixture must be a bit rich, maybe more than it needs to be. Anyway back to testing I reconnect the purge line, then activate the purge valve manually again at idle. an almost imperceptible change in idle, so clearly the canister itself must present a substantial restriction in the flow to minimize the effect of the open purge line. I try the same with the old OE canister, this time I note NO change in idle (and it would be hard to tell if the idle was worse than with the newer canister option) when the purge valve is opened manually (it should be close at idle since its operated on ported vacuum). My guess is its always open but as with the later model canister the restriction of air flow must be enough to mask the effects of an open/closed purge line. Bottom line, unless the canister is compromised to the point of allowing a massive vacuum loss (and I don't know how that would be) the restriction it presents to the intake manifold vacuum is enough that it will have little to no effect on idling. If it is indeed stuck open, then it will function to capture vapors and burn then in the combustion cycle. At this point I am not sure why there needs to be a open and close of the purge valve since my orig thought was to not effect idle adversely from a vacuum leak.

I think its pretty close, the spring in conjunction with the tiny bit of lift from the vacuum on the diaphragm uncovers the port, without the spring it would never release (like a counter balance). I think the spring is there to make the purge valve more sensitive to the ported vacuum switch. Of course its just a guess, but as you can see in the video the other canister works very well as far as the ported vacuum controlling the operation of the purge process. And how it holds vacuum with a single pump on purge fitting. That other canister may just function differently. Would be nice to know if a NEW diaphragm installed in the old canister works differently.

for ten miles that looks rich to me. you will need to determine what the actual temps are. IF its 120, then running too cool. Get a meat thermometer, remove the rad cap, put that in the rad, start the car, let it warm up. If the thermostat is working properly you should see it fully warmed up in 5-10min of idling. Just keep an eye on it you should see cold for a while then the T stat will open and the rad will suddenly get warm a the top. That would be the T stat opening. I don't think you are way off, just a bit too rich. Hopefully now its just down to fine tuning by correcting small issues. The ideal temp would be between 170-190, Getting the temp gauge to match up with what is going on should be next on the agenda. You really want that working right since its very bad to overheat the engine.

https://www.partsgeek.com/gbproducts/DC/6747-05178841.html

hmm guess I should have looked more closely at the year.

video

working on video right now, will be up in a few. I guess the only variable could be the amount of restriction in the draw of the vapor out of the canister into the intake manifold. I guess I could so a subjective test to see if I could feel any big difference by must pulling a constant vacuum with my pump and seeing what the readings are. I did that kind of test when checking out a AC evap valve. IF there was a huge difference I suppose it could be noticeable to the engine as a vacuum leak, but even then it would only happen at higher throttle settings. I will give it a drive test to see if I can notice anything different, but I doubt I will.

While futzing with my car I decided to check the operation of the carbon canister. The only real function is the vacuum controlled valve the activate the purge cycle (pull vapor from the can to the engine intake vacuum). What I found was the valve would not close in the absence of vacuum at the signal line (ported vacuum small hose). I test it using a hand pump and vigorously pumping. Now maybe in the presence of a constant vacuum source it would "catch", the design of the valve would tend to do this. I could make it catch by simply applying some pressure to the top of the valve, but that was not enough for me. I removed the valve cap, and found a good diaphragm, but it had a shiny spot where is sealed the port inside. Again I don't know just how aggressive the vacuum need to be, so I decided to see if I could find something a bit more positive in action. Trip to the local JY turns up a mid 90's I think, Nissan pathfinder. It had the same size canister and the 3 needed ports, for 5$ cant go wrong. When I got home I found it to work very well, any vacuum is instantly sealed by the valve, until just a light vacuum from the control line is applied. It was about a simple a swap as you could get. Just wanted to share. Oh for fun I did manage to get my OE valve working, I smeared a very thin film of non hardening sealer on the button of the diaphragm that is supposed to seal. Let it set up overnite. Now it works better, several aggressive pumps from the mini vac and it will seal up, and the control line will break the vacuum, but I still think the JY pull works more posistively, both on the seal and the release, so will stick with that on.

heres to drinking with …..

Did you ever get the crankshaft end play worked out?

ok found what may work for me and my inline solution a SP CP105, for a GM product mid 80's to mid 90's I don't know if this is a problem but for 20$ its something to try. maybe OP can test his canister as well, just see if you can suck air thru the purge fitting on the canister. I assume it should not allow air to flow since there will be no vacuum applied to the control line (do this with the motor off).

For fun I decided to go check out my connections, Now just recently I noticed my normally super easy to start car has getting a bit iffy on starts, more cranking than I like lower idle once it does (not the AAR checked it). On a hunch and with all this talk about EVAP I decided to check the function of my carbon canister. I hooked up the mini hand vac to the purge side (the line that goes to manifold vacuum, the large one) of the canister and to my surprise it would hold no vacuum what so ever. If I understand this it should only open and allow airflow when the control vacuum is applied to the purge valve (small hose). So I assume my purge is stuck open, creating a pretty good sized vacuum leak. I don't know if this is new or always been this way, but you can bet I am going to plug it up tomorrow and see if it has any effect on the start and idle of the car. Next up is IF the purge valve is indeed bad, what are my options? I does not seem to be serviceable (could not see how it is attached to the canister). But if it is stuck open I was thinking I could just ad a inline purge valve. Looking into this I find they are crazy expensive new, so the plan is to hit the JY tomorrow for some mid 90's era nissans that seem to have a vacuum operated purge valve.

I am thinking mainly to make sure things line up, some times installing the sprocket can get dicy with what link its on. Plus you will want it to check for wear later on. I would suggest you remove all the valve rockers and make sure you don't have any tight spots on the camshaft. If it does you maybe able to correct with careful tightening of the cam tower bolts.

you may want to make your own notch. I would put the two sprockets back to back, then using the old one as a guide, scratch in some marke where it should be. then use a v cut file and make your own. easy to do while its apart. did you try spinning the camshaft with the valve gear not in it? looking for a nice low drag, no tight spots spin.

Not sure about the 79, but maybe just the BCDD doing its thing. If it was suddenly cutting at 10mph anyway. Part of the emission control, consult factory manual for complete description and function.