I had a chance to work on my car today; wx was favorable for it. I put a vac gauge on the manifold to try and figure out why the idle spd fluctates and why the car chokes when I put it in gear. All vac lines under the hood has been replaced. I discovered the vac. goes frm abt 15"hg down to 10" w/ erratic idle. Also, I discovered a lot of smoke/exhaust coming frm the valve cover breather cap. Never seen that B4. the car does not smoke frm the exhaust and has consumed vry little oil since I owned it "3yrs". It revs up normally. I had stated in a recent post; I thought it might be a vac line to the trans or modulator that might be defective. As of now, I don't think that is the problem - I think some engine work may be in the future. Any ideas, as to what the cause may possibly be? Don't plan on doing much more to it till spring.
A vacuum guage is one of the best diagnostic tools you can use - BRAVO Everett for taking the time to use one - so many guys don't That said, sounds like it could be as simple as the idle mixture screws - but could be a more serious condition with the valves. Here is a very cool link with animated vacuum reading. Scroll down towards the bottom of the page and hit the buttons for each scenario and watch what the guage does. When you find the one that matches what you are seeing, you may have found your answer. Scenario #15 is bad mixture screws - but look at all of them to compare. http://www.secondchancegarage.com/public/186.cfm :Handshake
Idle screws Thanks for the link Eric. I don't think it's the screws - new carb and the carb I removed was new when I got the car. I have never had the valve covers off the engine. I guess it's time to remove them, but I don't have any strange noises or anything - yet. I will ck the link tommorrow - kind of tired tonite - remove all the plugs to see if any oil - none. Day's like this I wish I had inline engine...
If it is a burned valve or leaking seat you would not hear any noise from under the valve cover. When you get some time look over those animations.
Have you checked the PCV valve -- or maybe just replace it. You could temporarily disconnect and cap the vacuum supply to the HVAC system to eliminate the possibility of a vacuum leak in one of those motors, switches or lines. Same with the vacuum supply line to the vodulator, (power brakes?), vacuum canister?
I have not replaced the PCV valve. I can/will do that. It does rattle. I will also cap the vac lines to HVAC. I capped the lines to the trans today. I will do the canister too. I need to get my vac line diagram in hand to figure out where/what to plug. I have not looked under the dash. Wud a non-functioning PCV cuz smokin frm the vent cap? Thanks for the suggestions guys. Im hoping I don't have to remove the heads. I like riding - not to keen on wrenching - I just acccept it as part of the deal w/ old cars...
hate to say it.. but that sounds like pretty heavy blowby from a cracked piston.. cracked ring/s.. or blown head gasket. a compression test.. or better yet.. a leakdown test with a stethoscope or section of hose to hear where the air is leaking from will help to pinpoint it without having to remove much more than the breather cap.
I chked the amimations. I cud'nt wait till tommorrow - been losing some sleep over this dilema. I have not driven the car since Thanksgiving cuz don't want to have to put it on the back of the hauler when I am going to have to fix it anyway. It looks like my nx move after following Jim's suggestion maybe to remove the heads. The engine was suppose to have been rebuilt and had 7K miles on it when I got it. Seller did not have receipts on nothing but frt end alignment. The car was in reasonably nice shape otherwise, body, interior, etc. so I took chance buying it. Can't say I am disappointed - car has ran nice since I got it.
U might be right - don't have any history on the engine. Hopefully, it's not that serious - but - have open mind to anything.
yeah.. I hear ya. I used to be optimistic too. Nowadays I expect the worst and hope for the best. The one thing that I do know from experience is that burnt valves, PCV valve malfunctions, and idle mixtures have not much to do with crankcase pressures/blowby like you're describing. But I do hope I'm wrong just for your sake.
Before removing the heads - make sure you do a compression test and leakdown test on any bad cylinder - that will help you figure out where the problem is for sure.
All plugs were dry. They all look pretty much the same. I can't see oil leaking by the rings and all the plugs are dry. Farther testing/diagnosis in order.
