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Do your patient (engine) no harm. Also make things easier and cleaner with less potential leaks into the system. Simplify and use the KISS principle. Less parts= less problems..Just sayin.. something that many engineers overlook.
So here's a quick update - removing the evap system seemed to work for a bit, but the idle issue came back strong today. So I was looking for ways to pull the IACV to bench test it without removing the intake. When I took off the intake boot I noticed it was full of oil (from the AOS and I think this may be evidence of bad AOS seals). This had been recently cleaned out, so it was a lot of oil in a short period of time (probably 300 miles tops and oil level is dead center on the dipstick).
Anyway, as I was cleaning the throttle body and thinking maybe all this extra oil is messing with the throttle position switch I noticed that the throttle doesn't shut completely (not sure if it should be absolutely flush closed or not). I started messing with the throttle stop to see if it would close completely and I realized there is no click when the throttle opens. From my understanding the TPS should click when the throttle opens. This leads me to believe it's either bad or not adjusted correctly. I've read some conflicting information here. Is it confirmed that there should be a click?
I am optimistic this may be the issue I've been trying to find. I'll still test the IACV when I have the TB out for adjustment and hopefully addressing one or both of these things will fix the idle. I'm not sure how concerned I should be about all the oil from the AOS.
Edit to add side question: I've noticed the oil pressure is usually around 4.5 or maybe 5 bar which is normal as I understand it, but sometimes it drops to 2 bar. Could this be telling me something about the vacuum in the crankcase? (like, could a leak in the AOS be causing low oil pressure readings?)
PS the venturi delete is on my mind, but I want to get this thing running reliably first.
Sounds like a blow-by problem all right. AOS seals and the O-ring at the top of the AOS should get changed out for openers. If that still doesn't cure it, it may be a valve guide seal issue...You could check this with a vacuum gauge, Teed into a good sized vac line..Should read a constant 19 inches or so, with no major bouncing of the needle.. I'm sure that there is quite an extensive article on vacuum gauge readings and diagnostics on line..This used to be the almost only diagnostic tool that mechanics had in the old days. But it still might give you an indication of what's going on. If you go to your FLAPS, don't be surprised by the "deer in the headlights" look of the clerk when you ask for one. Just sayin..HTHsome.
Last edited by Tiger03447; 09-27-2021 at 09:56 AM.
Reason: Add'tl info.
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There is a O-ring under the lid that hose 20 joins to but it is not listed in the parts drawings. I took mine out and went to a local industrial seal dealer and got one for $2.
It can be removed. Not an everyday procedure, but something that can and should be done every few years. The O ring will gradually fail over time. These are old cars and age is a factor not considered too much by the factory. HTH some.
Looks dirty... the bottom is worse too. They were probably leaking. IACV was also dead. Also replacing all those old vacuum lines. Hoping I'll be good to go after this.
08-05-2021, 10:52 AM
