More than likely what your dealing with here is an aftermarket cam installation, where they just "lined up the dots". In a perfect world, that works.. but welcome to reality. I have seen cams ground so far off, I literally had to advance the upper gear on the timing chain one tooth, to get them to degree correctly. Retarded camshaft timing causes exactly what your describing. Here is how to check, with just taking the Driver side valve cover off. Rotate the engine until it's at split overlap on number one cylinder.. "Split overlap" is when both valves on number one cylinder are open the same amount.. in between the power and exhaust stroke.. number 6 cylinder will be near TDC if the cam timing is correct. Now look at the timing marks.. the mark on the balancer needs to be right around the zero mark on the tab, give or take 6-8 degrees in either direction. If the balancer mark is no where in sight, or way advanced or retarded, then you know the cam timing is incorrect, and the engine needs to have the camshaft degreed in. I'd wager a cold beer that this is your problem.. it's very common, very frustrating, you will chase your tail for weeks, and spend hundreds or thousands of dollars, and not solve it.. So take a look at this, before you do anything else. JW
JW, Wow that is a great tip. I can not thank you enough for the advise. I will have the garage do that test and report back our findings.
Ok, here is the latest update. The Garage I am using talked me out of changing the intake manifold gasket. They also talked me out of performing the test that JW suggested in this thread to check cam issue. They stated that JW's test would only work if it were a solid lifter set up. So I brought it home and did another test you can see in this video (link attached). When I spray carb cleaner at a certain point at the back side of the manifold on the passenger side, I get a significant Idle change. Please watch this video and weigh in on if you think I am on to something. I think this is all a bad intake manifold leak. The most I can get at 800 rpm is about 13lbs and in drive it drops below 9 lbs of mercury. When you Rev the engine it drops as it should, but then shows 20 lbs as it coasts down for a second and then settles in back at 13/14lbs. The engine runs great while driving (except for pinging at high load due to high timing setting) it also sounds tight and smooth when you rev in idle. If I bring the timing into specs it will not idle at all. It just plain falls apart when you put it in drive and you have to run 16 degrees advanced timing to get close to drivability. I am convinced this is a intake manifold leak and I am chasing my tail. I had to do a YouTube link for this video because I can not attach a video on this platform. If you copy and paste this link into YouTube you should see the video.
What happens to the idle vacuum when you spray and hear the idle change? Does the vacuum increase at the same time?
What happens if you partially smother the carb with your hand? Does the idle smooth out? That's usually an indication of a vacuum leak.
No, I tried that and it reacts opposite. It starts to kill the motor. This is what confuses me. Could this be a Vally manifold leak or something different?
Try what I suggested in post 15. Pull the PCV valve out of the intake. Plug all the vacuum ports going into the manifold and carburetor. Then see if there is vacuum inside the crank case. That would indicate a valley manifold leak.
Larry, A first I did not understand your question. You are asking if the Vacuum goes up or down when spraying the fluid. I did not have the vacuum gage on it but I will do it tomorrow.
