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Thanks for the explanation Mooks. I haven't dug that far into the engine to see what's nestled in the valley between the cylinder heads yet; that's why I didn't see it. Yes, most likely a project to tackle in the future. I have about 3 meters ofMB tubing left over. Hopefully it'll suffice.
Quick update, but I believe this issue has now been resolved. I replaced the vacuum line going from the Y-splitter from manifold to Y32 air switchover solenoid on Saturday morning. No new codes have appeared since then. I'll continue to keep an eye on it, but I do believe the problem has been rectified.
Ok so if the pump is turning on then yes its likely that you have vacuum leak. You can test the circular diverter valves as well. Apply a handheld vacuum pump to the feed and look inside to see if valve moves. Sometimes (on older cars) they get stuck.
FYI-The vacuum coming off intercooler and going to sensor-that is the MAP sensor and when it fails you do not get a check engine light you just get reduced power.
The dashpot is underneath the intake manifold between the v of the cylinder heads. It stores vacuum so that the system operates seamless when switching the diverter valves, boost pressure control valve etc. There are vacuum lines that run underneath the manifold and connect to this dashpot. The only way you could see it is to remove intake manifold.
I had my manifold off and could replace these rubber vacuum hoses underneath. I will tell you that they are prime to crack over time and will cause issues. May be a nice project for you in the future.
In this picture, the dashpot is number 280. Again, it is not the vacuum line going to the intake in the back-it is a separate canister between the v. AS you can see, the vacuum coming from the dashpot affects the changeover valve that controls the Smog Pump circular diverter valves. If there is a crack in any of these lines, it could be causing an issue.
Number 280 in this diagram.
Dear MooksM275, Look at vacuum #160 on the diagram, where should it connects to? or it is a dead cap. On my car, there is just a vacuum hole hung in there, I don't know what should it be? Thank you very much.
The dashpot is underneath the intake manifold between the v of the cylinder heads. It stores vacuum so that the system operates seamless when switching the diverter valves, boost pressure control valve etc. There are vacuum lines that run underneath the manifold and connect to this dashpot. The only way you could see it is to remove intake manifold.
I had my manifold off and could replace these rubber vacuum hoses underneath. I will tell you that they are prime to crack over time and will cause issues. May be a nice project for you in the future.
In this picture, the dashpot is number 280. Again, it is not the vacuum line going to the intake in the back-it is a separate canister between the v. AS you can see, the vacuum coming from the dashpot affects the changeover valve that controls the Smog Pump circular diverter valves. If there is a crack in any of these lines, it could be causing an issue.
Number 280 in this diagram.
I found the broken vacuum hose between vacuum reservoir #280 and Y-connector #60. As you mentioned, we have to remove intake manifold to access and replace. How hard to remove the intake manifold, do you know any links show how to remove intake manifold. Thanks in advance.
Pulling the intake is not particularly difficult. You will produce quite the pile of parts to keep in order for reassembly. Be careful with all the electrical connectors... Be sure to reconnect all the grounds. Replace ALL the vacuum lines while apart. Cover up inlets to turbos. Bleed charge cooling circuit after reassembling.
Those who have had the joy of getting to dig it out.... Vacuum reservoir under the intake is just that.... A reservoir; Yes? If so.... Should it fail in my car I'm inclined to run vacuum lines to a reservoir that I stick away in an inner fender or in the cowl by the windshield.
Pulling the intake is not particularly difficult. You will produce quite the pile of parts to keep in order for reassembly. Be careful with all the electrical connectors... Be sure to reconnect all the grounds. Replace ALL the vacuum lines while apart. Cover up inlets to turbos.
Thank you John, for removing the intake manifold, do we need to remove injection rail for unscrew the bolts that tide down the manifold? and do we need to replace all orings and gaskets?
Originally Posted by JohnLane
Bleed charge cooling circuit after reassembling.
I have been removed the intercooler many times but never bleed charge cooling circuit. Is it the air valve with black cover cap on intercooler? How to bleed it?
Originally Posted by JohnLane
Those who have had the joy of getting to dig it out.... Vacuum reservoir under the intake is just that.... A reservoir; Yes? If so.... Should it fail in my car I'm inclined to run vacuum lines to a reservoir that I stick away in an inner fender or in the cowl by the windshield.
Thanks John, it is a good advised. I will choose this approach which save a lot of headache and prevent of making broken parts.
I concerned about test line B (see picture below), I recall that I didn't see the line on my car (I will check again). Is it causing problem if we use difference vacuum reservoir?
I have other questions: what is the normal value of intake manifold absolute pressure, while engine at idle? My scanner read 34-35 kpa (is about 10 inchHg), is it too low? Thank you.
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