jimszx Posted November 29, 2005 Share Posted November 29, 2005 I appologise but I was unable to post a picture of this, it is a small round canister about 4 inches in diameter and is mounted forward of the R/H strut and aft of the charcoal canister. It has 2 small vacume lines and 4 wires attached to it, the vacume lines are common to the cruise control but it is not part of the cruise control system. I have not found this in the nissan parts cd and it does not seem to be inb the electrical schematics. Any assistance on identifying this part or how to load this darn jpg would be appreciated. Jim Quote Link to comment Share on other sites More sharing options...
skipzoomie Posted November 29, 2005 Share Posted November 29, 2005 Without seeing a picture it's my guess that it's the vacuum canister. It's used for the cruise and AC/heater functions. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted November 29, 2005 Share Posted November 29, 2005 Sounds like you have a ZX. It’s the vacuum canister used to operate the vacuum controlled interior vents. It consists of a plastic bottle with an integral vacuum check valve (connected to the intake manifold with a hose) and two solenoid controlled valves. The valves direct the vacuum to the passenger compartment heating/AC unit and also to the fast idle AC kick-up control valve on the intake manifold. Why do you need it? Well, the intake manifold vacuum level is a function of engine load and throttle position. In other words, it varies. The vacuum bottle and the check valve provides a reservoir of fairly constant vacuum despite the intake manifold fluctuations. And, yes it does not have anything to do with the cruise control. The cruise control operates only off intake vacuum alone. This is a safety feature so that the cruise control does not operate ("kicks out") when the engine is heavily loaded. Quote Link to comment Share on other sites More sharing options...
Cruez Posted November 29, 2005 Share Posted November 29, 2005 Speaking of the vacuum canister... not to hijack the thread.. but if you are running a higher than normal lift cam, wouldn't it be beneficial to have the vacuum canister as a reserve when at idle for the brakes, etc??? or no.. ? even without the vacuum controls ? Quote Link to comment Share on other sites More sharing options...
zcarnut Posted November 30, 2005 Share Posted November 30, 2005 ... but if you are running a higher than normal lift cam, wouldn't it be beneficial to have the vacuum canister as a reserve when at idle for the brakes... No. The brake booster is a vacuum chamber [canister] that operates a rubber diaphragm which in turn applies force to the pushrod which goes into the master cylinder. A vacuum canister does not increase the level of vacuum anyway. There are solutions for engine that have low levels of intake manifold vacuum, like diesels and turbocharged engines. The 300ZXT has an electric vacuum pump for example, and the early Maxima diesel has a vacuum pump driven off the rear of the alternator. In practice, a high lift cam has only a small effect on braking performance. The highest level of intake manifold vacuum is during de-acceleration and not during idle. In my 260Z with has a high lift cam and in which I have a installed a vacuum gauge (in place of the useless clock) I pull vacuum levels of 23 to 25 inches during de-acceleration. Quote Link to comment Share on other sites More sharing options...
jimszx Posted November 30, 2005 Author Share Posted November 30, 2005 Without seeing a picture it's my guess that it's the vacuum canister. It's used for the cruise and AC/heater functions. Thanks I ran across another zx today and after operating a few systems it is for the A/C and heater vacume system. Thanks again to all, for the great assistance. Quote Link to comment Share on other sites More sharing options...
HeatRaveR Posted November 30, 2005 Share Posted November 30, 2005 A vacuum canister does not increase the level of vacuum anyway. There are solutions for engine that have low levels of intake manifold vacuum' date=' like diesels and turbocharged engines. The 300ZXT has an electric vacuum pump for example, and the early Maxima diesel has a vacuum pump driven off the rear of the alternator.[/quote'] Does the L28ET have any such supplementary vacuum pump? Quote Link to comment Share on other sites More sharing options...
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