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#1
10-09-2023, 07:36 PM
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A.I.R. Pump Operation
I have a 1980 Trans AM w/ 4.9 regular engine & it's unmolested original. I'd like to eliminate possible vacuum leaks from the hundreds of vacuum lines . I was going to cap un needed at the carburetor. So far I have the Distributor direct to a vac. source. Plugged line to EGR. Line down to Exhaust pipe valve missing & capped. Now I'd like to leave the A.I.R. pump but run a vacuum line directly to the bypass valve. Will this work. Not sure exactly how this operates. I have the factory manual, but it's not clear. Does vacuum cause it to bypass, or does lack of vacuum at deceleration cause it to bypass? If no vacuum caused it to not send air to exhaust, plugging the vac line woul stop it from injecting air . I'm going to leave the lines to the tank evap cannister as only one carries vacuum & I can check it easily.
Thanks. Last edited by Falkon; 10-09-2023 at 07:42 PM. |
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#2
10-10-2023, 05:49 AM
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Hi.
I do not have the vacuum line schematic in hand right now to comment on all of your vacuum line changes you propose, but one thing I can tell you with certainty is that if the EGR system does not function when it’s supposed to then the motor will run nice and lean . In fact it will very likely ping and surge if the off idle air to fuel ratio is not recalibrated, or in the least run hotter then it should.
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#3
10-10-2023, 01:07 PM
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I'll have to rethink this. I have all the factory manuals. I'm just trying to minimize all the vacuum tubing on the car. My impression from reading up was that the EGR valve adds "air" in the form of exhaust gas to the intake. I thought the EGR engaging w/ vacuum applied would lean it out if anything. I disconnected the EGR & plugged it's feed line. My issue is that the car hesitates when not completely warmed up after the fast idle cam drops all the way. Another few miles & it runs fine. I'm assuming a vacuum leak somewhere. I've checked the lines but they are older & so many on a 1980 car. Just want to simply eliminate what I can. Distributor direct to vac. source. I'd like to plumb A.I.R. pump diverter valve direct to a direct source. Eliminate the signal line to bowl vent at the cannister & open bowl vent at the carb. I can easily reconnect the EGR to a vac source. Pretty much eliminate all the many sensors in the system. Thanks for the advice.
Last edited by Falkon; 10-10-2023 at 01:33 PM. |
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