460 Egr Question
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From: North Carolina
460 Egr Question
CAN UNHOOKING THE VACUUM FROM THE EGR CAUSE POOR PERFORMANCE? Mine was unknowlingly unhooked and I have been battling lack of low end power. istalling Edlebrock intake towmorrow, and I am keeping the EGR, want to keep this thing legal. Could this be part of the problem?
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From: North Carolina
no pinging, and the EGR on mine is ran through the thermal switch and is only supposed to work when the engine is cold. After taking a good look at it, I think there are just a ton of small vacuum, leaks. Carb mounting nuts were a turn loose. Once I get this new intake on, I am going to simplify the vacuum routing, leave thje EGR and PCV, but eliminate the temp valves. They aren't working anyway!
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My 93 EFI 460 doesnt have any emissions and runs great. I was planing on leaving the EGR hooked up and functioning but the tube rusted off the back of the manifold. The only sensors I have hooked up are the TPS,ECT,MAP,O2,ACT
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Melisa,
You are probably correct that your motor is suffering from many vacuum leaks. With the age of these trucks most all the rubber has dry rotted. This not only includes the many vacuum hoses, but also the many diaphragms that they operate.
When I got my truck I found all the hoses dry rotted and several of the diaphragms. If the vacuum advance diaphragm on the distributor is shot, then that would certainly give you off idle sluggishness, in addition to the effect of having vacuum leaks.
The carb hold down nuts/bolts should be torqued to about 160 in lbs. After you install the manifold make sure that all the leaks have been fixed with a good spray around everything using carb cleaner. Also, using a vacuum gauge, pull any line that has a diaphragm to see if the vacuum reading is higher with the line disconnected and the vacuum source plugged. This may include power brakes, EGR, HVAC, vapor canisters, and others.
Good luck,
Mark
You are probably correct that your motor is suffering from many vacuum leaks. With the age of these trucks most all the rubber has dry rotted. This not only includes the many vacuum hoses, but also the many diaphragms that they operate.
When I got my truck I found all the hoses dry rotted and several of the diaphragms. If the vacuum advance diaphragm on the distributor is shot, then that would certainly give you off idle sluggishness, in addition to the effect of having vacuum leaks.
The carb hold down nuts/bolts should be torqued to about 160 in lbs. After you install the manifold make sure that all the leaks have been fixed with a good spray around everything using carb cleaner. Also, using a vacuum gauge, pull any line that has a diaphragm to see if the vacuum reading is higher with the line disconnected and the vacuum source plugged. This may include power brakes, EGR, HVAC, vapor canisters, and others.
Good luck,
Mark
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I thnk when I finally put mine back together, (my Sunday water pump install has turned into a three day fight with a broken off bolt) I am going to reinstall the air pumps, but only hook up the vacuum to the brakes, distributor, pvc, only what is necessary. Then go back and start hooking it back up after I replace or check out the lines. I only have to pass the visual anyway. Have been soaking this bolt is pb blaster for 2 days now, the head is wrung off the alternator/smog pump bracket bolt, and the bracket will move, but the alternator is froze to the bolt, so if it will not come off peacably tomorrow about this time, going to break out the cut off wheel ,and cut it up!
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