Challenger Posted June 5, 2009 Share Posted June 5, 2009 I had a vacume leak on one of the fittings on my intake manifold. Its the one pictured to the left of the brake booster tube. I pulled off the metal tube and rubber connector that was on it and plugged the hole to see if my car would run any better (troubleshooting engine problems) I took it for a drive and now it takes a long time to shift and I find myself cruising at 3000 rpm sometime doing say 30-35 mph.. It also seems to shift alot harder, alot crisper shifts. Does the auto transmission rely partially on a vacume signal to tell when to shift up, down, etc? I was having a hard time tracing where the metal line went and am kind of curious what it did... Thanks BTW this is on my 81 turbo automatic. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted June 6, 2009 Share Posted June 6, 2009 That hardline goes directly to the vacuum modulator. If plugging the barb did no good, then there isn't a hole rubbed in the metal line or a bad diaphragm in the modulator. A bad modulator will usually foul out spark plug number six and the car will smoke badly at idle or decel. Quote Link to comment Share on other sites More sharing options...
RUZN Posted June 6, 2009 Share Posted June 6, 2009 AH ha!! That why im smoking on Idle to throttle at a light! Maybe lol... Good thing I pulled my Manual 5 Speed couple days ago! Now to get it in this Auto 280zxt! "Silly Auto", No shifting is for Chicks!!! Quote Link to comment Share on other sites More sharing options...
Challenger Posted June 6, 2009 Author Share Posted June 6, 2009 That hardline goes directly to the vacuum modulator. If plugging the barb did no good, then there isn't a hole rubbed in the metal line or a bad diaphragm in the modulator. A bad modulator will usually foul out spark plug number six and the car will smoke badly at idle or decel. Do you mean the VCM? The thing attached to the afm? If so I did remove the lines from that. It went into the smaller fitting (coming out the side) on the left bung in the picture. Im talking about the larger fitting. A metal line (not the small ones that run along the side of the intake) goes down towards the transmission and into the trans tunnel. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted June 7, 2009 Share Posted June 7, 2009 I mean the one you are talking about. The metal line that goes to the tranny..........it goes there for a reason. Quote Link to comment Share on other sites More sharing options...
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