73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: droe71 on February 14, 2010, 05:45:27 pm
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Let me start by saying that I recently replaced my carb with a quadrajet from a 1984 corvette with a 350. I installed and the only thing I noticed was that when it was idling it sounded like it wanted to die but it did not.
I had a friend come out and try to help me with my instrument panel lights and dome light not working. Although he was successful with the aftermarket gauges and those to light up, the instrument cluster lights did not work. He said that since one of the bulb bases was missing the entire panel could not light and also the previous owner jacked up the back of the board and the wiring there is screwed.
I had him mess with my idling and it idled better. I took it out of my neighborhood for a nice joy ride. I did a couple of passes by house, when i took it out to the mainstreet out of the clear blue the 350 transmission was not hitting 3rd gear and that scared me.
So this morning I took the truck out to oreilly's auto parts to buy some transmission non slip fluid. I put it in the transmission and proceeded to drive it home. The shifting was a little smoother. So I got home and started and went back out for another joyride. This time my transmission was hitting hard and the truck died on me at a 4 way stop. After 5 tries to start it, the engine came on and I proceeded with caution back to my house. As I neared my house it died again. It took another 5 tries to start it but once it did. I just left well enough alone.
The engine is a 305 from 87-91, It smokes alot now it has a 350 transmission. All fluids have been changed. It has had a tune up. Transmission flush, differential flush. The only thing left to do is put some valve cover gaskets. valve covers are leaking oil.
I would appreciate any help or suggestions, Other than buying new engine and rebuilding the transmission that's what i am going to do next but I just want to get at least a hint as to what my troubles are.
Thanks
aldo
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Check the vacuum modulator, make sure you have manifold vacuum there and make sure the diaphragm isn't leaking. No trans fluid should be present. This can cause your smoke and late/no upshift. Taking a carburetor off of a 1984 vehicle and expecting it to run correctly is taking a shot in the dark. Tune the truck up if you aren't the one who did it so you know what's in there, rebuild the carburetor and see what happens.
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where are those areas located? the diaphragm and the modulator thing? I know that I had him check the temperature gauge. He re tighten it when the gauge did not fit. I needed a adapter nut. I also do have pcv breathers in the valve covers. I know that the passenger side on smoke comes out of it.
Sorry if i sound retarded but I am not mechanic, but i do try to educate myself.
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the carb from the 1984 vette is good and was running very well. The guy who I bought it from showed it too me on the engine. And since I installed that carb i had no issues with the truck until yesterday when the transmission did not shift into 3rd gear.
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The gold cylinder in this pic (http://i50.photobucket.com/albums/f323/Kevredz/Th350/th350.jpg)
Just pull the vacuum hose off of it
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you mean this one on the bottom side?
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He meant by the tailshaft housing where it bolts up to. See it looks like a brass bell thats got a small nipple sticking out.
thanks
pat
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ok this one?
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Yes that 1..
thanks
pat
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ok so how do i check for vacumm? do i start the truck and go down and remove the tube and see how it's reacting. I know there is no fluids on my drive way nothing is leaking.
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First off, are you sure the carb is from an 84 corvette?
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Originally know I am not sure the carb came from the vette, but I was there when he took it off the vette's engine. He started and ran the engine with it so I could physically see that it worked. My truck was running great after I had installed it. But I guess you fix one thing and then another thing needs to be fixed. I almost sold the truck. But my wife wants me to see it through. So that's what I am going to do.
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ok so how do i check for vacumm? do i start the truck and go down and remove the tube and see how it's reacting. I know there is no fluids on my drive way nothing is leaking.
block your tires and set your park brake then start by removing the vacuum line and your trucks rpm should change. you will need a vacuum tester to check the vacuum modulator. they are pretty self explanatory and cheap if you need to get one.
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Thanks for the info. I will give it a shot tomorrow.
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Keep at it and don't despair. If anyone can help you, it's these guys on this forum. Just be specific in descriptions and take pics and they'll be more than helpful.
Good luck!
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After reading this post a second time i believe you might just have a vacuum leak somewhere. check your vacuum diagrams and follow all vacuum lines and check all connections where vacuum lines may go (while it is running) you could also hook up a vacuum guage. this would explain why the engine is running poor and dying out it also explains the trans acting the way it is becuase it may not be getting the vacuum required to work the vacuum modulator on your trans.
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Pull the hose off of the vacuum modulator. See if there is any fluid present in the line. Start the engine and feel for suction at the line.
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If i pull the hose off and find transmission fluid, what's my next course of action?
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replace the vacuum modulator
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Hi guys,
over the weekend I had a chance to mess with the truck. I pulled the hose off the vacuum modulator and found no transmission fluid. But I did not have the truck running. I can assure you though that it was a pretty dry hose and end tube of the modulator.
I did discover however that I do have a kickdown cable and it's not connected to my carb. So that may be my problem as well. I have capped everything off the carb that does not have hose connected to it. So I know that I don't have a vacuum leak.
Does anyone know have any directions on connecting my kickdown cable? Also changing the question up a little bit. I added pcv breathers to my valve covers. Is smoke supposed to come out from underneath them?