73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: All_American_C10s on May 14, 2020, 04:26:14 PM
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I recently had a local shop replace the valve seals on my all stock 1987 throttle body injected 5.7L Silverado. When I got her back, she ran fine but had little rougher idle than I remembered. Then on my first time out on the interstate about a week later I realized the cruise was no longer working. As I pulled the breather off, I quickly spotted that the crankcase vent rube running from the driver's side valve cover to the back of the throttle body was broken off flush with the valve cover. I smoke tested the engine and only found one other small vacuum leak in the system. I suspect this is my culprit. The trouble is...you can't find this vent tube as a replacement part. I've seen where it looks like others used a piece of vacuum or fuel line to make their own but I can't figure out how I would match that up with the grommet to get an adequate seal that would also not risk tubing sliding it's way down into the valve cover and interfering with the rockers.
Any ideas or suggestions on how to resolve this????
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Maybe I'm just not visualizing it correctly in my head, but are you just missing the PCV valve?
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No, sir. It's the "L" shaped vent tube in the attached photo that runs from a grommet on the driver's side valve cover to the back of the throttle body. There's no valve on this side. The tube has been broken off flush with the valve cover grommet.
The pcv valve is mounted in the passenger side valve cover.(https://uploads.tapatalk-cdn.com/20200515/fda75e4e9d916674dbcc1bc69fc6f8c4.jpg)
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I see a vacuum line missing from the check valve going to the cruise control.
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If you can't find that tube in a yard, it should be fairly simple to either fab one up, or braze yours back together.
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I see a vacuum line missing from the check valve going to the cruise control.
Yeah...I pulled that one to replace with new hose since it looked like it was on its last leg.
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If you can't find that tube in a yard, it should be fairly simple to either fab one up, or braze yours back together.
No luck finding them in a yard so far. You can find them,, but they are in worse shape than mine. Folks tend to break them off to get at the heads. 'm thinking about 3D printing one. A buddy of mine has a printer.
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Fabricate it out of 1/2" soft aluminum or copper tubing and paint it satin black. The missing vacuum line should connect the check valve at the top of the image to a single port manifold vacuum tree located behind the TBI assembly adjacent to the ignition coil. It might behoove you to make a thorough inspection and look for any other problems introduced by the smog shop.
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Run a search for Dorman 46001. Is that it?
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Run a search for Dorman 46001. Is that it?
Thought it was and picked one up but it didn't work. That's the only part # the parts stores show as a replacement.
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Fabricate it out of 1/2" soft aluminum or copper tubing and paint it satin black. The missing vacuum line should connect the check valve at the top of the image to a single port manifold vacuum tree located behind the TBI assembly adjacent to the ignition coil. It might behoove you to make a thorough inspection and look for any other problems introduced by the smog shop.
Good call out. I have a "smoke machine". Each time I fix an issue/replace a line, I hook the smoke machine back up to check my work. Usually end of finding another previously undiscovered issue to address. By the time I'm done, I should have a brand new vacuum system!
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if you have good relationship with a GM dealer parts man,Part# 14102133 is the number of the tube. There are about 10 dealers in the USA that show to have it still. Have the parts man call one of these dealers and see if they will sell it.
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if you have good relationship with a GM dealer parts man,Part# 14102133 is the number of the tube. There are about 10 dealers in the USA that show to have it still. Have the parts man call one of these dealers and see if they will sell it.
Thanks! I knew it was discontinued butbI didn't think about inventory still sitting on the shelf out at dealerships somewhere. I'll do that!
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If the local dealer doesn't want to arrange procurement of the part for you, (s)he should be able to provide a printout for the part that shows the "other" dealer addresses with phone numbers for you to call and arrange purchase directly. Request a physical stock check and verify the selling price including an estimate for shipping. A handful of dealers are quite proud of their "obsolete stock."
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If the local dealer doesn't want to arrange procurement of the part for you, (s)he should be able to provide a printout for the part that shows the "other" dealer addresses with phone numbers for you to call and arrange purchase directly. Request a physical stock check and verify the selling price including an estimate for shipping. A handful of dealers are quite proud of their "obsolete stock."
Thanks for the advice! Local dealership got me in contact with a dealer in Center, TX. They keep their obsolete stock in a separate building. Said they'd check Monday and give me a call back.
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I had or have the same problem on my 87 5.7, of the pipe broken at the valve cover. I finally used a few larger pieces of heat shrink tubing and not shrinking it so tight about 3/4" to 1" from the end and was able to slide it into the opening and it has worked for several years now. I still am keeping my eyes open at wrecking yards for the proper part. Let me know if you have any luck on the part, since i need one myself. Thanks and good luck.
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I had or have the same problem on my 87 5.7, of the pipe broken at the valve cover. I finally used a few larger pieces of heat shrink tubing and not shrinking it so tight about 3/4" to 1" from the end and was able to slide it into the opening and it has worked for several years now. I still am keeping my eyes open at wrecking yards for the proper part. Let me know if you have any luck on the part, since i need one myself. Thanks and good luck.
Will do!
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if you have good relationship with a GM dealer parts man,Part# 14102133 is the number of the tube. There are about 10 dealers in the USA that show to have it still. Have the parts man call one of these dealers and see if they will sell it.
Thanks! I knew it was discontinued butbI didn't think about inventory still sitting on the shelf out at dealerships somewhere. I'll do that!
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You saved the day on this one, Mike. A couple of phone calls and $13 later I now have the obsolete OEM part in hand. Thanks for the advice!
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I had or have the same problem on my 87 5.7, of the pipe broken at the valve cover. I finally used a few larger pieces of heat shrink tubing and not shrinking it so tight about 3/4" to 1" from the end and was able to slide it into the opening and it has worked for several years now. I still am keeping my eyes open at wrecking yards for the proper part. Let me know if you have any luck on the part, since i need one myself. Thanks and good luck.
Will do!
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Mike's advice was the ticket. Raymond Chevrolet in Center, TX showed two in their obsolete inventory bin. I tried to get 'em both so I could send you one but he ended up only having one on the shelf. Use the part # Mike listed in this thread and see if your local dealership will help you track one down. Good luck!
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