RE: [Chevelle-list] suddenly running really bad
As the others said, plug off the line at the booster, and then at the check valve to see if they are the problem first. I've had similar problems, but none were ever a blown booster. My booster is a bit newer, but even so, there are other places to check. The booster is really easy to isolate, so do that first. Next, plug every vacuum port at the carb to see if any other vacuum line, vacuum can at the distributor, or PCV valve is the problem. Next, check the electrical to be sure you have spark at all eight cylinders. You could have burned a plug wire or had something go bad with a plug. Pull the plugs one at a time and ground them to check for spark, and of course look at them to see if they are fouled, oil soaked, gas soaked, etc. Next, check your carburetor. A stuck float or bad needle and seat could cause problems with way too much or too little fuel. Finally, once you have ruled out vacuum, fuel, and spark, you are left with the engine. Pull the valve covers and check to see if all the rockers are on the pushrods. Yes, I have seen this (in a Ford) when the nuts backed out and let one rocker fall off the pushrod. My Chevelle somehow got a bent pushrod that also made the car run really rough in a similar fashion. If lots of rockers are loose, you could have a cam that went flat on you. Not to scare you, but this is just a more complete list of things to check. Since I had the bent pushrod, I got to go through this process pretty much all the way. Of course, it also let me "upgrade" the heads as long as I was at it... Brad Waller ([EMAIL PROTECTED]) '66 Corvette | 327/dead | 4-speed | Wilwood Brakes | 245/45/16 BFG R1 '67 Chevelle | ex-SS396 | 355/700R4 | F-Body Brakes | 275/40/17 Kumho MX > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of John Nasta > Sent: Tuesday, October 11, 2005 8:48 PM > To: The Chevelle Mailing List > Subject: [Chevelle-list] suddenly running really bad > > On my way home today my engine suddenly started running > really bad. In fact, > the only way to keep it running is to leave the choke on so > that it's on > fast idle. Putting it into gear immediately sucks power away > and with my > foot on the brake on the brake it can stall, even at fast > idle. My first > guess is that it's a massive vacuum leak. Can a blown brake > booster cause > that? The booster & master cylinder are among the few things > that I haven't > changed, and I know the booster uses vacuum. > > It was getting dark as I got home so I just parked it for the > night and will > look at it tomorrow in the daylight. It was running great all > day and this > first became noticeable at a stop light about a mile from > home. I had to > keep popping it into neutral and revving the gas at lights to keep it > running. At the light before that I had done a pretty strong > takeoff to get > ahead of another guy, but I doubt that that has anything to > do with it. As I > pulled up to the curb to park, it stalled out. The brake > pedal feels really > hard like it does when the engine dies and you no longer have > the power > assist. The pedal also seems to make a different squeak then > I've ever heard > before when I step on it. So, any chance it could have to do > w/ a vacuum > leak because of a ruptured booster diaphragm? > > Any advice is appreciated. The first thing I plan to do is > check all the > vacuum lines. This is a 1969 El Camino w/ a 1958 283 w/ HEI. > > Thanks, > John Nasta > > > > >
Re: [Chevelle-list] suddenly running really bad
At 09:41 AM 10/12/2005, you wrote: Also its been several years, but when I replaced the booster I found that it was about the same price to buy a booster with M/C. Now I have a spare M/C. Yep, their just about the same price.
Re: [Chevelle-list] suddenly running really bad
Or the check valve at the booster. Mine blew out once on the way home from a show & I almost didn't make it back. BL At 10:57 PM 10/11/2005, you wrote: yepBooster
Re: [Chevelle-list] suddenly running really bad
What Pelle said. Before changing the booster because it MAY be bad, isolate it. Either put a vacumn pump/gauge directly on the booster or plug it and see if it runs OK. The swap is reasonably straight forward. You can disconnect the M/C from it without breaking the hydraulic lines. You need to make sure that when you reconnect the push rod on the brake pedal arm that you put it in the same hole. Also its been several years, but when I replaced the booster I found that it was about the same price to buy a booster with M/C. Now I have a spare M/C. On 10/12/05, Pelle Andersson <[EMAIL PROTECTED]> wrote: Plug the vacuum hose that goes to the brake booster to see if it makes adifference?At sudden pwerful takeoffs the distributor might rotate a bit if you haven't tightenit enough and the felt gaskets sometimes used can get thinner over timemaking itpossible for the dist to rotate.Best Regards Pelle>From: "John Nasta" < [EMAIL PROTECTED]>>Reply-To: The Chevelle Mailing List <Chevelle-list@chevelles.net>>To: "The Chevelle Mailing List" < Chevelle-list@chevelles.net>>Subject: [Chevelle-list] suddenly running really bad>Date: Tue, 11 Oct 2005 23:48:03 -0400>>On my way home today my engine suddenly started running really bad. In >fact,>the only way to keep it running is to leave the choke on so that it's on>fast idle. Putting it into gear immediately sucks power away and with my>foot on the brake on the brake it can stall, even at fast idle. My first >guess is that it's a massive vacuum leak. Can a blown brake booster cause>that? The booster & master cylinder are among the few things that I haven't>changed, and I know the booster uses vacuum. >>It was getting dark as I got home so I just parked it for the night and>will>look at it tomorrow in the daylight. It was running great all day and this>first became noticeable at a stop light about a mile from home. I had to >keep popping it into neutral and revving the gas at lights to keep it>running. At the light before that I had done a pretty strong takeoff to get>ahead of another guy, but I doubt that that has anything to do with it. As >I>pulled up to the curb to park, it stalled out. The brake pedal feels really>hard like it does when the engine dies and you no longer have the power>assist. The pedal also seems to make a different squeak then I've ever >heard>before when I step on it. So, any chance it could have to do w/ a vacuum>leak because of a ruptured booster diaphragm?>>Any advice is appreciated. The first thing I plan to do is check all the >vacuum lines. This is a 1969 El Camino w/ a 1958 283 w/ HEI.>>Thanks,>John Nasta>>>>_Express yourself instantly with MSN Messenger! Download today it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/-- Rick Schaefer 72 TPI El Camino
RE: [Chevelle-list] suddenly running really bad
Plug the vacuum hose that goes to the brake booster to see if it makes a difference? At sudden pwerful takeoffs the distributor might rotate a bit if you haven't tighten it enough and the felt gaskets sometimes used can get thinner over time making it possible for the dist to rotate. Best Regards Pelle From: "John Nasta" <[EMAIL PROTECTED]> Reply-To: The Chevelle Mailing List To: "The Chevelle Mailing List" Subject: [Chevelle-list] suddenly running really bad Date: Tue, 11 Oct 2005 23:48:03 -0400 On my way home today my engine suddenly started running really bad. In fact, the only way to keep it running is to leave the choke on so that it's on fast idle. Putting it into gear immediately sucks power away and with my foot on the brake on the brake it can stall, even at fast idle. My first guess is that it's a massive vacuum leak. Can a blown brake booster cause that? The booster & master cylinder are among the few things that I haven't changed, and I know the booster uses vacuum. It was getting dark as I got home so I just parked it for the night and will look at it tomorrow in the daylight. It was running great all day and this first became noticeable at a stop light about a mile from home. I had to keep popping it into neutral and revving the gas at lights to keep it running. At the light before that I had done a pretty strong takeoff to get ahead of another guy, but I doubt that that has anything to do with it. As I pulled up to the curb to park, it stalled out. The brake pedal feels really hard like it does when the engine dies and you no longer have the power assist. The pedal also seems to make a different squeak then I've ever heard before when I step on it. So, any chance it could have to do w/ a vacuum leak because of a ruptured booster diaphragm? Any advice is appreciated. The first thing I plan to do is check all the vacuum lines. This is a 1969 El Camino w/ a 1958 283 w/ HEI. Thanks, John Nasta _ Express yourself instantly with MSN Messenger! Download today it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
Re: [Chevelle-list] suddenly running really bad
At 10:57 PM 10/11/2005, you wrote: yepBooster That's it, same thing happened to our 66 Elky.
RE: [Chevelle-list] suddenly running really bad
Thanks. That's what I figured but I wanted a second opinion. I hate to just buy & try stuff willy nilly. Do you suppose I should replace the MC too as long as I have it off? I guess so, huh. I'll need to read up on how to change them. For whatever reason, I've never changed a booster before. Any tips appreciated. John Nasta -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, October 11, 2005 11:58 PM To: Chevelle-list@chevelles.net Subject: Re: [Chevelle-list] suddenly running really bad yepBooster
Re: [Chevelle-list] suddenly running really bad
yepBooster
[Chevelle-list] suddenly running really bad
On my way home today my engine suddenly started running really bad. In fact, the only way to keep it running is to leave the choke on so that it's on fast idle. Putting it into gear immediately sucks power away and with my foot on the brake on the brake it can stall, even at fast idle. My first guess is that it's a massive vacuum leak. Can a blown brake booster cause that? The booster & master cylinder are among the few things that I haven't changed, and I know the booster uses vacuum. It was getting dark as I got home so I just parked it for the night and will look at it tomorrow in the daylight. It was running great all day and this first became noticeable at a stop light about a mile from home. I had to keep popping it into neutral and revving the gas at lights to keep it running. At the light before that I had done a pretty strong takeoff to get ahead of another guy, but I doubt that that has anything to do with it. As I pulled up to the curb to park, it stalled out. The brake pedal feels really hard like it does when the engine dies and you no longer have the power assist. The pedal also seems to make a different squeak then I've ever heard before when I step on it. So, any chance it could have to do w/ a vacuum leak because of a ruptured booster diaphragm? Any advice is appreciated. The first thing I plan to do is check all the vacuum lines. This is a 1969 El Camino w/ a 1958 283 w/ HEI. Thanks, John Nasta
