Pushing brakes stalls engine
Mountain Pass
Joined: Sep 2020
Posts: 167
Likes: 4
This error was occurring before I swapped out the booster. The old one also had a noticeable vacuum leak which was tolerable for a while until the engine started to kill after applying the brakes. Swapped and adjusted the pin and now the same issue is present. Maybe I should connect the booster vacuum on the carb? I will run your test also to be sure it’s not defective. Does the size of the booster affect anything? This one is much slimmer?
Lead Driver
Joined: Nov 2013
Posts: 7,174
Likes: 1,174
What was the reasoning to install the slimmer booster? Was it for a later model truck, perhaps fuel injected? Not sure if it would matter, just trying to decipher the clues.
Did you keep the original elbow connection? Not sure how important that piece is, but you didn’t answer the question.
The vacuum supply hose should connect directly to the manifold. The hose is large diameter and can only go one place. Don’t connect it to the fitting on the carb.
Have you tried running the engine with that big supply line plugged? Don’t drive it like that, as the brakes will require a lot of pressure on the pedal. But you should be able to simulate slowing down to see if the engine stalls with the booster out of the equation. If good, reconnect the booster and repeat the experiment. If the engine now stalls, you have confirmed the culprit.
Did you keep the original elbow connection? Not sure how important that piece is, but you didn’t answer the question.
The vacuum supply hose should connect directly to the manifold. The hose is large diameter and can only go one place. Don’t connect it to the fitting on the carb.
Have you tried running the engine with that big supply line plugged? Don’t drive it like that, as the brakes will require a lot of pressure on the pedal. But you should be able to simulate slowing down to see if the engine stalls with the booster out of the equation. If good, reconnect the booster and repeat the experiment. If the engine now stalls, you have confirmed the culprit.
Mountain Pass
Joined: Sep 2020
Posts: 167
Likes: 4
Yes the booster is the culprit and no I didn’t keep the elbow fitting. I simply installed the booster orielly recommended. It happens the be slimmer so I assumed it’s an updated part. Has nobody dealt with this issue. I’m depressing the vacuum out of my engine when braking. I’m running a low and smooth idle now which may be the issue but I like it quiet so hope I dont need to adjust that.
Lead Driver
Joined: Nov 2013
Posts: 7,174
Likes: 1,174
Ah, it’s all starting to make sense now.
I recommend you get an ill-tempered dog. Carefully train him to bite you aggressively if you pull into the O’Reilly’s parking lot. After a few such episodes, you will learn to shop elsewhere. In my over-inflated opinion, they are one of the worst vendors. There is a reason parts cost more where the professionals go, such as NAPA or CarQuest.
The AWOL elbow may be a problem, too. Can anybody else confirm it’s more than just a hollow fitting? I’m pretty sure but am not positive.
I recommend you get an ill-tempered dog. Carefully train him to bite you aggressively if you pull into the O’Reilly’s parking lot. After a few such episodes, you will learn to shop elsewhere. In my over-inflated opinion, they are one of the worst vendors. There is a reason parts cost more where the professionals go, such as NAPA or CarQuest.
The AWOL elbow may be a problem, too. Can anybody else confirm it’s more than just a hollow fitting? I’m pretty sure but am not positive.
Lead Driver
Joined: Nov 2013
Posts: 7,174
Likes: 1,174
Answered my own question:
https://www.rockauto.com/en/catalog/...eck+valve,1876
Note it’s called a check valve. If missing, that is likely the majority of the problem. I’d still recommend getting and training the dog, though.
https://www.rockauto.com/en/catalog/...eck+valve,1876
Note it’s called a check valve. If missing, that is likely the majority of the problem. I’d still recommend getting and training the dog, though.
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
Have you tried running the engine with that big supply line plugged? Don’t drive it like that, as the brakes will require a lot of pressure on the pedal. But you should be able to simulate slowing down to see if the engine stalls with the booster out of the equation. If good, reconnect the booster and repeat the experiment. If the engine now stalls, you have confirmed the culprit.
Mountain Pass
Joined: Sep 2020
Posts: 167
Likes: 4
I took off the check valve and it release a bunch of built up pressure. There was no air flow in either direction from the hose prior. Now it’s breathing right and the issue seems to have subsided. Not sure if it will last but perhaps there was pressure from the factory build? Anyway thanks for the help not sure why it was killing my engine if no air flow was permitted at all but who knows?
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