I do a ton of highway and am not interested in losing the AFM. I have pulled 28mpg average over 50 miles on the highway with AFM on, and it stays engaged at surprisingly high speeds (78-80 mph). Actually seems that sometimes it's in V4 more at 80 than it is at 65, maybe due to a little more torque available at that RPM in 6th. I did think about running a vacuum canister with two ports with check valves, one to the pump and one to the intake somewhere, so that I would get both pump and intake vacuum accumulated in the canister. Then a single outlet to the booster. But I don't want to drill holes in the intake while under warranty and I'm not sure if there's somewhere I could tap it without modifying it. Also reading about pump failures that take the brake booster down with it, or worse, part of me wants to just lose the noisy belt driven engine-oil-lubricated pump altogether. Me personally, what I will most likely do like I said is go with an electric vacuum pump and ditch the belt driven pump altogether if it acts up again. I need to search around to see if anyone makes a bypass pulley for the belt driven pump, or if there is a way to just remove the pump and re-route the belt if I do go with an electric pump. The whining noise creeping through the quiet campground is embarrassing, quite frankly.
So took the truck back Tuesday. Dealer called a few hours later, said they don't hear any whining noise from the pump and can not replicate the problem. They said they will go ahead and reprogram the EBCM per the recall anyway. Service advisor called on speaker with the tech there and we talked through exactly what I was experiencing. I mentioned I definitely hear the whine in the mornings and at low speed, they asked if they could keep the truck overnight to see how it sounds in the morning. I said fine. They called back yesterday afternoon and said they don't hear any noise, the pump still tests fine, they have no indication as to why I get the message on the dash and the hard clicking brake pedal. They did perform the recall / update. I go to pick it up, start it up and she's whining away, right there at the dealer, so I go back in and just ask if someone can come out here and listen. Service advisor brings the tech out and I run the rpm in park to about 1000rpm and there is an unmistakable whine, again to me sounds like when a steering pump is going bad on an old car. But it's coming from the vacuum pump. Tech tells me and the service advisor "yeah my 2017 makes the same noise." So which one is it? It's normal, or you don't hear it? I told him my 2016 didn't do it, and this truck didn't do it when it was new. Tech also starts telling me how the pump is only there to help out when there is not enough engine vacuum present. I say no, the pump is the only source of vacuum. He argues with me. I tell him there is no vacuum line from the booster to the intake, he says yes there is. I say to him "With all due respect, if you want to show me where that is, I have no problem learning something new" so I pop the hood and he says "Oh, yeah, there is none". Why do I know more about this truck than the service tech??? He also seemed to have no idea how the ABS system kicks in to assist in braking, and told me the ABS only works if the wheels slip, and if the ABS was kicking in the truck would come to an immediate stop. And that the ABS system has nothing to with any of this. Sensing I would not be getting through to him, I thanked him for looking at the truck and we went on our way. If it acts up again I'll be doing the electric pump and be done with this.
you're not in the dark, or missing anything, it's a software patch to mask the issue, plain and simple, we all know it. EDIT - only now, as a bonus, we will get the ABS assisting the system more, along with the same reduced braking effectiveness, just wont get that annoying message on the dash. The ABS system already assists when this happens, and it does very little to actually help you stop. When I almost blew that stop sign into cross traffic, the ABS was click-clacking away the entire time along with the message on the dash.
although, it might mate up to the plug on the back side of the trailer plug, and they might have had something else that got plugged into those 6 male spade connectors. Maybe a utility shell or like was said some old or custom trailer. Although I would question why they wouldn't just use a trailer-side 7-pin with the same pigtails to do the same thing. Now I'm interested
Those pins don't align with the 7-pin orientation, if you look at a 7 pin plug, the pins align with the 'edge of the circle' Those are all in line with each other. So I can tell you it's not a 7-pin. Unfortunately, I can't tell you what it is. It does look like some sort of test rig.
Well I can't argue with you about the squeaks, the rattles, the plastic, or almost anything else you said. But I love the car, and she runs great. It was fast for it's time. I've got a 2017 2SS if I want to go fast And the 700R4 in the 1989, well yeah I've had that out 4 or 5 times before I finally gave up and let a hot rod shop rebuild it. But the little 305, I get an average 20mpg overall, and I can get 25 if it's all highway. Sounds great and is 'quick' enough to be fun. She's a cruiser. Regarding the tire burning.....
My 30 year old Tuned Port Injection 305 in my old Camaro is still going strong. We all agree on one thing here, they don't make them like they used to.
Unfortunately not. The brakes pull no vacuum from the engine. All vacuum is from the pump, regardless of what mode you're in. There is no vacuum line that goes from booster to intake. Just to the belt driven pump.
You sure type a lot for someone who doesn't care There is finally a NHTSA recall of over 3 million trucks for this issue, but you still want to say there's nothing wrong with the pump??? Who the hell is drinking Kool Aid here??
Same here. My guess is that some of the 2018's got the new pump. This thread has great pics of the old and new pumps, there are external visual differences, so using these pics you should be able to look under the hood and check which one you have. I will be doing the same later today and will post back just for giggles.
Not sure what opinions I offered up. If you would like to point that out to me, I'm open to hearing it. I have stated nothing but facts in any of my posts. The vacuum pump design is garbage. Period. There, that's an opinion for you.
We have also had the issue since about 10,000 miles, that's when we first saw this warning on the dash. It would happen on startups, and we would just shut the truck down and restart it, which always cleared the problem. It was not until I was almost unable to make a stop pulling my boat at a crossroad with a 50mph highway a couple weeks ago that we made the appt to get it looked at, and I started digging further.
My 2018 5.3 Crew has 15,000 miles and is on it's third oil change, changed at or before oil life monitor on the dash (1,000 miles to clear breakin crap, ~7500 miles and 14,900 miles) and I have the issue. Compounding this is that my truck is not listed in the recall, so I expect a fight to get anything worthwhile accomplished. Blaming this on lack of maintenance is total nonsense.
No, The vacuum pump being defective coupled with the low RPM at idle causes this to happen at idle. The reason we even have the vacuum pump, and not just a port on the intake for the booster, is because overall, the engine vacuum in V4 mode is not always sufficient to maintain braking assist. Sadly, the vacuum pumps are no better. I am considering the electric corvette pump myself.
The AFM when engaged reduces the vacuum produced to the point where the power brakes can be ineffective. That is the reason.
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