Vacuum leak
I was down in the 9-10 in/hg vacuum range when mine stopped working.
After I replaced the valve springs it came back up into the 12-13 in/hg vacuum range which is where it was before when my booster was working.
After I replaced the valve springs it came back up into the 12-13 in/hg vacuum range which is where it was before when my booster was working.
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It's kind of funny, this is the third time I've had a hard pedal. The first time was 10+ years ago when I was still na, but then it was just a bad booster. The second time was before took it to the tuner the most recent time. It came back fine, but unfortunately my tuner passed at the beginning of 2023 so I can't ask him what he did about it... Which forum do you think I should post in? I've been a member for a while but luckily I've been able to solve any issues I've up until now by searching through old posts.
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I'll get a gauge on it this afternoon to see how much vacuum I actually have. Based on what you said, 12+ in/hg should be enough that the brake booster should work properly? It has enough vacuum to operate the bov's normally.
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It did for me, I know plenty of guys running big cams in their LS cars who still use the factory booster.
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I got the car to idle more normal than it was before, but the pedal is still a rock. I gave it a few revs once it warm to clear it out and this is what the driver manifold looked like after i managed to get a picture of it. Clearly something somewhere isn't right. It must be lean to run hot enough to make the manifold glow red. The number one cylinder runner was so hot my temp gun just says over temp when i check it.
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I'd recalibrate you're AFR sensor just to make sure your AFR readings are accurate.
Double check your tune, get a scan if possible and post it here.
I've seen boosters leak and cause a hard pedal as well as a vaccum leak.
Double check your tune, get a scan if possible and post it here.
I've seen boosters leak and cause a hard pedal as well as a vaccum leak.
That large of a vacuum leak should be easy to find. What head bolts/studs are you using? I've seen the top row of head bolts interfere with the intake surface, not allowing the intake to seat properly.
I bet if you log your idle, you will find timing at 0* or less. I would also guess that you will find a bad reading from at least 1 sensor, and odds are it will be the IAT sensor. I have doubts about a lean condition having anything to do with this.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
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Betting on this also , late timing leads to low vac , poor / incomplete burn leads to unused O2 which the sensor picks up as lean , definitely leads to high exhaust Temps. Aftermarket crank ? Could be an inaccurately mounted reluctor wheel ?
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Arp studs. I'll pull the intake again to make sure. But if it was leaking like that you'd think I could find it with ether when I checked it
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I bet if you log your idle, you will find timing at 0* or less. I would also guess that you will find a bad reading from at least 1 sensor, and odds are it will be the IAT sensor. I have doubts about a lean condition having anything to do with this.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
Last edited by moisbest42; Sep 17, 2024 at 01:12 PM.
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I've resorted to just plugging the port on the intake for the booster to eliminate that possibility, that's when I checked and found only 7 in/hg. I'm not sure how the tune could be off now after running fine before though?
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I bet if you log your idle, you will find timing at 0* or less. I would also guess that you will find a bad reading from at least 1 sensor, and odds are it will be the IAT sensor. I have doubts about a lean condition having anything to do with this.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
Thread Starter
Teching In
Joined: Jun 2017
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I bet if you log your idle, you will find timing at 0* or less. I would also guess that you will find a bad reading from at least 1 sensor, and odds are it will be the IAT sensor. I have doubts about a lean condition having anything to do with this.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
edit-- Or your reluctor wheel broke loose and it will require a timing light to verify actual timing.
Last edited by moisbest42; Sep 17, 2024 at 04:45 PM.