I've been chasing BL numbers without success. Eric @ TT redid the fuel curve and still no success. Finally he recommended I block off the PCV to check for unmetered air. The BL's are now perfect, but the PCV is disconnected. The PCV is an AC Delco and there is another brass inline check valve between the PCV and the vacuum block. I'm really happy with the BL numbers and would hate to go backwards at this point.
Bl's-Good news/Bad news.
- Thread starter mikec1969
- Start date
TurboBuickSix
Active Member
- Joined
- May 23, 2001
I had some problem for year and a half then finally pressure tested my intake system with the rockers out of the motor.Found my Throttlebody leaking but very little play,seals were shot.Had Steve Monroe upgrade me to 62mm and all new seal for $114.Put it back together and BLM's within a few numbers of 128 and runs better than it ever has.FP set at spec of 42-43 psi with TT chip and 60lb'ers.I made my pressure tester out of a scrap piece of 3" copper pipe.
stickybones
What?
- Joined
- Dec 27, 2001
mikec1969 said:
The PCV is a known vacuum "leak". Blocking it off will falsely give you the impression that it's the cause of your high idle BLM (assuming this is your problem). You need to look elsewhere for your suspected source of unmetered air.
Sticky-good point. I was chasing slightly high and inconsistent readings, especially after longer drives. Blocking off the PCV brought the numbers down to 127-130, they are consistent, and the car does not have that rich smell. I'm going to replace the PCV with one that Eric @ TT recommends and see if that helps. It's a Deutch brand PN PCV 162. Thanks.
stickybones
What?
- Joined
- Dec 27, 2001
Dave
Any idea how much of vacuum leak it takes to drive the idle BLM to the max (160 for me) or how much fuel pressure affects the idle BLM? As you know, I'm one of those poor unfortunate souls that's been chasing the high idle BLM since I've had a scan tool tell me it's high. (I wouldn't have been able to tell otherwise.) I've literally gone over just about everything except replacing the intake manifold gasket and mess with the fuel pressure. I've just recently pulled my headers looking for small cracks (there weren't any) but noticed I had a small leak at the p-side crossover connection. After reassembly (and resetting the ECM), my idle BLMs are worse and I don't think I have any leaks in the exhaust now! They march to 160 in about 20 seconds. It seems like all other driving conditions yields a BLM in the 131-133 range. Only idle is nuts. I'm now going to get another fuel pressure gauge to verify I'm at 45psi as per the Extender chip instructions. Maybe my old gauge is way off.
Anyway I was just wondering if a very small vacuum leak or a small adjustment in fuel pressure could/should result in a dramatic idle BLM change.
Thanks
Mike
P.S. Don't mean to hijack your thread mikec1969, but maybe any info from Dave or others can help...you and me and possibly others.
Any idea how much of vacuum leak it takes to drive the idle BLM to the max (160 for me) or how much fuel pressure affects the idle BLM? As you know, I'm one of those poor unfortunate souls that's been chasing the high idle BLM since I've had a scan tool tell me it's high. (I wouldn't have been able to tell otherwise.) I've literally gone over just about everything except replacing the intake manifold gasket and mess with the fuel pressure. I've just recently pulled my headers looking for small cracks (there weren't any) but noticed I had a small leak at the p-side crossover connection. After reassembly (and resetting the ECM), my idle BLMs are worse and I don't think I have any leaks in the exhaust now! They march to 160 in about 20 seconds. It seems like all other driving conditions yields a BLM in the 131-133 range. Only idle is nuts. I'm now going to get another fuel pressure gauge to verify I'm at 45psi as per the Extender chip instructions. Maybe my old gauge is way off.
Anyway I was just wondering if a very small vacuum leak or a small adjustment in fuel pressure could/should result in a dramatic idle BLM change.
Thanks
Mike
P.S. Don't mean to hijack your thread mikec1969, but maybe any info from Dave or others can help...you and me and possibly others.
the dreaded high idle BLM chase.
Anyone wanna hear my sob story ?
Put a Steve M. ported Tb/Plenum on first thing last spring.
Car was fine until the very end of last summer. Idle BLM's went up to ~144.
Tried 3 different PVC's,all new hose at the vac black.
Heard a whistle at light RPM's around the TB somewhere, blocked off vacuum block, taped up real good around Throttle Body to Plenum to seal it, removed and plugged EGR hole.
figured it was shaft seals on the throttle body so i changed those. Still had
high idle BLM's.
Swapped my original Throttle body and plenum back in the car and the BLMs
were even worse, still had the whistle but it was much less. I read on here that you can get a whistle when the throttle blade does open.
Put the ported stuff back in and for now they are holding at 134, but i am assuming they will creep back up. What a biatch !!!
Oh, the whistle is still there, louder than with the stock stuff.
Strange thing was, in closed loop, I blocked the Vac block one last time
and the BLMS didnt change and the int held steady at 128.
Im giving up for a while
Anyone wanna hear my sob story ?
Put a Steve M. ported Tb/Plenum on first thing last spring.
Car was fine until the very end of last summer. Idle BLM's went up to ~144.
Tried 3 different PVC's,all new hose at the vac black.
Heard a whistle at light RPM's around the TB somewhere, blocked off vacuum block, taped up real good around Throttle Body to Plenum to seal it, removed and plugged EGR hole.
figured it was shaft seals on the throttle body so i changed those. Still had
high idle BLM's.
Swapped my original Throttle body and plenum back in the car and the BLMs
were even worse, still had the whistle but it was much less. I read on here that you can get a whistle when the throttle blade does open.
Put the ported stuff back in and for now they are holding at 134, but i am assuming they will creep back up. What a biatch !!!
Oh, the whistle is still there, louder than with the stock stuff.
Strange thing was, in closed loop, I blocked the Vac block one last time
and the BLMS didnt change and the int held steady at 128.
Im giving up for a while
NHRA Super Gas
Member
- Joined
- Nov 18, 2005
TurboDave said:
Dave,
I did a search on PCV recently, as I'm having similar issues to what Mike C is having, plus I have the dreaded oil sucking as well. In about every post, you say 893 only, and you must run it. What is someone to do when they are having these issues? It seems fresh motors (which mine is) have it even worse as they have some pretty solid vacuum.
I am about to try going without one for a while. The car is far from a daily driver, I can handle an oil change every 500-1000 miles.
Thoughts?
stickybones said:
It doesn't take much of a vacuum leak or post maf leak to make a sizable difference. Pre turbo exhaust leaks need to be almost bad enough to hear before they'll drive the blm's up (almost). The wrong pcv or no pcv/check valve combo will also.
I haven't had to mess with/change my f.p. in so many years that I forget how much of a f.p. change it takes to move the blm's a significant amount, quite a bit I think
NHRA Super Gas
Member
- Joined
- Nov 18, 2005
TurboDave said:
Yes, brand new
It seems to me if we put breathers on the valve covers to vent the crankcase, then what's the purpose of the PCV? Is it to vent the crankcase of pressure on a "stock type" setup when there is no place for the pressure to go except for the PCV? Sounds like we can delete the PCV. I personally can't see the benefit of oil vapor being drawn into the intake charge especially from a performance standpoint. My BL's are "text book" correct without the PCV connected.
83ttypecooled
Active Member
- Joined
- Sep 14, 2003
pcv
Hi,
To MIKEC: Pcv systems are an emissions device. In the old days,Crankcase emissions were dumped to the atmosphere by a road draft tube, or similar device.Then, along came CARB and subsequently, the Federal Clean Air Act.While a lot of the stuff these changes did was harmful from a performance standpoint, it did a world of good when considering the quality of our air. Catalytic converters were the most influential member of the emissions technology group, finally allowing fast AND clean, along with such support items as air pumps,egr systems,and electroic controls.40 years later,we have 10% of the nations vehicle fleet heaving out excessive emissions, instead of a totality.
I hope you read this and think about it, because we only have one set of lungs to breathe with,and every bit of compliance helps us all! I don't mean to sound preachy, just thinking about the future.
Hi,
To MIKEC: Pcv systems are an emissions device. In the old days,Crankcase emissions were dumped to the atmosphere by a road draft tube, or similar device.Then, along came CARB and subsequently, the Federal Clean Air Act.While a lot of the stuff these changes did was harmful from a performance standpoint, it did a world of good when considering the quality of our air. Catalytic converters were the most influential member of the emissions technology group, finally allowing fast AND clean, along with such support items as air pumps,egr systems,and electroic controls.40 years later,we have 10% of the nations vehicle fleet heaving out excessive emissions, instead of a totality.
I hope you read this and think about it, because we only have one set of lungs to breathe with,and every bit of compliance helps us all! I don't mean to sound preachy, just thinking about the future.
mikec1969 said:
It's not only that they're an emissions device, but they ventilate the crankcase, as the name implies. Just having breathers isn't going to accomplish the task. The PCV works by pulling a vacuum on the crankcase, pulling air into/through whatever type breather setup you have, and pulling the crankcase gasses up out of the engine and burning them during combustion.
Eliminating the PCV (especially on a street driven car) will result in some real nasty stuff happing in the crankcase due to condensation. The breathers alone ARE NOT ENOUGH.
83 TType- I agree with the environment issues. The reason I started chasing BL's was because of the rich condition that existed. Lot's of fumes. Now that BL's are in check the car is much cleaner smelling. I am going to try a few different PCV's because my first choice is to have it connected. The car has 6500 original miles, and I might drive it 300 miles/ year so I won't be hurting us all too badly.
