PLeas elist all the reasons for HIGH BLM

[AsphaltAnihil8r]

I mean in pegged at 160 ,,unless I am driving

Headers seem OK
Cant find Vacuum leaks using propane to search
All hoses seem fine
PCV is new

What else causes this

Dennis

 

[TurboBob]

Leak at crossover pipe
Leaky EGR valve/gasket
Chip/MAF/injector combo
(these will have high BLM at idle all the time)

O2 sensor cooling off (unheated)
O2 sensor partially lead fouled
(These will (usually) have a normal BLM when pulling up to a light, but after idling for a while the BLM's will climb.)

Bob

 

[gnturbo]

could leaky egr gasket aide in knock.Vacuum robbed from fpr at wot

 

[Tow Man]

I wish I had asked this question about 3 weeks ago! I searched high and low for vacuum and exhaust leaks and couldn't find a thing

After the first time out with the new combo the O2 set a code13 on the way home Replaced the O2 sensor and all is well

Try the 02 before you pull too much hair out! Good Luck

 

[WarpSpeed]

Bad MAF sensor

 

[TurboDave]

All great suggestions, but THE most common causes of high block learns in the idle range are a pre turbo exhaust leak (either header or crossover), or a vacuum leak you just haven't found yet.

TurboBob's suggestions pretty much in correct order of likelyhood.

Not sure about a bad MAF causing it. That would usually drive them whacky across the board. And if the MAF were bad you would definately know it. They generally don't "ease" into a bad condition, they either work good or don't.

 

[Chuck Leeper]

BLM??

Where is the fuel pressure during this????

 

[gnturbo]

I don't have an extension for my rail mounted fp gauge so I don't know what the fp is when it occurs

 

[sixgun86gn]

I had the same problem until recently.My upper intake was leaking.I found out when I went to install a powerplate on it and the silicone was oily and it wasnt stuck good.I even tried the wd-40 and starter fluid tricks and never found it.I cleaned the surfaces with some of my alcohol and now they are sealed good.BLMs stay at around 127-133.

 

[AsphaltAnihil8r]

Originally posted by TurboBob
Leak at crossover pipe
Leaky EGR valve/gasket
Chip/MAF/injector combo
(these will have high BLM at idle all the time)

O2 sensor cooling off (unheated)
O2 sensor partially lead fouled
(These will (usually) have a normal BLM when pulling up to a light, but after idling for a while the BLM's will climb.)

Bob

Bob if it helps any ,,while cruising along at 35mph the blm are 133-138 and then when I stop at a light they just jump from 133 to 160 and stay there,until I leave the light

 

[AsphaltAnihil8r]

Re: BLM??

Originally posted by Chuck Leeper
Where is the fuel pressure during this????

Last night I pout one of those blood pressure bulbs on there and pumped it up to 52-55 psi and the blm came down to 155,not much change with pupming the psi up...

Dennis--
oh normally the FP is 42psi line off

 

[Eric Stage I]

I think Bob covered them all.

Did this condition just start?

What is your MAF (AF) reading at idle, warmed up? (I assume you have a scanmaster).

 

[AsphaltAnihil8r]

Originally posted by Eric Stage I
I think Bob covered them all.

Did this condition just start?

What is your MAF (AF) reading at idle, warmed up? (I assume you have a scanmaster).

Yes started about a month ago,,

Clt 164°
AF 06
IAC 68
hope this helps

 

[Eric Stage I]

MAF reading looks great.
The next thing I would do is pull off the pcv hose and plug it. What I usually do is have the car running, set the scanmaster to blm's, turn it around on the dash so you can see it when you're under the hood. Then pull off the pcv hose and put my finger on the metal line. Wait for a minute and see if the blm's drop down a bunch (it would be normal for it to drop some). Make sure the car is warmed up so its in learning mode. Hopefully this will at least rule out the pcv valve (these cars are real finicky about that valve). Make sure its a real AC Delco valve.
If that doesn't get you anywhere, change the O2 sensor just for fun.
And if that doesn't work, there almost has to be a leak somewhere. Or the chip is miscalibrated, but you said it worked at one point right?

Eric