Help on chasing high blm

[Murt TTA]

My blm is pegged at 150 at idle and at part throttle.

I have been trying different things and following razor's list to see if i can solve this.

Things I've tried already:

New 50# injectors
New turbo tweak chip
check valves
02 sensor
hose inspections

I tried putting a flat peice of gasket and hylomar for throttle body gasket, blm's went from 150 down to 136 with everything blocked off. Does this mean that I have a vaccuum leak somewhere?

I also put the MAF (3inch w/ translator) right on the throttle body, cleared ecm, blms are now 135-136 at idle with MAF on throttle body.

Should the blms be lower if it was an intake track leak?

 

[TurboDave]

My blm is pegged at 150 at idle and at part throttle.

<snip>

I tried putting a flat peice of gasket and hylomar for throttle body gasket, blm's went from 150 down to 136 with everything blocked off. Does this mean that I have a vaccuum leak somewhere?

<snip>

Absolutely!!!!

 

[Eric Stage I]

Just make sure you didn't block off vacuum to the fuel pressure regulator, or it will skew your results.

If putting the MAF on the TB helped, then maybe there's a leak in the intake plumbing or intercooler.

Eric

 

[Murt TTA]

my blm of 136 eventually climbed back up to 150!!!!
argh this sucks.

IT would stay around 136 after the reset, but as soon as i started driving around I watched the cruise numbers go to 150, then the idle numbers would climb as well.

This is a PITA....

I looked at all the intake plumbing and everything seems to look good, all hoses and clamps are good.

I think im going to pull my intercooler off next and see if its holding pressure.


also put in a AC delco PCV valve and checked egr and soilenoid, both seemed ok..

Charcoal canister seemd to hold vacuum on the nipple side.

Im going to keep at it...

Im thinking of swapping ECM's out and maybe trying to find another MAF sensor, i have the 3 inch w/ translator and it worked fine on my other car.

 

[stickybones]

I tried putting a flat peice of gasket and hylomar for throttle body gasket, blm's went from 150 down to 136 with everything blocked off. Does this mean that I have a vaccuum leak somewhere?

Not so fast. Blocking off the PCV, which is HUGE vacuum leak, albeit a "known" vacuum leak by the ECM, will skew your results. In other words, you're supposed to have the PCV vacuum leak. You need to keep the PCV functional, and functioning correctly, when you check for leaks.

 

[TurboDave]

my blm of 136 eventually climbed back up to 150!!!!
argh this sucks.

IT would stay around 136 after the reset, but as soon as i started driving around I watched the cruise numbers go to 150, then the idle numbers would climb as well.

This is a PITA....

I looked at all the intake plumbing and everything seems to look good, all hoses and clamps are good.

I think im going to pull my intercooler off next and see if its holding pressure.


also put in a AC delco PCV valve and checked egr and soilenoid, both seemed ok..

Charcoal canister seemd to hold vacuum on the nipple side.

Im going to keep at it...

Im thinking of swapping ECM's out and maybe trying to find another MAF sensor, i have the 3 inch w/ translator and it worked fine on my other car.

It's a matter of detail detail detail. You've got to check those vacuum lines VERY CAREFULLY!!!!!!!!!! One or more on the throttle body vacuum block could be cracked or split on the bottom side that you can't see well. follow ALL vacuum lines beginning to end and even little small ones, like the ones between the EGR valve and EGR solenoid, etc.

Any exhaust leaks on the headers????? That will also push your BLM's sky high.

Changing ECM's isn't going to solve anything. You've got a leak to track down.

 

[Lee_Burough]

Which method do you use to search for a vacuum leak?

Some people pinch hoses as they monitor BLM's....Some spray carb cleaner on every inch of the vacuum line....Some use a butane torch (UNLIT) and go inch by inch over the vacuum line....

 

[trbojo]

i would have to say, with all of your repairs, that you must have a cracked d/s header.

 

[Murt TTA]

I took my car to Russ Merritt after I gave up searching for the problem and he eventually had the BLM's down. We think it was due to the MAF sensor I had in the car, after russ put a stock style MAF in, the blms came down.

But, Russ cleaned my newer style MAF and I think that might of been the problem, my BLMs are now around were they should be and it seems to be running ok now.

Russ did also put on a cone style filter and a power plate, that might of led to lower blms somehow.

My blm problem is fixed now, and I only have a few other minor things to fix.

Thanks RUSS!