BLMs up at Idle

[speedskills]

Anyone have an idea why my BLMs are round 140s at idle? I lowered the fuel pressure to lean it out a little, didn't help. Vacuum leak? What's the best way to check for leaks? TIA

 

[bmackinnon]

Lowering the fp will INCREASE the blm, not lower it... because the ecm will have to compensate for the lower fp by adding even more fuel (increasing injector pulsewidth).... if the blms are fine everywhere else, and high at idle, a vacuum leak is likely....

 

[speedskills]

You're right. I had a brain fart. Now, is there any sure fire way to check for vac leaks?

 

[paulg]

Checkin for leaks.

You can use a propane torch with the gas all the way up but no flame and pass it very slowly around the Intake and and vacc lines. or I have found a couple by sticking a screw driver in between the stop screw and throttle to rev the car up to about 2000 rpms and i can hear the whistle. I zip tie all of my vacc lines to prevent leaks.

 

[speedskills]

Thanks. I'm going to get to It next week. These last two weeks I've been putting in about 80 hrs week. No time for crap. Would my egr valve cause this? Its still on but I am running a TT5.6 chip.

 

[paulg]

no tt chips cancel the EGR function. the egr vacc lines should be capped or left on the EGR.. I leave mine on to fool The Smog guy :biggrin:

 

[norbs]

read this about blms maybe it will help you understand better.

Block Learn Multiplier and Integrator

 

[berserker6]

Any updates? Did you raise your fuel pressure to 43lbs, reset the ecm, drive it around for a few miles and then recheck it?

 

[1KWIKSIX]

High BLM's at idle

Just thought I'd mention a very inexpensive option.

Buy AutoZone's PVC1162 valve. It's calibrated properly for our turbo buicks....and I was told by many buick owners who have switched over to this vs the factory AC Delco PCV Valve, that they found it lowered their BLM's.

For under $2.00 you can't go wrong. Heck, you can't buy chit for these cars for that price.

While you're at it.....may be a good idea to change over your PCV Grommett to rule this out too. Any leakage here will also lead to you chasing BLM issues. Dennis Kirban sells an exact replica of the factory PCV grommett which has been discontinued now by GM. Another high dollar investment at around $8.00.

So for around $10. these fixes are a bargain !!!!!

If you've got an inline check valve installed in your PCV line (this is in addition to your PCV valve)...take it out and see if this is the culprit. Many in line check valves are "spring loaded" and have a crack or unseating pressure that is too high which contributes to high BLM issues. Either remove the spring in it or purchase an in line check valve that has a zero to low crack pressure.

Anyways, from my own personal experience with the 1162 PVC Valve, it lowered my BLM's at idle and thru the entire RPM range too......have pulled some fuel out with my GenII and car has never run better. Heck maybe even picked up a mile or two better gas mileage now. (Will have to see about that).
LOL

Suggest you give it a go....you've got nothing to lose.

Good Luck


dave

 

[Sal 87WE2]

Just thought I'd mention a very inexpensive option.

Buy AutoZone's PVC1162 valve. It's calibrated properly for our turbo buicks....and I was told by many buick owners who have switched over to this vs the factory AC Delco PCV Valve, that they found it lowered their BLM's.

For under $2.00 you can't go wrong. Heck, you can't buy chit for these cars for that price.

While you're at it.....may be a good idea to change over your PCV Grommett to rule this out too. Any leakage here will also lead to you chasing BLM issues. Dennis Kirban sells an exact replica of the factory PCV grommett which has been discontinued now by GM. Another high dollar investment at around $8.00.

So for around $10. these fixes are a bargain !!!!!

If you've got an inline check valve installed in your PCV line (this is in addition to your PCV valve)...take it out and see if this is the culprit. Many in line check valves are "spring loaded" and have a crack or unseating pressure that is too high which contributes to high BLM issues. Either remove the spring in it or purchase an in line check valve that has a zero to low crack pressure.

Anyways, from my own personal experience with the 1162 PVC Valve, it lowered my BLM's at idle and thru the entire RPM range too......have pulled some fuel out with my GenII and car has never run better. Heck maybe even picked up a mile or two better gas mileage now. (Will have to see about that).
LOL

Suggest you give it a go....you've got nothing to lose.

Good Luck


dave

I would just like to say thanks!

I did a search and found this old thread. I want to give credit to dave since i had the same problem were my BLMs were locked at 142 (at idle and warmed up) after installing new injectors and a TT chip. I read this and a couple of other threads where Eric Marshall also commented on usng the PCV 1162 from Autozone. I did have a year old AC Delco brand PCV so i yanked it out and dropped in this $2.16 PCV from Autozone and guess where my BLMs are locked now (at idle and warmed up)???....128!!!

THANKS!!!!!!