At wits end with high BLM's, putting up the Guru Signal

[streetknight]

Please do so. I'm still chasing the same problem. Replaced all the vacuum lines, o2, and chip. Now the new chip makes the car go in open loop idle, but as I'm driving and coast to a stop. The 1st cell in the BLM's goes back up to around 148, better than the 160, but I wish it was better.

 

[DonnieShort]

Re: Second

Originally posted by quikv6
I second the MAF swap completely. I had blms at
160....but my idle was great and the car ran smooth. Swapped a GM maf...blms went to
120's

I'm running a GM maf, just the 3½" LS1 maf with my T+ and extender. The only other one I can get my hands on is a 3" LT1 from Dad's Vette and I'll do that this weekend. And I will post anything I find out. It seems like alot of us are having this problem as of late.

 

[streetknight]

my update..

I've had the high BLM'S and chasing this problem too. Here's what I've done and STILL no luck.

Replaced with new parts:all vacuum lines, check valves at egr and charcoal cannister(wasn't bad), egr, egr solenoid, o2 sensor(AFS 20), MAF (known good off friends GN).

On my car the BLM's went to 160 on the "0" cell.
On my friend's the BLM's were 122. with the same MAF, so I guess it's good.

Can't find anything spraying ether. Any Ideas before I start tearing into the TB, plenum, etc. to replace gaskets?

TIA

 

[TT/Ameasap]

I just had the same problem with my MAF sensor. Car ran excellent and I didnt want to swap it out cause I thought it would be a waste of time, but it sure enough fixed it...BL129 hot idle. Dont forget to reset your computer after you swap sensor.


HTH
Bo

 

[streetknight]

update...

Just wanted to let everyone know with Razor's help we figured out I had some bad fuel injectors. Replaced them and BLM's fixed.

Thank goodness

 

[2QWIK4U]

Glad you got it fixed.Tell me how you figured out it was the injectors, please.I've had the same problem and have done it all with no lowering of the idle bl #.Stays around 149-150.At cruise they are fine, only seem high at idle.Is there any way to tell if it is only one or two injectors or do you have to repalce all of them?Thanks.

 

[streetknight]

Let me start by saying without Razor's help, I never would have found it myself. That being said the single best thing I bought for this car was Direct Scan. Without that I don't know how long it would have taken. I replaced everything else I and Razor could think of. After finally taking a breather from being frustrated I noticed the fuel pressure would only hold for about 5 minutes after I cut the car off. I already had the BLM problem. So I sent Razor some Direct Scan files and he noticed my duty cycle on the injectors was 178%. So he said between that, the BLM, and the fuel pressure it had to be injectors. So I bit the bullet and just bought a new set, since I was going to go bigger anyway.

Fixed it right up, now if I can only figure out how to tune this thing.

Hope it helps, but definately try the cheap probabilities first.

 

[MistaScott]

Razor is the BLM god. I count myself as a student!

I find a lot of times, the high BLM issue has to do with the MAF. I wasted a lot of energy and frustration looking for leaks that weren't there. It is helpful to remember that sensors (o2/MAF) can cause the high BLM just as easily...

 

[DonnieShort]

Update!!

After taking a break from this blm issue, I decided to give it another try today. I decided to double check some of the things I had done before and everything checked out except for the exhaust. So I jacked the car up took off the ds wheel and crawled in. Seemed ok, but the cross over/header joint looked to be sitting funny so I took it apart and lo and behold I found my leak. The header flange was sitting cockeyed into the crossover and was leaking very bad, alot of black carbon almost all the way around. I loosened all of the header bolts and reseated the joint and tightened up then tightened the header back up. Reset the ecm and blms dropped like a pair of pants in Paris Hilton's bedroom ( couldn't resist ). Blms were pegged at 160 at warm idle and came down to 133. Bumped the fp up a knotch and set the T+ on rich idle and blms came down to 124-125. Had alot of exhaust leaks over the years, bad ones too but none affected the blms like this one did. Just goes to show that no matter how thorough you go over things, you can still miss something. I'd like to thatnk everyone who offered suggestions and help to me. And Razor, I would like to applaude you on your research and for your time to sit and write out all of the various things you have encountered to help all of us on this problem. Tip of the Stetson to ya.

 

[Razor]

Donnie, Benji, Mistascott... Anything I can ever do to help.. hollar. It gives me great pleasure helping others out. I know how frustrating problems can be, and how nice it is to have someone help. I cant tell you how many times others have helped me one way or another.

Sucks is when I call with a problem.. its gonna be a dooozy

The reason these cars are what they are is the sharing of information. If we all pool together and put thoughts in a positive way.. I tell ya nothing is impossible.

I owned a GN back in 1992 and sold it becuase nobody knew what to do with it's issues. And at the time bad choices in vendors made the problems worse.

Try go it alone.. fugedaboutit.. this has to be the best on-line car communitty for help. Proud to be a participant.