High BLMs

[Danster]

I just want to add for the record, I too always had high BLM's even after installing the correct PCV, checking/replacing all rodded hoses, etc. I even tried adjusting it through my Translator without success.

One day I came across this post http://www.turbobuick.com/forums/showthread.php?t=155295

I checked my solenoid and sure enough I had the wrong part number. I bought and installed a new one and low and behold my BLM's dropped. They dropped to about 132 or so, I then made some adjustments via the translator to get to the 128 ball park.

Maybe this might help others in this post who mentioned high BLM's.

Dannyo

 

[Marc87GN]

The problem isn't testing the vacuum lines once you start to crimp off each line individually. The PCV line is the only line that I can clamp off and it immediately causes the BLMs to drop to normal. I'm watching the screen of my laptop under the hood while I'm doing it so I can see any changes immediately. So I'm confident that my problem is related to the PCV. I have installed a brand new hose, but I didn't have a new AC Delco PCV to try. The original setup included the AC Delco part number mentioned and the check valve. As I mentioned before, I have new ones coming from Kirbans, which are the correct part number & I will install them without the check valve and see.

 

[87geeinn]

Did ya' check the vacuum block gasket? That little s.o.b. caused me problems for a while before I replaced it.

 

[Marc87GN]

Did ya' check the vacuum block gasket? That little s.o.b. caused me problems for a while before I replaced it.

I installed a new one when I installed the new block. At worse, it could be contributing, but the PCV valve, I believe, is causing my headache. Based on the posts above, the PCV should only be causing my BLMs to go up maybe 10-15 counts. When I clamp it off, it drops over 30 so we will see soon. I hope the new PCVs get here today. I usually get things from Kirban in 2-3 days.

 

[stickybones]

I don't know. I'm still skeptical the more I think about this. I mean how much of a difference can there be between 2 different manufacturers PCV valves both built for the turbo 231?

Once I get my car back together again I'm gonna look at this some more.

 

[Ormand]

I'm skeptical, too. The PCV system is a "controlled leak" as mentioned above, and it is designed into the system. Blocking off one leak will certainly cut down on air flow into the engine, and make it less lean, but blocking a "designed" leak, to make up for other leaks, is not really the right way to fix the problem, even though it might give the right BLM. It would be treating the symptom, rather than curing the disease. But if the PCV valve that Marc is using now is somehow not offering any restriction, then maybe a new one, that works properly, will cure the disease.

 

[Marc87GN]

These guys were 100% correct. I just received and installed one of the PCVs from Kirbans(funky green color), reset the computer and let the car idle for several minutes at operating temp. The BLMs never went past 139. Before I saw 155 & 160 sometimes. I put in a little bit of BLM correction in the Extender and now it stays at 127 at idle. Now I just need to install the Protorque converter and test the A:F with the LM1 I just bought.

Thanks alot for the help guys. This site is priceless when it comes to getting good information.

 

[suicide six]

Hasnt been a problem that someone hasnt seen with these cars,losing their cool over something so little.Past experiences are usually a present headache for someone.Its great to have sites like this one.

 

[dsa87gn]

Your BLM should come down way under 129 when this leak is stopped. More like 116-118. Remember 128 its already calculating for the PCV leak.

I've chased this problem on many Buicks.. its a bear on some..

Ive been watching this thread because right before i put my car away i had some high idle blm's ~144. tried new Delco PCV and grommet with the same result. When i put cardboard under the vac block it went to ~129. But it seems it should be even lower. Where do you start looking next ?


Marc..glad to see you got it staightened out

 

[stickybones]

That's great Marc. I wish a simple PCV swap would solve my problem.

 

[TurboDave]

Ive been watching this thread because right before i put my car away i had some high idle blm's ~144. tried new Delco PCV and grommet with the same result. When i put cardboard under the vac block it went to ~129. But it seems it should be even lower. Where do you start looking next ?


Marc..glad to see you got it staightened out

You don't need to look anywhere. What's wrong with 129!!!!???

 

[dsa87gn]

You don't need to look anywhere. What's wrong with 129!!!!???

Well, The 129 is with the vac block totally blocked, even the pvc.
According to Razor and some other posts it should be below 120.

 

[Ormand]

With everything blocked on top of the throttle body, I think it should be below 129, too. Must be another vacuum leak somewhere. Have you tried spraying around with ether or carb cleaner, to see if there is anywhere you can spray that affects the idle? Thottle shaft, the EGR valve, along the edge of the manifold, etc, all potential leaks. What's your IAC, by the way?

 

[dsa87gn]

With everything blocked on top of the throttle body, I think it should be below 129, too. Must be another vacuum leak somewhere. Have you tried spraying around with ether or carb cleaner, to see if there is anywhere you can spray that affects the idle? Thottle shaft, the EGR valve, along the edge of the manifold, etc, all potential leaks. What's your IAC, by the way?

I tried spraying with carb cleaner and the only place that seemed to affect idle was at the the vac block by the PCV hose.
IAC is less than 30.

I have a new Vac Block Gasket, Silicone Hose Kit, & new Throttle shaft seals for my next go at this.

 

[Razor]

Ive been watching this thread because right before i put my car away i had some high idle blm's ~144. tried new Delco PCV and grommet with the same result. When i put cardboard under the vac block it went to ~129. But it seems it should be even lower. Where do you start looking next ?


Marc..glad to see you got it staightened out

I've also seen those fancy dancy billet blocks leak air past those allen head screws.

Once you block off all the lines a few things happen, one is fuel pressure increases.. and all the leaks from hoses are eliminated. Having higher numbers than approx 120 at this point would point the leak elsewhere. Like EGR, TB shafts, plenum/TB gaskets, cracked headers, bad O2, bad injector's', bad chip, bad MAF, etc..

You have to be methodical. Helps to have spare parts when going through these steps. Some cars its 10 minutes like a PCV.. others are weeks/years.

Write down what you've done.. and use the search feature.. I have covered this on T6Plibrary and here..