BLM Still High, what now?

[NorEaster]

I have been chasing down high blm's since I installed my scanmaster. My car has 125K, and is currently all stock, save for dual dynomax mufflers.

I replaced the intercooler hoses, the vacuum lines to the waste gate, the pcv, and last night replaced nearly all of the other vacuum lines. The only ones left are the big one on the pcv, and the hard, small lines.

Here are my scanmaster readings, hot idle, in park

AF: 04
L8: 27
BAT: 14.0
INT: 150
BL: 150
CLT: 190
ATS: 69
r: 950
TPS: .44
IAC: 00
CC: 7 or so per count
MAL: 44 (I bought a bosch O2 and it wouldnt fit, had to put the old one back in, and it got upset)

On my autometer mechanical gauge I am seeing 21" of vacuum.

Its obvious that I still have a vacuum leak, but where should I be looking?

 

[Royal-T-Ltd]

I have been chasing down high blm's since I installed my scanmaster. My car has 125K, and is currently all stock, save for dual dynomax mufflers.

I replaced the intercooler hoses, the vacuum lines to the waste gate, the pcv, and last night replaced nearly all of the other vacuum lines. The only ones left are the big one on the pcv, and the hard, small lines.

Here are my scanmaster readings, hot idle, in park

AF: 04
L8: 27
BAT: 14.0
INT: 150
BL: 150
CLT: 190
ATS: 69
r: 950
TPS: .44
IAC: 00
CC: 7 or so per count
MAL: 44 (I bought a bosch O2 and it wouldnt fit, had to put the old one back in, and it got upset)

On my autometer mechanical gauge I am seeing 21" of vacuum.

Its obvious that I still have a vacuum leak, but where should I be looking?

have you ever replaced the check valves? or have you tried blocking off the vacuum block at the top of the throttle body to help eliminate external sorces...

 

[NorEaster]

have you ever replaced the check valves? or have you tried blocking off the vacuum block at the top of the throttle body to help eliminate external sorces...

Thank you for the quick reply.

I have not replaced the check valves. Thats a great point because the one by the egr did not pass the mouth blow suck test. Is there a good spot to get these or would universal one work?

I have not tried blocking off the vacuum block. What would be the best route for this? Just take it off and make a plate for the throttle body?

 

[GNRick]

Could be your egr valve. Took two before I found one that didn't leak, per my smoke machine. IAC should be 10 -20, not 0.

 

[JDEstill]

I think the best, most complete way to track down your various leaks is with a "leak down" type test. Use an air compressor to pressure up your intake system and then just start listening for leaks. Here's a thread that gives more info:
http://www.turbobuick.com/forums/showthread.php?t=75615

This has worked really well for me.

John

 

[GNVYUS 1]

Yep, do a boost leak test instead of replacing every part (unless you don't mind, I like new parts too).

Go with the Denso 02, it's cheap and lasts the longest.

BTW, 4 AF and 190 degrees are a little out of the norm. MAF usually 5 or 6 around 750-850rpm and many of us never see over 175 while idling so you probably need to look at your chips fan turn on, radiator flush/recore or the stock fan is in need of his Social Security check.

 

[jdsgnx]

IAC shouldn't be at 00, 10/20 idel and go up to 30/40 when A/C is turned on.

you can pull it out and clean with brake cleaner

GNTTYPE.org can also be a good place to help with searches!!

JD

 

[salvageV6]

Have you verified the chip is stock?

Get the O2 fixed first.

Set the IACV and TPS second.

gnttype.org or vortexbuicks have the info. as to how to set them.

 

[NorEaster]

Thank you

Have you verified the chip is stock?

Get the O2 fixed first.

Set the IACV and TPS second.

gnttype.org or vortexbuicks have the info. as to how to set them.

Chip is stock.

I tried ordering a Denso, but they are nationally back ordered, so I got an NGK, should be in tomorrow.

Thank you all for your replies, I really hope to have this figured out. I purchased all the normal upgrades this winter, and need to install them. I want to get back to square one while stock.

I purchased a ADFPR, Racetronix hotwire, Reds XP pump, RJC Powerplate, 42.5 lb injectors, 91oct street chip. LS1 MAF and Translator (good deal on them) but no intake yet.

 

[NorEaster]

Clt

Yep, do a boost leak test instead of replacing every part (unless you don't mind, I like new parts too).

Go with the Denso 02, it's cheap and lasts the longest.

BTW, 4 AF and 190 degrees are a little out of the norm. MAF usually 5 or 6 around 750-850rpm and many of us never see over 175 while idling so you probably need to look at your chips fan turn on, radiator flush/recore or the stock fan is in need of his Social Security check.

Does that temp seem high? I thought stock thermostat was a 190?

 

[87gninpa]

No, for a stock car that temp is fine. My WE4 is stock down to the thermostat and fans and it runs around the same temp. No problem there.

As for the high BLM problem, IAC at 0 points to big vacuum leak. Check the intake manifold. I also had an issue with maxed BLM's before that turned out to be a nasty exhaust leak. Be sure to check your headers for cracks.

 

[hansongn]

on a stock motor i thought 20 inches of vacuum was good or should u see more?

 

[NorEaster]

Vacuum

on a stock motor i thought 20 inches of vacuum was good or should u see more?

That is what is bothering me. BLMs and rpm point towards a major vacuum leak, but vacuum gauge is steady at 20"-21". I dont know if that is enough, but that sounds like a lot to me.

 

[streetknight]

Mine has 15-16" @ idle....I'd get a vacuum pump like a mity vac and check all the hoses, also check headers for cracks as stated before...FWIW, I chased high BLM's on my car for a long time, finally found it was injectors, put a fuel pressure gauge on the rail, turn the key on to prime...it should hold pressure for a while, if it starts falling immediately, you have a problem

Sent from my DROID2

 

[NorEaster]

Fuel Pressure

Mine has 15-16" @ idle....I'd get a vacuum pump like a mity vac and check all the hoses, also check headers for cracks as stated before...FWIW, I chased high BLM's on my car for a long time, finally found it was injectors, put a fuel pressure gauge on the rail, turn the key on to prime...it should hold pressure for a while, if it starts falling immediately, you have a problem

Sent from my DROID2

I have a gauge on my rail. I will check that.

As for header leaks, they seem tight. I would think I would hear something if there was a crack that big.

 

[GNVYUS 1]

I guess I didn't take your, stock, comment as even the thermo is stock still. I take it you still use the stock chip than too?

You're vacuum gauge doesn't change readings when you have a vacuum leak, my Talon had the hugest BOV leaks and it read the same.

You need to do a boost leak test and then listen for the leaks and spray water or water/soap etc.

Header leaks don't make the IAC go to 0 FWIW.

 

[750H.P.V6]

Your MAF reading is too low. The result is that your BLM will be high. I would suspect there is either a hole in the inlet hose between the turbo and the MAF or the MAF has been replaced at some point with a aftermarket one. Most of the aftermarket MAFs don't read correctly. As far as your IAC counts go it sounds like someone has adjusted the screw on the throttle body and the throttle blade is too far open. This is also why your car idles to high.

Neal

 

[GNVYUS 1]

^ Agree, I think MAF=4 at 950rpm is telling you to check out the MAF.

 

[turbobooster]

I found that part of capping off the vacuum block interesting how exactly is that done to check for leaks? Do I cap off all the ports and start the car ? Will it start with vacuum lines off it? I've been chasing this high Blm as well since I installed scanmaster

 

[NorEaster]

Ok

^ Agree, I think MAF=4 at 950rpm is telling you to check out the MAF.

I will check the pipe, and the MAF does have a NAPA rebuilt sticker on it.

I dont really want to get a new MAF as I have the LS1, but I dont want to throw money at it and get an intake just to rule out the MAF.