Why BL #'s ok at cruise but off at idle???

[2QWIK4U]

Been chasing bl# of 150 at idle...changed check valves,vacuum lines,O2,swapped MAF and no change.Put gasket paper under vacuum block and still 150,put on new vac. block gskt.
Found egr gskt leaking and replaced...now bl 144 at idle but fluctuates to 150 then back down.Tried different fuel pressure but no change.INT is now 121-133 instead of 134-145.While cruising around 2,000 rpm bl# is 127 but goes to 150 under accel.I'm confused and don't know what else to change or fix, used top engine clean and found no exhaust leak anywhere.Any ideas???
When I parked the car for the winter bl# was 119-124,only drive it approx. 1,500 miles a year.

 

[MistaScott]

I am in your same situation -- BLMs pegged at 150 at idle only. Welded the header, tested the vac system, new o2 sensor, etc. Still haven't found the problem. I am swapping out the MAF next week because my MAF # is only 4 gps at idle. What is your MAF at idle?




I hear throttle shaft seals can often explain the BLMs so listen at part throttle for a whistle that is not the turbo. Do a search for "throttle shaft seals" and there is plenty of info on replacements.

I'm interested in what usually causes BLMs to peg at 150 at idle only, if anyone has any experiences they wish to share.

 

[2QWIK4U]

In park at idle MAF is 4,in drive at idle it is 5.From everything I've been told that is perfect.
Throttle shaft seals aren't whistling and hear no change when squirting starting fluid around them.
I'm pretty much at a stand still and will just drive the car til I get a new idea.

 

[KillrV6]

same exact situation over here.

BLM 150 at idle, some times 144, mostly 150 or more.

that throttle shaft idea sounds like it might be on the right track

 

[MistaScott]

ttt

Anyone else?

 

[bigz]

I had the same problem and it was my MAF

 

[wiked87gn]

check valves, there is 2 of them, one going to the canister and one going to the egr selenoid, check both for leaks also check the EGR gasket.

 

[fast eddie]

Just instaled 50's and Extender chip,blm's 140 at idle,no vac leaks,throttle shafts replaced.with the Extender chip you can adj the blm's up or down.never had this problem before

 

[Razor]

Its like this... "if" you block off the vacuum lines on top of the throttle body and they dont come down.... its not a vacuum leak from those lines. In other words.. if you block the lines, they should come down to 120. If they dont, the issue is elsewhere. Always is.

The O2 reads the mixture, the computer adjusts. Simple. If the O2 reads lean.. the computer adds fuel and increments the BL table until the O2 reads stoich.

If you've narrowed down the items by doing the TB block, swapping chip, swapping ecm, replacing the O2(ac delco), swapping MAF, and asserting the intake or headers arent leaking.... heres the answer you dont to hear.. you have bad injectors.

If you have an injector thats not "spraying" enough cuase its clogged.. then you have a lean condition on one cylinder. That lean condition throws all your numbers into the trash.

And when cruising, depending on chips(lean cruise), the numbers really should come down to 105-115.. or mid 120's.. but the chip dictates this.

Lastly, some chips can exhibit this condition, especially with 009's since leaning the chip out makes the throttle response more crisp.

HTH

 

[2QWIK4U]

How can I tell which injector is bad?By looking at the plugs they all look about the same.

 

[2QWIK4U]

ttt

 

[MistaScott]

I think you have to take them off the rail and get them flowed at an injector shop.

From a previous post by Turbodave231:

Caspers Electronics, Precision Turbo, Kinsler Fuel injection to name a few. Expect to pay $10-12 per injector.

Kinsler will backflush, clean, replace the top feed screens, and flow test each injector and give you a written report. I use them because I can drive there at lunchtime.

Also, check out http://www.cruzinperformance.com/fuelinj.html

HTH.

 

[MistaScott]

and here http://www.t6p.com/forums/showthread.php?t=2056

 

[Razor]

Originally posted by 2QWIK4U
How can I tell which injector is bad?By looking at the plugs they all look about the same.

Leave this as the very last step in the process of troubleshooting, tho its not a bad thing to have your injectors serviced to assure proper operation.

HTH