BLM question

[1turbo6]

my car has always been on the lean side but this year I wanna figure it out. while cruising the blms are 133-137 when I let off the gas and coast they go to 128. also fuel pressure is at 44-45 vac line on. should I drop fuel pressure back to 42 and start looking for vac leaks?

 

[Royal-T-Ltd]

my car has always been on the lean side but this year I wanna figure it out. while cruising the blms are 133-137 when I let off the gas and coast they go to 128. also fuel pressure is at 44-45 vac line on. should I drop fuel pressure back to 42 and start looking for vac leaks?

put the fuel pressure at the chip makers designated fp... usually around ~43. and yes i would say check all of the easy inexpensive parts first [ie vacuum lines and check valves] definitely would NOT hurt imo.

What are your BLMs at idle and part throttle

 

[turbojd]

put the fuel pressure at the chip makers designated fp... usually around ~43. and yes i would say check all of the easy inexpensive parts first [ie vacuum lines and check valves] definitely would NOT hurt imo.

What are your BLMs at idle and part throttle

You are still within + or - 10 from 128.

 

[JST A 6]

put the fuel pressure at the chip makers designated fp... usually around ~43.

That level should be with the vacuum line off too. Probably will drop to 38 or 39 with the line back on, or at least mine does.

 

[1turbo6]

blm's are at 128 at idle (throttle closed) and vary when cruising 133-138ish also o2 mv's seem to bounce up to 800 quite often. the o2 sensor is new and the engine has about 3-4k miles on it. I will try to lower pressure and see if the blm's rise as a result of it. I am wondering if the throttle body is leaking vacuum off idle. I have been over every vac line a few times and never find anything. Maybe I should try to make a gasket and block off all the vac ports to eliminate them as a possible leak. any other ideas??

 

[mikestertwo]

Your BLM's don't really look that bad. Why do you think there is a problem

 

[JST A 6]

They don't look bad now but the question is if they'll stay within range once the fuel pressure is set @ 43 psi with the vacuum line off. Apparently last year there was something wrong so he cranked up the FP to compensate.

 

[1turbo6]

when I got it,the car would never make more than 14 psi boost without knock,and I couldnt figure it out so I took it to Russ Merrit and he couldnt figure it out either,So he recommended an alky kit. the car makes good boost now but the problem was never really solved. it also has a fairly rough idle(shake) only at idle. the BLM and idle problem was there with the last engine as well.