low blm's what gives?

[wiked87gn]

got rid of my high blm's now they are in the low 110 at idle what gives, any ideas what could cause this?

 

[turbot2112]

whats your fuel pressure set at, did you make any changes to the car recently, .could also be an exhayst leak. i hate blms.

 

[wiked87gn]

fuel pressure is set at 36 static line off, so that's not it, got new coil pack, new cables, and spark plugs, what else could be causing the car to run rich?, if i a correct low blm's means the ECU is taking fuel out not putting it in, correct?

 

[straycat990]

Originally posted by wiked87gn
fuel pressure is set at 36 static line off, so that's not it, got new coil pack, new cables, and spark plugs, what else could be causing the car to run rich?, if i a correct low blm's means the ECU is taking fuel out not putting it in, correct?

Yes, low blm's are a sign of fuel being removed. Blm's only do that as a way to correct the intergrator. The intergator is trying to maintain a reference number of 128. Seeing the intergrator reading any where between 118 and 138 is acceptable and normal. if the intergrator stays below 118 or above 138 of any length of time the Blms try to correct it.

Now as to why yours is doing that. How old is the O2 sensor? Have you run any leaded race fuel lately? The O2 sensor is what the computer uses to determine how much or how little fuel is needed.

 

[wiked87gn]

got me a brand new gnx 0'2 sensor, ran only 5 gallons of 114 on it, that is the only leaded fuel that 0'2 has seen and its not that old, bought it from kirbans performance.

 

[straycat990]

hmm I would not think that just 5 gallons of race fuel would foul the sensor, but I have killed them with just a 50/50 mix of cam2 and 93 octane gas. one tank of that mix and the O2 sensor fouled and started reading extremely lean. Do you have another O2 sensor to try. Also what are the O2s and blms doing while cruising? is fuel being removed through out the entire rpm range or is it just at idle?

 

[wiked87gn]

fuel is being added but at some points its also removed, but to be honest its all over the place, its not steady at all, and yes i have tried 2 other 0'2s they all ready the same.

 

[straycat990]

okay this is something to check ... do you have a fuel pressure gauge that you see while driving? It could be that the regulator is not maintaining the fuel pressure as it should. I had one that would vary as much as 8 psi. I could set it ..make a pass with the car come back in an the base fp would be off. The regulator should remove 1 psi of fp for every 1 inch of vac and raise it for every psi of boost. This is just something to check .. I don't think that this happens very often but it can.

 

[wiked87gn]

yes i have one mounted on the hood and it looks fine it gradually moves up as boost increases so fuel pressure is not the problem there.