Put the car on the dyno a few weeks ago to dismal results. On the drive home, notice the car is showing knock in kpro and running lean at the corresponding points in time. First instinct was I had a tank of bad gas, filled up half a tank of 93 from a different gas station and it didn't help. Turned off the o2 to make sure closed loop (short term correction was maxed out) wasn't the issue which also didn't help.

Immediately after the dyno one of the operators tried to test for a boost leak with a air compressor line and blew the coupler off the turbo inlet on the first try. My guess is it also blew off a vacuum line somewhere and that's what causing this. I've checked all the lines but can't find anything that looks out of the ordinary.

Only change I made to the car was a valve adjustment before the dyno and I test drove the car afterwords, it was not doing this. Car idles fine btw but AFR slowly but surely gets leaner the longer it sits. The biggest problem is at part throttle with barely any load, the knock counter starts ticking away and my AFR goes to 15-17+.

What's the best way to check for a vacuum leak? I've read about the propane trick, but was wondering if someone had a better way.

Ideas and suggestions plz...thanks.

 

if you had a leak wouldn't the car run richer?

 

No. It would run whatever it is tuned for at that rpm at that boost level.

Hmm...Sorry to hear this. I am trying to be creative with my problem solving but nothing is coming to mind. Little help from the peanut gallery?

 

if it is a map based map, or boost compensation map, if there was a leak, i beelive it would add less fuel based on the boost being seen at the intake mani. as long as the fuel/timing maps were scaled, which i know mase does, i dont see why that would be the issue. maybe an injector is sticking? bad ground somewhere? someone changed the map in the kpro? wideband is going bad?

just throwing some possiblities out.

 

D:

What map sensor are using?

J

 

Hondata 5 bar

 

It's supposed to be 15-17afr at part throttle. you talking about partial throttle boost? then that's a no no. but you said barely any load. so i don't see a problem there.

do a pull and cut the ignition at the load/rpm you want to check. let the car coast to a stop then pull the plugs (don't let the engine idle, which is impossible if you already cut the ignition lol)
read the plugs and let us know whats up. plugs don't lie

 

i have heard before people tune above 15:1 at idle and part throttle, this is ok? mine sees 15.0 at idle and 14.7:1 from -10 to -5ish psi, then from -5 to 0 i richen to 12.3:1. then 11.8:1 in boost no matter what rpm or positive load.

 

Not partial throttle boost. I'm talking just taking off from a stoplight type of load. AFR's are supposed to richen up to a certain point, instead they are leaning out way too much which I'm sure is the cause of the knock.

I'm not doing pulls and pulling plugs. I don't have the time nor the patience to find open road to tell me what I already know - the motor is predetonating. I've verified its not the tune. Nothing has changed in the map or kpro since before the dyno besides what I stated initially.

 

you are using a 3rd party wideband correct...can you throw up a datalog?