hi.

sorry for the long post but please take the time to read it as i really am in trouble at a dead end.

bought an E55 few months back, bone stock and had ECU remap done to it only. it performed pretty well, passed some cars that no one thought it should so out of curiosity took it to dyno to have it checked for power. much to our amazement, the results were incredible for just a tune:
445 whp @5000rpm in 4th gear. the dyno couldnt handle more speed and stopped at 250kph which is 5000 rpm in 4th. its safe to assume that it would ve done at least 460 whp if maxed out at 6550 rpm.
Nm could not be measured due to wheel spin.
however, the AFR was too rich dropping to 10.8 @ 5000 rpm. i m posting graphs for better illustration. hence we decided to write a leaner map for the ecu to get more power. went for 11.8

few weeks later went back to try out the leaner map, but before applying it, decided to recheck the old one again. it should 380whp in third gear with AFR dropping well into the 9s. then applied the new map, the car smoked the room out when first floored, but then on the second try it did a max of 393whp with AFR still dropping down to 9s.
initial thought was that the lamba sondes are messed up and we unplugged them but got 0 difference what so ever.

turns out fuel ventilation hose had unplugged itself, so we plugged it back in and went for another run. the computer showed errors of air leak and after plugging the hose back in there were no more errors.

on the third run the old ecu map showed max of 430 whp which was written to be richer and the new map writen for 11.8 showed max of 420.
although the whp between runs with same map fluctuated 15-20 whp. AFR still dropping to about 10.6.

so right now i have no idea what search for as computer is not showing any errors but it is clear that something is telling the ecu to use safe mode thus giving me rich AFR.
an idea i have is to install a smaller s/c pulley and increase boost to about 1 bar. now its blowing 0.75 bar as checked. logically this should give more air for leaner AFR. also, i plan to remove CATs in case they have malfunctioned and are stuffed limiting the air flow. other than that, i am running out of ideas.

please help me out those who have had experence in matters as such.

 

one more thin i forgot to mention:
in third gear my E goes 230-240 kph at 6700rpm on the road. on the dyno 3rd was maxed out at 6550 rpm at 195 kph. wtf?

 

Sounds like your IAT is getting too high and the ecu is dumping fuel to save the motor. Your intercooler pump may be dead. Are you monitoring iat's? Be careful driving it if your tune was leaned out to compensate for the ecu dumping fuel.

 

ok. how can i monitor AIT? when i bought the car the s/c kept shuttin off after half a run and it was the IC pump dead. would it not do the same if it died again? why would it go to duping more fuel rather than switching the charger off?

 

plus the tune cant do anything, it still keeps dumping more fuel despite what te tune is for.

 

sorry to bring up such an old thread.

has anyone found a fix for this.

I am currently having the same issues in the UK and would love some advice on the issue.

 

Datalog and keep the IAT's cool.

 

^ what he said. Iats are the key. And proper tune of course

 

so by bringing the IAT down you was able to sort the AFR issue.

How did you bring the IAT down..

I have a Eurocharged HE and a johnson pump. will check the pump is still working and the IAT sensor to make sure its not giving inaccurate readings.

 

Aquamist methanol injection. I also have a trunk tank but that doesn't help all that much on the street, once the coolant temp in the tank has reached equilibrium its nearly the same as not having a trunk tank. Though faster recovery times from having it are nice.

I've found through logging that my particular setup keeps IAT's roughly 8*-10*F above ambient through the top of third gear.

 

I got the car back from the garage. the car is now stock, except a johnson pump and EC heat excahnge.

I was using the torqu app last night and had the following.

ambiant temp 15c
IAT at cruise 23-26c
did a couple of WOT to about 140mp and found the intake temp going to 37 max, and then return to the mid 20c ..

The interesting this ii have noticed is that the car now struggles to get to 140mph and once there there is not much more to offer. When before in stock i was easily able to get to the 155 limiter and with the 84mm pulley and map i was able to get the car off the clock given enough room. (on private roads..)

The O2 sensors have been checked and seem fine, the boost pressure sensor has been replaced, the fuel rail has been changed, new NGK spark plugs and Coil packs have been installed. I presume the pump is working sufficiently as the IAT are fine...

its going on 4 weeks now and i cant seem to understand whats going.

Sorry for the Hi jack as this thread existed i though little point in starting a new thread. also shows the search function works

 

Have you checked compression?

 

i don't have the tools to complete this so will be taking it to the garage.

i have noticed that there is a slight leak on the right side of the engine by the rocker cover.

Still scratching my head over this.

 

An oil leak? If so, just a valve cover gasket. Compression is unrelated.