My E8 has been working flawlessly for the past almost two years now. However, few days ago I start my car from cold and it idles perfectly right through the warm up period. Just before I begin to drive it I notice it begins to run lean at idle and wants to stall. I quickly pull out my laptop and add fuel to the idle cells and this corrects the problem. Shortly after it again does the same thing then stalls. It since does not want to run. It often fires right up and runs for about one second then afterwards runs on one rotor.

Things I have checked:

Fuel pressure
Spark
Injectors

It seem to be related to the ecu since it will run on both rotors for a moment(probably on residual fuel from the primer) then one shuts off.

Please give some advice on the matter.

 

Have you checked that fuel pressure remains the same while the engine is running? That it doesn't fall of at some point once the engine starts? Could easily be an issue where the pump will prime the system but for one reason or another can't maintain pressure once the engine starts.

You might try removing the fuel pump relay and jumping it with a short piece of wire (14g minimum) so that the pump runs all the time and give it a try. Make sure it's not shutting down on you for some reason. Though a pressure check while the engine is cranked and/or running would confirm this too.

I'd also suspect an ECU/firmware issue. I had a ton of trouble with 1.89. Mostly inputs/outputs that would work one time you power the system and then not the next time. 1.62 and 1.71 were much more reliable IMO.

 

Thanks for the reply

Yes I have absolutely sure its not fuel pressure/pump issues I checked that throughly, any pressure is cosistanly 40psi during and after cranking. I too am leaning towards the ecu/firmware. I actualy just downloaded the firmware to attempt to reinstall it. Do you recommend this?

 

I'd recommend back dating to 1.71/build 32 firmware. That or build 29 were more reliable for me.

 

Thanks for the that suggestion. I really dont mind going back to the 1.71, but do you know i will have any issues with data logging and AFR. I read that there are some issues with the 1.71 and AFR readout while logging. I do my own street tuning so this is a must. Thanks again

 

Regarding firmware, has anyone seen that happen? Everything running as it should, and then the firmware begins to act up.

 

they had an issue if cranked to low volts and jumped could amount to corrupting the maps.. usually a line of corrupt values like zeros across the middle of the map.. usually apparent in the 3d maps for ignition.. and usually fixed by re-uploading the saved map

when swapping firmwares be sure to build the new map onto the correct base map taken from the correct firmware file .. else it can make for a bug where many aux functions like closed lop boost control will not function ..
ie.. base map written in 1.71 may not have working closed loop boost control if loaded directly onto a 1.89 machine
the trick there is to open the 1.89 base map... and import to it the fuel and ignition maps from the 1.71 file

 

Update: I reloaded my current map (the one I had saved before the problem started) I did not solve the problem but created a new one. The fuel pump does not prime or turn on anymore. I then also re installed the 1.89 firmware that also did not solve the problem.

The next thing to do I guess is to try the 1.71 with the build 32 firmware.

Does any one know if the 1.71 will run a tune map saved from 1.89 ?

 

load 1.71 onto machine.. load the 1.71 base map ( the one that comes in the 1.71 map file.. not yours )
setup the aux outputs as you have them before.. then import all maps from your saved 1.89 file ....

you must do things in this order else stuff like fuel pumps and boost control may not enable

 

Thanks for the instructions bumpstart.

I got the fuel pump issue resolved. It turns out that I damaged a wire to trigger the f/p relay when I was doing the the f/p relay bridge.

I am one step closer to solving the problem... The ig timing some how went out of wack. . This is one of the first things I should of checked Using the timing light, it shows about 180* off

But what causes that to happen?? I made no changes to my map, could it be the coils or ignitor going out? I use the stock FD crank sensors, coils and ignitor.

Any ideas?

 

FD setup is wastespark so your seeing 180 out pulse.. possibly cause you have inductive pickup clamp on facing wrong direction ( little arrow for spark direction usually )

it is also very possible that plug or coil is or ignition channel is giving up under load and only firing unloaded

check with new plug and lead.. then check at night and observe the coil for arcing

 

Ok I will check these things

 

Guys I am stumped on this problem. I have swapped out the crank sensors, coils and checked compression (100+ psi). The car refuses to start. It does intermitently fire the front rotor and spark plugs are sparking.

I am pretty sure something went wrong (possibly with the ecu) since the timing which was zeroed, is completely off. I did zero it again but had to change the tooth offset to 11 from 10, where it has been for past two years. Even with it zeroed with the new settings it will not start.