So here's my problem guys, occassionally under hard accelleration my car loses power. The pedal will be all the way to the floor, but the enging will stop reving. However if I get of the accellerator and shift into another gear the car runs normally. Now I know this sounds like boost cut given my mods, and I originnally thought thats what it was but when I got my limit less cable I check the Rom and my tuner had set boost cut colum to 319 I i think. Effectively disabling boost cut. I have been running some datalogs an have seen some low counts of knock but I have never observed more then a 3 count. Since I went to one step colder plugs I did a 7min datalog of all types of driving and didn't notice more then a 2 count. with some 1 counts hear and there. No consistant patern though. Any ideas to what the problem is? Mods listed in sig.

 

Clutch slipping? Does it only happen in higher gears? i.e. 4 and 5?

 

When u go WOT does logs show 100% throttle position?

 

Nope, I know what clutch slipping feels like, and its def not that. It's pretty intermitant, but I dont dog the crap out of my car all the time. If I had to guess I'd say its almost always 2 or 3rd. I originally wrote it off to my alternator wire coming loose again since it first started happening right before it broke off. But my mechanic just called and said the wire is on tight. Not sure if it helps but this time I noticed a drop in my volt meter down to about 12v. It was mere chance that I looked down and noticed it. That another reson I though alternator wire, but apparently thats not it.

 

Yes, but on my actual pulls its often not a complete 100%. But my latest log does show a couple 100% places.

 

does it jerk or anything funny like ?

 

This use to happen in my Mirage, it was due to a bad ground on the battery.

 

There is a definite jerk when it occurs but, I mean there would be anyway if you were going full throtle in 2nd and then let off (which was the gear it happened in last time). I'd love to be able to capture it on a datalog, but its intermitant enough, and my laptop doesn't have enoung battery power for me to log all the time. I really need to get one of those displays that limitless makes.

 

Its interesting that you should say that. When I reinstalled my grounding kit I accidentally sparked the intake manifold ground on the positive terminal. Car seeming ran fine, but I don't think they are connected as it occured with more frequecy before that, right as I was having my alternator wire problem (it eventualy completely disconnected, and my car died on the way to the mechanic, though I turned it off before it completely went out). My mechanic has also remarked how loose my negative terminal was due to me mini bat kit. DO you think my grounding kit or mini battery kit could be the culprit? (or at least the imperfect fit of the terminal)

 

Could fuel be the issue? Either a clogged fuel filter or an inadequate fuel pump? I'm still running the stock pump and injectors with all the mods listed in my sig? Could the ecu be cutting power do to insufficient fuel? That seems like it might make sense aince the car doesn't lose all electrical power and the motor keeps running and it only happens under high load.

 

not sure if it helps but some of my older logs show "injector duty %" of 90%. (On newer logs I havent really been logging it, but now that it is colder maybe its even higher?). That would seem to mean I'm really taxing the stock fuel system. I'm not sure but that would seem to mean that the fuel system is really working over time. If the duty % reached 100 in certain senarios would that cause the ecu to put a stop to things to save the motor? Is it time to upgrade the fuel system before I do anymore full throttle runs? Obviously a fuel system upgrade was next on my list, but I was going to install a few other things at the same time to make the retune worth it. Should I just granny the car till I upgrade the fuel system?

 

anymore thoughts, comments, ideas? could the fuel issue be it?

 

maybe boost leak or fuel cut?

 

This happened on my E55 and Acura TL when the batteries where going bad.

 

There is no boost cut as it has been effectivly disabled by my former tuner DTM as far as I can tell. Boost leakage might be possible but it isnt just a slight power loss when it occurs, nor are there any blown off pipes or evident leaks. It boosts fine on most occasions. And when it does occur my throttle will be 100% or close to it and it will be like I took my foot of the throttle completely. But the real question is does the ecu cut fuel/ignition when you max out the fuel system. I seem to be running near the maximum capacity of my system just judging by the logs. It's feasible that I hit 100% "Injector duty %" during the events. I really would like to capture one on a log to get a better idea of what is occuring, but they are intermitent enough that it isnt realistic to log often enough to catch one (unless I get lucky). Simply put my question to the folk who are highly knowledgeable regarding the factory ecu/tuning is "does the ecu cut all fuel and/or timing to save the engine when it 'sees' the fuel system maxing out?"

As to the electrical possibilities that have been mentioned, I have been told that my negative battery terminal is a little loose for my mechanics tastes. Its seems tight enough to me, but when I pick up the car I'll play with the grounding system and the terminals to see if that will resolve the issue. The electrically system in generally has been a bit more "jumpy" then usual as gauged by my volt meter so I suppose that is a potential cause.

I think its also worth mentioning that the last time period (as well as the first set of times) this issue occured I was running slightly higher boost. However it was also right before the main cable to my alternator failed and broke loose, causing the car to run off battery power and eventually forcing me to shut it down and have it towed on the way to the mechanic. If I can find a solution by playing with the grounding system and tightening the terminal, I may just crank the boost down a bit to lower the load on my fuel system and see if that resolves the issue. As always more thoughts or comments are appricieated, new perspectives are always welcome. Thanks.