Engine Power Drop Outs....
Discussion
Went on a drive yesterday. 30 Degr.Cent. oustide temp. For the first time I had some engine power drop outs. I mean, I went full throttle from appr. 2000rpm up to max....in different gears..From time to time, mostly around 4krpm the engine kind of broke the accel. for a short moment and then continued to top rpm....My pass. asked if I went off the gas pedal....Anyone had anything similar ? Could it be a problem of the engine getting not enough or warmed air ? Could it be something worse, like a mechanical problem in the inner engine ? Notice: Got an LS6 GenIII, injector, OBDII and 4 Lambda-Probes....Thanks for any hints
Had similar problems with fuel Vapourisation, but that's was after sitting in 35+ heat in the fire up lane at Santa Pod, never had it while driving....
Do any of your fuel lines sit very close to the exhaust ???? where you sold some really low grade fuel, it has happened that they have put the wrong fuel in the Petrol Stations tank...... Use the fuel then fill up some where else with Premium..
Do any of your fuel lines sit very close to the exhaust ???? where you sold some really low grade fuel, it has happened that they have put the wrong fuel in the Petrol Stations tank...... Use the fuel then fill up some where else with Premium..
Lutz, das liegt wahrscheinlich an deinem zitternden rechten Fuss....
The main reason why this problem occurs is insufficient fuel supply. This could be caused by a ECU malfunction (which I doubt as otherwise it`d occur all the time - unless you still haven`t connected the vehicle speed sensor...).
It`s no mechanical issue for sure, I`ve had the same effect "in the beginning" (not regularly). I solved it by reinstalling/upgrading my fuel lines and fuel supply (i.e. connecting the fuel lines to the right fuel feed, better fuel pump). It is important that you always have enough fuel supply, for an LS6 engine meaning enough fuel pressure which should be around 45-60 psi. The acceleration drop occurs when the fuel pump doesn`t supply sufficient fuel fast enough. What could also add to the effect is a clogged fuel filter - check it out and make sure it flows enough fuel for your demand - my 2 €-cents.
Sven
The main reason why this problem occurs is insufficient fuel supply. This could be caused by a ECU malfunction (which I doubt as otherwise it`d occur all the time - unless you still haven`t connected the vehicle speed sensor...).
It`s no mechanical issue for sure, I`ve had the same effect "in the beginning" (not regularly). I solved it by reinstalling/upgrading my fuel lines and fuel supply (i.e. connecting the fuel lines to the right fuel feed, better fuel pump). It is important that you always have enough fuel supply, for an LS6 engine meaning enough fuel pressure which should be around 45-60 psi. The acceleration drop occurs when the fuel pump doesn`t supply sufficient fuel fast enough. What could also add to the effect is a clogged fuel filter - check it out and make sure it flows enough fuel for your demand - my 2 €-cents.
Sven
Excellent Greg, it seems like we found the source of the problem. It must be Lutz`s subconscience telling him to lift his foot but the body still wants to go faster - resulting in a driving technique referredd to as "cangarooing", which can be observed watching upgraders (Smart --> Ultima) in the wild (i.e. autobahn)
schimms said:
Lutz, das liegt wahrscheinlich an deinem zitternden rechten Fuss....
The main reason why this problem occurs is insufficient fuel supply. This could be caused by a ECU malfunction (which I doubt as otherwise it`d occur all the time - unless you still haven`t connected the vehicle speed sensor...).
It`s no mechanical issue for sure, I`ve had the same effect "in the beginning" (not regularly). I solved it by reinstalling/upgrading my fuel lines and fuel supply (i.e. connecting the fuel lines to the right fuel feed, better fuel pump). It is important that you always have enough fuel supply, for an LS6 engine meaning enough fuel pressure which should be around 45-60 psi. The acceleration drop occurs when the fuel pump doesn`t supply sufficient fuel fast enough. What could also add to the effect is a clogged fuel filter - check it out and make sure it flows enough fuel for your demand - my 2 €-cents.
Sven
The main reason why this problem occurs is insufficient fuel supply. This could be caused by a ECU malfunction (which I doubt as otherwise it`d occur all the time - unless you still haven`t connected the vehicle speed sensor...).
It`s no mechanical issue for sure, I`ve had the same effect "in the beginning" (not regularly). I solved it by reinstalling/upgrading my fuel lines and fuel supply (i.e. connecting the fuel lines to the right fuel feed, better fuel pump). It is important that you always have enough fuel supply, for an LS6 engine meaning enough fuel pressure which should be around 45-60 psi. The acceleration drop occurs when the fuel pump doesn`t supply sufficient fuel fast enough. What could also add to the effect is a clogged fuel filter - check it out and make sure it flows enough fuel for your demand - my 2 €-cents.
Sven
I don't think it can be a basic fuel supply issue as in low pressure or low volume otherwise it would not continue to accelerate up to max revs after the 'flat spot'.
I'm still sticking with fuel/ignition mapping. Now this may be, as above, because the ECU is expecting data that has not been connected but I would have thought this would result in a fault code.
Steve
You`re right Steve, I`d also expect an error code if that was the case. But as I said, I experienced exactly the same difficulties prior to upgrading my fuel system - no more flot outs since that time. And as it only occured recently, I`d expect the main issue to be the fuel system (i.e. pump / filter). But we`ll see...
Lutz, you haven`t filled her up with diesel in order to get a better fuel economy, have you?
Lutz, you haven`t filled her up with diesel in order to get a better fuel economy, have you?
Not yet running an LSx engine, but on my carbed SBC I exactly the same problem. In the end I found that it was the fuel pressure regulator, I lost a screw and it was loose. Obviously under hard acceleration it started to move or vibrate and the fuel supply was then stopped. Very strange. But putting there a new screw resolved the problem completely. So I opt also for a problem with fuel supply.
p15ton said:
Another 30 guesses might get it....
The more experience you have with this stuff, the more the 'advice' looks like a stab in the dark.
Take the car to someone who knows about fuel injection systems & can test it on a rolling road with diagnostic equipment.
The more experience you have with this stuff, the more the 'advice' looks like a stab in the dark.
Take the car to someone who knows about fuel injection systems & can test it on a rolling road with diagnostic equipment.
Best(most useful) advice so far!!!!
Edited by m3desmo on Thursday 14th September 12:52
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