Performance problems

S

Steve126

Hi guys can any 1 help with a few problems I'm having with k11 1.3 ?
My son has just started a racing formula we have a 1.3 micra running a 1.0 flywheel I've had the head ported and polished but after a few laps the car starts to loose power I have changed the throttle body and dizzy but we are still having the same problem any help would be great thanks
 
Agent_Sm1th said:
Overheating issue maybe?
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Hi thanks for your reply I don't think it is a overheating problem as the cars always get very hot when racing you can't run a rad or fan we are only allowed to run a large water box. We have never had this problem before it is only this engine we seem to be having the problem with I have had the head ported and polished and I have a remapped ecu
 
frank said:
sounds like some sort of limp mode kicking in, coilpack engine steve ?
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Hi frank no mate it is about a 96 cg13de running a dizzy we also run the standard injection system and I have a remapped ecu but everything else is done away with it is the same set up as a banger car but I've just had a couple of bits done to it to speed it up a bit as some of the other cars out on track or so quick. But we have to run the standard exhaust manifold and injectors so can't really gain any power that way.
 
if you connect the diag port and/or checklight, you will probably find its flagging a fault when the power drops off steve, my white 96 did whenever the temp went over a set limit
are all your sensor earths still connected ? because you banger guys tend to rip out most of the wires and just earth the ecu :)
 
frank said:
if you connect the diag port and/or checklight, you will probably find its flagging a fault when the power drops off steve, my white 96 did whenever the temp went over a set limit
are all your sensor earths still connected ? because you banger guys tend to rip out most of the wires and just earth the ecu :)
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Yes your right frank most of the wires get ripped out we run the loom from the ecu to the throttle body dizzy and I think another couple of sensors but all the rest are done away with. The ecu we have is a fusion but my boy has just told me he did not put the fusion ecu in he had just put a standard 1.3 ecu do you think this could be the prob? Thanks
 
i doubt it steve, the sensors need their dedicated earth for a clean signal (thats why all the signal wires are braided/shielded too) i doubt if it will ever run right without the full set of sensors (bar the lambda)
 
frank said:
i doubt it steve, the sensors need their dedicated earth for a clean signal (thats why all the signal wires are braided/shielded too) i doubt if it will ever run right without the full set of sensors (bar the lambda)
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Do you think it could be where my boy has fitted the standard ecu as apposed to the remapped 1?
 
I use the same wiring loom in each car I build but for some reason this 1 with the ported head just loses power after about 3 laps I changed the throttle body and he took it back out on track and it was flying but then after a few laps done the same thing again but we don't normally get this problem!!! As the head has been ported is there anything else that should be changed to manage the difference with the petrol flow and stuff?? I'm really at loose ends now :)
 
the k11 ecu,s have subtle differences steve, i,ve had 4 different preface models and they all acted differently
my red one ran weirdly when i did the rev limiter delete, and the white one would flag a light and would fuel-cut if the temp gauge went to max (none of the others did that) the blue one had no mil light and only an led on the side of the ecu
 
Hi Steve . I raced 1300 stockcars and I had the same problem after about three laps it would not accelerate out of the bends. It turned out to be crushed fuel lines.( they were braided)
Just a thought.
 
frank said:
the k11 ecu,s have subtle differences steve, i,ve had 4 different preface models and they all acted differently
my red one ran weirdly when i did the rev limiter delete, and the white one would flag a light and would fuel-cut if the temp gauge went to max (none of the others did that) the blue one had no mil light and only an led on the side of the ecu
Click to expand...
I've just taken the wiring loom out of my sons other car and still get the same problem once it is warm.
 
frank said:
i,m saying that the ecu,s react differently tho steve, have you tried another ecu ?
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Yes mate I've tried 2 different ecu' sand the fusion ecu.
When I put a different ecu it was fine then as soon as it warmed up the same problem happened again but when I put the fusion 1 on it was running like a bag of s**t
 
i dont know then mate, i doubt the gas flowing/porting is causing it tho personally, and i doubt if valve clearances will either (the clearances actually increase with heat)
this is where ecutalk type diagnosis is invaluable, to check what the sensors are outputting at the moment that the engine starts holding back
even the lambda readings will help to pinpoint the problem
 
frank said:
i dont know then mate, i doubt the gas flowing/porting is causing it tho personally, and i doubt if valve clearances will either (the clearances actually increase with heat)
this is where ecutalk type diagnosis is invaluable, to check what the sensors are outputting at the moment that the engine starts holding back
even the lambda readings will help to pinpoint the problem
Click to expand...
I have done away with the lambo would this have any effect? I think this is going to be 1 of those problems that will give me a headache for the next few days! Lol
 
yes most stock cars delete the lambda eh steve, but even the stock narrowband ones can be a very useful diagnosis tool
 
frank said:
i dont know then mate, i doubt the gas flowing/porting is causing it tho personally, and i doubt if valve clearances will either (the clearances actually increase with heat)
this is where ecutalk type diagnosis is invaluable, to check what the sensors are outputting at the moment that the engine starts holding back
even the lambda readings will help to pinpoint the problem
Click to expand...
Just a thought but I'm going to check that the inlet manifold is inline with the head just to make sure that it all lines up exactly if the inlet gasket is slightly bigger than the ported head do you think this would cause the problem as petrol would not be flowing perfectly would it?!!
Only thing that puzzles me is it idles perfect and is totally fine until it's hot
 
nah :) it might be something simple like the battery voltage is dropping below a certain threshold (yours has no alternator ?) and the ecu is throwing in some sensor voltage correction
or maybe that the car runs fine on the coldstart fuel correction table (like an electronic choke) and then runs crap when it switches over to normal temp fuel table (where the k11,s are usually running lambda/closed loop)
on my van i can log every little item with some £20 software, and analyse it afterwards
livedatatextbefore.jpg
 
Up at 5:30 this morning over to the unit tried another 2 ecu's checked all earths and sensors cleaned all plugs took her far a spin she was flying 20-30 min later same problem back to running like a bag of ****!!!! Again!!
I'm thinking could it be somethings breaking down under load!!! Spark plugs ?? Dizzy??
 
is the thermostat fitted steve ?
ecu,s are designed to protect the engine if something is amiss, iirc the pdf says that k11 one runs the injectors semi sequentially if a sensor is down, and it probably pulls a load of spark timing too (so that the owner feels a power loss and takes it in for a checkup)
 
Steve126 said:
We do away with the thermostat mate
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its not something i would do steve, the engine needs to get to a set temperature then stabilise at that temp, be it the stock 90 deg or else a slightly lower temp for more power
your big bulkhead water tank will take ages to get up to proper temp without a stat
 
Can I just pick your heads a min?
We have to run the standard manifold so not good !!! But we have a straight pipe from the cat back but the box we have has no baffle! Would this effect the performance? Do these engines rely on back pressure? Thanks
I also put new plugs in aswell as the dizzy.
 

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