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PK under 3500rpm & also weird decel

VR_IV_MR

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Dec 4, 2007
Messages
283
Location
Queens, NY
Im pretty sure I finally have base idle and base speed set up correctly but I am seeing PK usually under 3500rpm unless i start seeing it under 3500 and keep on the gas then it will stay throughout the entire rpm range. However, I have been feathering it up until 3500 (to avoid PK) then i can go WOT above 3500 without having to worry about PK.

Also every now and then, when i start the car it shuts off right away almost as if it didnt have enough gas. I have to let the ecu "click" and then I can try again but I usually have to hold the gas pedal a little bit in order for it to catch.

Also, say im cruising at 30mph in 2nd... and I drop to neutral as Im slowing down, my rpms will drop to 1000 but then oscillate between 1000-1400 until i come to a complete stop. Then it drops down to a firm 850rpm. (BTW, before I just replaced the BISS, in the same situation, my RPMS would drop to 500 until i came to a full stop then come back up to 850 firm.)


Im only running 8psi on the 2nd oil change of a breaking-in motor. and no, i dont have a wideband.

the exhaust also smells kinda bad
 
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VR_IV_MR

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Joined
Dec 4, 2007
Messages
283
Location
Queens, NY
i was just assuming since i dont hear any bad noises
 

VR_IV_MR

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Joined
Dec 4, 2007
Messages
283
Location
Queens, NY
2g pistons on 1g rods on 93 octane at 5* BTDC

i havent made any changes in ECMLINK yet to timing nor fuel


also, the PK doesn't really happen for the first few minutes of driving (seems as if only when hot)


the ISC coils checked out fine
 
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Well, see, there's your problem. You are trying to use 2G 8.5:1 pistons with stock, very aggressive 1G 7.8:1 timing maps. What version DSMLink? For v2.0 the DSMLink site has a white paper on how to set the timing sliders to sort of make them like the 2G maps. Its not as good a fix as my 2G hybrid maps, but its much better than trying to use the stock 1G maps.
The reason it doesn't do it when the engine is cold is twofold:
1) the engine is adding enrichment while warming up, which helps suppress knock
2) the ECU ignores knock until a certain coolant temperature has been reached.
 

VR_IV_MR

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Dec 4, 2007
Messages
283
Location
Queens, NY
I have the new V3 one

thanks jeff

yay here it is

click

just to double check, i put in the values on the second table, right?
 
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VR_IV_MR

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Dec 4, 2007
Messages
283
Location
Queens, NY
but the thing is i dont get knock while i am boosting so why would i need to remove timing from 3500 up?
 

VR_IV_MR

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Dec 4, 2007
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283
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Queens, NY
im only running 8lbs of boost....

i hope i get this worked out today i cant stand having this car so close yet so far
 

VR_IV_MR

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Dec 4, 2007
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283
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Queens, NY
do i also need to adjust the fuel to compensate for 2g pistons? or just the timing?
 

1990ggsxnj

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Nov 21, 2008
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Blackwood, NJ
If you were the last to post, just edit your last post. Put multiple comments and questions in one. It's easier on the eyes and a board rule.

The ecu adds more fuel while you're in boost and accelerating during open loop.

I believe both fuel and timing differ on the 1g and 2g maps but you're problem is more likely due to timing than anything else. You may want to compare the maps and see for yourself.
 
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I tend to base the AFR on the octane used, not on compression. The factory AFR maps at WOT are about the same for both 1G and 2G. If you compare the 1G and 2G maps, as I have, you find that they are very different in the midrange rpm's. If you have v3.0, you should probably just load the 2G timing maps, instead of trying to edit the 1G maps. The new DSMLink also allows you to load the EVO maps, which are made for 8.8:1 compression I believe.
 

VR_IV_MR

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Dec 4, 2007
Messages
283
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Queens, NY
hmmmm.... now what about base timing? should it still be set to 5* BTDC? what are the 2g's set to?



do i copy over all 4 of these maps? they are openloopmaxoct, openloopminoct, timingmaxoct, and timingminoct

if i copy over the maps do i still need to do the 2g timing in 1g ecu corrections found here click ????

something is totally up because at idle my airflowperrev is at .23gm/rev (should be .28), my fronto2 doesnt really seem to go much higher than .7 and sometimes it just sits at .02 at idle, intake temp >136*, tpsvolts .47
 
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VR_IV_MR

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Dec 4, 2007
Messages
283
Location
Queens, NY
ok so i found out i needed to upload only the timing maps not the other two b/c those are for fuel. however uploading the 2g maps resulted in more knock?? wtf... i ultimately uploaded the evo8 maps and these are working the best so far however i am still seeing knock. let me try to explain exactly when i see it....

if my rpms are in the range of 2000-2500, no matter what gear im in, and i hit lets say 25% throttle, i will start to knock. if i keep the throttle pressed then the knock will continue through the entire rpm range. however if i drop to 0% throt, it goes away, and if my rpms are above 2500, i can give it any throttle i please (25%, 50%, 75%, WOT) with no knock throughout the rest of the range.

i have to feather the gas from 2000 up above 2500 and then i can friggen throttle with absolutely no knock whatsoever.

i think im going to try to pull timing at 2k and 2.5k to see if it goes down any.



anyone have any idea why sometimes my car wont turn over on ignition and why it will turnover on the next attempt with a little pressure on the gas pedal?
 

turbowop

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Apr 29, 2001
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11,971
Location
Yakima, WA
The knock issues actually do sound like PK to me. If you can rev it out to redline with no knock, but can't cruise without seeing it, you likely have a PK issue. There are some weird things that can cause it that you should probably look into before getting a DSMchip with PK code in it, but that's your option if you can't get it fixed otherwise.

I'm not sure what you're asking about the ignition however. Are you saying that the starter won't spin the engine unless you step on the accelerator, or that the engine won't fire up unless you do?
 

brisvr4

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Joined
Feb 13, 2004
Messages
955
Location
brisbane australia
Also, have you tried raising the knock threshold to see if that helps down low?
Just don't raise it too much if you try it.
 

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