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R34 gtt issues whilst mapping


kramit

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I have attatched a log file and a copy of the map (still in progress)

 

Whilst trying to trim the fuel map, I managed to start the cruising / very light load map, 22% throttle or less. However once i went to put a bit more throttle in it kept wanting to, what seemed like, ignition cut at around 5700 rpm, throttle about 33%, so still a really light pull, i also didn't get any map limit codes (set to 300kpa), boost control was turned off, wastegate spring is set to 17psi. 

 

I am hoping that i have overlooked something really simple and stupid.

attempt1.pclr log1.llg

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The are no cuts being applied in your log (except RPM limit once at 6900).  If it feels like a cut and it isnt the ECU applying a cut then it is likely a misfire.  Maybe need a bit more dwell or smaller plug gap?  The only thing I see happening around that RPM is the cam turning off at 5400RPM.

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Well i also thought misfire might be causing it so last night i regapped them from .8mm to .6mm to try and rule it out. But that didnt seem to help, i also altered the dwell time after this and it also didnt seem to help out much. 

 

I know the fuel map also looks like a pig at the minute, but i will be smoothing that out later tonight, im just a bit perplexed by it, the only other thing i though is, is the CAS trigger affecting it all

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could be timing scatter. See how your RPM trace looks "fuzzy", and the ROC + dwell times jump around all over the show? try turning the trigger 1 & 2 filtering level up and see if it improves the misfire issues.

Interestingly your engine spike rich just after most of the what look like misfire events. A misfire would normally spike lean. Your injector pulsewidths dont jump up to explain it either.

What are you using for boost control? its turned off in the ECU, but the pattern in the logs is usually:

1) boost pressure jumps up 10-15kpa, and at nearly the same time there is a rich spike

2) boost pressure jumps down about 30-40 kpa

3) boost recovers for a bit

4) you get off the throttle

(all in the space of about half a second, but its all happening before the TPS% changes)

image.thumb.png.6b7bac37ec02baed4608c45f486eaf5e.png

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Cj - i will try the trigger filtering later on today and see if that makes any difference at all. Worth a try, so thank you for that.

The boost control is currently just controlled by a EWG spring  (hypergate 45) i have set it with a 17psi spring,  it is trurned off on the ecu at the minute as was going to get the car running well with just the speing rate first,  then it will be turned on in which it has a 3 port mac valve plumbed into the wastegate in dual port mode. 

The boost spike, i believe thats just when i add a bit of throttle because the boost does come on extremely quickly, (sxe252 supercore) its very responsive any ever so slight throttle makes a huge difference. 

Im also going to smooth the fuel map out alot probably today / tomorrow whenever i can get a spare couple of hours. Hopefully coupled with the trigger filtering it will be okay.

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Also, just want to clarify, to make sure all my grounds are correct, 4 x ground pins (2 on each plug) are to two separate points on the block / head.

The ground and shield ground cables are all green, if using a link ecu loom, im using the factory, so any can be used for any sensor which makes sense.

 

My question is the injector ground from the oem pin 124 / 116. Where should they go ideally?

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9 hours ago, kramit said:

Also, just want to clarify, to make sure all my grounds are correct, 4 x ground pins (2 on each plug) are to two separate points on the block / head.

They can all go to the same point, just run as seperate wires however.

 

9 hours ago, kramit said:

My question is the injector ground from the oem pin 124 / 116. Where should they go ideally?

I suspect they orignally were the ground for the injector drives in the OEM ecu.  Our ECU does not need those, you can leave those disconnected.

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Well i am going to disconnect the old one (pin 124) from the body then. And check the continuity reading from the ecu grounds, i will also move them all to the best measured point this morning, as well as giving the trigger its own sensor ground, which im doing now. So hopefully i will have some results within the next couple of hours.

 

Thanks for everyones replies so far.

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Well i double checked the ground outs. Were all good even re ran them and that was no help so i removed them again.

I had the fuel map smoothed, iginiton increased, reducded my wastegate spring down to a 7 psi spring, turned on closed loop boost control, set to 0%, trigger filtering upped to level 2, spark plugs still gapped to .6mm.

Now from the old ecu pin 45 (trigger ref) is set as trigger 2, pin 46 (trigger pos) is set as trigger 1, the interesting thing is though when i moved the ground to a position by itself the car had no trigger sync, so, i reverted it back to where it was, as i am on the wirein as apose to the plugin wheres the "ideal" place to put the cas ground with introducing the minimum amount of noise.

On the OEM ecu the braided shield itself went to pins 32 / 25 which are control unit grounds. I am assuming thats the old ecus ground outs.  So is it best to just connect all of these straight to the body of the car together, want to check everything simple and eliminate any case / chance of interference first

I dont just want to go ahead and chuck a crank trigger kit at it (even though it would do it wonder)

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updated log / maps attached - the issue isn't any better re-done grounds, earth braids, power grounds and have tried trigger filtering levels 1/2/3. works fine on mild throttle, however once it is under more load well, i wouldn't call it a misfire, its kind of just dies and comes back on the power, i don't really know how to explain it.

 

the time between 5:55:600 and 5:57:100 is my main concern, its when there is some wastegate voltage it just seems to go to pot. this is what i see, on the log linked below the cas line looks stable where the issue is, the KPA hits 212, then there is some DC voltage on the boost control, so it opens, pulse width drops by 3% on the injectors, injector duty then falls by about 8% (whilst i am still on open throttle) due to the drop in boost pressure, so the map drops and the wastegate shuts then i can have fuel again all in a split second.

 

whats your thoughts?

07-05-19 last run.llg map01.pclr

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  • 1 year later...

I kinda had the same issue back when I First started tuning my rb25 neo. Turned out it had to do with a (too aggressive) timing map. The ecu was trying to pull to much Timing to quickly once it came into boost.can u post a pic of ur timing map?

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Thanks for your reply. But it was nothing to do with my map in the end, all to do with a mechanical issue, map was spot on timing wise, fueling, ethrottle, wastegate, shame i spent ages chasing myself in the map. 

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Assuming here, you have a 3 port MAC boost solenoid.. 

You are running at 10% duty cycle and thats where the solenoid starts working..  (10-90% is the range)

Try lowering your solenoid frequency so your range starts above 10%.

 

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